evolution

Question 1

adaptation

Answer 1

a heritable trait that enhances the ability of an organism to reproduce in a particular environment

Question 2

alleles

Answer 2

alternative versions of genes that differ in nucleotide sequence
- different alleles may produce differences in character expression

Question 3

biological fitness

Answer 3

the ability of an individual to contribute offspring to the next generation

Question 4

differential success

Answer 4

the differing biological fitness of individuals with some traits compared to individuals with other traits

Question 5

evolution

Answer 5

change across generations in the distribution of heritable phenotypes and genotypes in a population

Question 6

fixation

Answer 6

the chains in a gene pool from a situation where there exists more than one variant of a particular gene (allele) to a situation where only one allele remains

Question 7

gene flow

Answer 7

the movement of alleles among populations due to migration and subsequent interbreeding

Question 8

genetic drift

Answer 8

random changes in allele or genotype frequencies within a population

Question 9

heritability

Answer 9

a measure of how much of the variation in a given trait among individuals in a population can be attributed to genetic variation among those individuals.
- higher heritability means that offspring will more strongly resemble their parents
- low heritability means that individual variation in a trait is due largely to variation among individuals in their environment

Question 10

macroevolution

Answer 10

evolution across geologic timescales (generally mya) involving groups of species

Question 11

microevolution

Answer 11

evolution within a population or among populations within a species, over shorter timescales than those examined in macroevolution

Question 12

natural selection

Answer 12

individuals that have traits that increase their biological fitness within their environment reproduce more than those with less beneficial traits
- traits differences are heritable = the more fit parents will pass their trait to their offspring and the pop. will evolve as the freq. of the more fit trait increases in the next gen
- vice versa if the traits aren’t heritable = trait won’t evolve = freq wont increase in next gen

Question 13

null hypothesis

Answer 13

an assertion that there is no relationship among observations that the relationship is due to chance, or than an experimental treatment has no observable effect other than that expected by chance

Question 14

population

Answer 14

a group of interbreeding individuals that belong to the same species and occupy a similar geographic area

Question 15

population genetics

Answer 15

an approach to understanding microevolution that combines mathematical theory and experimental data to understand the effects of mutation, genetic drift, gene flow, and natural selection on genes within and among populations

Question 16

character

Answer 16

an observable feature, such as eye color or a behavior or a specific locus in a sequence of dna

Question 17

character matrix

Answer 17

an array that constrains the character states (along the top) of a group of taxa (along the left)

Question 18

character state

Answer 18

a specific form of a character
- ex: eye color is a character, where as brown eyes and blue eyes are character states
- character = gen, character state = more specific within that topic

Question 19

clade

Answer 19

a monophyletic group made up of on an ancestor (node) and all of its descendants (also called a phylogenetic group)

Question 20

cladogram

Answer 20

tree-like representation of proposed relationships among taxonomic groups; branch lengths DO NOT represent time

Question 21

convergence

Answer 21

when organisms share similar characteristics states but do not share them with their most recent common ancestor
- ex: the character states evolved independently of one another, such as the ability to fly in bats, birds, and insects

Question 22

derived

Answer 22

a new character or character state to present in the ancestor

Question 23

fossil

Answer 23

any preserved remnant of impression of an organism that lived in the past

Question 24

fossil record

Answer 24

all of the fossils that exist from the history of life, whether discovered or undiscovered by people

Question 25

homolog

Answer 25

one of two or more features in different species that are similar due to descent from a common ancestor - don’t necessarily have the same structure, function, or behavior

Question 26

homology

Answer 26

a similarity between 2 or more features that is inherited from a common ancestor, such features are referred to as homologous and each feature is called a homolog of other features

Question 27

homoplasy

Answer 27

a character state of 2 or more taxa that WAS NOT inherited from a common ancestor of those taxa character states that arise independently in 2 or more lineages - can result from evolutionary convergence, parallel evolution or evolutional reversal

Question 28

outgroup

Answer 28

group of organisms used as a point of reference for comparison with the groups of primary interest; typically the most closely related taxonomy to but not the same ancestor of, the set of taxa under study

Question 29

phylogenetic tree

Answer 29

tree-like representation of proposed relationships among taxonomic groups; branch lengths DO represent time

Question 30

polarization

Answer 30

the process of indicating the directionality of character state changes from ancestral to derived - ancestral =0 -derived = 1 or higher

Question 31

reversal

Answer 31

the change in character states from a derived state to an ancestral state

Question 32

synapomorphy

Answer 32

a derived or changed character state shared by 2 or more lineages in a particular clade; indicators of common ancestry

Question 33

uniformitarianism

Answer 33

assumption of uniformity of processes over time the idea that processes in action in the past were different than those today

Question 34

mutation

Answer 34

the result of an error in DNA replication

Question 35

point mutation

Answer 35

a change in a single nucleotide

Question 36

fitness

Answer 36

if individuals with different genotypes differ in their chances of survival and reproduction, then there are differences is fitness that cause allele frequencies to change depend and change on the environment the organism is in

Question 37

directional selection

Answer 37

occurs when on allele results in higher rates of survival and reproduction

Question 38

purifying selection

Answer 38

ensures that deleterious mutations cannot take over a population

Question 39

balancing selection

Answer 39

if heterozygous individuals have a higher fitness than either homozygote, selection will maintain both alleles in the population

Question 40

stabilizing selection

Answer 40

individuals with moderate or average phenotypes are more fit

Question 41

disruptive selection

Answer 41

both extreme traits are favored in an environment

Question 42

genetic drift

Answer 42

occurs bc populations are not infinitely large a process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to the next most pronounced effects in small populations

Question 43

bottleneck event

Answer 43

reduction in size of an existing population cause rapid changes in allele frequencies that would occur in a large stable population

Question 44

founder events

Answer 44

the establishment of a new population of smaller size cause more rapid changes in allele frequencies than would occur in a large stable population

Question 45

gene flow

Answer 45

reduces differences between populations results from movement of individuals or gametes the transfer of alleles from one population to another, resulting from the movement of fertile individuals or their gametes

Question 46

isogamy

Answer 46

produce gametes of the same size and form

Question 47

anisogamy

Answer 47

produce gametes that differ in size and form