Isaac Cox, Morgan Hartman, Melinda Owens, and Timothy Passalacqua

Figure 1. One otter in water holds another otter.

Intro

Sea otters are more than the cute, cuddly creatures seen in many zoo exhibits. These fluffy creatures hold great importance in their ecosystem, naming them a keystone species. These sea dwellers, while great for their environments, are not flourishing in population numbers, still recovering from near extinction in the 18th and 19th centuries. Now that scientists are aware of the impact of these marine mammals, they have been protected under the Marine Mammal Protection Act and Endangered Species Act, providing protection from their main threats, humans. Sea Otters promote the overall health of not only their ecosystems, but surrounding species populations as well (1).

Background

Sea Otters (Enhydra lutris) are primarily found along the coasts of the Pacific Ocean in North America and British Columbia. Their diets are primarily carnivorous, but at times can be omnivorous (1). Sea otters are members of the family Mustelidae which includes other animals like badgers and weasels. The similarities between otters and weasels likely isn’t anything surprising if you were to just look at them. They live mostly in giant kelp forest and all daily activities such as eating, resting and grooming are done on the water’s surface. While they can dive upwards of 45 meters(145 ft), they prefer waters closer to 30 meters(100 ft). They also vary in size depending on where in the world they live. A specific example of the size difference is that of the Alaskan sea otter which weighs a good 10 kg(22 lbs.) more than their Californian counterpart. Sea otters also do not have any insulating fat and must rely on their fur to maintain heat. Everyone is familiar with otters using rocks for tools to open different foods, but were you aware they have patches of loose skin below their forearms to store these tools? Sea otters are unique compared to other carnivores in only having 4 lower incisors that are used for cutting food (7).

Why Sea Otters Are A Keystone Species

Sea otters play a vital role in biodiversity, food webs, and trophic cascades. In all ecosystems food webs are present. Food webs are defined as the relationship between all food chains, interconnected as one. It is the complex network in which matter and energy is transferred from prey to predator to decomposer. Our food web starts with producers who convert solar energy into sugar through the process of photosynthesis. Next in the web comes the primary consumers which consume producers. Above the primary consumer is the secondary consumer, then tertiary consumer, apex predators, and finally decomposers who break down and digest dead or decaying organic matter. In relation to sea otters, a simple food chain breaks down as such, great white sharks and killer whales eat sea otters, sea otters eat sea urchins, and sea urchins eat giant kelp (1). The balance of this cycle allows for greater biodiversity and healthy populations of organisms.

Figure 3. Left: a muddy ecosystem with less plants more crabs and no sea otters, right: a clean ecosystem with more plants, less crabs, and sea otters.

Keystone species are considered species that the ecosystem as a whole depends on and the removal drastically changes these ecosystems. Sea Otters are considered keystone species because of their ability to exert a trophic cascade or in other words top down pressure. By directly consuming Sea Urchins they indirectly promote kelp growth because there are less Sea Urchins to graze on the kelp. Consequently, other species such as crabs and abalone that depend on kelp can share this vital resource. Kelp serves not only as a vital food source, but also as a shelter and habitat for a myriad of fish and invertebrate populations. The presence of kelp forests invites greater biodiversity and safer nesting grounds. Furthermore, Sea Otters indirectly promoting kelp growth allows for kelp structures which reduce storm driven tides. These kelp structures help prevent erosion from shores by fencing invading erosion (3). This is important to reduce pollution, stabilize marine structures, and prevent degradation of shores.

What Our Ecosystems Are Like Without Sea Otters

A study conducted in Australia observed that grazing rates of kelp were greater in temperate Australia. Correspondingly, temperate Australia lacks Sea Otter presence. This same study found that North Pacific areas lacking Sea Otters showed even greater grazing rates of kelp, more so than areas with Sea Otters and more so than temperate Australia (4).

Figure 2. Otter ecosystem showing the balance of sea otter, sea urchins, and kelp forests.

What We Can Do

As previously stated sea otters were near extinction in the 18th-19th century this was primarily caused by the fur trade. It was not until 1977 that the sea was listed under the Endangered Species Act (ESA) which was established in 1973. However as of today sea otters have not fully bounced back even with certain protections in place. These protections include being listed under the Endangered Species Act, protecting them under the International Fur Seal Treaty and the Marine Mammal Protection Act (MMPA). However there is more that can be done to help these hand holding animals(5). The largest current threats against sea otters is white sharks, contaminants, oil spills, and human disturbance (6). Certain things are difficult to control such as the white sharks because the threat is not created by humans, however there are many other things we can do. The decreased use of fertilizer and pollutants by people would decrease the contaminants that negatively affect the sea otters. Also there are chances to volunteer to clean and help rehabilitate sea otters that have been affected from oil spills. It’s best to avoid disturbing sea otter habits and harassing the animals by trying to get their attention. If people want to help, but do not know they can always donate to programs such as the California Sea Otter Fund which provides support to sea otter research and conservation (6).

Figure 4. Group of many sea otters lying on their back in the water.

Conclusion

The loss of any keystone species is catastrophic, but the loss of sea otters can cause problems that will devastate a number of organisms. The conservation and protection of sea otters is utterly important to conversely benefit the surrounding organisms such as kelp, urchins, whales and sharks. This correlation between species is an important relationship that must be understood when preserving biodiversity. Protecting estuaries in which otters inhabit are especially important in terms of the fishing industry, recreational sport and biodiversity as a whole. Protection and conservation should be the first priority when ensuring the survival of sea otters, rather than damage control after catastrophic events, such as the fur trade.

Figure 5. Sea otter biting a sea urchin.

Text Citations

1. Sea otter. Defenders of Wildlife. (n.d.). Retrieved April 10, 2022, https://defenders.org/wildlife/sea-otter
2. Womble, J. (2016, July 29). A keystone species, the sea otter, Colonizes Glacier Bay. National Parks Service. Retrieved April 10, 2022, https://www.nps.gov/glba/blogs/A-Keystone-Species-the-Sea-Otter-Colonizes-Glacier-Bay.htm#:~:text=Sea%20otters%20are%20a%20%22keystone,the%20presence%20of%20sea%20otters.
3. Greg Helms Author, Helms, G., Author, Frey, M., Hogge, K., Brandon, A., Lewis, J., & Perez, J. (2021, July 12). Kelp’s mighty role in our ocean. Ocean Conservancy. Retrieved April 10, 2022, https://oceanconservancy.org/blog/2019/05/23/kelps-mighty-role-ocean/
4. Steinberg, P. D., Estes, J. A., & Winter, F. C. (1995). Evolutionary consequences of food chain length in kelp forest communities. Proceedings of the National Academy of Sciences, 92(18), 8145-8148.
5. Conservation & Research. SeaWorld Parks & Entertainment. (n.d.). Retrieved April 10, 2022, https://seaworld.org/animals/all-about/otters/conservation/
6. Sea otter conservation. SeaOtters.com. (n.d.). Retrieved April 10, 2022, https://www.seaotters.com/sea-otter-conservation/
7. Allegra, J.; R. Rath and A. Gunderson 2012. “Enhydra lutris” (On-line), Animal Diversity Web. Accessed April 10, 2022 https://animaldiversity.org/accounts/Enhydra_lutris/
8. What are Keystone Species? National Marine Sanctuary Foundation. (2020, May 11). Retrieved April 10, 2022, https://marinesanctuary.org/blog/what-are-keystone-species/?gclid=CjwKCAjwur-SBhB6EiwA5sKtjhL4M8W_QWExPkyl-49cFIpGq_bJiJOeb7s5qQMzD6ytIDkMNq2MmhoCJxMQAvD_BwE

Image Citations

1. https://smea.uw.edu/currents/cuddle-party-one-grad-students-reflection-on-her-love-for-sea-otters/
2. https://www.nationalgeographic.org/media/delicate-balance/
3. https://futureoftheocean.wordpress.com/2015/09/25/sea-otters-and-eelgrass-in-one-infographic/
4. https://lpfw.org/our-region/wildlife/southern-sea-otter/
5. https://www.aquablog.ca/2012/09/sea-otters-more-than-just-a-cute-face/

Jessie Rizk, Sarah Corbin, Austin Krupar, and Macy Tetrick

Coral reefs are important to marine life for so many reasons. They house many different species and play an important role in the marine food chain. For example, plants, prey, and predators can all call coral reefs home and provide each with shelter. Without the coral reefs as their home, prey would have nowhere to hide and would throw the food chain out of balance. Coral reefs also play a big part in protecting humans around the shoreline and sustaining our economy. Coral reefs take the biggest hit from large waves, storms, and floods. This lessens the damage that property would otherwise have without coral reef. As for our economy, there are so many different kinds of fish that live near coral reefs, therefore, many commercial and local fisheries rely on it for this large fish population. From the US alone, coral reefs are responsible for about $100 million from fisheries. Another reason that coral reefs are important to our economies is because it is a tourist attraction. Locations that have coral reefs on their shoreline gain so much money by supporting different activities like scuba diving, snorkeling, and glass bottom boating near coral reefs. It is a beautiful underwater sight which can allow local economies to boost from the revenue they receive solely based on these coral reef activities.

