Wake-up Which of the following is NOT homologous to the human arm? a. Whale forelimb b. Insect wing c. Bat forelimb Explain how a seal and penguin are an example of convergent evolution.

Wake-up A 15.5lbs baby was born in China and survived. How does this go against Natural Selection (sorry baby and family)? What is meant by fittest?

Wake-up Brown hair (B) is dominant to blond hair (b). There are 168 brown hairs in a population of 200. Find the frequency of the heterozygous genotype. Find the frequency of the homozygous dominant genotype. Find the frequency of the homozygous recessive genotype.

Speciation Christopherson

What is Speciation? Formation of a new species; one species changing over time becoming two species

What is a species? Organisms that can interbreed and produce viable (usable) and fertile (able to reproduce) offspring

Can these birds interbreed???? NO: They have similar body and colorations, but are different species because of their songs and other behaviors; do not interbreed Can these birds interbreed???? Eastern Meadowlark Western Meadowlark

How does Speciation occur? Biological barriers prevent species from producing viable and fertile offspring; reproductively isolated

Isolating mechanism: Geographic Isolation Separation of of species by a geographical feature such as a river, mountain range, ocean, or desert

Darwin’s Finches Finch species have become adapted for different diets: seeds, insects, flowers, the blood of seabirds, and leaves.

Isolated by the Galapagos Islands

Harris Antelope Squirrel and Tassel Eared Squirrel in the Grand Canyon

Isolating mechanism: Habitat Isolation Occurs when two species live in different habitats within the same area. Do not interbreed

Ex: Two species of Garter snakes-Thamnophis One lives in water and the other is terrestrial (lives on land)

Ex - Lions and Tigers could interbreed, but live in different habitats Lions live in the grasslands and tigers live in the forest

Isolating mechanism: Temporal Isolation Species breed at different times of the day, different seasons, or different years Do not interbreed

Example: Skunks Western Spotted Skunk Eastern Spotted Skunk Reproduce late summer Eastern Spotted Skunk Reproduce late winter

Example: Frogs

Isolating mechanism: Behavioral Isolation Species have unique courtship behaviors to attract mates. Do no interbreed

Example: Blue Footed Booby

Example: Birds of Paradise Planet Earth: Jungles

*Example: Peacock Spider

Post-Reproductive Isolation Interbreeding occurred Result: Unhealthy and Sterile if born at all

Can a zebra and a horse reproduce? Horse has 64 chromosomes Zebra has 32/46 chromosomes depending on the species

Zorse: Infertile organism with 54 chromosomes

Can a horse and a donkey reproduce? Horse has 64 chromosomes Donkey has 62 chromosomes

Mule: Has 63 chromosomes and very vigorous, but sterile