After test 2

Question 1

Name 3 types of mutations and explain their effects

Answer 1

1. Delerious- changes an individuals structure, function or behaviour in a harmful way
2. Lethal- causes great harm (death) to the organisms carrying them
3. Neutral- do not cause harm nor are helpful

Question 2

True of False: Mutations introduce genetic variation into populations; they change allele frequencies quickly.

Answer 2

False: They do introduce genetic variation into population but they change allele frequencies slowly

Question 3

What is gene flow

Answer 3

changes in allele frequencies as individuals join a population and reproduce. May introduce genetic variation from another population

Question 4

What is genetic drift

Answer 4

Random changes in allele frequencies caused by chance events, usually reduces genetic variation in a population.

Question 5

What are the two types of genetic drift

Answer 5

Population bottle neck: evolutionary event that occurs when a stressful factor reduces population size greatly and eliminates some alleles from a population. (Greatly reduces genetic variation)
Founder effect: A population established by a few colonizing individuals only has a fraction of the genetic diversity of the population it was derived from.

Question 6

What Inbreeding

Answer 6

Non-random mating. Genetically related individuals mate. Consequences: increases the frequency of homozygous genotypes, therefore recessive phenotypes are expressed = inbreeding depression.

Question 7

Sexual selection

Answer 7

Form of non-random mating (choosing certain phenotype to mate with)

Question 8

Intersexual selection

Answer 8

One sex chooses. The sex that chooses has limited options & must be selective to ensure quality of offspring

Question 9

Intrasexual selection

Answer 9

Individuals of the same sex compete for mates of the opposite sex.

Question 10

Assortative mating

Answer 10

Mating b/n similar phenotypes. Promotes inbreeding and homozygosity

Question 11

Disassortative mating:

Answer 11

dissimilar phenotypes. Promotes heterozygosity. (outcrossing- mating b/n unrelated individuals)

Question 12

Difference b/n reduced fitness from sexual selection and natural selection

Answer 12

Sexual: reduced fitness b/c individuals fail to reproduce due to competition, or choice of individuals of their own species
Natural: reduced fitness b/c individuals fail to survive and reproduce

Question 13

What are the female gametes like

Answer 13

large, not very mobile, not very numerous, need resources to nourish and produce these large gametes and the fertilized zygote

Question 14

What are the male gametes like

Answer 14

small, mobile, only need access to females

Question 15

What are Cheaters and Sneakers

Answer 15

Fast males who sneak in and mate quickly w/o the dominant male noticing. Or impersonate females to access guarded females.

Question 16

Scrapers

Answer 16

Scrape out sperm deposited by other males

Question 17

Mating plugs

Answer 17

After mating, leave plugs to prevent other males from mating

Question 18

Why are females usually more selective?

Answer 18

reproduction is limited to their access to resources to nourish and produce large gametes. Mother usually makes a larger ‘parental investment’ than fathers.

Question 19

Direct and Indirect benefits of being selective

Answer 19

D: Attractive individuals are good parents. Provide food, protection and territory for offspring. I: Attractive individuals have good genes. Improve survival or attractiveness of offspring.

Question 20

Sexual Dimorphism

Answer 20

distinct differences in size or appearance beyond the difference in their sexual organs.

Question 21

How does relative role in parental care affect the degree of sexual dimorphism

Answer 21

Less parental care= stronger sexual selection. Biparental care= sexually monomorphic species

Question 22

What is sex?

Answer 22

the exchange of genetic material b/n individuals

Question 23

Reproduction without sex

Answer 23

Asexual reproduction. Creates genetically identical offspring= clones

Question 24

Costs of sex

Answer 24

• competition for finding mates
• exposure to predators when trying to attract mates
• sexually transmitted diseases

Question 25

Evolutionary costs of sex

Answer 25

• Why exchange genetic material? Breaking up a successful combination of genes exchange for potentially flawed combination in your offspring
• Two-fold cost: producing males (useless bc they cannot produce offspring). All female populations grow faster. Only half the genes are passed onto offspring. Fitness for sexual population is 2x lower

Question 26

Evolutionary Benefits of Sex

Answer 26

• Changes genotype frequencies but not allele frequencies
• Sex and recombination reshuffles the genetic variation of the population (Crossing over in M1)
• Breaks down linkage-combination of alleles due to recombination
• Reproducing sexually generates new multilocus combinations of alleles
• Offspring, genetically distinct from either parent (and usually) from each other
• Maintains population variation= greater adaptability
• Sex makes it easier to remove bad mutations that are worse with epistasis

Question 27

Mutational Meltdown

Answer 27

if most mutations are deleterious, the accumulation of mutation may cause a small population to go extinct

Question 28

Mullers Ratchet

Answer 28

smaller populations=greater effects from mutations

Question 29

Clonal Interference

Answer 29

Adaptive mutations that emerge in different backgrounds cannot be combined in asexual populations. (sex makes adaptation more efficient, combines helpful mutations at multiple loci)