COMMUNITY ECOLOGY

CHAPTER 20

COMMUNITY ECOLOGY-CHAPTER 20 Vocabulary (27 words)

Character displacement prey

Resource partitioning competition

secondary compound Competitive exclusion

pollinator

Climax community commensalism

symbiosis ectoparasite

Species-area effect endoparasite

species evenness Herbivore

species richness pioneer species

Host Stability

Mutualism mimicry

parasite Primary succession

parasitism secondary succession

Predator succession

I. Species Interactions: Symbioses

A. Predation: One

organism kills and

eats another

organism

1. Predators

2. Prey

3. Natural selection

occurs between

species.

Escaping Predation

B. Mimicry

1. Look like a distasteful species.

2. Dangerous species look alike.

C. Plant-herbivore interactions

a. Herbivores are plant eaters.

b. Plant defenses: thorns, spine, sticky hairs,

tough leaves, and secondary compounds

D. Parasitism: one organism feeds off another organism making it sick or slowly killing it.

1. Ectoparasites:

external

2. Endoparasites:

internal

E. Evolution of Parasites and their hosts

1. Hosts have bodily defenses to ward off

parasites.

2. The immune system fights parasites.

F. Adaptations of Parasites

1. Tapeworms have no digestive system.

G. Competition: Two or more different species competing for the same resources

1. Some plant species release toxins to keep

other plants away.

H. Research studies on competition

1. Competitive exclusion: one species is

eliminated because another species

competes for the same resources.

a. Parameciums

b. barnacles

I. Competition and Community Structure

1. Character Displacement: Natural selection between competitors.

a. Finches and beak sizes

2. Resource Partitioning : similar species coexisting use only part of the available resources

a. Warblers of closely related species hunting insects in different parts of the same tree

3. Mutalism: both species benefit

a. Pollinators and

plants

4. Commensalism:

one species benefits

and the other is not

affected in any way

II. Properties of Communities

A. Species richness: the number of species in

an area.

B. Species evenness: the number and

abundance of species in an area.

C. Patterns of species richness

1. The closer to the equator the more species

are found

a. Stable climate

b. More photosynthesis for energy

D. The species-area effect

1. Larger areas

contain more species

than smaller areas

E. Species interactions and species richness

1. Predation can keep

prey populations

from lowering

species diversity

F. Community Stability

1. The communities ability to resist change.

2. The more species richness found in a

community, the more stable it is.

III. Succession

A. Successional changes in communities

1. Succession is the gradual regrowth of an area after a disturbance.

2. Primary succession is the development of a community in an area that has not supported life because of harsh conditions

a. Rock, sand dunes, volcanic formations, glaciated areas

3. Secondary succession is the sequential replacement of species that follows disruption of an existing community.

a. Fire, storms,

logging, mining

4. Pioneer species are adapted to inhabit newly formed areas

a. Seed dispersal is efficient.

5. Primary succession

a. This is a very slow process in which soil forms from decaying plant material and rocks.

6. Secondary succession

a. Soil is already present for plants to establish themselves in.

B. The complexity of succession

1. The end point of succession is called a climax

community.

a. Different climax communities develop

because of species present and climate.