1. Community Ecology
Chapter 20

2. Species Interactions
Section 20.1

3. Predation
One species benefits (predator) while the other species gets eaten (prey).
Predator/Prey adaptations:
Mimicry
Secondary Compounds
Physical abilities
Etc.
12/1/2018

4. Mimicry A harmless species replicates a poisonous species.
Can you guess which snake is the mimic?
The one on the left is a scarlet king snake and is the mimic The coral snake on the right is the poisonous snake.
12/1/2018

5. Secondary Compounds Plant defense chemicals against herbivores.
Ex) poison ivy and poison oak
12/1/2018

6. 12/1/2018

7. Competition Caused by niche overlap of 2+ species Can lead to…
1. Reduction in # of either species
2. The elimination of one of the 2 competitors
12/1/2018

8. Definitions:
Competitive Exclusion: where one species is eliminated due to competition for same limited resource
Ex) bacteria
12/1/2018

9. Resource Partitioning: a pattern of resource use in which species reduce their use of shared resource thus less competition
Ex) barnacles
12/1/2018

10. Character Displacement: evolution of anatomical differences that reduce competition
Ex) Darwin’s Finches
12/1/2018

11. Symbiosis
Definition: Relationship between different species living in close contact with each other
3 Types:
1. Parasitism
2. Mutualism
3. Commensalism
12/1/2018

12. Parasitism
One species benefits (parasite) while the other species is harmed (host).
2 types:
Ectoparasite
Endoparasite
Adaptations
12/1/2018

13. Mutualism Both species benefit from one another
Pollinators & plants- pollination is the most important mutualistic relationship on Earth!
Adaptations
12/1/2018

14. Commensalism
One species benefits while the other is not affected at all.
Ex) cattle egrets (birds) feed on insects that the buffalo force out of their hiding places from grazing
Ex) sharks and remoras
12/1/2018

15. WHAT’S THE TYPE OF SYMBIOSIS?
TICKS live and feed on other animals. They suck blood from these animals for food. Dogs may pick up ticks from the outdoors. The ticks cause skin irritation on the dogs. The ticks also transmit diseases to the dog that they are carrying.
WHAT’S THE TYPE OF SYMBIOSIS?
12/1/2018

16. WHAT’S THE TYPE OF SYMBIOSIS?
Snapping shrimp have poor vision. They depend on their goby fish roommate to give the danger signal whenever predators approach. The goby fish guides the shrimp back home if they wander too far. Goby fish who don't have a place to hide are quickly eaten. They find a shrimp roommate who digs a hole for both of them to live in.
WHAT’S THE TYPE OF SYMBIOSIS?
12/1/2018

17. Notebook Quiz What are 3 characteristics of a population?
What is carrying capacity?
What is an abiotic factor that can limit the size of a population?
What is the main difference between a parasite and a predator?
Pollinator and plants have which type of symbiosis?
What is the competitive exclusion principle?
12/1/2018

18. Properties of Communities
Section 20.2

19. Species Richness The number of species a community contains.
The value depends on the sample size.
Varies with latitude (distance from the equator). OR
12/1/2018

20. Species-Area Effect
Larger areas usually contain more species than a smaller areas do.
Usually applied to island species.
Question:
Why is species-area effect important in efforts to conserve species?
12/1/2018

21. Stability A communities resistance to change
How it responds to disturbance
Ex) Drought
12/1/2018

22. Succession: The gradual, sequential re-growth of species in an area
12/1/2018

23. 2 Forms of Succession Primary Succession Secondary Succession
Development of a community in area that never had life before
Extremely slow process
Secondary Succession
Change of community makeup after a disturbance (farming, flood, fire, etc.)
12/1/2018

24. Ex) bare rock, sand dune, or newly formed volcanic island
Primary Succession
Ex) bare rock, sand dune, or newly formed volcanic island
12/1/2018

25. Secondary Succession
12/1/2018

26. Pioneer Species: species predominate in early succession
Small, fast growing, & fast reproducing
Climax Community: community makeup that will last for a long period of time
The end result of succession
12/1/2018

27. 12/1/2018

28. 12/1/2018