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BI302 > Chapters 4,5+6 > Flashcards

Chapters 4,5+6 Flashcards

1
Q

What do phylogenetic trees represent?

A

the branching pattern of evolution over time

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2
Q

Who proposed evolution being like a branching tree?

A

Darwin

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3
Q

Why are phylogenetic trees advantageous?

A

Because we can understand how and when species evolve and as simply or as complex as we may need

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4
Q

what is a branch in a phylogenetic tree

A

a lineage evolving through time that connects successive speciation

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5
Q

what is phylogeny

A

a visual representation of evolutionary history

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6
Q

What are nodes in a tree

A

points in a phylogeny where a lineage splits

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7
Q

What is a clade

A

single branches in the tree of life, each clade represents an organsim and all of its descendants

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8
Q

what is monophyly

A

a group of organisms that for a clade

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9
Q

what is polyphyly

A

a taxon that does not include the common ancestor of all members of the taxon

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10
Q

what is paraphyly

A

a group of organisms that share a common ancestor but not all the descendants

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11
Q

what do split branches in trees represent

A

a trait change or addition to a common ancestor in the tree itself

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12
Q

what are taxa

A

groups of organisms that a taxonomist judges

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13
Q

what is synapomorphy

A

a derived form of a trait that is shared by a group of related species

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14
Q

what is an outgrup

A

group(s) of organisms that are outside the monophyletic group being considered

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15
Q

what is convergent evolution

A

the independent origin of similar traits in separate evolutionary lineages

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16
Q

All phylogenetic trees are a _________

A

hypothesis

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17
Q

what is parsimony

A

a principle that guides the selection of alternative hypotheses, the alternative requiring the fewest assumptions or steps is usually best

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18
Q

trees are most accurate when they have shared ______ characters

A

derived

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19
Q

what is horizontal gene transfer

A

it describes the transfer of genetic material-other than parent to offspring- to another organism without reproduction

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20
Q

what is evolutionary reversal

A

describes the reversion of a derived character state to a form resembling its ancestral state

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21
Q

what is polytomy

A

describes an internal node with more than two branches

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22
Q

What are the three types of mammals

A

monotremes, marsupials and eutherians

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23
Q

what are monotremes

A

do not have specific nipples for secreting milk and lay eggs like birds (ex. platypus)

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24
Q

what are marsuipals

A

young crawl into pouch of mothers belly after birth and are carried until they can survive on their own (ex. kangaroo)

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25
Q

what are eutherian mammals

A

develop a placenta to feed embryos to the uterus

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26
Q

what part of the human body can tell us a lot about our phylogeny

A

the inner middle ear

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27
Q

what is exaptation

A

a trait that initially carries out one function and is later opted for a new function (eg. feathers)

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28
Q

what are the three kinds of molecules that are especially important for evoluion

A

DNA RNA and proteins

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29
Q

proteins are made up of …

A

amino acids :-)

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30
Q

what is gene expression

A

the the process by which information from a gene is transformed into a product

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31
Q

what is the role of RNA polymerase

A

the enzyme that buildsthe single stranded RNA molecule from the DNA template during transcription

32
Q

translation happens inside the ________.

A

ribosome

33
Q

what is the gene control region

A

upstream section of DNA that includes the promoter region that influence the transcription of DNA

34
Q

what is a repressor

A

proteins that bind DNA or RNA and inhibit the expression of genes

35
Q

what is a transcription factor

A

proteins that bind to specific DNA sequences and act like a lightswitch turning sequences on and off

36
Q

what are enhancers

A

short sequences of DNA within the gene control region where activator proteins bind to activate gene expression

37
Q

what is RNA splicing

A

modifying RNA after transcription but before translation where introns are removed and exons are joined together to create a continuous strand

38
Q

what is alternative splicing

A

process of comining different subsets of exons together, yeilding different mrNA transcripts from a single gene

