Lecture Exam 2

Question 1

Law of Segregation

Answer 1

sperm and egg cells contain only one allele for each gene b/c allele pairs separate from one another during meiosis

Question 2

Law of Independent Assortment

Answer 2

each pair of alleles segregate independently of other pairs of alleles during gamete formation

Question 3

Heterzygous

Answer 3

Aa (different alleles)

Question 4

Homozygous

Answer 4

AA or aa (same alleles)

Question 5

Genotype

Answer 5

genetic variation

Question 6

Phenotype

Answer 6

physical characteristic variation

Question 7

Complete Dominance

Answer 7

dominant allele completely overtakes the recessive allele (black or brown)

Question 8

Incomplete Dominance

Answer 8

heterozygotes phenotype expression is an intermediate to that of both homozygotes (red, white, or pink)

Question 9

Codominance

Answer 9

heterozygotes express both alleles at the same time (stripes, blood types)

Question 10

X linked genes

Answer 10

2 copies on women
1 copy on men

Question 11

Y linked genes

Answer 11

0 copies on women
1 copy on men

Question 12

Recessive, sex linked disease alleles will most often be expressed in …

Answer 12

MEN

Question 13

Pleiotrophy

Answer 13

One gene will effect multiple aspects of an organism’s phenotype (albinism)

Question 14

Polygenetic

Answer 14

traits appear to exibit continous variation and are often under the influence of a large number of genes (skin color)

Question 15

Epistasis

Answer 15

expression of one gene influences the phenotypic expression of another one (coat color in labs)

Question 16

Besides, pleiotropy, polygenetic, and epistasis, what can influence gene expression

Answer 16

environment

Question 17

How many crosses does mendelian inheritance employ

Answer 17

a single cross

Question 18

Population genetics allows us to estimate the allele and genotype frequency of how many crosses

Answer 18

many

Question 19

Hardy-Weinberg Equillibrium

Answer 19

a population’s allele and genotype frequencies are constant, unless there is some type of evolutionary force acting on them

Question 20

What five truths must be true to preserve Hardy-Weinberg

Answer 20

no mutation, no genetic drift, no gene flow, no selective mating, no selection

Question 21

mutation introduces

Answer 21

new alleles

Question 22

what is the source of all new genetic variation

Answer 22

mutation

Question 23

mutation is

Answer 23

random

Question 24

on its own, mutation is

Answer 24

weak

Question 25

in combination, mutation is

Answer 25

powerful

Question 26

natural selection produces

Answer 26

adaptations

Question 27

fitness =

Answer 27

survival, reproductive success, mating success

Question 28

traits are subject to natural selection if they are

Answer 28

heritable, variable, and associated with variation in lifetime reproductive success

Question 29

genetic drift leads to

Answer 29

random change

Question 30

what are the two ways genetic drift occurs

Answer 30

- some gametes participating in fertilization at the expense of others - unpredictable events that remove some alleles at greater frequencies (bottlenecking events)

Question 31

genetic drift is more pronounced in _______ populations

Answer 31

smaller

Question 32

gene flow _______ populations

Answer 32

homogenizes

Question 33

gene flow works counter to

Answer 33

selection

Question 34

non random mating

Answer 34

alters genotypes

Question 35

what is assortive mating

Answer 35

individuals choosing mates that are phenotypically similar

Question 36

what are produced as a product of assortive mating

Answer 36

excessive homozygotes

Question 37

biological species classification

Answer 37

species based on reproductive isolation -pro: clear criteria for defining -con: difficult to apply to certain populations

Question 38

morphospecies

Answer 38

defines species on same or different phenotypic /morphological features -pro: easy to apply to a wide range of organisms -con: subjective, may miss cryptic species, may split up polymorphic species

Question 39

phylogenetic

Answer 39

defines species based on monophly -pro: easy to apply to a wide range of organisms -con: requires good phylogeny, can over estimate a number of species

Question 39

how do new species originate?

Answer 39

genetic isolation -> genetic divergence

Question 40

diploidy

Answer 40

2 sets of chromosomes

Question 41

polyploidy

Answer 41

more than 2 sets of chromosomes

Question 42

allopatric speciation

Answer 42

populations are genetically isolated via geographic border

Question 43

sympatric speciation

Answer 43

populations are genetically isolated by non random mating

Question 44

autopolyploid

Answer 44

duplication of the same genome; requires one genome; produces a tetraploid

Question 45

alloployploid

Answer 45

combination of 2 distinct genomes; requires 2 distinct species; produces a polyploid

Question 46

outcomes of secondary contact

Answer 46

1) populations diverge successfully, cannot interbreed -> reproductive isolation complete 2) populations interbreed successfully, gene flow continues -> differences between populations eliminated 3) populations interbreed successfully, offspring are not viable -> reinforcement occurs 4) populations interbreed successfully to product viable and fertile offspring -> hybrid zone forms