Evolution notes Part III
Types of Evolution/Extinction
 Types of Evolution:
o Divergent Evolution - Multiple species of organisms
descended from the same common ancestor at some point
in the past.
 Method of evolution accounting for the presence of
homologous structures.
 Adaptive Radiation.
 Ex. Darwin’s finches
o Convergent Evolution - Organisms of different species
often live in similar environments, thus explaining the
presence of features with similar functions.
 Method of evolution accounting for the presence of
analogous structures.
 Ex. Dolphins and shark
o Coevolution –Organisms that are closely connected evolve
together.
 Method of evolution accounting for specialists.
 Ex. Monarch butterfly and milkweed, insects and
flowers
 What happens to an organism if a population cannot adapt to the
changing environment? Extinction
 Mass Extinction: Many species become extinct at one time.
o How many have there been? At least 5
o What can cause them? Change in atmospheric gas
concentrations, Meteor impacts, Desertification, pollution