A recent and exciting ecological discovery was the discovery of the trophic cascade, in which a change at the top of the food chain has effects and influences that can go all the way down to the bottom of the food chain. A trophic cascade was observed in an almost controlled setting when wolves were reintroduced to Yellowstone national park in 1995. Before the reintroduction of wolves, the population of deer in the park had skyrocketed. This population boom had severe effects on the ecosystem of Yellowstone park. The deer had grazed many parts of the park to be barren. One of the initial impacts of the reintroduction of wolves to Yellowstone was a decrease in the population of deer. However, this was not the most significant impact on the ecosystem the wolves had. Their reintroduction forced the deer to avoid areas where the wolves could easily hunt them, allowing these areas to recuperate and recover their natural flora. The wolves’ impact influenced many species, and the most notable species impact their reintroduction had was the ability for the flora to recover and produce forests. The recovery and development of forests lead to new habitats, and population booms for different species. However, these forests had an even more substantial impact; their roots created much sturdier and more erosion-resistant dirt mounds and river beds. Making the rivers would meander less as they grew older. The trophic cascade that the wolves had on the ecosystem did not only influence the animals and plants of the ecosystem, but they went as far as to change the inorganic aspects of the ecosystem as well.
Life on earth began with the rise of the first single-celled organisms or prokaryotic cellular organisms. Eventually, a single-celled organism engulfs another, forming the first organelle and eukaryotic cell. Eukaryotic cells are cells with internal organs. Eventually, these cells begin to form colonies resulting in the first multicellular organisms. These colonies give way to the development of sea plants and then early sea animals. These early animals were invertebrates, such as trilobites and early vertebrates such as precursors to the fish. Eventually, plants colonize landmasses, and land mammals would quickly follow. Animals adapt and change, leading to insects and early reptiles dominating the land until mass extinction events give rise to the dinosaurs. Eventually, the dinosaurs go through an extinction event as well, and mammals replace them during the “age of mammals.” In terms of a day, the entirety of human recorded history lasts only for a few seconds.
The 2nd chapter of the textbooks discusses the principles and concepts of the physical sciences. Miller also describes that the role of scientists in the field of environmental science is to “collect data and develop hypotheses, theories, and laws about how nature works” (Miller 2018). This helps us create an understanding of the process in which the science behind environmental studies functions. Some are directly applicable to environmental studies, such as understanding energy flow within an ecosystem. The law of conservation states that energy is not created or destroyed; it merely transitions in form, and this concept applies directly to energy flow in ecosystems. Organisms within an ecosystem require nutrients, and they can receive them in many different ways, plants are autotrophs and create/absorb their food from sunlight and dirt through internal processes.
On the other hand, most animals are heterotrophs and receive their necessary nutrients through consuming other organisms. Finally, there are cycles within ecosystems these cycles are one of the many components of ecosystems that Miller describes as “any set of components that function and interact in some regular way” (Miller 2018). Energy and nutrients flow through food chains, starting with photosynthetic (or chemosynthetic) autotrophs that “produce the nutrients they need” (Miller 2018) and then are consumed by herbivores and that may be consumed by carnivores. Eventually, the energy and nutrients are recycled back into the ecosystem by decomposers such as bacteria and fungi. Chapter 4 goes in-depth on biodiversity and its origins. Ecosystems achieve biodiversity through genetic variation where mutations and miscoding during the DNA replication process do not get corrected and end up causing changes in an organism.
The wolves’ disappearance in the first place shows a level of a trophic cascade. When wolves went extinct in the Yellowstone area, it allowed the deer population to boom, and that had adverse effects on the ecosystem. The impact of the wolves shows just how delicate the balance of nature is.
My mind wandered to my interests; it would be interesting to learn about the cascading trophic effects of many predatory species in the everglades. I am very interested in herpetology, and the everglades have had many large reptiles introduced to the area. Invasive anacondas and argentine tegus wander the marshland and present an invasive threat to the ecosystem there. A quick search through google scholar and other research journal sources show there is research done on that topic; however, the entire trophic cascade has not been condensed into a single more consumable media like the video on reintroducing wolves to Yellowstone national park.
It is interesting to think about if the reintroduction of wolves had any adverse effects on the ecosystem as well. For example, Japanese Knotweed (Pictured below) is an invasive species of weed from Japan. It is a widespread species found in many areas of the United States. This plant dominates ecosystems and heavily outcompetes native plants that are not adapted to compete with it. With the reduction of deer populations in Yellowstone park, make the area less susceptible to invasive plant species?
The second video is full of many inaccuracies and a somewhat misguided narrative. I believe the video should start from a point even before the early prokaryotes that gave way to life and begin with theories on how changes and combinations of organic compounds lead to the creation of organic life. Perhaps something akin to this video:
I apologize for the inappropriate language and joking demeanor, but I do think the beginning parts of this video do a better job conveying how life came about.
Other inaccuracies in the video coincide with the timeline. Firstly, it states that plants and mammals colonize the land, which isn’t true. Mammals never colonized land and evolved from therapsids who themselves evolved from early lizards and amphibians. The first animals to colonize land on earth were the amphibians who were capable of breathing on both land and in water. The video also ignores the evolution of sponges and tube worms, which is arguably one of the most important evolutions of life as most animals are essentially tube worms with extra parts. My final issue with the video is that it states eukaryotic single-celled organisms combining created colonies and the first multicellular organisms. I find this part extremely misleading as prokaryotic cells would have aggregated and would have formed colonies far before then. Instead, I think the video should explain how the interaction of cells within that colony lead to the development of multicellular life.
Discussion Question: With the reduction of deer populations in Yellowstone park, make the area less susceptible to invasive plant species?
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Environmental Studies and Science 