Unit 2: Artificial Selection and Domestication

Question 1

What is the red queen hypothesis

Answer 1

• describes the competitve nature of adaptation
• coevolution
• hosts continually change to stay one step ahead of their pathogens

Question 2

the difference between natural and artificial selection can be [–]

Answer 2

hard to define

Question 3

methicillin is a type of

Answer 3

• penicillin (beta lactams)
• toxins derived from molds

Question 4

natural selection in terms of toxins

Answer 4

development of resistance to an environmental toxin

Question 5

artificial selection in terms of toxins

Answer 5

deliberate exposure of staph aureus to the toxin

Question 6

artifical selection

Answer 6

the identification by humans of desirable traits in plants and animals, and the steps taken to enhance and perpetuate those traits in future generations

Question 7

natural selection

Answer 7

the process whereby organisms better adapted to their environment tend to survive and produce more offspring.

Question 8

Continuous competition also occurs [–]

Answer 8

within species

Question 9

antibiotic resistance is which type of selection

Answer 9

• directional
• mutant shifts toward the goal of being antibiotic resistant

Question 10

Domestication syndrome was described by Darwin an includes

Answer 10

a suite of commonly recognized traits

Question 11

domestication syndrome

Answer 11

the characteristic collection of phenotypic traits associated with the genetic change to a domesticated form of an organism from a wild progenitor form

Question 12

dog traits demonstrate variability consistent with

Answer 12

artificial selection and domestication syndrome

Question 13

Dmitri Belyaev fox domestication

Answer 13

• wild animals kept in cages
• started breeding foxes
• got to point of true breeding domesticated foxes
• started seeing white patches
• floppy ears

Question 14

What are specific markers of fox domestication?

Answer 14

• two different phenotypic changes in an Ss heterozygote: the star depigmentation and a floopy right ear
• homozygote for the star mutation (SS)
• Phenotypica similarity between brown mottling in fox and dog

Question 15

Using selective breeding, Belyaev’s experiement generated

Answer 15

foxes with clear hallmarks of domestication

Question 16

HPA Axis and Domestication

Answer 16

• the CRH tells the pituitary to release ACTH
• this causes cortisol to be released
• domestication = decreased cortisol release
• foxes with less cortisol = less threat posture

Question 17

What are the domesticated foxes dog-like similarities?

Answer 17

• coat depigmentation
• curly tail
• tail carriage
• floppy ears, wider face
• long jaw
• skull elongation

Question 18

domestication changes [–] as well as [–]

Answer 18

behavior and morphology

Question 19

domesticated foxes are referred to as the

Answer 19

behavioral elite

Question 20

Domestication syndrome and the neural crest cell hypothesis

Answer 20

shorter snouts and smaller teeth

Question 21

the neural crest hypothesis referes to

Answer 21

• certain stages of development and may explain many of the changes found in domestication syndrome
• a few key mutations in developmental genes (pleitropy) would have a profound impact on many traits observed in domesticatied animals

Question 22

Cell migration from the neural crest during the neural crest hypothesis results in

Answer 22

• weakened ear cartilages: floppy ears
• shortened snout
• reduced brain size
• odontoblasts: reduced tooth size
• melanocytes: pigment changes
• sympathetic ganglia
• adrenals
• cartilages of tail (shortening, curling, etc.)

Question 23

According to the neural crest hypotheis, the significant features of domestication may be [–]

Answer 23

“unselected by-products”

Question 24

Selection for Tameness results in

Answer 24

reduced neural crest input (mild neurocristopathy)

Question 25

what are the unselected by-products of reduced neural creast input

Answer 25

• white patches (melanocytes)
• floppy ears (chondrocytes)
• Reduced muzzles & jaws (osteoblasts)
• reduced teeth (odontoblasts)
• reduced forebrain size (potential indirect side-effect)

Question 26

what are the selected traits for reduced neural crest inputs

Answer 26

• reduction in adrenals & sympathetic ganglia
• reduced stress
• reduced fear of humans
• learning: “humans OK”