Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology 2 Lecture > Chapter 24 > Flashcards

Chapter 24 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

when does speciation begin

A

when gene flow between populations is reduce or eliminated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what does an elimination of gene flow cause

A

genetic isolation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

allopatry

A

populations that are geographically separated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the term for speciation that begins with geographic isolation

A

allopatric speciation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

allopatric speciation

A

speciation that occurs when population of same species become geographically isolated, often due to dispersal or vicariance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the two ways speciation starts

A
  1. dispersal
  2. vicariance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

dispersal

A

movement of individuals from one place to another
- disperse to new habitat, colonize it, and found new population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

vicariance

A

physical splitting of a habitat
- new geographic barrier can split population into 2 or more subgroups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

biogeography

A

study of how species and populations are distributed geographically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Allopatric Speciation by Dispersal Case Study

A
  • ground finches
  • migration from home island to Daphne Major during breeding season
  • some individuals remained on Daphne Major and produced offspring
  • these individuals represented a new population, allopatric with migrant source population
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

why were the ground finches of the case study who remained on the island represent allopatric speciation

A
  • the two populations bred and nested on different islands
  • when compared, the two populations of ground finches had different beak sizes
  • genetic drift and natural selection were at play
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is though to lead to speciation in many island groups, including finches

A
  • dispersal and colonization
  • genetic drift
  • natural selection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Allopatric Speciation by Vicariance Case Study

A
  • collected tissue samples from trumpeters throughout the Amazon and compared DNA sequences of four genes to estimate phylogeny
  • compared phylogenetic data to biogeographical analysis of formation of Amazon river system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How did the creation of the Amazon river cause vicariance speciation in the trumpeters case study

A

when the river was formed, it split the population in two, limiting gene flow
- since trumpeters cannot fly over the distance of the Amazon river, they were isolated from one another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the first requirement of speciation

A

genetic isolation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

sympatry

A

condition in which two or more populations live in the same geographic area, or close enough to permit interbreeding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

sympatric speciation

A

speciation that occurs even though populations live within the same geographical area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what does sympatric speciation not require

A

geographic isolation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what two factors can initiate the process of sympatric speciation

A
  1. extrinsic factors (external)
  2. intrinsic factors (internal)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

extrinsic factors example

A

disruptive selection for extreme phenotypes based on different ecological niches or mate preferences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

example of intrinsic factors

A

chromosomal mutations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what does disruptive selection favor

A

extreme phenotypes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

if disruptive selection persists over time, what happens to the two subsets of the population

A

can become genetically isolated and diverge from each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

case study for disruptive selection (sympatric speciation)

A
  • currently described as single species
  • two groups of travelers: larger and smaller
  • transient killer whales looked different from the resident killer whales
  • ecotypes were not mixing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what were the killer whales in the case study separated by

A

feeding cultures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

niche

A

describe range of ecological resources that a species can use and range of conditions that it can tolerate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what did the two ecotypes of killer whales occupy

A

different niches within the same area of ocean

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is the particular type of mutation that is extremely important in speciation

A

polyploidy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

polyploidy

A

condition of possessing more than two complete sets of chromosomes
- caused by massive error in mitosis or meiosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what are the two types polyploids

A
  1. autopolyploid
  2. allopolyploid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

autopolyploid

A

individuals are produced when a mutation results in doubling of chromosome number and chromosomes all come from same species

32
Q

allopolyploid

A

individuals are created when parents of different species mate and then an error in mitosis occurs
- results in viable, nonsterile offspring with two full sets of chromosomes

33
Q

what is the hey even leading to autopolyploid

A

nondisjunction during meiosis resulting in diploid gametes

34
Q

autopolyploid is the duplication of

A

the same genome

35
Q

speciation occurs with what generation and when

A

single generation and instantaneously

36
Q

allopolyploid is the combination of

A

two genomes

37
Q

when is speciation by polyploidy common

A

in plants

38
Q

what is speciation by polyploidization driven by

A

chromosome level mutations and occurs in sympatry

39
Q

what is the simplest outcome of 2 populations coming into contact

A

populations fuse over time as gene flow erases any distinctions between them

40
Q

if two populations have diverged and are distinct genetically, what is expected of their hybrid offspring

A

have lower fitness because they will not be well adapted to either habitat

41
Q

when should their be a strong selection

A

when postzygotic isolation occurs because hybrid offspring have reduced fitness

42
Q

reinforcement

A

natural selection for traits that prevent interbreeding among populations
- selected traits reinforce differences that evolved while populations were isolated from one another

43
Q

if closely related species are sympatric, what will the mating pattern be? (study on fruit fly species)

A

individuals from the two species will seldom mate with one another in lab

44
Q

if species are allopatric, what will the mating pattern be (study on fruit fly species)

A

individuals from the two species will often mate with one another in lab

45
Q

hybrid zone

A

geographic area where interbreeding occurs and hybrid offspring are common

46
Q

what can determine if hybrid zones are narrow or wide, long or short lived, and move over time?

