1. Niches & Community Interactions
BIOLOGY

2. Warm Up
On the whiteboard to the left, calculate the amount of energy at the producer, 1st consumer, 2nd consumer, 4th consumer, and 5th consumer level.
What does the amount of energy at the top consumer level tell you about the number of large carnivores?

3. Niche and Habitat
Niche: An organism’s role in the ecosystem (&food chain/food web)
Habitat: Physical place where an organism lives

4. Competitive Exclusion Principle
States that no two species can occupy exactly the same niche in exactly the same habitat at exactly the same time.
Why??

5. Biotic & Abiotic Factors
Biological components of an ecosystem are called biotic factors. Examples?
Animals, plants, mushrooms, bacteria..
Physical components of an ecosystem are called abiotic factors. Examples?
Sunlight, heat, precipitation, humidity, soil type,…
How do these factors influence in each other?

7. A keystone species is a species that has an unusually large effect on its ecosystem.
Why are they called a “Keystone” species?

8. Keystone species form and maintain a complex web of life.
creation of
wetland
ecosystem
increased waterfowl
Population
increased fish
population
nesting sites for birds
keystone species

9. Keystone Species How might the grey wolf be a keystone species?
What about the honeybee?

10. Symbiosis: any relationship in which 2 species live closely together
1. Mutualism -Both benefit
2. Parasitism -One benefits, other is harmed
3. Commensalism -One benefits, other is neither helped nor harmed

11. Symbiosis
Cuckoo (till 3 min)
Wasp & Caterpillar

12. Parasitism versus Predation
Predation: Predator kills prey instantly Predator normally much larger than prey
Parasitism: Parasite kills prey slowly or not at all Parasite normally smaller than prey

13. Exit Slip (on your own)
Do you think humans are in a symbiotic relationship with any other organisms? 1) Name one, and 2) EXPLAIN which type of symbiotic relationship it is & why.

14. Warm Up: What’s the difference between niche & habitat?
Where did “keystone species” get its name?
What form of symbiotic relationship is the following:
Vulture & Lion Crocodile & Bird Cuckoo bird & other birds

15. Do Cats Make you Crazy? Toxoplasma Virus
Can only reproduce inside cats Make rats more trusting and attracted to cat smell “Groundbreaking research showed that infected men tend to be more suspicious, withdrawn, and prone to breaking rules, while infected women are more trusting, outgoing, and law-abiding.”

16. Competitive Exclusion Principle
What happens to the “losers”?
Adaptation & finding a new niche?