Coral reefs are found all over the world in warm waters. Mostly found near the equator, over half the world’s reef populations are found in Australia, Indonesia, Philippines, Papua New Guinea, Fiji, and the Maldives. They are made of three components: a hard surface, coral polyps, and reef animals. A hard surface is often a submerged rock but could be any submerged hard surface. Coral polyps are tiny animals that are related to anemone and jellyfish. These grow and reproduce to form layers of coral. Lastly, reef animals contribute to the health and function of a reef. There are different types of coral reefs. The most common is the fringe reef. This is the kind that grows near coastlines. There are also barrier reefs, atolls, and patch reefs. These mainly vary by depth and size. Coral reefs need to be in warm, clean water with a healthy wildlife population to survive and reproduce. Water that has been polluted by runoff or overfished will not allow for corals to reproduce.

Corals are in the kingdom animalia and phylum cnidaria. Thus, they are closely related to jellyfish, sea anemones, and hydroids, all of which also occupy the same phylum. Like all cnidarians, anatomy of coral polyps is relatively simple, with one opening into the stomach that acts as both the mouth and as a way to excrete waste. Surrounding this mouth is a ring of tentacles at the coral used for defense and capturing prey items. Furthermore, some groups of coral secrete calcium carbonate skeletons that form the foundation of coral reefs, with their hard skeletons providing many species of marine life with shelter. Corals have a complex endosymbiotic relationship with zooxanthellae, a group of symbiotic dinoflagellate algae commonly found in marine water. Zooxanthellae can be obtained via vertical transmission in which zooxanthellae is placed within the coral egg from the parent. However, horizontal transfer of zooxanthellae is more common, in which zooxanthellae is engulfed by the coral from the environment. Zooxanthellae are stored within the cells lining the coral’s stomach in special structures called symbiosomes. While inside the coral cell, the zooxanthellae continues to produce photosynthate like sugars and amino acids, up to 95% of which is transferred to the host coral. In return, the coral provides the zooxanthellae with metabolic waste that the algae needs in order to grow including nitrogen, carbon dioxide, and phosphorus. However, under conditions of extreme stress, this symbiotic relationship can break down, resulting in the loss of photosynthetic pigment or zooxanthellae altogether. This phenomenon is known as bleaching (picture below depicts a healthy coral on the left and a bleached coral on the right). With the increasing average temperature due to the increase in carbon emissions from the industrial revolution, there has been a large increase in the thermal stress corals regularly experience, leading to mass bleaching events around the world.

Clearly, coral reefs have impressive adaptations and responses. This translates into their defense mechanisms as well. Coral reefs essentially have two types of defenses: chemical and physical. Toxins are their main chemical defense and have evolved over many years to become one of their greatest assets. The toxicity levels of each reef fluctuate depending on their surrounding environment, level of predation, etc. If a reef has high levels of nutrition, it is likely that this specific reef does not experience much predation. If, suddenly, the coral reef is preyed on more than usual, it will begin to adapt by decreasing its nutrient levels in order to make itself less “desirable” for predators. If a coral reef has low nutrient levels already, it would be safe to assume that the reef is preyed on often. Along with advanced chemical responses, the coral reef has developed impressive physical defenses as well. On the ends of each coral tentacle contains stinging cells, or nematocysts. These nematocysts are used to sting, capture or kill prey. Reefs also emphasize the “survival of the fittest” concept by “fighting off” other reefs for desired space.

As discussed earlier, coral reefs play a huge role in human life as a food and economic resource. However, coral also presents a multitude of medicinal benefits for humans. The “underwater pharmacy” has provided medicinal components from bone grafts to antiviral drugs to anticancer agents. The calcium carbonate is a key material in a lot of bone grafts, and it has been proved to be even better quality than ceramic. Coral reefs have also been used to produce HIV treatments like Zidovudina, antiviral drugs like Ara-A that are used to fight RNA tumors, and Ara-C anticancer agents used to fight leukemia, breast and liver cancer. As if that wasn’t enough, coral reefs also possess a protective enzyme called secosteroids. Secosteroids are utilized by coral reefs to fight off their own infections, similar to our own immune system. Researchers have discovered a way to extract the secosteroids and convert them to fight off human infections like asthma, arthritis, and other inflammatory issues amongst humans.

Works Cited

“Types of Coral Reefs.” Coral Reef Ecology, Coral Reef Alliance, 9 Sept. 2021, http://coral.org/en/coral-reefs-101/types-of-coral-reef-formations/?gclid=Cj0KCQjwjN-SBhCkARIsACsrBz6-ackvLbZlHbOgfQhwCIYM2ppe13zJfafrTMT1wfyrCL4oQYixxDwaArVxEALw_wcB.

“Value of Reefs.” Reef Resilience, The Nature Conservancy, 2022, http://reefresilience.org/value-of-reefs/.

Krosofsky, Andrew. “Why Are Coral Reefs Important to the Ecosystem?” Green Matters, Green Matters, 23 Dec. 2020, http://www.greenmatters.com/p/why-are-coral-reefs-important.

“Quick Question: Why Are Coral Reefs Important? .” National History Museum, National History Museum, http://www.nhm.ac.uk/discover/quick-questions/why-are-coral-reefs-important.html.

“The Importance of Coral Reefs.” Corals Tutorial, National Ocean Service, 1 June 2013, http://oceanservice.noaa.gov/education/tutorial_corals/coral07_importance.html.

“Coral Reef Food Web.” Resource Library, National Geographic Society, 9 Nov. 2012, http://www.nationalgeographic.org/media/coral-reef-food-web/.

Bruckner, Andrew W. “Life-Saving Products from Coral Reefs.” Issues in Science and Technology, Arizona State University, 18 Mar. 2021, http://issues.org/p_bruckner-coral-reefs-importance/#:~:text=The%20antiviral%20drugs%20Ara%2DA,medicines%20obtained%20from%20coral%20reefs.

Camillo Thompson, Daniel. “Did You Know Coral Reefs Produce Medicine?” Interamerican Association for Environmental Defense (AIDA), Interamerican Association for Environmental Defense (AIDA), 8 Jan. 2019, http://aida-americas.org/en/blog/did-you-know-coral-reefs-produce-medicine.

“Defense Mechanisms.” Coral Digest, 2013, http://coraldigest.org/index.php/DefenseMechanisms#:~:text=Nematocysts,-Discharge%20of%20a&text=In%20a%20cross%20between%20a,a%20continuous%20battle%20for%20space.

Lesser, Michael P. “Coral Bleaching: Causes and Mechanisms.” SpringerLink, Springer Netherlands, 9 Nov. 2010, http://link.springer.com/chapter/10.1007/978-94-007-0114-4_23.

Veron, J.E.N. “Classification.” Corals of the World, Ocean Ark Alliance, 2016, http://www.coralsoftheworld.org/page/classification/.

Hoegh-Guldberg, Ove. “Climate Change, Coral Bleaching and the Future of the World’s Coral Reefs.” CSIRO PUBLISHING, CSIRO PUBLISHING, 1 Jan. 1999, http://www.publish.csiro.au/MF/MF99078.

Hu, Minjie, et al. “Lineage Dynamics of the Endosymbiotic Cell Type in the Soft Coral Xenia.” Nature News, Nature Publishing Group, 17 June 2020, http://www.nature.com/articles/s41586-020-2385-7#citeas.

“Coral Reefs.” Endangered Species International, 2012, http://www.endangeredspeciesinternational.org/coralreefs.html.

Smith, David J., et al. “Is Photoinhibition of Zooxanthellae Photosynthesis the Primary Cause of Thermal Bleaching in Corals?” Global Change Biology, vol. 11, no. 1, 9 Dec. 2004, pp. 1–11., doi:10.1111/j.1529-8817.2003.00895.x.

Quigley, Kate M., et al. “Heritability of the Symbiodinium Community in Vertically- and Horizontally-Transmitting Broadcast Spawning Corals.” Scientific Reports, vol. 7, no. 1, 15 Aug. 2017, doi:10.1038/s41598-017-08179-4.

Shana Weidner, Paige Peck, Sarah Hubbard, and Guilli Dia

What are flatworms?

Flatworms, making up the phylum Platyhelminthes, are a group of invertebrates that are soft-bodied and flat. They are often, but not always, parasitic to both humans and animals. Their detriment spans the globe, but countries with improved and accessible healthcare and more frequent sanitation have much lower rates of infection. Widespread infections occur in underdeveloped countries with limited access to sanitation supplies and methods.

There are four types, or classes, of flatworms: Trematoda (flukes), Cestoda (tapeworms), Turbellaria (planarians), and Monogenea. There are upwards of twenty thousand species of flatworms that have been identified. Most of the flatworms that are parasitic are a part of the fluke and tapeworm classes.

How do flatworms affect humans?

An estimated 25-35% of all humans are currently infected with at least one parasitic worm species, and there are over 200 million infections each year. Many cases originate in poverty-stricken areas in Africa, South America, and east Asia but flatworms pose a threat around the globe. With travel opening up and climate change and global warming worsening, flatworms are expanding their reach even more. Two main classes of flatworms cause most of human infections: tapeworms and flukes.

