Ecology and Evolutionary Concepts

Organisms

The individual living unit

Population

Group of same species in one area

Community

All species in one area interacting

Ecosystem

Community and abiotic (non-living) factors

Biosphere

All ecosystems on Earth

Mutualism

+/+ Both benefit (Ex: Bees and flowering plants)

Commensalism

+/0 One benefits, other unaffected (EX Barnacles on whales)

Parasitism

+/- Parasite benefits, host harmed (Ex Ticks on mammals)

Predation

+/- Predator benefits, prey killed (Ex Lion and Zebra)

Competition

-/- both harmed

Producers

Plants, algae - convert solar energy into chemical energy via photosynthesis.

Primary Consumers

Herbivores that eat producers

Secondary consumers

Carnivores that eat herbivores

Tertiary Consumers

Predators at the top of the food chain

Decomposers

Fungi and bacteria - break down dead matter and recycle energy via photodynthesis

Exponential growth

Occurs when resources are unlimited (J shaped curve)

Logistic Growth

Resources are limited; population levels off at carrying capacity (K) (S-shaped Curve)

Density-dependent factors

intensify with population size: competition, disease, predation

Density-independent factors

affect populations regardless of size: natural disasters, climate events

Natural Selection

Organisms with favorable traits survive and reproduce more successfully, passing those traits on. Requires variation, differential reproduction, and heritability

Genetic Drift

Random changes in allele frequencies, especially significant in small populations. Includes bottleneck and founder effect

Gene flow

Movement of alleles between populations, increasing genetic diversity

Mutations

The ultimate source of new genetic variation - may be neutral, beneficial, or harmful