Predators: Vital Species in Worldwide EcosystemsKatarina W. MeekerPaw Paw High SchoolAbstractPredators within various ecosystems are essential in providing benefits to their species and to their environments. From any biological lens, the role of predators in global ecosystems, whether they are large or small, aids in the establishment of homeostasis due to an incredibly numerous variety of specialized traits. The advantages of predators in specific environments identify the traits that were determined successful in a certain species over an evolutionary time frame. When analyzing the inputs and outputs involved in flourishing ecosystems, a vital foundation is constructed around predators and their genetic advantages over other species. Not only have predators improved the balance and unity in varying environments, but they serve as natural evidence surrounding the importance of existing worldwide. As it may be difficult to explain numerous amount of predators that have existed and are still existing on Earth, there are a certain few that serve as great examples involving benefits to their ecosystem. Whether they are predators that are classified as apex predators, or simply determined at differing parts in the food chain, without their evolutionary benefits to their ecosystem, the homeostasis and biological significance would fade and do more harm to global environments. Predators, viewed as potentially dangerous, highly intelligent, and overall intimidating, are actually stereotyped quite harshly, for their genotypes and phenotypes are purposefully selected for the survival of various species. Overall, a select few predators will be examined characteristically to show the benefits to their ecosystems. While scientists were not around to primarily observe what prehistoric predators were like, they can infer through evolutionary and biological evidence about what they did to beneficially affect their environments. As Charles Darwin presented his famous work, “The Origin of Species” in 1859, the answers to understanding organisms’ evolutionary biology broadened. Nevertheless, this has made the characteristics of predators something less unknown. Predators, being organisms that kill and consume other organisms and reside at or near the top of the food chain, are notorious for evolving to fit their needs and improve their biological advantages. Within an online eBook by The Gutenberg Project, an electronic source on Charles Darwin’s “On The Origin of Species (2009),” Sue Asscher and David Wilder conveys Darwin’s idea by expressing that, “Man selects only for his own good; Nature only for that of the being which she tends” (4), in which he goes on to say that: It may be said that natural selection is daily and hourly scrutinising, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good; silently and insensibly working, whenever and wherever opportunity offers, at the improvement of each organic being in relation to its organic and inorganic conditions of life. (4) Essentially, the traits and behavior of a species, or a group like predators seen through the past and present, are passed down to future generations to benefit themselves and the life around them. From an ecological perspective, the effect of predators and the dominance of their positive traits in an ecosystem improve the biodiversity, creating a sense of homeostasis between different species. As a species reproduces, their genotypes are passed down hereditarily, which determines the phenotype in species variation. These variations are what are determined to help the organism survive more efficiently and reproduce as well. Therefore, predators, as seen through those in prehistory and present day, have evolutionarily developed biological traits that act as advantages for their species, as well as their ecosystems.First off, successful breeding within predator populations is a primary advantage of providing benefits to a specific ecosystem. Being able to breed and pass down traits to a set of offspring is naturally an advantage on its own, but the traits that inhibit positive responses on the ecosystem as well as increase the chances of survival of the predator is what dominates its affectancy. Through a study conducted by three researchers, they discovered that, “Recently, much interest has focused around the question of optimal breeding adjustment in predator-prey cycles” (Hanna Kokko, Graeme D. Ruxton, 2000). Furthermore, predator populations must have access to an abundance of prey, especially during their breeding season(s), as well as the ability to adapt to areas that correlate with the prey’s population sizes. In relation to these population sizes, it is natural to see a predator increase with an increase of prey, and vice versa. However, as prey starts to decrease due to the higher amount of predators in an ecosystem, predator recoveries are a biologically stabilizing result (Milstein). In this case, another study emphasizes the