Unit 5 Target 3: Energy Flow Through EcoSystems

The first trophic level of any ecosystem is occupied by plants, bacteria, and algae. These organisms are called producers as they are capable of converting sunlight into energy through the process of photosynthesis. They form the base of the food chain and provide energy and nutrients to the organisms in higher trophic levels. Lions, wolves, snakes, humans, bears, pigs, cows, horses, and caterpillars are all consumers and occupy higher trophic levels in the ecosystem.

Producers are organisms that manufacture organic nutrients for an ecosystem through the process of photosynthesis. They convert sunlight, carbon dioxide, and water into glucose, which serves as a source of energy for themselves and other organisms in the ecosystem. Consumers, on the other hand, obtain their energy by consuming other organisms. Predators are consumers that hunt and kill other organisms for food, while omnivores are consumers that eat both plants and animals. Therefore, the correct answer is producers, as they are responsible for producing organic nutrients in an ecosystem.

The given answer "sun > plant > mouse > snake > owl" best illustrates one way energy travels through a forest ecosystem. This is because the sun provides energy through photosynthesis in plants, which are then consumed by mice. The energy is transferred to snakes when they consume the mice, and finally to owls when they consume the snakes.

An energy pyramid represents the flow of energy through different trophic levels in a food chain. In a desert food chain, the cactus is the primary producer and has the highest amount of energy. The insect feeds on the cactus and has a lower energy level. The snake feeds on the insect and has an even lower energy level. The hawk is at the top of the food chain and feeds on the snake, making it the tertiary consumer with the lowest energy level. Therefore, the energy pyramid should show the cactus at the base, followed by the insect, snake, and hawk at the top.

In the given food chain, the correct sequence for the flow of energy starts with phytoplankton, which are tiny plants that convert sunlight into energy through photosynthesis. Krill, small shrimp-like creatures, feed on phytoplankton, transferring the energy from the plants to themselves. Penguins then consume krill, obtaining the energy from them. Finally, the leopard seal, being a predator, feeds on penguins, thus obtaining the energy from the previous organisms in the food chain.

An ecosystem consists of various organisms that are interconnected through feeding relationships. These relationships form a complex network known as a food web. Unlike a food chain, which only shows a linear sequence of energy transfer from one organism to another, a food web depicts the interconnections between multiple organisms and their feeding interactions. Therefore, the correct answer is "web."

The organisms in level 3 receive about 10 percent of the energy in level 2. This is because energy is transferred between trophic levels in an ecosystem, and each level only receives a fraction of the energy from the level below it. Therefore, level 3 would receive a smaller amount of energy compared to level 2, approximately 10 percent.

As energy moves up the trophic levels in a food chain or food web, there is a decrease in the amount of usable energy available. This is because energy is lost as heat during metabolic processes and as organisms consume other organisms, not all of the energy is transferred. Therefore, as you move up the trophic levels, there is less energy available for organisms at higher levels to consume.

Biomass refers to the total amount of living tissue within a specific trophic level. It includes the mass of all organisms, such as plants, animals, and microorganisms, present in that level. Biomass is an important measure as it indicates the amount of energy available in an ecosystem and can be used to study the flow of energy and nutrients through food chains and food webs.

The zooplankton in Food Chain 1 is considered a primary consumer because it feeds directly on the phytoplankton, which are the primary producers. The primary consumers are the organisms that consume the primary producers and are the first level of consumers in the food chain.

The correct answer is released as heat. This is because as energy is transferred from one trophic level to the next, some energy is always lost as heat due to the inefficiency of energy transfer and metabolic processes. This lost energy is not available for the next trophic level and is instead released into the environment as heat.

The correct answer is biomass pyramid. This is because the pyramid represents the different trophic levels in an ecosystem based on the amount of biomass (organic matter) present at each level. The lower levels, such as producers, have the highest biomass, while the higher levels, such as top predators, have the lowest biomass. This pyramid helps to illustrate the transfer of energy and nutrients through the ecosystem.

In the given food chain, the tertiary consumer is the organism that feeds on the secondary consumer. In this case, the Perch is the secondary consumer as it feeds on the Dragonfly larvae. Therefore, the correct answer is Perch.

In Food Chain 1, energy is transferred from phytoplankton to zooplankton, smelt, trout, and finally to humans. Each trophic level transfers approximately 10% of the energy to the next level. Therefore, by the time the energy reaches humans, it has gone through four trophic levels, resulting in a significant loss of energy.

In Food Chain 2, however, the energy only goes through two trophic levels, from phytoplankton to smelt and then to humans. Since there are fewer trophic levels involved, more energy is available to humans in Food Chain 2 compared to Food Chain 1. Hence, the energy available to humans in Food Chain 2 is 100 times more than in Food Chain 1.