Chapter 20Community Ecology

20-1: Species Interactions

What’s a community?

5 Comm. Interactions:PREDATION

COMPETITION

PARASITISM

MUTUALISM

COMMENSALISM

Predation

Predator eats preyAdaptations!– Being a good predator:

– Being a good escaper:

Mimicry: Avoiding Predation!

Batesian Mullerian

CompetitionInterspecific

Intraspecific

Research in the Lab

Gause, 1930s– Yeast

http://jeb.biologists.org/cgi/reprint/9/4/389.pdf

Research in the Wild

Connell, 1960s– Barnacles

– Fundamental niche

– Realized niche

Competitive Exclusion Principle

One species is excluded from a comm. b/c competition for same limited resource

No 2 species can occupy same niche at same time/place!

Resource partitioning

Niche Activity

SYMBIOSISParasitism

Mutualism

Commensalism

PARASITISM

MUTUALISM

COMMENSALISM

The goby is essentially the 'guardian of the hole' as the shrimp has very limited visual abilities. Because of this, the shrimp, while outside the burrow, holds one antennae on the goby. If the goby sees a potential threat, it will give a slight tail flick. This vibration is picked up by the shrimp who consequently darts into the hole. If the danger approaches further, the goby will shoot into the hole through a quick C-bend of the body and enter the hole.

Concept map in groups

http://my.hrw.com/sh2/sh07_10/student/flash/concept_maps/00176.htm

I’m checking today!

Chapter 20Community Ecology

20-2: Patterns in Communities

Species Richness vs. Evenness

http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/60359.htm

Latitude & Species Richness

Trend?

Hypotheses:http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/60360.htm

Area & Sp RichnessTrend?

Species-area effect

Habitat destruction...

Sp Interactions & RichnessPredation – keeps prey # in check

Paine, 1960s– Removed sea stars – Mussels previously coexisted w/several

sp– Overabundance outcompeting for

space, etc– # sp from 20 <5 !

Richness & Community Stability

Tendency of comm to maintain ~constant conditionsResponse to disturbanceMore species more interactions, spread out effects, lessen the blow

http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/60362.htm

p. 410—I’m checking it!Brain Break…

Ecological Succession

Primary

Secondary

Glacier Bay, AK

http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/60363.htm

Pioneer Species

http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/60364.htm

Climax Community

http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/60365.htm

p. 410—I’m checking it!

HW Tonight--Ch 20 Review p. 412, quiz tomorrow (THURS)