Module 4: Natural Selection & Human Impact

Trophic Level

Each step in a food chain or food web

Producer

An organism that can make its own food using the suns energy.

Primary Consumer

An organism that eats producers (plants).

Secondary Consumer

An organism that eats primary consumers

Tertiary consumers (carnivores)

organisms in the fourth trophic level, that obtain their energy by eating secondary consumers.

Energy pyramid

diagram that compares energy used by producers, primary consumers, and other trophic levels

Food Chain

Series of steps in an ecosystem in which organisms transfer energy by eating and being eaten.

Food Web

A network of food chains formed by the feeding relationships among organisms in an ecosystem.

Limiting Factors

abiotic or biotic factors that restrict population growth.

Abiotic factors

nonliving parts of an ecosystem

Biotic factors

living parts of an ecosystem

Carrying capacity

The largest population that an area can support

Selective Pressure

environmental conditions that select for certain characteristics of individuals and select against other characteristics.

Natural Selection

A natural process resulting in the evolution of organisms best adapted to the environment.

Biological Fitness

a measure of the ability to survive and reproduce relative to other members of the population

DNA Fingerprinting/profile

pattern of DNA fragments obtained by analyzing a person's unique sequences of noncoding DNA