Chapter 2 SECTION 2 NUTRITION AND ENERGY FLOW

Ecology is the study of interactions between organisms and their environment. Ecology combines the science of biology, chemistry, physics, geology and others. Ecology involves the interaction of the biotic and abiotic factors:

Biotic and Abiotic Factors Biotic factors are all living things that inhabit an environment Abiotic factors are all non living things that inhabit an environment.

Biosphere Ecosystems Communities Populations Organisms Levels of organization

Levels of Organization Biosphere – The portion of the Earth that supports life. Ecosystem – populations of plants and animals that interact with each other in a given area and with the abiotic components of that area Communities – All the populations of different species that live in the same place at the same time Population – A group of organisms, all of one species, which can interbreed and live in the same place at the same time Organism – An individual living thing that is made of cells, uses energy, reproduces, responds, grows and develops

Biotic Factors Living things are adapted to their environment and impact their community Changes in abiotic factors can change environment No rain can lead to drought. Abiotic Factors

Where and How Organisms Live Niche - the role a species plays in its community Habitat - the place where an organism lives out its life

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? Lost as heat or by living Producers using sunlight constantly adds energy back to the ecosystem.

Pyramid of Biomass/Numbers Populations and biomass amounts will usually decrease as you go up the trophic levels. Can you think of an example where the pop. Size will increase at each higher trophic level?