1. Community Ecology
Chapter 20

2. Species Interactions
Section 21.1

3. Predation
One species benefits (predator) while the other species gets eaten (prey).
Predator/Prey adaptations:
Physical abilities
Mimicry
Secondary Compounds
Etc.
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4. Mimicry A harmless species replicates a poisonous/harmful 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.
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5. Secondary Compounds Plant defense chemicals against herbivores.
Ex) poison ivy and poison oak
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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
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8. Definitions:
Competitive Exclusion: where one species is eliminated due to competition for same limited resource
Ex) bacteria
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9. Resource Partitioning: a pattern of resource use in which species reduce their use of shared resource thus less competition
Ex) barnacles
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10. Character Displacement: evolution of anatomical differences that reduce competition
Ex) Darwin’s Finches
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11. Symbiosis
Definition: Relationship between different species living in close contact with each other
3 Types:
1. Parasitism
2. Mutualism
3. Commensalism
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12. Parasitism
One species benefits (parasite) while the other species is harmed (host).
2 types:
Ectoparasite
Endoparasite
Adaptations
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13. Mutualism Both species benefit from one another
Pollinators & plants- pollination is the most important mutualistic relationship on Earth!
Adaptations
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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
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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?
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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?
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17. Now its your turn:
With a partner, come up with an example for each symbiosis.
I will be asking you to share these examples in a few minutes!
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18. 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?
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19. Properties of Communities
Section 20.2

20. Species Richness The number of species a community contains.
The value depends on the sample size.
Varies with latitude (distance from the equator). OR
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21. 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?
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22. Stability A communities resistance to change
How it responds to disturbance
Ex) Drought
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23. Succession:
The gradual, sequential growth or re-growth of species in an area
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24. 2 Forms of Succession 1. Primary Succession
Development of a community in area that never had life before
Extremely slow process
Ex) bare rock, sand dune, landslide, or newly formed volcanic
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25. Change of community makeup after a disturbance
2. Secondary Succession
Change of community makeup after a disturbance
Ex) farming, flood, fire
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26. An example of Secondary Succession by stages: 1
An example of Secondary Succession by stages: 1. A stable deciduous forest community 2. A disturbance, such as a wild fire, destroys the forest 3. The fire burns the forest to the ground 4. The fire leaves behind empty, but not destroyed, soil 5. Grasses and other herbaceous plants grow back first 6. Small bushes and trees begin to colonize the area 7. Fast growing evergreen trees develop to their fullest, while shade-tolerant trees develop in the understory 8. The short-lived and shade intolerant evergreen trees die as the larger deciduous trees overtop them. The ecosystem is now back to a similar state to where it began.
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27. 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
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29. video
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30. Notebook Quiz
Which biome is characterized by having the most annual rainfall and soil low in nutrients?
What type of vegetation is found in the temperate forest?
What process done by bacteria converts nitrogen gas in the atmosphere into a usable form?
Distinguish between abiotic and biotic factors and give an example of each.
How do producers and consumers obtain energy?
What is carrying capacity?
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