Midterm 1 (Part 2)

Question 1

What is negative frequency dependance?

Answer 1

directional selection for a phenotype is stronger when the phenotype is less common, this is one form of balancing selection

Question 2

What traits are needed for natural selection to occur

Answer 2

individuals vary in a trait, there is association between trait and success, trait is heritable

Question 3

What is inbreeding avoidance?

Answer 3

Kin recongnition, dispersal, delayed maturation, self-incompatability , etc

Question 4

What are Mendels 3 laws?

Answer 4

Law of segregation: 2 allelles for each gene per gamete
Law of indep. assort.: inheritance of one gene doesnt affect inheritence of the other
Law of dominat: one allele is dominant and expressend

Question 5

What is genetic drift?

Answer 5

finite populations are subject to random changes in allele frequencies across generations due to chance , occurs due to sampling variation

Question 6

What is germ plasm theory?

Answer 6

proposed that genetic info tramistted by germ cells in gonads, all other cells dont transit genetic info

Question 7

Impacts of mutations?

Answer 7

delterious (reduce fitness) or beneficial, can be neutral which creates neutral genetic variation in a population

Question 8

A cross between monohybrids…

Answer 8

monohybrid cross (between hetero. individuals)

Question 9

Why is there inbreeding in agriculture?

Answer 9

so genetic variation is lost and a single genotype is fixed

Question 10

What is relative fitness

Answer 10

individuals contribution to next generation relative to that of other individuals

Question 11

What can cause inbreeding depression? (2)

Answer 11

dominance hypo- deletrious alleles tend to be recessive
heterozygote advantage- some hetero have higher fitness that homozygote

Question 12

6 HW assumptions?

Answer 12

Dipliod locus reproduce sexually, random mating, no nat. selection, no mutattion, no migration, no genetic drift

Question 13

What is a population bottleneck?

Answer 13

rapid decrease in pop size which reduces variation and enhances genetic drift

Question 14

What does it mean if allele has a plus?

Answer 14

more common and likely dominant

Question 15

How does quantitative variation arise?

Answer 15

many loci can affect the trait, enviroment also affects expression of the trait

Question 16

what is outbreeding?

Answer 16

mating between individuals who are less related than would be expected by random mating, increases heterozygosity, increase in fitness over non outbred individuals (heterosis)

Question 17

What does inbreeding cause?

Answer 17

increase in frequency of homozygotes across genome, deviation from HW, decrease in fitness called inbreeding depression

Question 18

What makes a event independant?

Answer 18

outcome of one has no affect in outcome of other

Question 19

2 features of HW principle?

Answer 19

1- certain conditions, there is a predictable relationship between allele and genotype frequencies in a population
2- Medilian inheritence does not alter allekle frequencies in abscene of evolutionary processes

Question 20

preservation of genetic variation?

Answer 20

from mutation, by balancing selection, mutation drift slection balance, spatial variation

Question 21

what is positive frequency dependence

Answer 21

direction selection for phenotype stregthens as phenotype becomes more common

Question 22

what is a population?

Answer 22

group of individuals that live in same area and interbreed

Question 23

What did mendel propose?

Answer 23

a model where heredity was controlled by factirs, each individual gets one factor from their parent- factors now known as genes, was partially correct

Question 24

4 issues with mendels laws?

Answer 24

complete dominance is far from universal, allelles dont always segregate equally (50:50), assortment of alleles at one locus is not independant o fother locuses, inheritence patters are more complex

Question 25

Biometricians vs Mendelians:

Answer 25

B- continous traits, thought evolution happened slowly with no large jumps M- discrete traits, thought sudden dramatic changes in phenotype occured (saltationism)

Question 26

phenotype vs genotype?

Answer 26

P- quantifiable character of organism (color, size) G-makeup of alleles it carries (PP, Pp, pp)

Question 27

Why is mating often non-random?

Answer 27

relatives mate more or less often (inbreeding/outbreeeding), self fertilization, may mate with ppl more or less similar by chance

Question 28

What is blending inheritance?

Answer 28

Phenotypes in offspring are average of parents, was argued this is ineffective because variation is lost

Question 29

what is local adaption

Answer 29

Population adapts to local environment, gene flow can hinder as it causes outbreeding depression

Question 30

What is a founder event?

Answer 30

small group colonizes new geographic area

Question 31

the probability of recombination between two loci...

Answer 31

Increases as the distance between them increases

Question 32

What does natural selection act on?

Answer 32

Acts on phenotypes

Question 33

Who is August Weismann?

Answer 33

evolutionary theorist, not a creationist, agaist lamarks thoeries, developed germ plasm theory

Question 34

What is random mating?

Answer 34

mate randomly with respect to the genotype at locus of interest, sometimes called panmixia

Question 35

Mutpilcation rule?

Answer 35

Pr (A & B)= Pr(A) X Pr(B)

Question 36

what are three forms of selection

Answer 36

linear/ directional, stabalizing, disruptive

Question 37

Micro vs macro evolution?

Answer 37

change in allele frequency over short periods of time compared to long periods across generations

Question 38

What contributes to fitness?

Answer 38

survivorship, fecundity, mating success

Question 39

What is co dominance/ partial dominance

Answer 39

partial (pink flower) co (white and red flower)

Question 40

What are alleles and locus/ loci?

Answer 40

L- specific location on chromosone A- unique variation of gene

Question 41

What are effects of genetic drift?

Answer 41

causes random change in allele frequency across generations, reduces variation because alleles are lost, causes populations to diverge

Question 42

What was mendels work?

Answer 42

Used peas, worked with discrete varaibles and used true breeding, crossed P generation to make F1

Question 43

What is the HW equation?

Answer 43

p^2 + 2pq +q^2 =1

Question 44

As the number of loci increases...

Answer 44

phenotypic variation becomes finley graded (skin colors)

Question 45

Ex. of small/large scale mutations

Answer 45

Substitutions, intersetion, deletion, or large scale like translocations, chromosne loss or gain

Question 46

Parts of germ plasm theory?

Answer 46

germ cells produce somotic cells, germ cell not disposable, in plants corals and sponges soma produce germ cells and if mutation occurs it affects all future cells

Question 47

What is gene flow

Answer 47

migration, movement of alleles between populations , greater than affects of mutation because is more frequent

Question 48

Addition rule?

Answer 48

Pr (A + B)= Pr(A) + Pr(B) for only one outcome

Question 49

What is a mutation?

Answer 49

change in genetic info, arises from errors during DNA replication, ultimate source of genetic variation, random in occurrence

Question 50

What is a gene pool

Answer 50

All copies of each allele at given locus