importance of predator dynamics: “Since breeding-habitat preference is one of the most important behavioral considerations of predator recoveries, this helps predators in an ecosystem find the most suitable place to breed to have success and pass their traits to their offspring” (Adrian C Stier, Jameal F. Samhouri, Mark Novak, Kristin N. Marshall, Eric J. Ward, Robert D. Holt, Phillip S. Levin, 2016). To demonstrate this, Rowen van Eeden, Philip Whitfield, Andre Botha, and Arjun Amar conducted an experiment which studied and observed the effect of the Martial eagle (Polemaetus bellicosus) and their breeding ground preference in which they felt most appropriate for the production of their offspring: “During the breeding period, birds showed preference for lower elevations within their breeding home ranges. Furthermore, as expected, birds tended to be found closer to their nest sites” (Rowen van Eeden et al., 2016). As the predator (Martial eagle) arranged its necessities for breeding successfully, this directly affects their population by increasing the amount of eagles found in that specific ecosystem. Taking into consideration that Polemaetus bellicosus is just one of thousands of examples of predators to examine within their breeding season(s), it is clear to see how important the effects of successful breeding on the outcome of positive, selective traits are in relation to flourishing ecosystems. For any predator species to survive and maintain superior in a food chain, feeding trends must be established instinctively due to options within a certain species’ environment. Biologically, this is relevant to physical traits that increase advantages of feeding on prey in different environments. So, “such a predator with a prestigious feeding advantage would be a very dangerous species of fish from the order Lophiiformes: the Anglerfish” (The Tree of Life Project: Lophiiformes, Anglerfishes Pietsch, 2005). Female anglerfish have evolutionarily developed a superior mouth trait that is filled with translucent teeth to trap prey, which allows them to swallow prey up to twice their own size (National Geographic: Anglerfish, 2017). When a predator, like the anglerfish, is capable of doing such extreme positions when feeding, it is able to consume a large amount of the victimized prey populations. In this case, this would lead to an increase in the amount of crustaceans, such as shrimp, other fish, and snails residing on the ocean floor (UCSB Materials Research Laboratory, 2002). Ultimately, the increase of the anglerfish population due to advantages of feeding on crustaceans does not negatively affect the crustacean population or the surrounding environment to a point of concern; the substantial abundance of deep-sea crustaceans at depths of 800-1,000 meters (twilight zone), or a half-mile below the ocean’s surface, does not risk harvesting due to human interference as crustaceans do at more shallow and therefore more vulnerable ocean depths (American Museum of Natural History: Anglerfish, n.d.). It is evident that biological feeding advantages do support predators’ continuous evolutionary effectiveness on resulting generations, as well as offering positive motion to various ecosystems. So on, anglerfish are one of thousands of predator species that demonstrate such characteristics in their fixed ecosystem, which also are scientifically observable and testable. Moving forward, feeding may be dependent on another extremely significant and particular biological attribute to predator species: locomotion. The evolutionary abilities of various predator species to increase their skills in locomotion have generated great success in them feeding on prey and surviving well. Like most predator species, a hunter must go out in search of prey they know is present within their habitat. The hunt most likely resolves as follows: the predator hunter either kills the prey for their own survival, or they are not equipped enough to kill the prey due to an advantage the prey has over the predator. But, predator species usually dominate over the prey species due to more developed and efficient characteristics. In a study conducted in 2017 by researchers Leslie F. Noe, Michael A. Taylor, and Marcela Gomez-Perez titled “An integrated approach to understanding the role of the long neck in plesiosaurs,” they found that: Neutral buoyancy in the water would allow the plesiosaur body to act as a feeding platform, by permitting the animal to hover in, or move slowly through, the water column whilst minimizing limb action, and maximising the efficiency of locomotion. To explain, neutral buoyancy describes “organisms that want to maneuver vertically” (The Sextant: Locomotion in Water, 2002). As seen here, larger predators in marine ecosystems such as the prehistoric plesiosaur, have adaptive characteristics due to their neutral buoyancy in the water that help with their locomotion. The advantage of the predator’s density being similar