Community

1. Community ECology
Big Idea 4: Biological
Systems Interact

2. ECology
• Study of
living
organisms
and their
interactions
w/ non/ living
environment

3. Who livEs WhErE?
• Orgs adapted to a specific set
environmental conditions, through
evolution (natural selection)
Peppered Moths of
England

4. • Dispersal:
Movement of
species from areas
of high pop.
density to low.
• Can be caused by:
• Species expanded
range naturally
• Species was
transplanted Great tailed grackle: Moved
north to Gulf of Mexico
Who livEs WhErE?

5. • Abiotic and Biotic
Factors are Limiting!!
• Abiotic: temp., H2O,
sun, wind, soil, climate.
• Biotic: animals, plants,
bacteria
Ex: Tidepools in Intertidal Zones,
Must withstand exposure to sun at
low tide.
Who livEs WhErE?

6. • An area where different pops
interact w/ each other w/ no
boundaries
• Leads to creation of ecological niches-

7. What’s
My
Niche?

8. • Interspecific Competition: occurs b/t
diff. species.
• Due to resources in short supply.

9. Intraspecific
Competition

10. Intra or Interspecific Competition?

11. • 2 species cannot coexist in
a community if their niches
are identical. (Gause’s Law)
Paramecium caudatum Paramecium aurelia
Gause’s Experiment

12. Logistic Growth

15. • Species can
evolve to
coexist
• Resource
partitioning- a
species
changes
behavior so
it can
coexist w/ a
similar

17. Keystone Species
• Key members of community
– Critical elements
– NOT always most abundant
– ALWAYS most important
• KEY to conservation efforts

18. • Members of a predator species prey on
members of a prey species

19. • Stalking, Keen eyes, Venom
• Natural Weapons: Fangs, claws
• Flexible bodies and Larger Size

20. Defense Techniques: Inflate, Flee,
Fight Back, Stab, Poison

23. Mimicry
• Batesian mimicry: a
harmless species
looks like a harmful
species
• Mullerian mimicry: 2
harmful species look
like each other
Scarlet King Snake
Coral Snake
Cuckoo Bee
Yellow jacket

24. Predation Feedback Systems
• Positive feedback (outcome is +) for predator
• gets to eat prey, can reproduce…
• Negative feedback (outcome is -) =
• prey population falls, no food, decrease in
predator population

25. • Herbivore only eats a part of
plant/alga.
• Plants may have chemicals to
deter

26. Symbiosis:
relationship b/t
2 species
•Mutualism (+,+)
•Commensalism
(+,0)
•Parasitism (+,-)

27. • Both Species Benefit
• Rhinos and

28. • Symbiotic fungus
found on plant
roots
•Aids in water
retention, mineral
uptake (nitrates)
W/out M With M

29. • One member is helped, the other
neither benefits or is harmed
• Cows and Cattle Egrets

30. • + and -
relationship
•parasite benefits,
host loses
•parasite usually
smaller than host
Leech Bite, Thailand