Chapter 12- Genetics and Evolution

Question 1

Genes

Answer 1

DNA sequences that code for heritable traits that can be passed from one generation to the next

Question 2

Alleles

Answer 2

Alternative forms of genes

Question 3

Genotype

Answer 3

Genetic combination possessed by individual

Question 4

Phenotype

Answer 4

Manifestation of a given genotype as an observable trait

Question 5

Homologues

Answer 5

2 copies of each chromosome

Question 6

Locus

Answer 6

Location of a gene on a specific chromosome

Question 7

Dominant allele

Answer 7

Only one copy of allele is needed to express phenotype

Question 8

Recessive allele

Answer 8

2 copies are needed

Question 9

Homozygous genotype

Answer 9

Both alleles are the same for a given gene

Question 10

Heterozygous genotype

Answer 10

Alleles are different for a gene

Question 11

Hemizygous genotype

Answer 11

Only one allele is present (X and males)

Question 12

Complete dominance

Answer 12

Only one dominant and one recessive allele exists for a gene

Question 13

Codominance

Answer 13

More than one dominant allele exists for a gene

Question 14

Incomplete dominance

Answer 14

Phenotype is intermediate between 2 homozygous genotypes

Question 15

Penetrance

Answer 15

Proportion of individuals in the population carrying the allele who actually expressed the phenotype

Question 16

Expressivity

Answer 16

Varying phenotypes despite identical genotypes

Question 17

Transforming principle

Answer 17

Live, non-virulent bacteria must have acquired the ability to form smooth capsules from dead virulent bacteria

Question 18

Epigenetics

Answer 18

Changes in DNA that do not involve an alteration to the nucleotide sequence

Question 19

Chromosomes

Answer 19

Contain genes and a linear sequence

Question 20

Mendel’s first law of segregation

Answer 20

States that an organism has two alleles for each gene, which segregate during meiosis, resulting in gametes carrying only one allele for a tray

Question 21

Gene pool

Answer 21

All of the alleles that exist within a species

Question 22

Mutations

Answer 22

Change in DNA sequence that results in mutant allele

Question 23

Mutagens

Answer 23

Substances that can cause mutations

Question 24

Transposons

Answer 24

Insert and remove themselves from genome

Question 25

Point mutations

Answer 25

One nucleotide and DNA is swapped for another

Question 26

Silent mutations

Answer 26

Change in nucleotide has no effect on the final protein synthesized from the gene

Question 27

Missense mutations

Answer 27

Change in nucleotide results in substituting 1 amino acid for another

Question 28

Nonsense mutations

Answer 28

Change in nucleotide results in substituting a stop codon for an amino acid

Question 29

Frameshift mutations

Answer 29

Nucleotides are inserted or deleted from genome

Question 30

Deletion mutations

Answer 30

Large segment of DNA is lost from chromosome

Question 31

Duplication mutations

Answer 31

Segment of DNA is copied multiple times

Question 32

Inversion mutations

Answer 32

Segment of DNA is reversed

Question 33

Insertion mutations

Answer 33

Segment of DNA is moved from 1 chromosome to another

Question 34

Translocation mutations

Answer 34

Segment of DNA from 1 chromosome is swapped with a segment of DNA from another chromosome

Question 35

Founder effect

Answer 35

Small population of a species finds itself in reproductive isolation as a result of natural barriers, catastrophic events, or other bottlenecks

Question 36

Genetic drift

Answer 36

Occurs when the composition of the gene pool changes as a result of chance

Question 37

Punnett squares

Answer 37

Diagrams that predict the relative genotypic/phenotypic frequencies that will result from the crossing of two individuals

Question 38

Monohybrid cross

Answer 38

Only one trait is being studied - Parent (P) generation is being crossed - Filial (F) generation is offspring

Question 39

Recombination frequency

Answer 39

Likelihood that two alleles are separated from each other during crossing over

Question 40

Natural selection

Answer 40

Theory that certain characteristics or traits possessed by individuals within a species help those individuals have greater reproductive success

Question 41

Fitness

Answer 41

Reproductive success related to the relative genetic contribution of this individual to the next generation

Question 42

Modern Synthesis Model

Answer 42

When mutation or recombination results in a change that is favorable to the organisms reproductive success, that change is more likely to pass on to the next generation

Question 43

Differential Reproduction

Answer 43

Traits passed on by the more successful organisms will become ubiquitous in the gene pool

Question 44

Inclusive fitness

Answer 44

Measure of an organism's success in the population, based on the number of offspring, success and supporting offspring, and ability of offspring to then support others

Question 45

Punctuated Equilibrium

Answer 45

Suggests that changes in some species occur in rapid bursts

Question 46

Adaptive radiation

Answer 46

Rapid rise of a number of different species from a common ancestor

Question 47

Stabilizing selection

Answer 47

Keeps phenotypes in a narrow range, excluding extremes

Question 48

Directional selection

Answer 48

Moves the average phenotype toward 1 extreme

Question 49

Disruptive selection

Answer 49

Moves the population toward two different phenotypes at the extremes and can lead to speciation

Question 50

Divergent evolution

Answer 50

Occurs when 2 species sharing a common ancestor become more different

Question 51

Parallel evolution

Answer 51

Occurs when 2 species sharing a common ancestor evolve in similar ways due to analogous selection pressures

Question 52

Convergent evolution

Answer 52

Occurs when 2 species not sharing a recent ancestor evolved to become more similar due to analogous selection pressures