Tapeworms
Taeniasis

Within tapeworms there are two main contributors to human disease, T. saginata (beef tapeworm) and T. solium (pork tapeworm). Both tapeworms can cause a disease called taeniasis through ingestion of undercooked, infected meat. The life cycle of these tapeworms begins when the eggs are ingested by cows or pigs, hatching and circulating to muscle tissue causing cysts. The juvenile forms of the tapeworm can be transferred to humans through ingestion of raw or undercooked meat of the infected animal. The adult worms travel to the small intestine where they lay eggs that pass through the feces and may be ingested, starting the cycle over.

Many people may be unaware they have the disease as often there are no short-term symptoms. Because beef tapeworms, on average, are larger than pork tapeworms, symptoms are more likely to occur in those infected with beef tapeworms. Potential symptoms include loss of appetite, nausea, vomiting, diarrhea and in rare, long-term cases include malnutrition and intestinal blockage.

Cysticercosis

The pork tapeworm can have a secondary branch in their life cycle, causing a more devastating human disease called cysticercosis. As mentioned, tapeworm eggs are passed through the feces. If a human ingests feces with eggs directly, cysticercosis occurs as opposed to taeniasis caused by ingesting juvenile tapeworms in an animal host. These eggs hatch inside the human host and travel to the muscles where they can form cysts in various locations including muscles, brain, eyes, spinal cord and in rare cases can form in the liver, lungs, heart, thyroid, or pancreas.

Due to their life cycle, it is possible for a person with taeniasis to accidentally ingest their own infected feces and contract cysticercosis which is much more serious. Depending on size and location of cysts, symptoms may not be present or can include soreness, headaches, confusion, balance issues, brain swelling, seizures, stroke, or death.

Flukes
Schistosomiasis

Caused by blood flukes of the genus Schistosoma, schistosomiasis is a widespread, devastating disease. There are other diseases caused by flukes, including those caused by tissue flukes, but schistosomiasis is the most prevalent and in need of attention. Second only to malaria in terms of impact, schistosomiasis is considered one of the neglected tropical diseases (NTDs). It is contracted through skin penetration by juvenile flukes when in waters populated by the flukes’ host snails. Infections may be asymptomatic and if present, symptoms are not directly caused by the flukes but rather the body’s reaction to the eggs.

Common symptoms include rash, fever, chills, cough, muscle aches, while chronic symptoms include abdominal pain, enlarged liver, blood in stool/urine, and increased risk of liver fibrosis and bladder cancer. In rare cases, schistosomiasis can cause seizures, paralysis, spinal cord inflammation, or death. School-aged children are more at risk for contraction due to more exposure and time spent swimming/bathing in unsafe waters. Repeated infections can also cause malnutrition, anemia, and learning disabilities. Flukes can survive in their hosts for many years, possibly not showing symptoms short-term. This adds to the reason deaths caused by schistosomiasis are difficult to estimate in addition to its hidden pathologies.

How can we fight the detriment caused by flatworms?

Treatments are available to fight flatworm-related diseases. Antiparasitic, particularly anthelmintic, drugs are used for parasitic worm infections and diseases. Common antiparasitics used include praziquantel, albendazole, and triclabendazole and in some cases may be used alongside corticosteroids and/or antiepileptics. In rare tapeworm cases, surgery may be necessary for removal. Drugs are generally single-dose or a few doses administered over the span of a couple days, so they do not require long-term treatment. More research is currently taking place to search for alternative treatments, particularly for schistosomiasis, as praziquantel is heavily relied on and there need to be back-ups in case resistance is ever developed.

In general, flatworm infections can be prevented by regularly washing hands with soap and water, especially before handling or eating food. Teaching children about proper hand washing habits is also extremely beneficial. Drinking and bathing in safe water is also important and there are methods to purify potentially unsafe water like boiling, filters, and iodine tablets. Properly disinfecting surfaces/tools when cooking and thoroughly cooking meats all help prevent infection. In broader terms, ensuring safe access to water and healthcare including the necessary antiparasitics is needed to truly protect people from these devastating diseases. Many people end up in cycles of poverty causing disease, making them lose money to treatment or family deaths or disabilities not allowing them to work, which intensifies their poverty.

Do flatworms do us any good?

Flatworms provide new insight to organ regeneration by studying protonephridia of flatworms. Protonephridia are hollow cells in the excretory system of some invertebrates, containing a tuft of rapidly beating cilia that serve to propel waste products into excretory tubules. Humans can also use planarians as a model to begin how an animal maintains their form and function over a very long time. Scientists have also discovered that flatworms are good for toxicity testing. Since flatworms have unique features such as a brain of intermediate complexity, short generation times, and the possibility of studying adult and developing worms in parallel, they are a good alternative system to lab mammals. Flatworms can help model the human nervous system’s response to chemicals, and by providing this information, flatworms may be able to reduce the need to use mammals for this type of testing.

Flatworms are also beneficial to their ecosystem by regulating the dynamics of zooplankton in ponds. They also consume protozoans, rotifers, and algae, and help to regulate populations of these organisms too. Researchers found that flatworms living in estuaries can indicate the health of the ecosystem. Some free-living flatworms also help the environment by acting as decomposers. While there are many parasitic species of flatworms, there are also some free-living and nondestructive species too. Research using flatworms is underway, and evidence has shown that continuing research on flatworms can provide new insights to human health.

References

Centers for Disease Control and Prevention. (2020, September 22). CDC – Cysticercosis. Centers for Disease Control and Prevention. Retrieved April 10, 2022, from https://www.cdc.gov/parasites/cysticercosis/index.html

Centers for Disease Control and Prevention. (2018, April 11). CDC – Schistosomiasis. Centers for Disease Control and Prevention. Retrieved April 10, 2022, from https://www.cdc.gov/parasites/schistosomiasis/

Centers for Disease Control and Prevention. (2020, September 29). CDC – Taeniasis. Centers for Disease Control and Prevention. Retrieved April 10, 2022, from https://www.cdc.gov/parasites/taeniasis/index.html

CK-12 Foundation. (2016, August 17). Flatworm Diseases – Advanced. CK-12. Retrieved April 10, 2022, from https://www.ck12.org/book/ck-12-biology-advanced-concepts/section/15.14/

Flatworms could replace mammals for some toxicology tests. Flatworms Could Replace Mammals for Some Toxicology Tests. (2015, June 29). Retrieved April 11, 2022, from https://ucsdnews.ucsd.edu/pressrelease/flatworms_could_replace_mammals_for_some_toxicology_tests

Hoffmann, K. (2018, August 31). Parasitic flatworms affect millions in developing countries, but new research offers hope. The Conversation. Retrieved April 10, 2022, from https://theconversation.com/parasitic-flatworms-affect-millions-in-developing-countries-but-new-research-offers-hope-98780

Myers, P. (2002). Platyhelminthes (flatworms). Animal Diversity Web. Retrieved April 9, 2022, from https://animaldiversity.org/accounts/Platyhelminthes/

Pietrangelo, A. (2021, December 21). What you need to know about parasitic worm infection in humans. Healthline. Retrieved April 10, 2022, from https://www.healthline.com/health/worms-in-humans

ScienceDaily. (2011, August 12). Flatworms provide new insight into organ regeneration and the evolution of mammalian kidneys. ScienceDaily. Retrieved April 11, 2022, from https://www.sciencedaily.com/releases/2011/08/110810085544.htm

World Health Organization. (2021, May 17). Foodborne trematode infections. World Health Organization. Retrieved April 10, 2022, from https://www.who.int/news-room/fact-sheets/detail/foodborne-trematode-infections

Ben Kuntz, Jake Lanning, Wyatt Sopher, and Owen True

Earth has been around for about 4.6 billion years allowing for the diversity of animals to flourish and also get wiped out. Over the course of Earth’s history, there have been five known mass extinction events. These are characterized by a global environmental disruption that results in large percentages of marine and terrestrial species dying out. All five of the previous extinction events caused at least more than half of all species living on the planet to go extinct with the Permian extinction killing 96% of all species. With these extinction events occurring, only 2% of all the species that lived on Earth are actually alive today. These are usually caused by volcanic activity, an asteroid strike, climate change, or changes in the chemistry of the ocean. However, extinctions aren’t all that bad. After an extinction event, new niches are open and able to be replaced so the species that have survived experience rapid evolution. For example, after the terrestrial dinosaurs went extinct, mammals were able to replace them as the large predators. While extinction over millions of years can be beneficial, current extinction rates, during the Holocene, are currently hundreds of times higher than normal leading researchers to believe they will likely not be able to bounce back. The Holocene Epoch began about 11,700 years ago up until the present time. The Holocene has only lasted for a few thousand years and hundreds of species have already gone extinct. Why is this happening?

