An Essay on Ecosystem

An ecosystem is all the living and nonliving things in an area. Ecosystems of similar types are classified together as biomes. The tropical rainforest is shown in the episode of Planet Earth titled “Jungles” is a biome located in areas closer to the equator with temperatures averaging between 80 and 90 degrees Fahrenheit. The rainforest has the largest annual rainfall of any biome averaging anywhere from 80-400 inches per year. Rainforests have the most diverse collection of organisms on the planet. They take up only 3% of Earth’s land, but harbor 50% of all species. There are approximately 5 million different animal species living in the rainforest including monkeys, snakes, birds, frogs, and more. The rainforest is split up into four different zones, the emergent layer, the canopy, the understory, and the forest floor. The canopy has the most abundant amounts of life with a large variety of species, such as the tamarin, a type of small monkey that can be found in South American rainforests (Planet Earth “Jungles”).

The other biome shown in the “Ocean Deep” episode of Planet Earth was the marine biome. It has a largely varying temperature because the ocean takes up such a vast amount of space from tropical waters near the equator to frigid arctic oceans near the poles. The temperature can range from -40 to 100 degrees Fahrenheit and usually averages around 39 degrees overall. It has an average rainfall of between 60 and 250 inches per year, and there is a wide range of vegetation from kelp to coral and other underwater plants as well as a very diverse community of wildlife. Around one million species live in Earth’s oceans, and the oceans themselves cover around 70 percent of Earth’s surface.

Community Ecology is the study of communities, an assemblage of populations living close enough for potential interaction, in an ecosystem. The term interspecific interaction is a broadly used term to cover specific interactions in communities. An example of an interspecific interaction can be seen in the regeneration, or rebuilding, of the rainforest after a treefall because when a large tree falls in the rainforest, a number of plants then compete for the spot in the light. The open sunlight from where the large tree fell causes many seeds to begin to grow, competing with one another for space higher up to be able to survive in the long term. Hundreds of plants and trees will begin to grow, but only a few will continue to reach the top as light diminishes. In four years the light will be gone as the trees have grown tall enough to take up all of the open space, and the lack of sunlight will cause the smaller plants to die off. The same trees usually survive, such as Hardwood trees, which are abundant and live for around 200 years. Another example of community ecology is seen in keystone species, a species that has a strong effect on the composition of a community. An example of a keystone species is the Tropical Fig Tree because the figs successfully feed 44 types of animals and birds on a single tree. Without this plant, the community would change dramatically since the organisms that feed on it would lose a valuable source of food and some species could potentially go extinct from lack of resources (Planet Earth “Jungles”).

Featured in the marine biome, aspects of community ecology can be found in the relationship between a monkfish and its prey. This is an example of a predation relationship because a monkfish lures prey towards it by laying itself on the ocean floor, camouflaged by the sand, and waving back and forth an apparatus that looks like a piece of meat. This draws in other organisms so the monkfish can prey on the defenseless fish (Planet Earth “Ocean Deep”).

Symbiosis is a relationship between two organisms that live in direct contact with one another. A type of symbiotic relationship is parasitism, a relationship in which one organism benefits and the other is harmed. An example of parasitism is the relationship between a Bullet Ant and the Cordycep Fungus because the fungus grows inside the ant’s body and infiltrates its brain. The infected brain directs the ant upwards on trees. The fruiting body of the Cordycep then erupts from the ant’s head, killing it. In three weeks or less, deadly spores will sprout from the ant’s corpse, infecting any ants within reach. The Cordycep Fungus has a home, but at the cost of the Bullet Ant’s life (Planet Earth “Jungles”). In the marine biome, another type of symbiotic relationship can be found with commensalism, a relationship in which one organism benefits and the other is unaffected. A commensalistic relationship can be seen between White-Tip Sharks and Pilot Fish because the fish swim closely to the White-Tip Shark in order to gain protection and easier access to prey. The shark locates the prey and then proceeds to kill it, while the fish take the scraps left over from the shark’s meal. The shark is unaffected and the fish have a way to survive by being provided with protection and resources in the form of food (Planet Earth “Ocean Deep”).

