Midterm 1 (Ch. 25-28)

Question 1

Node (phylogenetic tree)

Answer 1

where ancestral lineage splits

Question 2

Tip (phylogenetic tree)

Answer 2

recently evolved; can be species but doesn’t have to be

Question 3

Properties of living organisms (5)

Answer 3

• made of cells (cell theory)
• use energy to stay alive and reproduce
• process info to respond to ext. and int. environment
• reproduce/replicate
• products of evolution

Question 4

Proximate question

Answer 4

mechanistic question (how does it work)

Question 5

Ultimate question

Answer 5

evolutionary (why and how does it exist)

Question 6

Parts of scientific method

Answer 6

observation, hypotheses, predictions, test predictions (experiment), conclusions

Question 7

Null hypothesis (H_0); what is it and how is it used

Answer 7

• thing being tested has no effect, or that there is no pattern other than chance (random) effects
• try to prove predictions by disproving (rejecting) null hypothesis

Question 8

Inferential statistics

Answer 8

compare data to null hypothesis of no pattern or chance pattern

Question 9

Homologies (and types)

Answer 9

similar traits due to shared ancestry (can be genetic or development)

Question 10

Structural homology

Answer 10

similar structures across related organisms despite different functions

Question 11

Evolutionary lineage

Answer 11

one or a series of ancestor-descendant relationships, often in context of evolutionary tree

Question 12

Speciose (adj)

Answer 12

species-rich

Question 13

Speciosity (n)

Answer 13

measure of how many species are in a group

Question 14

speciate (v)

Answer 14

ancestral lineage evolving into one or more different descendant lineages

Question 15

Darwin’s four postulates

Answer 15

• variation among individuals of a population or species
• at least some heritable traits
• struggle for existence: more offspring produced than can survive
• certain kinds of individuals produce more surviving offspring

VHS Center

Question 16

Natural selection

Answer 16

mechanism of evolution; populations change when individuals with certain heritable traits have more surviving offspring because those traits help the parents survive and reproduce

Question 17

Adaptations

Answer 17

“fit” between organism and its environment (produced by natural selection)

Question 18

Fitness

Answer 18

measure of ability to survive and create viable offspring

Question 19

Mechanisms of evolution (name them)

Answer 19

Natural selection, genetic drift, mutation, gene flow

NGMG

Question 20

Genotype frequency

Answer 20

frequency of homozygous and heterozygous genotypes in population (e.g., MM, Mm, mm)

Question 21

Allele frequency

Answer 21

frequency of each kind of allele (e.g., M, m)

Question 22

p (HW)

Answer 22

frequency of dominant allele

p=freq(AA) + 1/2 freq(Aa)

Question 23

q (HW)

Answer 23

frequency of recessive allele

q=freq(aa) + 1/2 freq(Aa)

Question 24

HW frequency of homozygous dominant genotype

Answer 24

p^2

Question 25

HW frequency of heterozygous genotype

Answer 25

2pq

Question 26

HW frequency of homozygous recessive genotype

Answer 26

q^2

Question 27

HW assumptions (5)

Answer 27

- random mating - no genetic drift (population must be infinite) - no gene flow (no immigration/emigration) - no mutation - no natural selection

Question 28

Geneticist definition of ecolution

Answer 28

change in allele frequencies over time

Question 29

Violations of HW lead to____.

Answer 29

evolution

Question 30

Genetic drift

Answer 30

evolutionary mechanism; comes from sampling error (sample of gametes leading to a generation may not be representative of parent population allele frequencies); larger effect in smaller populations

Question 31

Kinds of nonrandom mating (2)

Answer 31

Inbreeding and sexual selection

Question 32

Inbreeding changes ____ and not _____; decrease in _____.

Answer 32

genotype frequencies; allele frequencies; heterozygotes

Question 33

Inbreeding depression

Answer 33

lower fitness due to higher than HWE frequency of expressed deleterious alleles

Question 34

Directional selection

Answer 34

one extreme has higher fitness

Question 35

Stabilizing selection

Answer 35

intermediate value has higher fitness

Question 36

Disruptive selection

Answer 36

intermediate value has lowest fitness

Question 37

Balancing selection

Answer 37

variation maintained through: heterozygote advantage and frequency dependent selection

Question 38

Frequency dependent selection

Answer 38

rare genotype/phenotype has highest fitness

Question 39

Which mode of selection increases genetic variation?

Answer 39

disruptive selection

Question 40

Gene flow

Answer 40

migration (immigration and emigration) introduces alleles from other populations, reducing differences between or among populations

Question 41

Mutation

Answer 41

source of all genetic variation; introduces new alleles into a population

Question 42

Morphological species concept (MSC)

Answer 42

species are groups of organisms that look similar to each other

Question 43

Polymorphic species

Answer 43

many kinds within a species

Question 44

Sexually dimorphic species

Answer 44

males and females look different

Question 45

Cryptic species

Answer 45

separate species that look nearly identical

Question 46

Biological species concept (BSC)

Answer 46

species are reproductively isolated

Question 47

Prezygotic isolation

Answer 47

individuals can't mate

Question 48

Postzygotic isolation

Answer 48

hybrid offspring don't survive or reproduce

Question 49

Phylogenetic species concept (PSC)

Answer 49

species are single evolutionary lineages; smallest monophyletic group on a phylogenetic tree

Question 50

Synapomorphy

Answer 50

shared, derived character

Question 51

Allopatric speciation

Answer 51

physical, generally geographic isolation

Question 52

Founder effect

Answer 52

small population taken from larger population to start new population (genetic drift)

Question 53

Vicariance

Answer 53

physical splitting of population

Question 54

Reinforcement

Answer 54

selection favoring pre-zygotic isolation

Question 55

Sympatric speciation

Answer 55

species from common ancestor in same place

Question 56

Order of taxonomic ranks

Answer 56

domain, kingom, phylum, class, order, family, genus, species

Question 57

Symplesiomorphy

Answer 57

shared trait but not derived; shared due to older common ancestor

Question 58

Homoplasy

Answer 58

convergent evolution; similar characteristics but not bc of shared ancestry

Question 59

Paraphyletic group

Answer 59

doesn't include all descendants of a common ancestor

Question 60

Polphyletic group

Answer 60

doesn't include most recent common ancestor

Question 61

Natural taxon

Answer 61

monophyletic group

Question 62

Eras in Phanerozoic Eon

Answer 62

Paleozoic, Mesozoic, Cenozoic

Question 63

Start of Paleozoic era

Answer 63

Cambrian explosion

Question 64

Adaptive radiation

Answer 64

rapid diversification of organisms to fill ecological niches

Question 65

Criteria for mass extinction

Answer 65

at least 60% of species go extinct

Question 66

Permian extinction (at end of Permian); rate

Answer 66

at least 90% of all species lost

Question 67

Genetic bottleneck

Answer 67

sudden reduction in the number of alleles in a population (genetic drift occurs)