a.Offer a description of the species including i. Physical characteristicsThe Texas Pimpleback is a type of mussel that is only fount in Texas, USA. It has a moderately inflated shell that reaches 60– 90 mm (2.4–3.5 in) which is relatively smooth and moderately thick. Its outer shell’s coloration ranges from yellowish-tan to dark brown with some individuals spots of color(speckled) or with dark green rays and its inner shell(nacre) is white and iridescent towards the rear.Ii. Taxonomy -Kingdom–Animalia(Animals) -Phylum–Mollusca(Invertebrates) -Class–Bivalvia(Mollusks) -Order–Unionoida(Freshwater Mussels) -Family–Unionidae -Genus–Quadrula—–21 species, Genus size is D -Species–petrinaiii.Location and description of the ecosystem/biome in which the species is foundThe Texas Pimpleback resides in freshwater bodies of water. These bodies are typically medium to large rivers with low gradients. A special feature for their environments is that they require a Benthic Zone. A Benthic Zone is the ecological region at the lowest level of a body of water. It begins at the shoreline and continues down until it reaches the floor, consisting of a sediment surface and subsurface layers. Microscopic benthic organisms live in the zone and act as a source of food for bottom feeding animals(Lamprey, Sturgeons, Paddlefish,bass, and Catfish) In essence, the Texas Pimpleback resides in the substrates of bodies of water, typically consisting of mud gravel and sand.iv.3-5 adaptations of the species particular to the environment -young mussels use cilia(little hairs) on their bottoms to capture algae -Mother’s take their eggs and they develop into specialized larvae called glochidia. The mother, after keeping the larvae in their pouch for four to six weeks, release them either alone or in small groups. Sometimes, the mother will embed groups into large mucus structures called conglutinates. Conglutinates serve as a hook for the larvae to attach to fish for days or weeks(a period of metamorphosis) before they detach and live as independent, young, maturing mussels. These areas typically have low/not strong currents of water so the mussels won’t get caught in the stream, where they can’t survive. -NEED THIRDv.B. The primary factors caused by humans that are hypothesized to threaten the Texas pimpleback leading to it being placed on the endangered species list are the degradation and loss of their habitats(i.e. Dams and impoundments), dewatering, sedimentation, climate change, sand and gravel mining, chemical contaminants,Dewatering has led to lower water levels in streams in rivers which in turn has resulted in mussels being stranded and dying in areas that were once underwater. This has become especially troublesome for pimplebacks living near reservoirs where water levels in the reservoir and downstream can change rapidly(i.e. for hydropower facilities, they release water during peak energy demand periods.Sand and gravel mining have led to stream instability through increasing erosion. It has also led to an increase amount of sedimentation deposition downstream.Chemical contaminants can be extremely detrimental to Texas pimpleback because they expose the organisms to concentrations of contaminants that far exceed toxic levels. These contaminants, such as oil, can have long term effect. In one case, oil residue was found downstream five years after the spill. For an organisms that is essentially immobile, it is very problematic that contaminants that are undoubtedly toxic remain in their environments for extended periods of time. Other examples of toxic contaminants found to affect pimpleback populations are ammonia, agricultural runoff , excessive amounts of nitrogen and phosphate,metals(found to negatively affect organism growth, filtration efficiency, enzyme activity, valve closure, and behavior. Behavior is important because it is a reproductive factor), mercury, and pesticides. Lastly, a more subtle chemical contaminant are prescribed drugs such as antidepressants, antihistamines, and several other pharmaceutical creations. Although this factor has not been explicitly proven, there have been remnants found in pimpleback environments.Climate Change can be defined as the changing in temperatures and weather. Climate Change affects the population of the Texas Pimpleback because changes in temperature and precipitation can affect the amount of flooding or drought, and since Pimplebacks are essentially immobile, they cannot migrate to regions with more favorable qualities.A primary factor caused by natural events believed to threaten the population of the Texas Pimpleback is predation. Even so, predation is a natural occurrence in life and the main reasons behind the decreasing population of the Texas Pimpleback do not include predation, rather they are human caused factors. Other factors include sedimentation and drought which can spur from both human and non-human factors.Sedimentation has led to reduced feeding and respiratory efficiency from clogged gills, disrupted metabolic processes, increased substrate stability, limited burrowing