Ecology Standards 6a. Know biodiversity is the sum total of different kinds of organisms

& is affected by alterations of habitats 6b. Know how to analyze changes in an ecosystem resulting from

changes in climate, human activity, introduction of non-native species, or changes in population size.

6c. Know how fluctuations in population size in an ecosystem are determined by the relative rates of birth, immigration, emigration & death.

6d. Know how water, carbon, & nitrogen cycle between abiotic & biotic resources and organic matter in the ecosystem & how oxygen cycles through photosynthesis & respiration.

6e. Know a vital part of an ecosystem is the stability of its producers and decomposers.

6f. Know at each link in a food web some energy is stored in newly made structures, but much energy is lost to the environment as heat, represented in an energy pyramid.

Ecosystem Structure

Passing of Energy

All Energy starts from the sun

Photosynthetic plants convert energy from the sun into food

The energy moves through the ecosystem as one organism eats another

Autotrophs = Producers

An organism that converts the sun’s energy into food

Heterotrophs = Consumers

Organisms that obtain energy by eating other organisms

Can eat plants or animals Or BOTH

Food Chains

A model of the flow of energy through organisms in a community

Flow of energy is shown by arrows

Transferred Energy

At each step in the food chain only 10% energy is passed to the organism

90% of the energy is lost in the form of HEAT

90%HEAT

90%HEAT

90%HEAT

Trophic Level

A step in the transfer of energy

Producers are the 1st trophic level

** they form the base of all food chains

Primary Consumers = Herbivores

Feed directly on producers

Make up the 2nd trophic level

Secondary Consumers = Carnivores

Eat only meat

Feed on primary

Make up the 3rd

Omnivores

Eat both producers and consumers

Scavengers

Consumer that feeds on the tissue of dead animals

Decomposers (recyclers)

Feed on wastes and dead organic matter from all trophic levels

VERY IMPORTANT Waste would pile up

without them to recycle it!

Ecological Pyramid

Shows the relationship between producers & consumers in 3 ways: Biomass Energy # of organisms

Biomass Pyramid

Biomass – mass of living organisms

There is less biomass as you move up trophic levels

Energy Pyramid & 10% Law

Only 10% of energy is passed to next level

1st trophic level is important in determining the rest of the levels

# of organism pyramid

Population of each trophic level decreases as you move up the trophic levels

Food Web

Shows the interconnected food chains in a community or ecosystem

A lot of food chains together