An adaptation is a change an organism makes in order to better survive in its environment. An example of an adaptive behavior are Birds of Paradise developing different mating calls and dances to catch the attention of females in order to improve their chances of intersexual selection, a type of natural selection in which females choose their male mates, causing the males to develop adaptations in order to have better chances of being chosen. Another type of adaptive behavior are species developing tendencies of parental care, in which an organism cares for its young after they give birth. For example, the mother leads its beetle larvae to food throughout their young life in order for the larvae to survive and have a better chance of growing up and reproducing themselves (Planet Earth “Jungles”). In the aquatic biomes, different types of adaptations can also be found. For instance, the sawtooth eel uses deception as a defense against predators and a way of tricking its prey. The eel hangs motionless, gazing upwards as it looks out of the corner of its eye for food. When something gets close enough, it strikes. The eel lashes out and kills whatever is close by. Its previously harmless and still demeanor tricks other organisms into believing the creature is dead or harmless (Planet Earth “Ocean Deep”).

There are also different types of ecological relationships, in which organisms interact among overlapping niches. One example of an ecological relationship is competition, when organisms compete against one another for a specific resource such as food. An example of competition is the Whale Shark, Yellowfin Tuna, and Baitfish all come to feed on plankton off the coast of Venezuela. Originally, the Baitfish use the Whale Shark as a shield to protect itself from the tuna as it feeds because all fish seem to be prey to larger fish. Then, the Whale Shark dives downwards, leaving the Baitfish unprotected as the tuna then eat them, with the shark coming back to eat all three creatures: plankton, fish, and tuna. In the deep ocean, all organisms can become prey, and a lot of the time, the largest wins (Planet Earth “Ocean Deep”). Another example of an ecological relationship is resource partitioning, species dividing a niche in order to avoid competition with one another. Resource partitioning can be seen in Birds of Paradise, which are comprised of forty different species. They avoid competing with one another for mates by living in different parts of the rainforest. For example, the Six-Plumed Bird of Paradise displays himself on the forest floor while the Magnificent Bird of Paradise favors low branches of bushes and trees (Planet Earth “Jungles”).

Energy flow is also an important way that an ecosystem fits together. All energy comes from the sun, where it is then given to producers, which are eaten by primary consumers, which are eaten by secondary consumers, and so on. In the rainforest, fig trees are an example of a primary producer as they absorb sunlight and convert it to energy using photosynthesis, obtaining 100% of the energy they convert. The figs are then consumed by Howler Monkeys, a primary consumer, and they receive ten percent of the fig’s energy. The other 90% is lost as heat during the transfer of energy. Howler Monkeys are preyed upon by the Harpy Eagle, a secondary consumer, and the eagle would then receive ten percent of the energy from the Howler Monkey, and only 1% of the original amount of energy. Each trophic level receives less and less energy compared to the one before it, with primary producers obtaining the most energy overall. (Planet Earth “Jungles”).

Humans can have severe impacts on an ecosystem. In rainforests, deforestation and pollution are two ways that humans can disrupt the balance of an ecosystem. A rainforest has a very fragile ecosystem because of the wide diversity, which leaves it greatly susceptible to the destruction caused by human growth. As humans cut down trees and build up more cities and civilization, animals are left without homes and plants are killed. This can cause Earth to lose diversity in its species due to extinction (Planet Earth “Jungles”).

Due to human impacts on an ecosystem and other limiting factors, organisms develop evolutionary adaptations, which are adaptations that are developed across multiple generations and can change the genetic makeup of an organism. Chimpanzees have opposable thumbs to climb trees, long arms in proportion to their legs to reach and swing on branches, and develop social hierarchy and interactions to better survive in large numbers in order to thrive in rainforests (Planet Earth “Jungles”). Another example found in the marine biome is the Nautilus, a relative of the squid and octopus, which has chemical sensors to detect predators and prey on the ocean floor, a shell with gas chambers to control its depth in order to conserve energy and keep from swimming, and a siphon that jets out water in order to move and dig in the sand for prey so that the Nautilus can survive in the deep ocean (Planet Earth “Ocean Deep”).


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