activity, reduced birth rates, physical smothering, and disrupted host fish attractant mechanisms.C. I think that the Texas Pimpleback does need to be considered endangered and protected under the Endangered Species Act because; 1.the population, due to human involvement, has steadily decreased over time, threatening its existence; 2. They filter out microscopic organisms and pollutants(if not overwhelmed), keeping their environments clean and pollutant free; 3. They play a vital role in their food webs, often as the secondary consumer, preying on producers and supplying energy for tertiary and quaternary predators. An example of population decreasing thanks to human activity can be seen through the creation of dams. Dams result in deeper water and lower velocities upstream. As water velocity decreases, the water can no longer support sediment, which then falls to the substrate, cramming mussels as well as decreasing water quality. Regarding their ability to filter threats from their environment, if the Texas Pimpleback disappears, the water quality in their rivers, already affected by sedimentation, will become even worse, eventually affecting the lives of all organisms residing in their area. Native mussels can filter approximately two liters of water a day, and with rivers polluted thanks to human involvement, it is essential that the Pimpleback survives. An example of water pollution causing massive destruction is the BP oil spill in the Gulf of Mexico, which as a result, have, according to scientific estimates, have killed billions of organisms. The number of turtles dead as a result is approximately 170,000. Lastly, an important player in their food web, the Pimpleback is able to eat algae and phytoplankton and zooplankton, unlike larger consumers. This allows for the mussels to provide energy for species which, without them, would not be acquiring the same amount of energy, ultimately leading to decreases in tertiary consumer populations.D. In terms of the effects of Texas Pimpleback extinction on its food web, the results would be problematic. The Pimpleback along with other threatened mussels, are responsible for filter-feeding, both consuming plankton and algae which in turn will provides energy for their predators. Considering the Pimpleback, along with more than a dozen native mussels in Texas, are the main source for consuming algae and plankton(producers), without them there would be relatively no organisms(some exceptions, but no orgs to assume role of mussels) to bridge the gap between producers and tertiary consumers.E.ccccf.If humans were not to intervene on the protection of the Texas Pimpleback and all current threats remained, there could be no viable courses of natural selection that would lead to ensuring the survival of this species. I say that because all the major threats currently terrorizing the Texas Pimpleback are man-made, and to stop man made destruction, humans need to interfere(i.e. Placing the Pimpleback on the ESA). Threats such as chemical contaminants in excessively large abundances and dams creating irregular and volatile water flows downstream just simply cannot be counteracted by natural selection. This being said in a perfect world, the Texas Pimpleback would be able to survive if it was more mobile(could move farther downstream, protecting it from volatile water flows), could survive in crowded areas(sedimentation), and had stronger filters(allowing them to filter much more contaminants from water).Now If humans were not to intervene on the protection of the Texas Pimpleback as well as not interfere on their environments(i.e. Creating dams, impoundments, dewatering, mining, and releasing contaminants), there would be a much greater chance of the Quadrula petrina(Pimpleback) surviving because human factors are the real culprits behind the decrease in population. Predation can be blamed in part, but that is a natural occurrence and unpreventable. Human interference, though, is preventable.NatureServe. “Quadrule Petrina.” NatureServe Explorer, NatureServe, Nov. 2016, explorer.natureserve.org/servlet/NatureServe?searchName=Quadrula+petrina.RMBEL. “The Aquatic Food Web: Who’s Eating Whom?” RMBEL, RMB Environmental Laboratories, 11 May 2015, www.rmbel.info/the-aquatic-food-web-whos-eating-whom/.Texas Living Waters Project. “Fewer Heelsplitters, Fatmuckets and Pimplebacks Signals Trouble for Texas Rivers.” Texas Living Waters Project, Texas Living Waters Project, 19 Sept. 2017, texaslivingwaters.org/fewer-texas-mussels-signal-river-trouble/.Palermo, Elizabeth. “Underwater Maids: Mussels and Clams Could Mop Up Waterways.”LiveScience, Purch, 20 Aug. 2014, 10:51, www.livescience.com/47453-underwater-maids-mussels-clams.html.Smith, Matt. “The Federal Government Says Billions of Animals Died From the BP Disaster.”Vice News, 15 Oct. 2015, news.vice.com/article/the-federal-government-says-billions-of-animals-died-from-the-bp-disaster.Watersheds Canada. “The Benthic Zone: A Glimpse of Life within the Substrate.”Watersheds, watersheds.ca/wp-content/uploads/2016/02/Benthic-zone-Final.pdf.