39
Q

in humans, the average gene can splice to express one of __ different proteins

A

six

40
Q

proteins can be modified even after translation (T or F)

A

T, called post-translational regulation

41
Q

what is epigenetic

A

the functional modifications of DNA that do not involve nucleotides

42
Q

what is a genome

A

all the hereditary infromation of an organism

43
Q

what are pseudogenes

A

genes that can no longer produce a functional molecule

44
Q

mutations happen within the ____

A

mRNA

45
Q

what is aneuploidy

A

chromosmoes are duplicated or lost leading to an abnormal number or chromosomes

46
Q

what are cis acting elements

A

stretches of DNA located near a gene that influence the expression of that gene, often binding sites

47
Q

what are transacting elements

A

sequences of DNA located away from the focal gene that generally code for a protein or other molecule that then influences expression of the focal gene

48
Q

what are germ-line mutations

A

mutation that affect the gametes and can be transmitted from parents to offspring

49
Q

what is genetic polymorphism

A

the simultaneous occurenceof two or more discrete phenotypes within a population

50
Q

what is polyphenism

A

a trait for which multiple discrete phenotypes can arise from a single genotype depending on environmental circumstances

51
Q

what is a morphogen

A

a signaling molecule that flows between nearby cells and acts directly to later expression of target genes

52
Q

what is phenotypic plasticity

A

refers to changes in the phenotype produced by a single genotype if a different environment

53
Q

what is population genetics

A

the study of the distribution of alleles within a population and the mechanisms that can cause allele frequencies to change over time

54
Q

what is a genetic locus

A

specific location of a gene or piece of DNA sequence on a choromosome

55
Q

what is hardy-weinberg equilibrium

A

in the absence of drift, selection, migration and mutation, allele frequencies at a genetic locus will not change from one generation the the next

56
Q

what is a null hypothesis

A

default hypothesis that concludes that no changes were found

57
Q

what is a fixed allele

A

an allele that remains in a population when all of the alternative alleles have dissapeared

58
Q

the smaller the population sample, the ____ deviations you will have (more or less)

A

more

59
Q

what is a genetic bottleneck

A

an event in which the number of individuals in a population is reduced drastically

60
Q

What is the founder effect

A

type of genetic drift that describes the loss of allelic variation that takes a small population from a larger one and colonizes in a different environment

61
Q

The reproductive success of a particular phenotype is known as _______

A

fitness

62
Q

what is relative fitness(of a genotype)?

A

the success of the genotype at producing new individuals standardized by the entire success of all the fitness of other genotypes

63
Q

what is pleiotropy

A

the condition when a mutation in a single gene affects the expression of more than one different phenotypic trait

64
Q

what is antagonistic pleiotropy

A

occurs when when a mutation with beneficial effects for one trait also causes effects on other traits

65
Q

what is negative selection

A

selection that decreases the frequency of alleles in a population

66
Q

what is posititve selection

A

selection that increases the frequency of alleles in a population

67
Q

what is epistasis

A

occurs when the effects of an allele at one genetic locus are modfied by alleles at one or more loci

68
Q

what is an additive allele

A

an allele that yields twice the phenotypic effect when two copies are present versus one

69
Q

are dominant and recessive alleles additive?

A

no

70
Q

what is inbreeding depression

A

reduction in the average fitenss of inbred individuals relative to that of outbred individuals

71
Q

inbreeding (increases/decreases) the precentage of genetic loci that are homozygous for alleles and changes allele frequenceis

A

increases

72
Q

what is genetic distance

A

a measure of how different populations are from each other genetically

73
Q

what is gene flow

A

movement or migration of alleles from one population to another

74
Q

population subdivision increases the effects of _____ ____.

A

genetic drift

75
Q

what is the average excess of fitness

A

the difference between the average fitness of individuals bearing the allele and the average fitness of the population as a whole

76
Q

what is the inbreeding coefficient

A

the probability that two alleles at any locus will be identical because of common descent

BI302 (3 decks)

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