Microevolution vs.

Macroevolution

What is microevolution?

• microevolution = evolution

• The change in allele frequencies in a population from generation to generation

• Small changes happening within a species (i.e. natural selection, mutation, drift, gene flow, result of humans [breeding], hybridization)

What is macroevolution?

• This is evolution at or above the species level

• It encompasses the grandest trends and transformations in evolution

• Macroevolution is evolution on a grand scale — what we see when we look at the over-arching history of life: stability, change, lineages arising, and extinction

- General examples : anagenesis, cladogenesis, evolution of new families/phyla/genera

- More specific examples : origin of mammals, radiation of angiosperms

• The basic evolutionary mechanisms – natural selection, mutation, genetic drift, and gene flow – can produce major evolutionary change if given enough time

• Macroevolution, therefore, is often considered a large collection of microevolutionary changes that accumulate over time

Macroevolutionary Patterns

1. Stasis

- no change

2. Speciation

3. Extinction

- over 99% of all species that have ever lived have gone extinct

4. Adaptive radiation

- emergence of numerous species from a common ancestor introduced into an environment, presenting a diversity of new opportunities

- ex. creation of volcanic islands, wings, shells/skeletons, extinction of major predator

5. Coevolution

- likelier to happen if different species have close ecological interactions with one another

- most pronounced in symbiotic relationships

- ex. predator/prey, parasite/host, competitive species, mutualistic species

Snake vs. newt

Giant star orchid and giant hawk moth

Ant and Acacia