The simple answer to the cause of the Holocene extinction is human activity, whether it be direct actions such as habitat encroachment and unethical hunting, or indirect actions such as pollution and climate change. On the topic of habitat encroachment, there is of course deforestation, which is the mass cutting down of trees and vegetation in a single area. Deforestation is usually due to something being built, such as a shopping mall, the need for more housing for people to live in, or the biggest reason of all: the need to raise more food for human consumption. Industrialization is a double whammy whe it comes to being harmful to the environment. This is because of the harmful emissions that are emitted in the production of these products, and then the loss of natural habitat in order to build a place to sell these products. Not to mention the amount of waste that is produced per capita, it seems that we are truly running out of space, but not just on land. Global warming is another huge issue due to these emissions like methane and carbon dioxide. This causes sea levels to rise, and extreme fluctuations in weather. This is harmful to many organisms because the one downside to evolution is that it is very slow, so it is completely useless when it comes to dealing with immediate problems with an animal’s environment. Unethical hunting is perhaps the most direct method of causing many species to go extinct. There are trophy hunters that hunt animals where it is not needed to keep the population in check, and there is also over-hunting. Over-hunting is a problem when lawmakers are not quick enough to set stipulations for hunting, or when hunters disregard the current laws that are in place regarding a certain species. A species being hunted down to such low numbers lowers its genetic diversity, making it prone to extinction.

As mentioned thousands of species have already been officially classified as extinct since the beginning of the Holocene Epoch, but many of those species met their end since the start of the Common Era. Advancements in human technology, including modern hunting and agricultural practices, have accelerated the rate of extinction even further. Many species from larger families have fallen at the hands of humans, including multiple species of tigers, rhinoceroses, and otters, all of which were hunted for their desirable tusks and furs. The explosion of the human population has driven the demand for crop and livestock space to a new extreme, and all that land that needs to be cleared causes those species that cannot adapt to a new habitat to fall as well. Many species of birds around the globe have been lost due to habitat loss as a result of deforestation, unable to cope with new ecological niches as well as modified migratory and breeding patterns. These are only a few of the vast list of species that have fallen as a direct result of human action, and there are many, many more that have still been lost in some way due to our presence. Humanity’s fight for survival has cost many species their existence, but if we can help to mitigate the unnecessary damage we cause to our planet and everything that calls it home, we may have a chance to help save some of the ecological diversity while we still can.

Valerie Haddix, Gina Hill, Margaret Lange, Maina Miranda, and Raina Rindani

Introduction

Species have long since been evolving and will continue to evolve for years to come. Evolution has also given rise to intelligence, which can vary from species to species. Humans are considered the most intelligent, however there are many other species that possess an incredible amount of intelligence. One such species that is often forgotten about is the octopus. They possess a great amount of intelligence and many fun adaptations as well. But first, what is an octopus and what adaptations does it possess? An octopus is an organism with no bones and eight long limbs with suckers lining each one. Their lack of bones allows them to squeeze into many tight spaces with ease, which is impressive considering how large they normally are. Not only this, but they are also known for their ability to blend into their surroundings by changing their color and texture. However, some lesser known abilities that they possess is the ability to use tools, and even shell drilling. These abilities plus others will give a better picture as to the intelligence of an octopus.

Tool Usage

Approximately 75 million years ago, ancient octopuses were drilling into their prey (Gramling 2021). There were three fossil clams found that had tiny holes drilled into them. The clams that once lived in what is now South Dakota were found with telltale oval-shaped holes. They were between 0.5 and 1 millimeter in diameter, which is thinner than a strand of spaghetti. Modern octopuses will use their sharp ribbon teeth, called a radula, on its tongue in order to drill a hole into thick shells of their prey (Gramling 2021). This is useful because oftentimes the shells are too tough for the octopus to pry them apart with its suckers. Once the hole is created, the octopus will inject venom into the hole, which paralyzes the prey and dissolves it enough to eat. The holes left by these octopuses are easily identifiable through fossil records. However, due to the soft bodies of octopuses, they tend to not fossilize well enough to identify what they looked like 75 million years ago. With the few fossils that do exist, there is little change in the basic body plan from these ancient octopuses to the modern-day ones. The finding of this little change of body plan puts the evolution of octopus drilling directly within the Mesozoic Marine Revolution (Gramling 2021). This was an escalation in the ancient arms race between ocean predators and prey. Those predators that were lurking on the seafloor became adept at crushing or boring holes into the shells of their prey.

In addition to shell drilling-techniques, octopuses have been known to use tools, which is an extremely advanced behavior for an invertebrate (Keim, 2009). The first tool usage recorded was by octopuses in Indonesia, which were observed to be using coconut shells as tools (Keim, 2009). The reason this was considered tool use as opposed to sheltering like crustaceans is because these carried these shells for future use (Keim, 2009), engaging in behaviors such as stilting, during which they use six of their arms to carry shells and two of their arms to “walk” on the bottom of the ocean floor (Waterman, et al., 2011). They also use the coconut shells in a variety of ways for hunting crab (Waterman, et al., 2011). Other tool use behaviors that have been observed are the use of rocks and shells to barricade themselves from predators and cover their dens, and play-like behavior with small rocks and with schools of fish (Thiyagarajan, 2020).

Color/Shape Changing Abilities

Octopuses are fascinating creatures with amazing abilities. One example being, octopuses can change color and even their texture. This ability is mostly used to evade predators (Two Oceans Aquarium, 2021). They can camouflage themselves by matching the color and texture of corals, rocks, and other objects nearby. To achieve the changing color effect octopuses have thousands of cells just below their skin called chromatophores (Two Oceans Aquarium, 2021). Each of these cells has a small sac filled with either red, orange, brown, yellow, or black pigment (Two Oceans Aquarium, 2021). By stretching and squeezing these sacs they can rapidly change the brightness of each color. Under the chromatophores is a specialized cell layer called iridophores. These cells are filled with thousands of tiny mirror-like structures called reflectosomes that reflect light back up through the octopus’s skin (Two Oceans Aquarium, 2021). This allows the colors to appear brighter. It is also responsible for adding shades of blue and green. The final structure involved in this process is the leucophore. This is another reflective structure that lies below the iridophores. Leucophores scatter light so on the surface it looks white but in the ocean the octopus can passively scatter light at whatever wavelength is present in its environment (Two Oceans Aquarium, 2021). This whole process takes around 200 milliseconds. No other creature on earth can camouflage as fast and effectively as an octopus. They can change their skin color, contrast, brightness, and pattern faster than a human can blink. They also can change their texture and shape drastically. This is done by contracting small regions in their skin called papillae (Two Oceans Aquarium, 2021). In papillae muscle fibers run in a spiderweb pattern (Two Oceans Aquarium, 2021). When these fibers contract they draw the soft tissue in the papillae towards the center ultimately changing their shape and texture.

Due to the high intelligence of octopuses, it is important to provide enrichment to them in captivity to keep them mentally stimulated. They are known for their ability to learn and retain information as well as their highly developed intelligence. To keep the octopuses in captivity physically and mentally active, the New England Aquarium gives their two, giant Pacific octopuses puzzle boxes (Blasi 2016). They place crab meat inside a clear box, and the octopus opens three latches to reach the treat inside. The octopuses are even given other puzzle boxes that have different shaped latches to keep the activity new and stimulated (Blasi 2016). Additionally, octopuses show a high play drive, so it can be beneficial to give them toys to play with in their enclosure. At the Seattle Aquarium, a study was conducted with three types of toy, named “ball, cow, and pliers” to see which type of toy they generally preferred and gave the best play experience (Anderson n.d.). Results showed that the octopuses preferred playing with the cow toy, presumably due to the movable rings attached to the toy, and played with it the longest (Anderson n.d.). Since the cow toy had moveable parts, there was a greater enrichment experience for the octopuses. Sometimes, the octopuses are given pill bottles to open as enrichment. Since the pill bottles have to be pressed down before opening, providing the octopus more of a challenge than other bottles. One octopus at the Seattle Aquarium opened the first pill bottle within 15 minutes (Anderson & Blunstein n.d.). However, the other times she was given the bottle, the octopus was able to open it, on average, in 2 minutes (Anderson & Blunstein n.d.). This shows their ability to take what they’ve learned from previous tasks and apply their knowledge to future enrichments. It is interesting to see how different areas of captivity enrich their octopuses, giving mental stimulation for such intelligent creatures.

Conclusion

Through adaptations, behaviors, and ability to learn, we have observed the extremely high level of intelligence that octopuses exhibit. Not only are octopuses extremely intelligent creatures in general, but they are especially intelligent because no other invertebrates have been known to exhibit such high level cognitive functioning. Researchers explain such high intelligence because octopuses live alone and have relatively short life-spans, meaning in order for their species to survive, they must be extremely likely to reach adulthood and reproduce successfully. Through octopus captivity and through long-term research projects, humans have cultivated meaningful and deep relationships with these creatures of high intelligence, and many scientists hope to continue in the future.

References

“About the Film.” The Making of My Octopus Teacher, Sea Change Project, 10 May 2021, https://seachangeproject.com/stories/the-making-of-my-octopus-teacher/.

