IB 362 Lecture 3 – Evolutionary and Ecological Principles
Charles Darwin About time of voyagesAbout time of Origin of Species
H. M. S. Beagle
Alfred Russel WallaceAlfred Russel Wallace
“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 anemoneDungeness crab Dog whelkBarnacles seaweeds “loco” snail zonation
Predation and defense
Grazing (herbivory)
Territoriality in sea anemones
Removal experiments Food webs
Geerat Vermeij, UC Davis The role of predation in shaping gastropod shell morphology