to the density of the water they move in allows the predator to either hunt the prey more accurately, or escape the predator more quickly. Moving forward, the size of a specific predator impacts the way in which they are able to move, feed, and essentially hunt prey.Predators are generated into all different sizes; predators are not only large organisms. An example of a small but deadly predator would be the shrew, the “smallest living terrestrial mammal” that “must eat 80-90 % of their own body weight in food daily” (One Kind Planet: Shrew, n.d.). The size of the shrew is vital to the collection of worms in which consists of a major part of their huge diet. However, there is an advantage to larger predators because of their intimidation. When prey living in close proximity of a larger predator come into contact with one another, the predator is naturally a threat and acts as a weakness on the helpless prey. The famous Megalodon was a dangerous animal that was notorious for being “one of the most mysterious and elusive prehistoric animals in the world” (Whale Facts: Megalodon Shark Facts, n.d.). Due to its insane size of approximately “16 meters, it makes it the largest megapredatory shark known among both fossil and extant taxa” (Humberto G. Ferron, 2017). Within the study “Regional endothermy as a trigger for gigantism in some extinct macropredatory sharks,” conducted by Humberto G. Ferron, he implied that, ” hunting strategies implying ambushing behaviour and/or attacks under specific ambient conditions could be reasonable for massive otodontids minimizing prey reaction time in a similar way to living great white sharks.” It is evident that the gigantism of the Megalodon was a detriment to the behavior and overall survival of prey, being that they left the prey with less chances of escape. Even though the Megalodon is extinct based on scientific evidence, the existing great white shark exhibits traits very similar to that of their ancestor. Gigantism, a very prominent and intimidating predator trait, is one of the most observable and testable due to the analyzation of phenotypes through ancestry DNA. A more highlighted image of what is happening within the ecosystem due to certain advantages can be seen thoroughly through different food chains. While it is important to know different traits some predators are born with for the sake of the success within their ecosystem, it is also very crucial to see the overall stance in which predators take within an ecosystem. Essentially, “top predators are at the top of food chain” (Michigan Sea Grant: Food Chains and Webs, n.d.). Within this basic idea of predator belonging, it clearly goes to show that the predators are going to display varying traits over their prey in the food chain, such as producers, and primary and secondary producers. Predators can be identified as all consumers, due to the fact that they feed on another living and breeding organism or species to survive. From a prehistoric perspective, some of the traits that led to a certain species being classified as a predator in a food chain is due to evolutionary advancements that proceeded on to future generations, until ancestor species inhabited present environments. In summary, these traits becoming prominent to benefit ecosystems are highly caused by the habitat they live in, and the pool of predators with similar phenotypes to show. Habitats are geographically different and even more different biologically. Habitats are studied to show the way in which predators’ traits are used effectively within the habitual ecosystem. Take a wolf – a dangerous, yet biologically fast predator that is carnivorous and scarce, yet resides in multiple different habitats worldwide. A habitat where wolves greatly reside is Yellowstone National Park. Wolves and their high speeds, levels of intelligence, and dominance over smaller predators and prey are easily capable of benefiting their ecosystem through purposeful demonstrations. In an article published in 2009 titled, “The Rise of the Mesopredator,” the authors Laura R. Prugh, Chantal J. Stoner, Clinton W. Epps, William T. Bean, William J. Ripple, and Andrea S. Laliberte, concluded that, “Reintroduced wolves reduced elk populations through direct killing, but the extent of the wolves’ influence in the ecosystem was greatly increased because of the fear-induced shift in elk behavior.” Likely, the shift in elk behavior was to benefit the environment due to the reintroduction of wolves and their evidential dominance over the elk. Overall, these fluctuations would bring a sense of homeostasis once again to Yellowstone. As seen before, the traits exhibited by the wolves are used to scare off a population to better the ecosystem overall. In the same article, “The Rise of the Mesopredator, 2009,” the authors reference that, “Elk began to avoid the riparian areas they had favored in the absence of wolves and moved to safer areas. As a result, the vegetation