Ecosystems
What is necessary for life in an environment?
Food Chains & Webs
How does the flow of energy go through a food chain?
This unit focuses on the interdependence of life, with a focus on energy movement within systems. All living things need energy to live. A food chain shows the transfer of energy through one possible set of organisms. If several of these simple food chains are connected, a food web is created. A food web shows all the possible ways that energy might move through a system. Energy is given off from the Sun in the form of light, and green plants convert this energy into a usable form of food energy through a process called photosynthesis. All energy comes from the Sun initially.
What are the roles of the producers, consumers, and decomposers in a community?
In every food chain, there is a producer, a consumer, and a decomposer. Green plants are considered producers because they make the food that animals higher on the food chain eat, or consume. Consumers may eat only plants, only other animals or both plants and animals. If a consumer eats only plants, they are an herbivore. If they eat only other animals, they are a carnivore. If they eat both plants and animals, they are an omnivore. Once a plant or animal has died, their energy must be returned to the soil. This is accomplished through decomposers. Decomposers, such as microorganisms, break down the nutrients in living things, and return these nutrients back to the soil, which in turn feeds the plants, beginning the cycle all over again.
Ecosystems
How does the population and scarcity affect the number of plants and animals in the community?
Ecosystems need a balance of producers, consumers, and decomposers. If the ecosystem is not balance, one part of the systems will die off until it rebalances. For an ecosystem to survive, there must be many more organisms at the producer end of the food chain, and fewer at the top end of the food chain. Energy is lost at each step of a food chain. Animals that eat plants directly receive much more energy than animals that eat other animals that have eaten plants. The closer to the producer, the more of the original plant energy the animal receives.