Sponge: Set up Cornell Notes on pg. 45

Topic: 5.4 Evolution: Evidence for Evolution: Artificial Selection

Essential Question: NONE

5.4 Evolution: Evidence for Evolution: Artificial Selection

Key Vocabulary:Artificial Selection

Artificial Selection• The art and science of breeding domesticated animals provides a good record

of recent changes in heritable characteristics• Cattle• Horses• Dogs• Sheep • Pigeons

Artificial Selection• Artificial selection (or selective breeding) describes intentional breeding for

certain traits, or combination of traits. • humans favor specific traits• The deliberate exploitation of artificial selection has become very

common in experimental biology, as well as the discovery and invention of new drugs.

• Artificial selection can also be unintentional; it is thought that domestication of crops by early humans was largely unintentional.

Artificial Selection: Pigeons

• Dogs belong to a single species, Canis familiaris• Comprised of about 400 different breeds

• Since they are a single species, they can mate and have viable offspring• Recognized dog breeds take generations to establish through selective breeding or

artificial selection. • Many of the breeds we have today are the result of people's desire to have dogs with

specific features that make them suitable for performing particular tasks• Such as: retrieving, protection, assistance, hunting, and companionship, to name

just a few. • The process of breeding a new type of dog often involves 1) identifying desired

features, 2) finding dogs with those features, 3)then performing a series of matings to produce offspring with the appropriate combination of traits. After a number of generations, a new breed may be established!

Artificial Selection: Dog Breeds

Artificial Selection: Dog Breeds

Heritability is the ability of a trait to be passed down

LabradorPoodle

Labradoodle

Artificial Selection: Dog Breeds

*They are not considered a breed by any major fancier and breeder organization

Artificial Selection• By watching which males mated with which

females, breeders could see which characteristics the offspring would have

• Of the offspring produced, not all would be equally valuable in the eyes of the breeder

• Certain cows produced better quality milk and meat

• Over the years, breeders learned to choose the males and females with the most desirable genetic characteristics and breed them together

Selective Breeding

• https://www.youtube.com/watch?v=W_CnR0Ak604

Artificial Selection• After practicing selective breeding for dozens/hundreds of generations,

farmers and breeders realized that certain varieties of animals had unique combinations of characteristics which did not exist before

Artificial Selection: Corn

Zea Mays: maize, or corn, the only domesticated taxon in the genus Zea

• Corn, is a large grain plant domesticated by indigenous peoples in Mesoamerica in prehistoric times. The leafy stalk produces ears which contain the grain, which are seeds called kernels. Maize kernels are often used in cooking as a starch.

• The first corn plants only grew small, one-inch long corn cobs, and only one per plant, but artificial selection by the indigenous people of the Americas made it to grow several cobs per plant, and usually several inches long each time.

Artificial Selection: Greens

Artificial Selection: Bananas

Artificial Selection• Although this is evidence that evolution is happening due to an

accumulation of small changes over time, the driving force is…• HUMAN CHOICE!!!!

• The farmers and breeders choose which animals will reproduce, and which will not

• It should be obvious that this is not the driving force of evolution in natural ecosystems

Artificial Selection (4m38s)

Artificially Selecting Dogs Activity

We crossed English, French, and Irish foxhounds to get today’s American Foxhound!

American Foxhound

English Foxhound French

Foxhound

Use Dog Traits Teacher Sheet as your guide

Science Today: Creating the Perfect Pet• https://www.youtube.com/watch?v=bi9Pa0DHG5Y

Artificially Selecting Dogs• Objective: You and your group will artificially create a

new dog breed with by selecting desired traits, and crossing two existing breeds.

Ownership Card

Artificially Selecting Dogs Activity• Using the “Dog Breeds” side, please put a check mark next to all dog

traits that match your selected traits• Circle the BEST two dogs to mate• Choose which dog to make the mother/father • Since there are three offspring, flip a coin three times for each trait to

be inherited. • keep track of the results of their coin flips on the "Puppy Traits"

worksheet.

•Heads = the female's (mother's) feature•Tails = the male's (father's) feature.