Evolution Part 1

Question 1

what is artificial selection?

Answer 1

• Selectively selecting certain varieties of an organism over others via breeding programs
• Human beings selecting for traits while breeding animals (can be behavioural or physical traits)
• Ex. Pigeon breeding (for physical traits), crop breeding, fox breeding (for personality traits, which ended up leading to morphological changes and reproductive changes

Question 2

proximal causes of morphological changes in Siberian foxes caused by artificial selection

Answer 2

• hormone & neurotransmitter changes

- Adrenal gland decreased, decreased cortisol (stress hormone) levels

Question 3

natural selection

Answer 3

traits that confer the highest reproductive success increase in frequency over time

Question 4

Darwin’s theory

Answer 4

• Darwin’s theory of natural selection: 1859; Mendel’s work on genetics: 1865-1866
• Darwin described his theory without even being aware of genetics

Question 5

selective advantage

Answer 5

traits increases or decreases in frequency as a function of how well they suit organisms to their environment

Question 6

fitness

Answer 6

• individual reproductive success; equal to the average contribution to the gene pool of the next generation that is made by individuals of the specified genotype/phenotype
• A fitness advantage of just 1% per generation is sufficient for one behaviour to replace another over evolutionary time

Question 7

phenotype

Answer 7

observable properties of an organism

Question 8

genotype

Answer 8

genetic makeup; results in phenotype

Question 9

gene

Answer 9

Unit of heredity that is transferred from parent to offspring and is
held to determine some characteristic of the offspring

Question 10

allele

Answer 10

Gene variant; one of two or more alternative forms of a gene

Question 11

pre-reqs for natural selection

Answer 11

• variation in the trait
• fitness consequences of the trait
• mode of inheritance
• limited resources
• Ex. Rock mice example -> meets all pre-reqs for evolution (there’s a variation [colour of mice], it has fitness consequences (mice who can’t camouflage are eaten more frequently), it has mode of inheritance (can be passed down)

Question 12

variation in the trait

Answer 12

• results in variation in behaviour, for example

- comes from mutations, recombination, and non-genetic changes

Question 13

mutations

Answer 13

• change in genetic structures (ie. Addition/deletions)

- results in a variation in the trait

Question 14

genetic recombination

Answer 14

• crossing over during cell division - “swapping” chromosome sections (random)
• results in variation in the trait

Question 15

non-genetic changes

Answer 15

ex. Migration – new individuals introducing new trait variations

Question 16

fitness consequences of the trait

Answer 16

• different varieties must have a differential impact on reproductive success
• ex. Male raven eggs -> males with different behaviours have different numbers of eggs with females

Question 17

mode of inheritance

Answer 17

traits must be able to be passed on to the next generation (individual learning doesn’t usually cover this)

Question 18

limited resources

Answer 18

some sort of pressure on the system that necessitates a change

Question 19

environmental influences

Answer 19

• animals aren’t affected only by genotype/phenotype
• different environments have influence too
• ex. diet, location/climate, other species

Question 20

example: mouse babies and alcohol

Answer 20

Alcohol effect on mouse babies are truly due to alcohol, not parenting (cross-fostering of control and experimental groups showed this)