Ecology Biology I – Chapters 13-16

What is Ecology? The study of the relationship among organisms and their environment. Abiotic vs Biotic factors Biotic: Living (animals and plants) Abiotic: Non-Living (climate, rocks, sunlight…)

Levels of Organization Biome – the organisms, climate, and plant communities Ecosystem – includes all biotic and abiotic factors Community – includes all the biotic facts that interact Population – all individuals of single species The single organism Levels of Organization

Changing 1 factor in an ecosystem can affect many other factors…. Biodiversity: The variety of living things in an environment. Many times it is dependent on the amount of natural resources (food/water/shelter) available. Question: Can you think of an area that would have the greatest biodiversity?

Keystone Species: An organism that has an unusually large effect on its ecosystem. Example: Beavers build dams and change flowing streams into ponds and wetlands. This effects fish, fish-eating birds, insects, water birds, and the animals that feed on the eggs of these birds. Take away the beavers and all the other animals are affected.

List at least 5 different organisms that were affected by returning the wolves. How did the wolves change the rivers?

Life in an ecosystem requires a source of energy Producers: Also called autotrophs. Produce there own food from non-living resources. Almost all get their energy from the sun. Consumers: Also called heterotrophs. Get their energy from eating other organisms.

Food chains and food webs model the flow of energy in an ecosystem. Herbivores: eat only plants Carnivores: eat only other animals Omnivores: eat both plants and animals Detritivores: eat only dead matter Decomposers: break down organic matter into smallest compounds (fungus and microorganisms)

Pyramid models the distribution of energy and matter in an ecosystem. Biomass (amount of dry mass of organisms in a given area) goes down the higher in the pyramid The amount of energy in the system goes down the higher in the pyramid. The number of consumers goes down higher in the pyramid.