1. Ch 54-Community Ecology organism population community ecosystem
biosphere

2. Community Ecology Community Community Ecology
all the organisms that live together in a given place
Community Ecology
study of interactions among all populations in a common environment
To answer:
In what way do the populations interact?

3. Why is the beetle rolling the fecal ball?
Niche
An organism’s niche is its ecological role
habitat = address vs. niche = job
Ex: what it eats, what it lives in, time of day when active, behavior, etc…
“How it fits into that ecosystem.”
Why is the beetle rolling the fecal ball?
Is that frog noctural?

4. Competition
Interspecific competition- interaction between different species competing for the same resources, which limits their growth and survival (-/-)
Ex- weeds and garden plants; grasshoppers and bison

5. Competitive Exclusion Principle
No two similar species can occupy the exact same niche at the same time. Know: Fundamental niche vs Realized niche
High tide
Competitive Exclusion
If Species 2 is removed, then Species 1 will occupy whole tidal zone. But at lower depths Species 2 out-competes Species 1, excluding it from its potential (fundamental) niche, so occupies it’s realized niche.
Species 1
Low tide
Chthamalus sp.
Species 2
Fundamental
niches
Realized
niches
Semibalanus sp.

6. Reduce competition through microhabitats
Resource partitioning-coexistence between species because one’s niche becomes ‘modified’
Reduce competition through microhabitats
Resource partitioning among Dominican Republic lizards. Seven species of Anolis lizards live in close proximity, and all feed on insects and other small arthropods. However, competition for food is reduced because each lizard species has a different perch, thus occupying a distinct niche.
Sympatric species often partition available resources, reducing competition between them.

7. Symbiotic Relationships
competition (-/-)
predation / parasitism (-/+)
herbivory (-/+)
commensalism (+/0)
mutualism (+/+)
lichens (algae & fungus)
“Freddy fungus and Annie algae took
a Lichen to each other!”

8. Symbiosis
mutualism
+/+
commensalism
+/0
predation
+/-
competition
-/-

9. Predation drives evolution
Predators adaptations
locate & subdue prey
Prey adaptations
elude & defend
Predation provides a strong selection pressure on both prey & predator
horns, speed, coloration
spines, thorns, toxins
Predation provides a strong selective pressure on prey populations. Any feature that would decrease the probability of capture should be strongly favored.

10. Defensive Adapations Mechanical Defense Chemical Defense
Aposematic coloration
Cryptic coloration
Batesian Mimicry
Mullerian Mimicry
**All heavily rely on operant conditioning, trial and error learning, in order to be successful. They rely on predators learning what not to eat, and the predator remembering what not to eat.

11. black, red, orange & yellow means: DON’T EAT ME!
Coloration
Aposematic species resemble each other, whereas cryptic coloration means ‘camouflage’. Which pic is cryptic?
black, red, orange & yellow means: DON’T EAT ME!

12. Batesian Mimicry Convergent evolution green parrot snake
palatable or harmless species mimics a harmful model
green parrot snake
Hawkmoth larva puffs up to look like poisonous snake
hawkmoth larvae

13. Which is the moth vs. the bee? Which is the fly vs. the bee?
Nonpoisonous Mimic!
Batesian mimicry
Viceroy male
edible
Monarch male
poisonous
Which is the moth vs. the bee?
Which is the fly vs. the bee?
fly
bee
moth
bee

14. Mullerian mimicry cuckoo bee yellow jacket
two or more harmful species look like each other
cuckoo bee
yellow jacket
- group defense advantage
- predators may evolve innate avoidance

15. Coral snake is poisonous
Red on yellow, poison fellow; red on black, safe from attack
What kind of mimicry?
Coral snake is poisonous
King snake is not

16. Coevolution in Community
Predator-prey relationships
Parasite-host relationships
Flowers & pollinators
Long term evolutionary adjustments between species

17. Predator/Prey Coevolution…
*TTX- toxin produced by newt
Biowarfare arms race with garter snakes and newts.