Artificial SelectionAn introduction to evolution

Question? What is artificial selection?

Where humans select organisms with certain desired characteristics to breed and produce the next generation.

What types of things do humans artificially select for

Artificial Selection in Carrots

Inbreeding The continued breeding of individuals with

similar characteristics. Often seen in dogs

Helps ensure that the characteristics that make breeds unique will be preserved

Not always a good thing: most members of a breed are genetically similar so there is a chance to pass down bad recessive alleles

Artificial selection gone wildEnglish bulldog

Due to artificial selection for a very large head, almost all need to be born via C-section

Artificial Selection in Cows We are going to watch a few clips of

artificial selection in cows.

In your notebooks, write down the questions for each clip so that you can answer them as you watch. Biology is the funniest class ever.

http://www.pbs.org/wnet/nature/lessons/the-perfect-cow/video-segments-holy-cow/1536/

Clip 1: A Cow’s Digestive System

What role do microbes serve in a cow’s rumen?

Does this clip illustrate naturally or artificially selected attributes?

Why would a cow’s ability to eat grass make it ideal for human domestication?

Clip 2: Desirable Breeding Traits in Cattle How many different breeds of cattle

have humans created?

Would the qualities that make good beef cattle help them survive in the wild?

Besides milk and meat production, what other traits might humans wish to breed in cattle?

Clip 3: Different Breeds of Cattle

What might indicate that a cattle breed is adapted to cold climates like Scotland?

What do the different breed names refer to?

Why might “adaptability” be a desirable trait in a specific breed?