COMMUNITY ECOLOGY

When organisms live together in ecological communities, they interact constantly.Community interactions, such as competition, predation, and various forms of symbiosis, can affect an ecosystem.

INTERACTIONS

What is included in an organism’s niche?Range of temperatures necessary for survival

Position in food webTime of year it reproducesType of shelter it occupies

No two species can share the same niche in the same habitat.

Different species can occupy niches that are very similar.

NICHES

Any relationship where two organisms are living closely together.

SYMBIOSIS

When organisms of the same or different species attempt to use an ecological resource in the same place at the same time.

COMPETITION

Great White Shark Competition Video

Resources are limited.

No 2 species can occupy the same niche in the same ecosystem at the same time.

Direct competition will result in a winner and loser. The loser will fail to survive.

COMPETITIVE EXCLUSION PRINCIPLE

The distribution of these warblers avoids direct competition, because each species feeds in a different part of the tree.

EXCEPTION

An interaction in which one organism captures and feeds on another organism is called predation.

The organism that does the killing and eating is called the predator, and the food organism is the prey.

PREDATION

Praying Mantis Predator Video

A symbiotic relationship where one organism benefits and the other is neither benefited nor harmed.

COMMENSALISM

Dust Mites on Eyelash

A symbiotic relationship where both organisms benefit mutually.

MUTUALISM

Clown fish and sea anemone

Ants and acacia tree

A symbiotic relationship where one organism benefits and the other suffers.

PARASITISM

Wasp parasite on caterpillar

Birds use another host to raise their young & kill that host’s

eggs

Zombie Brain Snail Parasite Video

1. Disruptive ColorationAnimals, like the zebra, use their coloration patterns to make it hard to see them.

2. Counter ShadingCounter shading is seen mostly in aquatic animals. They are light on the bottom and dark on the top.

ANTIPREDATOR ADAPTATIONS (CRYPSIS)

3. Color Change Some animals can

even change their coloring to try and fool predators.

4. Camouflage (appropriate background)

Another group of animals look like something commonly in their environment.

ANTIPREDATOR ADAPTATIONS (CRYPSIS)

5. Warning ColorationAnimals that are poisonous often advertise this by using bright colors and patterns to discourage predators.

6. MimicryAn organism copiesthe crypsis of anothermore dangerous organism

ANTIPREDATOR ADAPTATIONS (CRYPSIS)

ECOLOGICAL SUCCESSION

Predictable changes that occur in a community over time.

Ecosystems are constantly changing in response to natural and human disturbances.

Older inhabitants gradually die out and new organisms move in.

WHAT IS ECOLOGICAL SUCCESSION?

Primary SuccessionNo exposed soil

Pioneer SpeciesThe first species to populate a new area.

Tend to be small, fast growing and fast reproducing.

ECOLOGICAL SUCCESSION TERMS

Each stage of succession alters the physical environment in ways that make it less favorable for their own survival but more favorable for the organisms that will replace them

Climax CommunityA stable, mature community that marks the “end” of succession.

ECOLOGICAL SUCCESSION (CONT)

Secondary Succession-Occurs where an existing community has been cleared by a disturbance, natural or man-made, but the soil has been left intact.

ECOLOGICAL SUCCESSION (CONT.)

In this example, a volcanic eruption has destroyed the previous ecosystem.

ECOLOGICAL SUCCESSION

The first organisms to appear are lichens.

ECOLOGICAL SUCCESSION

Mosses soon appear, and grasses take root in the thin layer of soil.

ECOLOGICAL SUCCESSION

Eventually, tree seedlings and shrubs sprout among the plant community.

ECOLOGICAL SUCCESSION