Anderson, R.C. (n.d.). Evaluating Toys for Octopuses (Enteroctopus dofleini, Cephalopoda). The Cephalopod page. http://www.thecephalopodpage.org/OctopusToys.php

Anderson, R.C. Blunstein D. (n.d.). Smart Octopus?. The Cephalopod page. http://www.thecephalopodpage.org/OctopusSmarts.php

Blasi, J. (2016). The Octopus and their Puzzles. New England Aquarium. https://www.neaq.org/blog/octopus-box/

Gramling, C. (2021) Predatory Octopuses Were Drilling into Clamshells at Least 75 Million Years Ago. Science News. https://www.sciencenews.org/article/predatory-octopuses-drilling-fossil-clam-shells#:~:text=Octopus%2Ddrilled%20holes%20were%20previously,fossil%20record%20of%20octopus%20evolution.

How does an octopus change its colour and shape? (2021, July 23). Two Oceans Aquarium. https://www.aquarium.co.za/blog/entry/how-does-an-octopus-change-its-colour-and-shape

How smart is an octopus? Science ABC. (2022, January 19). Retrieved April 18, 2022, from https://www.scienceabc.com/nature/animals/how-smart-is-an-octopus.html

Keim, Brandon. “Tool Use Found in Octopuses.” Wired, Conde Nast, 14 Dec. 2009, https://www.wired.com/2009/12/octopus-tools/#:~:text=In%20captivity%2C%20some%20species%20of,what%20might%20be%20called%20mischief.

Waterman, C. et al. “O Hai Octopi: Tool Use in Cephalopods.” Reed Bio 342: Tool Use in Cephalopods, 2021, https://www.reed.edu/biology/courses/BIO342/2011_syllabus/2011_websites/CWEFEL_cephalopods/index.html.

Melissa Danner, Savanna Eggart, Sarah Rensko, and Gautam Apte

Sharks have senses that allow them to track things such as predators, mates, and prey at large and small distances. At closer ranges they rely on a network of sensors called the ampullae of Lorenzini which got the name from a scientist who discovered them many centuries ago. The network is made of many pores on the shark’s head that are able to be seen by the naked eye. The pores on the head open onto canals that are lined with many small hairs similar to the ones that are inside the human ear. Every canal within this system leads into a chamber filled with a gel-like substance called the ampulla, within this chamber it is lined with nerve cells. The ampulla detects electrical impulses given off by the muscle contractions of nearby organisms such as fish, seals, and other sea creatures. The ampullae are very sensitive; they can even detect a beating heart within other creatures and can find fish that have buried themselves within the sand. The ampulla only works within close range, not at long distances.

The ampullae of Lorenzini play other roles other than tracking prey; they allow for sharks to follow currents of water and also serve as an internal compass which helps sharks navigate across many miles of open water by following earth’s magnetic field. These receptors are extremely sensitive and can easily be overstimulated.

Scientists take advantage of the sensitivity of the ampullae of lorenzini to get up close when carrying out research. They can carefully flip a shark horizontally in a state of temporary hypnosis by rubbing the small pores on the snout of the shark. If not done carefully, the researchers could be seriously injured. This overstimulation of the jelly-like receptors does not harm the shark in any way, but relaxes them temporarily.

The knowledge of the ampullae of lorenzini has led to advances in the world of surfing. Scientists worked with a company called “Sharkbanz” to create a bracelet that repels sharks. This bracelet works by disrupting the electro-receptors of the shark and deterring it from coming any closer. These bracelets do not hurt the shark, but simply deter it. Research like this can help both sharks and beach goers to stay safe and coexist.

The development of the sensory organs that sharks use and how they determine the arrangement on the shark does not have a lot of studies currently. There are two major markers, Sox8 and HNK1, that selectively mark sensory cells in the ampullary organs. These markers are parts of the DNA that are specific to the electrosensory organs like ampullae of lorenzini. The expression of these gene markers means that the organism is going to have that specific trait. Researchers are continuing to look into the sensory systems of animals like sharks.

Sharks are not the only animal to have electrosensory organs. Many other animals like salamanders, sturgeons, lampreys, and bichirs all have similar electrosensory organs that allow these animals to sense electrical currents in their environment. Some groups; however, have lost this trait. Frogs, some amniotes, and hagfish are some of the other groups that do not have electrosensory organs anymore. In teleost (ray-finned fishes) and mammals, this trait has been regained. Osteoglossomorpha and Ostariophysi in teleost and dolphins and monotremes in mammals have regained electrosensory organs even after other members in the group have lost it. This is an example of convergent evolution. Convergent evolution is when a trait from a previous ancestor is lost and then reappears later in the evolutionary history.

Ampullae of Lorenzini have potential implications for research advancements in the fields of marine biology. Because oceans are large and vast, mostly inaccessible environments, it’s hard and often impossible for scientists and researchers to sample both biotic and abiotic data from oceans. Remote-sensing technologies that are often used for sampling terrestrial and atmospheric data are useless in the ocean due to the high-pressure environment and lack of light or the insulating properties of water. Accordingly, researchers believe it may be possible to apply their current understanding of electroreceptors in sharks to advance remote-sensing technologies for marine ecosystems. By cross-disciplinary development aiming to replicate the effects of the ampullae of Lorenzini, some products have proven to be capable of detecting marine life and oceanic conditions and effectively recording and transmitting this data. Advancing and refining this technology could lead to huge advancements in marine biology, and help with sampling fisheries and oceanic conditions across the oceans, a task that is currently costly and difficult, and our oceans remain poorly mapped and understood as a result of this difficulty.

Citations

Ampullae of Lorenzini | Science and the Sea

A shark’s 6th Sense: Ampullae of Lorenzini. (orcaireland.org)

Freitas R, Zhang G, Albert JS, Evans DH, Cohn MJ. Developmental origin of shark electrosensory organs. Evol Dev. 2006 Jan-Feb;8(1):74-80. doi: 10.1111/j.1525-142X.2006.05076.x. PMID: 16409384.

https://www.orcaireland.org/a-shark-s-6th-sense-ampullae-lorenzini

King, Benedict, Yuzhi Hu, and John A. Long. “Electroreception in early vertebrates: survey, evidence and new information.” Palaeontology 61.3 (2018): 325-358.

https://www.google.com/url?sa=i&url=https%3A%2F%2Fvectormine.com%2Fitem%2Fdivergent-vs-convergent-evolution-with-ancestors-development-outline-diagram%2F&psig=AOvVaw1pc-lbn_Kka_8-Hp5YPBuo&ust=1650928557030000&source=images&cd=vfe&ved=0CAwQjRxqFwoTCIjVqaTqrfcCFQAAAAAdAAAAABAD

Zhang, Z., Robison, B., Ramanathan, S. “Marine biology requires new line of inquiry in materials research”

Rileigh Dunn, Jasmine Taulborg, and Monica Perez-Manrique

Introduction

Life can be found almost, if not, everywhere on Earth. Organisms have evolved to survive harsh environmental conditions that make life almost impossible. Throughout this organismal diversity class, we have observed and described a wide array of abilities and characteristics that individual species have developed to aid their survival amidst an ever changing world. In order for their species to live on, individuals were forced to adapt, we will be reviewing some of the individuals that prove to be successful in their extreme niches.

Desert Environments

There are 16 major deserts in the world which cover about a fifth of the surface of the planet. These ecosystems provide some of the harshest environmental conditions making the possibility of life very difficult. There are five main types of desserts however, our focus will be placed on the hot and dry deserts, also known as arid deserts. The temperatures are warm and dry year-round, these ecosystems can experience daytime temperatures of 130° Fahrenheit and usually they don’t receive more than 10 inches of precipitation a year. The terrain is often covered in rocky and gritty substrate since the lack of rainfall means that there is little weathering that occurs, so vegetation’s success is limited. Living in the deserts requires organisms to develop adaptations to extremes of water deficits and temperatures. They have to face periods of low precipitation and strategically race against the rapid rates of evaporation. Many organisms that live in these temperate conditions have to withstand prolonged periods of starvation.

All these unfavorable conditions have forced individuals to speciate or develop very unique characteristics that address some of the issues that were previously mentioned. Some of the organisms that have been able to successfully adapt characteristics which allow them to survive life in the desert are Arabian camels and Fennec foxes. Arabian camels are native to the Sahara desert and parts of Africa and parts of the Middle East into northern India. They have one hump on their back which is composed of fatty tissue that can be utilized as an energy reserve when camels have little to no access to food or water. The fat is also used to avoid overheating and regulate the animal’s body temperature. Since the fat is condensed into one area, camels do not have to worry about their entire body heating up as a result of fat causing insulation heat. The heat from their fat is restricted to the top of their back while it is daylight and the scorching sun is beaming down at them.

Another organism that was able to adapt a unique trait in order to survive the desert’s conditions, is the Fennec fox. This fox also lives in the Sahara desert, and one of its most notable characteristics is their large upturned ears. Their ears allow them to hear their prey and aid them in detecting any possible threat. They can also be used to disperse heat, due to their large surface area, the foxes can release or disperse heat using the many blood vessels in their ears. Despite their unique exterior features, one of the most important adaptations lies internally–the kidneys. These foxes’ kidneys have an enlarged medulla area inside their kidneys where urine can become concentrated to ensure that the most water is being retained by the individual’s body. Fluid moves from their bloodstream to the glomerulus in the medulla, which leads the urine to the Loop of Henle where water is separated from the other compounds in the liquid through osmosis. Typically the longer the loop then the more water can be successfully retrieved and separated from the urine. This results in a highly concentrated urine however, the fox is able to take in water successfully from their food rather than having to drink water directly. As we know, coming across water sources in the Sahara desert, or any other arid desert, is a challenge so with specialized kidneys foxes are able to go for long periods of times without drinking water.

