UNIT 4- interdependent Relationships

Immigration

Movement of individuals INTO a population

Emmegration

Movement of individuals OUT of a population

Population growth rate

How fast a population changes in size

Positive growth rate

increase in population

Negative growth rate

population is decreasing

Species

A group of similar organisms that can breed and produce fertile offspring.

Migration

A movement from one country or region to another

Exponential growth

The population starts growing slowly, but grows faster and faster as the population size increases

carrying capacity

Largest number of individuals of a population that a environment can support

K selected species

Species that produce a few, often fairly large offspring but invest a great deal of time and energy to ensure that most of those offspring reach reproductive age.

R selected species

reproduce early in their life and produce large numbers of usually small and short-lived offspring in a short period.

Trophic Level

Each step in a food chain or food web

How much energy is transferred from one trophic level to the next?

10%

When do trophic levels max

4 or 5

Biomass

total mass of organisms at a trophic level

Autrophs

Organisms that make their own food

Heterotroph

can’t make their own food.

herbivore

A consumer that eats only plants.

Carnivores

Consumers that eat only animals

Omnivores

eat both plants and animals

Scavengers

an organism that feeds on the dead bodies of other organisms.

Decomposers

Organisms that break down the dead remains of other organisms and restore nutrients back into the soil for plants

Niche

Physical and environmental conditions necessary for survival

Competition in

Food, water, space, and sunlight

Interspecific competition

competition between different species

intraspecific competition

competition between members of the same species

Symbiosis

organisms that mutually benefit

Mutualistic (+/+)

both species benifeit

Commensalism (+/n)

One organisms benefits while the other remains unaffected

Parasitism (+/-)

One organism benefits and the other is harmed