Convergent – DivergentAdaptive Radiation

Gradual and PunctuatedCoevolution

- When a species diverges over time into two different species, resulting in a species becoming less like the original one

- Live in different ways than the common ancestor- Caused by migration or nearby extinction of a nearby environment- Prime example are the dinosaurs

Divergent Evolution

When unrelated organisms evolve similarities when adapting to similar environments- Live in the relatively same way as each other- Emus, rheas, and ostriches are prime examples of convergent evolution

No Common ancestor involved

Convergent Evolution:

The importance of these types of evolution is generating variation, as well as species performing their niche in their environment. As every species has a role to play, these types of evolution ensure that these are carried out.

Significance…..

An adaptive radiation generally means an event in which a lineage rapidly diversifies, with the newly formed lineages evolving different adaptations.

Different factors may trigger adaptive radiations, but each is a response to an opportunity.

Best example- Darwin’s Finches

Adaptive Radiation

Gradual- slow changes to an organism that accumulate over time

Punctuated- long periods of stability with abrupt evolutionary changes happening rapidly.

Gradual equilibrium vs punctuated equilibrium:The rate at which evolution moves

Co evolution Two organism evolve together due to a

dependence on each other. The term coevolution is used to describe cases where two (or more) species reciprocally affect each

other’s evolution. So for example, an evolutionary change in the morphology of a plant, might affect the morphology of an herbivore that eats the plant, which in turn might affect the evolution of the plant, which might affect the evolution of the herbivore...and so on. http://evolution.berkeley.edu/evosite/evo101/IIIFCoevolution.shtml

Just some extra slide…..

Polypoloidy in plants Two Anemone species

◦ One is polyploidyMultiple sets of chromosomes due to non separation of chromosomes in meiosis.

Affects evolution of a new species because the different organisms will not cross-pollinate.

Aneuploidy- an abnormal number of chromosomes. The number of chromosomes are not an exact multiple for the monoploid number. Can be too many or too few chromosomes.