Transcript Artificial Selection Key Vocabulary

Sponge: Set up Cornell Notes on pg. 45
5.4 Evolution: Evidence for Evolution:
Artificial Selection
Topic: 5.4 Evolution: Evidence for Evolution:
Artificial Selection
Essential Question: NONE
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
Artificial Selection: Dog Breeds
• 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
Poodle
Labrador
Labradoodle
*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!
English
Foxhound
French
Foxhound
American
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.