Species Interactions
Mr. Beaty
2009-10

Bellringer
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Have notes ready for species interactions discussion.
I will call each up to see their grades after the notes.
Defend the following statement:
Species interactions are the driving force behind natural selection.

Ecology terms:
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Biotic factors
Abiotic
Niche (Fundamental and Realized)
Competition

EQ: How do species interactions drive changes in organisms?
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Predator/Prey
Parasitism
Commensalism
Mutualism
Commensalism

Predator-Prey

Parasatism
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Parasitism

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Mutualism

Commensalism

Competitive Exclusion
 two species competing for the same resources cannot stably coexist
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Connell
(1961)

Competitive Exclusion Principle
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Tansley (1917) showed
(1) that the presence of absence of a species could be determined by competition with other species; (2) that conditions of the environment (in this case, soil type) affected the outcome of competition;
(3) that competition might be felt very broadly at first
(i.e., from other vegetation throughout the community); and (4) that the present ecological segregation of species might have resulted from competition in the past.

Competitive Exclusion Principle
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2.
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Gause: used cultures of protozoans to develop the competitive exclusion princple
(1934).
two species cannot coexist on the same limiting resource.

Limiting Resource

Resource Partitioning
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Charles Darwin noticed that competition is most intense between similar species that require the same resources.
Robert MacArthur studied several species of warblers that foraged in the same tree.
A closer look showed that each species hunts for insects in a different part of the tree. process by which natural selection drives competing species into different patterns of resource use or different niches.

of resource partitioning.

Coevolution
Here you can see two Heliconius eggs that have been layed on a passionflower leaf.
Here you can see the leaf on one passionflower species which has evolved to "fake eggs"
(nectaries) to make the moth think that the leaf is already occupied.

Adaptations
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Mimicry
Toxins
Aposomatic coloration
Plants: Physical defenese, chemical defenses
Secondary compounds – nicotine, strychnine, poison ivey

Batesian Mimicry

Coevolution at its best!
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This tropical ant of the species Cephalotes atratus is infected with a parasitic roundworm that makes its bulbous rear end, called a gaster, look like a juicy red berry.
Researchers believe the parasites transform the gasters to trick foraging birds into eating the
ants. Birds poop out parasite eggs, allowing the worms to spread to new ant colonies.

Ecological Succession
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Primary Succession
Secondary Succession
Pioneer Species
Climax Community

Ecological Succession

Primary or Secondary

Primary or Secondary

Primary or Secondary

Primary or Secondary

Primary or Secondary

Primary or Secondary

Primary or Secondary

Bellringer (Begins on pg
436)
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How does the greenhouse effect occur?
What is biodiversity?
Compare species richness and species evenness.
Compare species diversity and genetic diversity.
Calculate the species richness and species evenness for each island. Island X has 50 individuals of species A, 200 of species B and
2000 of species C. Island Y has 300 of species
A, 300 of species B and 500 of 200 of species C and 500 of species D.
Which island has the greatest biodiversity?

Environmental Issues
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Pollution – smog
Ozone thinning
Global Warming
Acide Rain
Biological magnification
Extinction
Keystone species
Sustainability
Environmental Footprint