1. COMMUNITY ECOLOGY
Honors Biology

2. OBJECTIVES
Describe and give examples for all species interactions and arrange in a graphic organizer
Contrast species richness and diversity
Describe stages of succession
Community are species interacting in a given area

3. SPECIES INTERACTIONS Symbioses: Close interactions among species
Five types
Predation
Parasitism
Competition
Mutualism
Commensalism

4. PREDATION Predator captures, kills and consumes prey
Natural Selection:
Predators: find, capture and consume prey
Prey: avoid being captured
Flee
Hide and camouflage

5. PREDATION Mimicry: Herbivores eat plants
Harmless species resembles poisonous species
Poisonous resembles other poisonous
Herbivores eat plants
Plant adaptations:
Physical: sharp thorns, spines, tough leaves
Chemical defenses: bad tasting, irritating, poisonous (secondary compounds)

6. PARASITISM
Species interaction where one species is harmed and the other benefits
No killing and consuming
Parasite and host
Ectoparasite: live on body; ticks
Endoparasite: live in body: tapeworm

7. PARASITISM Evolution:
Defense mechanisms: skin, chemical protection in openings
Parasites: tapeworms absorb through skin

8. COMPETITION Fundamental niche overlap – use of same resource
Competitive exclusion: one species is eliminated from community because of competition for resources

9. COMPETITION Character Displacement: Resource Partitioning
Differences between competitors
Beaks on finches
Resource Partitioning
Each use part of resources
Time partitioning

10. MUTUALISM Both species benefit Ants in the acacia plant
Flowers and pollinators

11. COMMENSALISM One species benefits and other is not affected
May not be any true cases
Egrets feeding on buffalo

12. SPECIES RICHNESS AND DIVERSITY
Number of species in a community
Closer to equator: greater richness
Larger areas have more species: species area effect
Species Diversity
Relative abundance of each species in a community

13. SUCCESSION
Disturbances can trigger a sequence of changes in the composition of a community
New species come right in  new species
Gradual sequential regrowth of species in an area
Pioneer Species: small, fast growing, fast reproducing

14. PRIMARY SUCCESSION Development where life was never supported
Slowly – minerals needed for growth are unavailable

15. SECONDARY SUCCESSION
Replacement of species in area following disruption from natural disaster or human activity
Cleared by agriculture or natural disaster
Soil intact
About 100 years for original return; stages
Annual Grasses  Perennial Grasses  shrubs  trees

16. COMPLEXITY Succession until climax community
Organisms alter environment to make it favorable for next organisms