Evolution ID: eee105 Password: prAIRie Lec 13 15Feb02

The ecological theater The evolutionary drama

Evolution by Natural Selection is not random Selection is non-randomnon-random

How are complex structures “designed” by natural selection?

Eyes have evolved in many animals In single celled animals light meters direction detectors In multicellular animals

Eyes have evolved in many animals a pinhole camera a shadow detector

Octopus eye is a camera eye

Vertebrate eye Octopus eye

Vertebrate eye Octopus eye Convergent Evolution a “backwards” retina a direct eye

How did eyes evolve? A better question is how do genes control the construction of an eye?

If a characteristic is genetically controlled it has evolved

Nature red in tooth and claw? not necessarily

e.g. mutualismoften cooperation Nature red in tooth and claw? not necessarily

Mutualism mycorrhizal fungi

Mycorrhizal fungi share nutrients with tree roots share nutrients with tree roots

e.g. mutualismoften cooperation Nature red in tooth and claw? not necessarily

Cleaning symbioses

Symbiosis = living together

often cooperation Nature red in tooth and claw? not necessarily e.g. pollination

Wind-pollinated plants have inconspicuous flowers

An example of coevolution Pollination

Bees see ultraviolet light nectar guides

Honeybees learn

and communicate flower location to fellow workers