Tundra Environments

There are two kinds of tundra found on our planet: the arctic tundra located in the arctic, which contains the arctic circle, Alaska, and the northernmost regions of Canada, Russia, Iceland, Scandinavia, and all of Greenland, then you have alpine tundra found at the tops of mountains worldwide. The climate there is often characterized by a bitterly cold climate, ice and snow, wind, and little rainfall. Once trees are spotted, often conifers, the tundra has shifted to taiga. This kind of climate seems less than ideal for organisms and yet many live and even thrive in these locations. Living in the arctic means months of very cold temperatures at night and days of bright sun meaning most animals need a way to keep warm that still keeps them camouflaged. Many arctic animals with fur or feathers will be white with some black during winter and shift to brown or gray during the summer. Many water-dwelling animals will have a streamlined body with large flippers. Most of these animals will have thick fur, blubber, or feathers and sometimes mixtures of the three. Many of the mammals on land will have more compact bodies, with smaller or shorter legs, ears, and tail and larger paws than their non-arctic counterparts. Even among these adaptations there are extremes.

As one of many birds of the arctic Fratercula arctica, or the Atlantic or Common Puffin is adapted to such a climate. Their beaks are specialized from most birds and hinge with the top and bottom closing at different angles which along with a thick, rough tongue allow them to catch multiple fish in one trip. These birds can dive down to about 60 meters and can stay underwater for up to a minute. They use their feet like a rudder and extend their wings to move forward in the water. Another amazing organism found here is Balaena mysticetus, or the Bowhead whale, these massive baleen whales use their thick skulls to break through ice to the surface. They reside exclusively in arctic and subarctic waters. They also have the thickest blubber of all whale species on average being from 17 to 19 inches thick! Finally, the plants of the tundra, like the Salix arctica, or Artic Rock Willow need to grow low to the ground and often have some form of insulation to keep themselves warm. Arctic Rock Willow grows hairs on their leaves and grows in clusters close to others to keep the heat in. They also form their own pesticides, so insects do not eat them; however, that does not stop mammals from eating them.

Extreme Environments

Extremophiles, tiny microorganisms that live in very harsh conditions, are perhaps some of the most numerous organisms on the planet. This is due to their adaptations that allow them to live almost anywhere-from deep sea hydrothermal vents to ecosystems polluted by mining waste to even the coldest parts of Antarctica. There are five different kinds of extreme conditions that extremophiles are commonly categorized by: extreme pH levels, temperature, salinity, pressure, and radiation.

Alkali/Acidophiles, organisms that exist in extremely acidic or basic environments, have been shown to survive at pH levels of 0 and 12.5 before. They have adapted to control their internal pH levels by producing compounds like lactic acid, which changes the pH levels of the cytoplasm surrounding it. To control salinity levels, halophiles (organisms existing at high salinity) will similarly produce compounds like sugars or amino acids, which help to dilute the salt in their system.

Thermophiles survive extremely high temperatures, as high as 120℃, by protecting against protein denaturation through the production of other proteins that re-strengthen them; at the other end psychrophiles, surviving through as low as -25℃, adapt by entering a “slumber state” when it gets too cold to continue life processes. Having a cell membrane that contains more fatty acids allows hyper-piezophiles to live at high pressure and radiant-resistant microbes have multiple DNA adaptations like modified DNA repair functions and smaller amino acids.

One of the most famous extremophiles are tardigrades (aka water bears), which can withstand a number of extreme conditions.They do so by entering a dormant state-one that they can awaken from completely unharmed even after many years. These resilient life forms have given scientists cause to believe that life could exist on other planets besides Earth; as long as water is present, an organism similar to an extremophile like the tardigrade could exist.

Conclusion

Life has adapted to the different environments of Earth in many ways. Animals like the fennec fox and Arabian camel have adapted to the arid desert through strategies like water conservation, specialized kidneys, and modified body features that aid in heat dispersal. Organisms like the bowhead whale and the puffin have evolved to the cold tundra and arctic sea through strategies like modified beaks and insulating blubber. Extremophiles have adapted to multiple different harsh environments, using strategies like that of the tardigrade, which goes dormant when their surroundings become too harsh to carry out life processes.

References

Noll-Banholzer, U. (1979). Water balance and kidney structure in the fennec. Comparative Biochemistry and Physiology Part A: Physiology, 62(3), 593-597.

D’Amicis, B., Stone, S., (2019). Wild Life Spirit of the Sahara. BioGraphic. https://www.biographic.com/spirit-of-the-sahara/

USGS (2001). What Is A Deserts https://pubs.usgs.gov/gip/deserts/what/

Boudreau, D., McDaniel, M., Sprout, E., Turgeon, A., (2011). Desert. National Geographic Resource Library Encyclopedia. https://www.nationalgeographic.org/encyclopedia/desert/

University of California Museum of Paleontology. (2019). The desert biome. https://ucmp.berkeley.edu/exhibits/biomes/deserts.php

Gonzalez, N. (n.d). Do Camels Store Water in Their Humps?. Encyclopedia Britannica. https://www.britannica.com/story/do-camels-store-water-in-their-humps

National Geogrphic. (n.d.) Arabian Camel (Dromedaries). Mammals. https://www.nationalgeographic.com/animals/mammals/facts/arabian-camel/

Encyclopedia Britannica, inc. (n.d.). Tundra. Encyclopedia Britannica. https://www.britannica.com/science/tundra

National Geographic (2020). https://www.nationalgeographic.org/article/tundras-explained/

Oceanwide Expeditions (n.d.) https://oceanwide-expeditions.com/to-do/wildlife/puffin

National Oceanic and Atmospheric Administration (NOAA) n.d. https://www.fisheries.noaa.gov/species/bowhead-whale#overview

Capece, M. C., Clark, E., Saleh, J. K., Halford, D., Heinl, N., Hoskins, S., & Rothschild, L. J. (2013). Polyextremophiles and the constraints for terrestrial habitability. Cellular Origin, Life in Extreme Habitats and Astrobiology, 3–59. https://doi.org/10.1007/978-94-007-6488-0_1

Merino, N., Aronson, H. S., Bojanova, D. P., Feyhl-Buska, J., Wong, M. L., Zhang, S., & Giovannelli, D. (2019). Living at the extremes: Extremophiles and the limits of life in a planetary context. Frontiers in Microbiology, 10. https://doi.org/10.3389/fmicb.2019.00780

Ben Nemish, Anna Weiker, Amanda Hawk, Sabrina Nichols

Mammals

Of all the mammals that live on earth, only 20% of them can be considered aquatic in one way or another. Within this 20% they can be divided into two categories: fully aquatic, and semi-aquatic.

First things first: what makes a mammal, a mammal? A defining characteristic of mammals is to have mammary glands that allow offspring to directly feed off of the mother. Another feature that is very evident among mammals is that the majority of them give birth to live young, which also means that they do not lay eggs. When it comes to their hearing, mammals have three distinct middle ear bones: the malleus, the incus, and the stapes. Another very defining feature of mammals is to be “warm-blooded”, or endothermic. To be warm-blooded means to be able to regulate one’s own body temperature. Being endothermic has given mammals the ability to live in a very diverse set of environments, anywhere from the desert to the Arctic.

Fully Aquatic Mammalian Species

https://www.thoughtco.com/characteristics-of-different-cetaceans-2291901

When talking about mammals that live solely in the water, one must ask the question, “what makes a mammal fully aquatic?” To start off, these animals have had to find a way of obtaining oxygen as they do not have gills.  The solution for most of them was to have a spiracle, more commonly known as a blowhole, that allows the mammal to breathe oxygen without having to raise their entire head above the water. All whales have these spiracles, along with dolphins and porpoises. Dolphins and whales have adapted their bodies to maximize their success in the fully aquatic environment. For example, their bodies are very streamlined bodies that aid them in gliding through the water. They also have a unique tail that lies horizontally when the organism is lying upright. This tail arrangement specifically helps with propulsion through the water.

While some organisms breathe through blowholes, some have their nostrils towards the tip of their heads. With nostrils at the tip of the head, this allows the mammal to raise just the tip of their nose out of the water. The mammals that use this breathing mechanism include the manatees, and dugongs. Manatees and dugongs belong to the sirenia order.