recovered along stream banks, sparking the recovery of the beaver (Castor canadensis) populations” (Ripple and Beschta, 2004). Magnificently, the intimidation of the wolves due to their more viscous traits allowed for the growth of vegetation as a result of the absence of the elk, partially due to a biological phenomenon called a trophic cascade: a process that occurs when the prey population fluctuates or decreases, which causes the immediate lower trophic level to arise. To conclude, the habitat in which a predator belongs to is overall positively impacted by the predator and prey interactions, specifically when the predator has dominance due to specific phenotypes. Trophic cascades can be detrimental to an ecosystem if a predator that has traits needed for survival and existence are eliminated from the cycle. A type of ecosystem that would be tragically affected if its top predators were taken out would be marine ecosystems. The article, “Ecosystem Effects by Removing Sharks and Trophic Cascades, n.d.” expresses the detrimental effect of the removal of sharks in marine ecosystems. In the article, the author addresses that, “sharks play a vital role in maintaining the health of coral reefs. . . A decrease in the Caribbean shark population is met by an increase in its prey, the grouper fish. The expanding grouper or population takes parrotfish, normally responsible for clearing coral of algae, in greater numbers.” In essence, the traits that the sharks have evolutionarily expressed would no longer be of importance due to overfishing in these regions, and the trophic cascade would hinder the homeostasis of the region. Overall, this could cause detrimental effects that would very easily become widespread. Potential dangers based on trophic cascades are a definite outcome to an ecosystem when the there is a disappearance in predators, along with their genetic contribution. The author in the same article continues to say that, “This the decrease of parrotfish could explain why algae now dominates many degraded reefs in the Caribbean” (Shark Stewards: Ecosystem Effects by Removing Sharks and Trophic Cascades, n.d.). To explain, the algae that would then populate those coastal regions could result in hazardous conditions, as well as affect other species and their populations. Furthermore, the drop in predators would completely disturb the evolution of those species in a specific ecosystem: if a shark has an advantage over prey, in the fact that it has higher swimming speeds and higher metabolic rate, then they are more adept to catch prey and continue with their biological cycle. Naturally, these predator-prey relationships would not occur any longer due to not having another species with those same phenotypes being present. In actuality, the next level in the food web would take the top predator’s place, but would still interrupt the cycle. As seen through the algae, there could be more toxins released into the water, as well as an increase in dangerous populations that the predators once consumed as prey. Predatory traits are very important in maintaining ecological homeostasis and preventing disastrous events, such as extinctions, dangerous trophic cascades, and diseases that may result from new species introductions. Regarding disease within ecosystems, predators are highly responsible for preventing illnesses that infect populations. First off, Patricia, part of the CCF staff, stated that, “Predators will catch healthy prey when they can, but catching sick or injured animals helps in natural selection and the establishment of healthier prey populations as the fittest animals are left to survive and reproduce” (CCF News: Why are predators important?, 2011). Going back to natural selection, the predators are responsible for eliminating the unhealthy prey, which not only benefits the ecosystem by avoiding a potential outbreak, but the evolutionary benefits for that specific species. In the end, disease is one of the most dangerous environmental factors that could violate ecological homeostasis, and affect the passing of similar phenotypes between generations.Since before humans interacted with species on the planet, predators have dominated worldwide environments for a cause. Their genetic traits have been distributed among generations to adapt within a plethora of ecosystems. Without these trait adaptations, as well as the implementation of predator populations, the way in which ecosystems thrive and survive effectively would be lost. As the observation of multiple trait variations are observed, it is clear to see how and why predators biologically maintain the traits that they do. The importance of predator evolutions, as well as their placement in ecosystems, are continually something of interest to a large community of scientists. As the world continues to grow older and morph into perhaps a different place, the species within it, the predators, will continue to evolutionarily change as well.