SECTION 2 NUTRITION AND ENERGY FLOW Chapter 2 SECTION 2 NUTRITION AND ENERGY FLOW

How Do Organisms Obtain Energy? Autotroph Heterotroph

Autotrophs Organisms that use energy from the sun or chemicals to make their food; also called producers

Heterotrophs Organisms that depend on autotrophs for nutrients and energy; also called consumers.

Types of Heterotrophs Carnivores Herbivores Scavengers Omnivores Decomposers

Carnivores Only eat meat

Herbivores Only eat plants.

Scavengers Feed on carrion, refuse, and similar dead organisms

Spotted Hyena chasing away a vulture.

Omnivores Eat a variety of plants and animals

Decomposer Break down complex compounds of dead and decaying organisms into small, absorbable molecules; these are fungi or bacteria.

How Does Matter and Energy Flow in Ecosystems?

Food Chain A model that shows how matter and energy move through an ecosystem. algae  fish  bird Arrows show direction of energy

There are usually no more than 5 links because the amount of energy has been lost.

Trophic Levels A feeding step in a food chain. Many different species occupy each trophic level in an ecosystem. Many organisms feed from several different trophic levels.

Food Web Food webs express all of the possible feeding relationships at each trophic level in a community.

Ecological Pyramids Show energy conversion in a ecosystem. Pyramid of energy - energy decreases at each higher trophic level. Pyramid of numbers - population size decreases or increases at each higher trophic level.

Pyramid of Energy The total transfer of energy from one trophic level to the next is 10%. What happens to the rest of the energy?

Pyramid of Numbers Can you think of an example where the pop. Size will increase at each higher trophic level?