Sirenians are the only aquatic mammals that are solely vegetarians. Their mode of locomotion is a singular paddle or flipper on the backside of the animal. They move this paddle up and down to propel themselves forward, using their front flippers to guide themselves.

https://www.savethemanatee.org/manatees/facts/

Semi-Aquatic Mammalian Species

What makes an animal semi aquatic? Semi-Aquatic mammals do not live permanently in water, but they live on land and go into water for food and shelter. Some adaptations of these mammals include: webbed feet, flattened nails, small external ears, subcutaneous fat, and internal organs or tissues that prevent drowning. These species have made these physical adaptations to better live in the water and on land. Some examples of these creatures are beavers, muskrats, otters, minks, nutrias, polar bears, platypuses, and even hippopotamuses! Beavers, minks, platypuses, and hippopotamuses all have webbed feet in order to swim and propel throughout the water.

Many of these species also have the adaptation of an oily, hollow, water repellent fur in order to prevent them to stay warm in cold temperatures while being able to swim without the water get

https://www.cbsnews.com/news/nature-up-close-beavers-the-master-engineers/

ting to their skin. Most semi-aquatic mammals have a reduced heart rate that aids with slow respiration, meaning that it is easier for these species to stay submerged in the water for a small amount of time. Beavers have a special epiglottis at the back of their nostrils to prevent water from entering the windpipe while swimming. Beavers are also interesting in the fact that they store fat in their tail that is used in helping with thermoregulation. Otters, minks, and polar bears also have thermoregulation but they store extra fat as blubber in their bodies.

Hippopotamuses are strange creatures in that they do not actually “swim” in the water. Due to their very heavy body weight, they sink to the bottom of the lakes and walk on the ground. Their ears, eyes, and nostrils are all positioned high on their heads so that when they are submerged in the water, they can still see, hear, smell, and breathe above the water. Hippopotamuses are the closest living relative to whales, as we mentioned some similarities between these two species, they are quite different. Although hippopotamuses cannot breathe underwater, they can hold their breath for about 5 minutes at a time, and then come up for air. They also do not sweat, but instead, secrete a thick, red substance that acts as sunscreen, keeping their skin moist to protect them from sunburn when they sulk in the sun on land.

https://www.bbc.com/news/science-environment-60115512

Mammals have developed to fit almost every ecological niche in the world. Whether or not mammals are aquatic or terrestrial does not change the fact that they are all still mammals. Although they all share some of the same characteristics, there are key differences between them. Aquatic mammals have evolved to have more streamlined bodies and some have even evolved to have the loss of four limbs. These different adaptations front the aquatic mammals help to shape the way they live their lives and survive.

Castro, P. (2021, June 12). Marine Mammals ~ marinebio conservation society. MarineBio Conservation Society. Retrieved April 13, 2022, from https://www.marinebio.org/creatures/marine-vertebrates/marine-mammals/#:~:text=One%20of%20the%20major%20behavioral,orcas%20can%20reach%2050%20kph

Kaupp, L. (n.d.). Exploring our Fluid Earth. Adaptations | manoa.hawaii.edu/ExploringOurFluidEarth. Retrieved April 12, 2022, from https://manoa.hawaii.edu/exploringourfluidearth/biological/mammals/adaptations

Yuan, Y. (n.d.). Comparative genomics provides insights into the … – pnas.org. Retrieved April 13, 2022, from https://www.pnas.org/doi/10.1073/pnas.2106080118

Veronica Dellerba, Alex Bi, and Dhwani Patel

Tardigrades, also more commonly known as water bears or moss piglets, are microscopic aquatic animals. They were first discovered by German zoologist Johann August Ephraim Goeze, in 1773. They were given the nickname “water bear” because their gait when walking resembles that of a bear. They are 0.1 to 0.5 mm long on average and have 4 pairs of legs.

There are over 1000 species in three classes and can be found in a wide range of habitats, from freshwater to saltwater, and tropical to desert. Their bodies are bilaterally symmetrical, meaning that they have the same body parts on both sides when cut through the median axis. Their growth occurs through a series of molts, with each molt taking about 5-10 days to complete. Their entire outer layer, known as the cuticle, is shed during this process, and they are unable to feed. A tardigrade will require anywhere from 3-6 molts to reach maturity.

Tardigrades can reproduce sexually and asexually, depending on the species and their habitat. Those that live on land tend to reproduce asexually via parthenogenesis, requiring no mate, while those in aquatic environments mostly reproduce sexually.  Some species have the male place sperm inside of the female’s cuticle. In other species, the females will shed their cuticle and then lay their eggs inside of the shredded cuticle to get fertilized by males later. Their larvae hatch from eggs and reach maturity between 14 – 90 days. Water bears reproduce year-round as long as conditions are favorable.

Tardigrade Resilience

Tardigrades are known for their hardiness as they are considered to be one of the most resilient animals on our planet. They can withstand low temperatures, pressure, oxygen and water levels. Furthermore, they can also tolerate high temperatures and pressures, radiation exposure, and variable salinity. Multiple experiments have been conducted to test the water bears’ unrivaled hardiness. These include: being frozen at absolute zero (-272.95°C) for 20 hours, being stored at -200°C for 20 months, and being heated to 150°C. Other experiments subjected them to pressures reaching over 400 times normal atmospheric pressure, as well as exposure to high concentrations of suffocating gasses like carbon monoxide and dioxide, nitrogen, and sulfur dioxide. Despite these extreme conditions, the tardigrades were all able to recover without issue.

The secret to tardigrades’ survivability is their use of cryptobiosis, entering a state of incredibly low metabolic activity. Tardigrades enter a dormant form commonly referred to as a tun in response to extreme conditions. In conditions without water they will retract their limbs and curl into a ball. They will also lower their metabolism rate down to 0.01% so energy is retained as much as possible. When faced with extreme salinity levels they will rapidly convert to their tun state. Due to low studies, the process and mechanisms used are not well known. In response to low temperatures it is believed that they protect themselves by releasing cryoprotective chemicals. It is also thought that they will manage ice crystal formation so their cells do not get damaged.

Because of their high radiation and pressure resistance, tardigrades can survive being exposed to the vacuum of space. To test this, several space missions by both NASA and the European Space Administration (ESA) have been launched with tardigrades on board. These missions sought to examine the effects of spaceflight stress and direct exposure to space and its radiation on living organisms. One of the projects flown during these missions, known as TARDIS (Tardigrada in Space), directly exposed the animals to the vacuum of space. Experiments under this project found that tardigrades could survive exposure to the vacuum, but solar and cosmic radiation greatly reduced their survival rates. All of the factors combined have led some people to speculate that tardigrades may have originated somewhere other than the Earth.

Benefits to Humans

Currently, tardigrades are of limited benefit to humans outside of a small hobbyist following. However, scientific research into their unique traits tardigrades have broadened the scope of their use to us. Research at the University of Tokyo, led by molecular biologist Takekazu Kunieda has investigated a protein found in tardigrades known as Dsup, believed to prevent DNA breakdown from cosmic radiation. The protein was bound to human cells and irradiated, and results found a 40% reduction in x-ray damage. Research involving sugars produced by tardigrades has also produced promising solutions to blood loss and other health problems related to blood flow, like strokes or heart attacks.

But ARE they extraterrestrial…?

After all of this information, the question of whether or not tardigrades are extraterrestrial remains. A study conducted in 2021, published by the University of Kent, found that tardigrades would not be able to survive direct impact on landing if they were to come from outer space and crash onto Earth. Using gunpowder and hydrogen gas, researchers launched tardigrades at increasing speeds to determine the upper limit of their resilience. Their survival topped out at a speed of 0.9 kilometers per second, and as speeds increased, it eventually reached a point where the animals were destroyed by the impact, making it unlikely that they arrived to Earth through extraterrestrial means. However, slower-moving impact debris may allow some life to survive. So, while it is still highly unlikely, the idea that tardigrades or any other form of life has its origins somewhere else in the universe has yet to be entirely disproven.

References

Georgiou, Aristos. “Secrets of Tardigrades Extreme Survival Abilities Unlocked by Scientists.” Newsweek, Newsweek, 1 Oct. 2019, https://www.newsweek.com/secrets-tardigrade-extreme-survival-abilities-scientists-1462275

Miller, William Randolph. “American Scientist.” American Scientist, https://www.americanscientist.org/.Wright, Jeremy. “Tardigrada (Water Bears).” Animal Diversity Web, https://animaldiversity.org/accounts/Tardigrada/.Bradford, Alina. “Facts about Tardigrades.” LiveScience, Purch, 12 Nov. 2021, https://www.livescience.com/57985-tardigrade-facts.html.

“Tardigrade-Tough Applications for Humans.” Sealevel, 28 Sept. 2020, https://www.sealevel.com/2020/09/22/tardigrade-tough-applications-for-humans/.“Hardiness of Tardigrades Tested to Simulate Transmission of Life through Space.” News Centre – University of Kent, 21 May 2021, https://www.kent.ac.uk/news/science/28775/hardiness-of-tardigrades-tested-to-simulate-transmission-of-life-through-space

Weronika, Erdmann, and Kaczmarek Łukasz. “Tardigrades in Space Research – Past and Future.” Origins of Life and Evolution of the Biosphere : the Journal of the International Society for the Study of the Origin of Life, Springer Netherlands, Dec. 2017, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5705745/

Reymond Miyajima, Alex Papouras, Eddie Rice, and David Childress

More than 800 million people are faced with hunger and malnutrition, and 15 million people, mostly children, die as a consequence each year (1). Our planet currently produces 4 million metric tons of food yearly, with 1.3 million tons going to waste according to the UN’s Food and Agriculture Organization (FAO) (2). Food loss occurs for multiple reasons: crops may not be harvested because of damage by disease, pests, and weather. For that reason, to protect against weather and pests, farmers will often plant more crops than what consumers need (3). With global temperatures increasing more than double than that of the past 50 years, diseases and pests that are restricted to certain regions of the world are now being found in new places presenting a major threat for food security. However, one crucial and yet overlooked facet of biodiversity for food is genetic diversity.

