1.4 evolution

Convergent evolution

different organisms independently evolve similar traits

Anagenesis

gradual transformation (along branches) of one species into another (one species becomes another species)

Cladogenesis

rapid splitting of a species into 2 or more parts (one species splits into ≥2 species)

sources of variation

what kind of progeny are produced

what are 4 sources of variation?

- mutation
- recombination
- phenotypic plasticity
- constraints

modifiers of variation

what kinds of progeny are in the next generation

3 examples of modifiers of variation

- natural selection
- sexual selection
- genetic drift

phylogeny

diversification of lineages through evolution, each animal shares a trait with its neighbour

adaptation

a trait which arose historically, enhancing fitness as a result of natural selection

Key innovations

novel trait which originated in a particular lineage, providing evolutionary "advantages", ex

key innovations lead to ________ _________

key innovations lead to adaptive radiation

Adaptive radiation

explosion of speciation in a lineage, that can be causally linked to its key innovation, involving ecological & phenotypic diversification