Download IB 362 Lecture 3

IB 362
Lecture 3 – Evolutionary and Ecological Principles
Charles Darwin
About time of voyages
About time of Origin of Species
H. M. S. Beagle 1831-1836
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“Wallace’s Line”
Helped found
the field of
biogeography
Why are the organisms we see the way they are (structure, behavior,
chemistry, etc.)
Why do the organisms that we find living in a place live there,
and not in other places?
Why are some organisms more abundant than others in a given
habitat?
What determines which different organisms live together in the
same community and which do not?
Which is more important for determining the structure of
communities: predation? competition? symbiosis?
Ecology – the study of interactions between organisms and their
environment, and the effects of these interactions on the
distribution and abundance or organisms.
Can be studied at different hierarchical levels:
Biosphere
Ecosystem
Community
Population
Individual
Evolution – heritable changes in organisms over time .
Can be due to:
Random drift in small populations
Natural selection
Immigration and emigration
Mutations
Molecular drive (not so relevant for our interests here!)
Kinds of species interactions
Territoriality
+/- or -/-
Competition
+/- or -/-
Predation
+/-
Commensalism
+/0
Mutualism
+/+
Parasitism
+/-
A couple of examples of more modern ecological and
evolutionary studies
Connell and Paine – Pacific intertidal communities
Vermeij – impact of predation on morphology
Joseph Connell
UC Santa Barbara
Robert Paine
University of
Washington
North Pacific intertidal communities
Sea anemone
Dungeness crab
zonation
Dog whelk
“loco” snail
Barnacles
seaweeds
Predation and defense
Grazing (herbivory)
Territoriality in sea anemones
Food webs
Removal experiments
Geerat Vermeij, UC Davis
The role of predation
in shaping
gastropod
shell morphology