Losing species and crop varieties is not only detrimental to biodiversity and ecosystem processes, but also decreases the total amount of genetic diversity. Losing genetic diversity limits the amount of material for natural selection to act on, selection by farmers and plant breeders, and has consequently increased the vulnerability of agricultural crops to sudden changes in climate, and to the appearance of new pests and diseases (1). To combat issues associated with limited genetic diversity and food security, scientists are now focusing research efforts on the discovery and preservation of plant genetic diversity.

One of the biggest threats to our planet and society is climate change. Changes in the climate have not only led to a loss in biodiversity, but threaten food security both globally and for local communities; disrupting food availability, reducing access to food, and affecting food quality (4). These losses in biodiversity and the genetic losses that come with it, will have huge consequences on the ability of mankind to feed itself in the future, with people in poorer regions of the world experiencing worse food shortages (5). As heat waves, drought, pests and diseases become exacerbated in the face of climate change, genetic information for traits such as fast-growing, disease-resistance, and high-yielding varieties held in certain crop varieties are necessary to reduce food insecurity in light of climate change (5).

Many of our important crops such corn and wheat come from a few varieties and were found to have extremely low genetic variation. Having low amounts of genetic variation has proven to be detrimental. For instance, in the United States in 1970, the fungus Helminthosporium maydis destroyed more than half the standing maize crop in the southern part of the country. The crop had been grown from seeds that have a little genetic variation and are susceptible to this disease. However, the fungal problem was solved by breeding resistant varieties using genetic resources that were obtained from other parts of the world (7). Thus, highlighting the importance of preserving genetic diversity and varieties of plants for food security.

One method for preserving the genetic diversity of crops is to store a variety of plants and seeds in specialized “gene banks.” These banks are collections of seeds and live plants that allow public and private scientists to access a staggering range of plant diversity (Crop 2022). Over the last twenty years, as awareness for the preservation of biodiversity has increased, there has been an explosion of new gene banks across the world (5). Currently, there are around 1,750 gene banks spread around the world, including the famous Svalbard Global Seed Vault in Norway (5). There are, however, some drawbacks to storing seeds in a vault. Some seed species, for example those of tropical fruits, cannot be stored in a freezer for long periods of time, and need to be grown in vaults themselves (6). This makes some species of plants more vulnerable to diversity loss than others.

Much of plant biodiversity loss is the result of mass agricultural practices. For example, producers typically prefer to grow crops that yield the most amount of product for the lowest cost, while consumers prefer better tasting and “prettier” produce (6). These types of growing practices preserve some “favorable” genes in the gene pool, but severely limit the genetic diversity found in mass-produced crops. One way to remedy this is to alter producer and consumer preferences, which would take a long time to enact and seems unlikely. Another solution is to sample wild relative crops for unique genetic diversity (6). These plants are usually more resistant to the elements, but are also typically less productive. By isolating the resistant genes from these wild plants, scientists would be able to breed crops that are more resistant and higher yield, all while preserving the genetic diversity of the chosen crops!

GMOs or genetically modified organisms have left a beneficial mark in the food supply. GMOs lead to a faster production of crops, better pest resistance, and the food can be made more nutritious. However, despite the benefits of GMOs, there will always be a huge concern when it comes to plant diversity and how it’s impacted by GMOs. This is because GMOs will tend to bring in similar advantageous DNA to a single population, which will affect what characteristics show up in the plant. If a majority of the plants in an area all have a similar DNA sequence, that will directly decrease the biodiversity of said plant ecosystem(Landry 2015 Aug 10) . With a decrease in the genetic diversity there is a less likely chance that these plants can adjust to a changing environment because of all the organisms sharing DNA & certain characteristics not given a chance to help the plant adapt.

If GMOs weren’t bad enough before, how do you feel after hearing the GMOs actually take more than 85% of U.S. crop land(2021 GMO). On top of that, a majority of those modified crops are just from THREE crops; corn,soy, and cotton. Three types of crops definitely won’t benefit any kind of plant diversity. While GMOs do hold some benefits, these benefits are also disadvantageous in other ways. Yes, GMOs help with farmers being able to spray herbicide on them without harm among other things but diverse plants (non-GMOs) help protect soil from erosion and various nutrition losses. Pollinators and other insects that are seen to help support U.S. agriculture are better off with diverse plants too, as they can’t be sprayed with nearly as much toxic chemicals as GMO crops can. As stated by Livingnongmo.org, GMOs are a “double decker biodiversity-wrecker” (2021 GMO).

GMO crops have had a long standing presence both in the US, and abroad. The selection for crops with better, more desirable qualities and traits has always been a part of the domestication process (6). Problems begin to arise when crops are genetically modified in a laboratory setting for traits and functions which would not otherwise occur in a natural setting. This is especially a problem with staple food crops such as corn, wheat and soy. When these crops are introduced to the open ecosystem, more often than not, they cause a lot of issues in the grand scheme of biodiversity (Landry 2015 Aug).The lack of functional traits and the accumulation of traits outside of the scope of the natural world has created an epidemic of mass proportion(9).

This is not to say that GMO crops have not had their role in benefitting human existence. GMO crops have had a higher overall output of nutritional material than their ancestral counterparts. This has assisted humanity in not only the growth of populations in years past, but the sustaining of our populations today. In many cases, people who are living impoverished have been saved by crops and staple foods which are by nature, GMOs (7).

One of the most crucial aspects and pressing problems with GMOs is the limitation of their implementation on ecosystem diversity. This can be both a supply chain issue, as well as an ecological one. On the one hand, having such low diversity in our staple foods has proven in the past to be an extreme limitation. When confronted with new diseases and outbreaks which damage crops, how will we be able to recover the loss in available nutrition? By diversifying our food crops to make them more ecologically stable, we will be more able to prevent mass destruction of our food supply chain (5). From an ecological perspective, these crops with such low diversity take up giant swaths of farmland across the country. This farmland is required to be upturned and tilled constantly (9). From past tragedies such as the dust bowl, we know that practices like tilling destroy natural grasslands which sequester carbon and nutrients in the soil. Although it is not feasible to expect to go back to a society which does not employ large scale farming techniques without GMO usage, more environmentally conscious methods as well as increasing diversification of crops will in the long term benefit humans and the earth to a greater degree than GMOs ever have.

References

1. Esquinas-Alcázar, J. (2005). Protecting crop genetic diversity for food security: political, ethical and technical challenges. Nature Reviews Genetics, 6(12), 946-953.
2. Bloomberg. (n.d.). Bloomberg.com. Retrieved April 25, 2022, from https://www.bloomberg.com/news/features/2020-12-15/no-more-hunger-how-to-feed-everyone-on-earth-with-just-the-land-we-have
3. The problem of food waste. FoodPrint. (2022, March 15). Retrieved April 25, 2022, from https://foodprint.org/issues/the-problem-of-food-waste/#:~:text=Food%20is%20lost%20or%20wasted,at%20stores%20and%20in%20homes
4. Falzone, J. (2019, May 14). Plant biologist: Genetics Crucial for Food Security and Sustainable Agriculture. BIO. Retrieved April 25, 2022, from https://www.bio.org/blogs/plant-biologist-genetics-crucial-food-security-and-sustainable-agriculture
5. US EPA. Climate Impacts on Agriculture and Food Supply | Climate Change Impacts | US EPA. (n.d.). Retrieved April 25, 2022, from https://climatechange.chicago.gov/climate-impacts/climate-impacts-agriculture-and-food-supply
6. United Nations. (2010, October 26). Conserving plant genetic diversity crucial for future food security – un | | UN news. United Nations. Retrieved April 11, 2022, from https://news.un.org/en/story/2010/10/357072-conserving-plant-genetic-diversity-crucial-future-food-security-un#:~:text=Genetic%20information%20held%20in%20certain,the%20face%20of%20climate%20change
7. Crop Science Society of America. (2022). Crop Conservation. Crop Science Society of America. Retrieved April 12, 2022, from https://www.crops.org/about-crops/plant-preservation
8. How Do GMOs Affect Biodiversity? | Living Non-GMO : The Non-GMO Project. 2021 Apr 13. livingnongmoorg. https://livingnongmo.org/2021/04/13/how-do-gmos-affect-biodiversity/
9. Landry H. 2015 Aug 10. Challenging Evolution: How GMOs Can Influence Genetic Diversity. Science in the News. https://sitn.hms.harvard.edu/flash/2015/challenging-evolution-how-gmos-can-influence-genetic-diversity/