A

fitness of hybrid offspring and extent of breeding between parental species

47
Q

how can hybridization cause speciation

A

if hybrid offspring can not only survive and reproduce but also possess a unique combination of traits that are adaptive in their environment

48
Q

secondary contact of two populations can produce…

A
  • fusion of populations
  • extinction of one population
  • reinforcement of divergence
  • founding of hybrid zones
  • formation of new species
    (look at table 24.4 for summary)
49
Q

example of fusion of populations

A

open water whitefish population fused with sympatric benthic whitefish population after introduction of invasive open water competition

50
Q

example of one population

A

open water whitefish population may go extinct after fusion

51
Q

example of hybrid zone formation

A

hybrid zone between hermit and Townsends warblers appeared to have moved over time

52
Q

example of formation of new species

A

hybridization between sunflowers gave rise to a new species with unique characteristics

53
Q

speciation

A

splitting event that results from a 2 step process
1. genetic isolation
2. genetic divergence

54
Q

genetic isolation

A

occurs when some sort of barrier to gene flow isolates 2 populations within a species

55
Q

in genetic isolation, what does the absence of gene flow mean for the alleles

A

alleles are not exchanged

56
Q

genetic divergence

A

occurs when mutation, natural selection, and genetic drift occur in each of isolated populations
- populations begin to evolve independently

57
Q

species

A

an evolutionary independent population or group of populations generally distinct from other species

58
Q

what are some ways species will differ or be distinct from each other in

A
  • appearance
  • behavior
  • habitat
  • ecology
  • genetic characteristics
59
Q

what are the three main criteria used to identify species

A
  1. biological species concept
  2. morphospecies concept
  3. phylogenetic species concept
60
Q

biological species concept

A
  • main criteria is reproductive isolation
  • members of same species cannot interbreed successfully
  • no gene flow
61
Q

what are mechanisms that stop gene flow

A
  • prezygotic isolation
  • postzygotic isolation
62
Q

prezygotic isolation

A

prevents individuals of different species from mating successfully

63
Q

postzygotic isolation

A

hybrid offspring of mating between members of different species either do not survive or reproduce

64
Q

what are the causes of why mating wouldn’t occur in prezygotic isolation

A
  1. temporal- breed at different times
  2. habitat- breed in different habitats
  3. behavioral- have different courtship displays
65
Q

mating occurs bit no zygotes produced because of

A
  1. mechanical- male and female repro. structures are incompatible
  2. genetic barrier- egg and sperm are incompatible
  3. hybrid inviability- do not develop normally and die during early development
  4. hybrid sterility- offspring mature but are sterile
66
Q

what are some disadvantages to biological concept

A
  • criteria of repro. isolation cannot be evaluated in fossils
  • concept difficult to apply when closely related populations don’t overlap with each other geographically
  • repro. isolation can be a complex gradient
67
Q

morphospecies concept

A

identify evolutionary independent lineages by difference in size, shape, or other features
- if populations are independent and isolated from gene flow
- widely applicab;e

68
Q

what are some disadvantages of the morphospecies concept

A
  • may lead to naming of 2+ species when there is only 1
  • cannot identify cryptic species
  • subjective
69
Q

polymorphic species

A

species that has two or more distinct phenotypes in the same interbreeding population at same time

70
Q

cryptic species

A

species that cannot be distinguished from similar species by easily identifiable morphological traits

71
Q

phylogenetic species concept

A
  • identifies species based on evolutionary history
  • all species form a monophyletic group
72
Q

what does a monophletic group/clade/lineage consist of

A
  • ancestral population
  • all of its descendants
  • and ONLY those descendants
73
Q

what is one method to identify monophyletic groups

A
  • one snip test
  • imagine cutting one branch with scissors, everything that would fall off is a monophyletic group
74
Q

how are monophyletic groups identified

A

traits called synapomorphies

75
Q

synapomorphies

A

trait that is formed in certain groups of organisms and their common ancestors but missing in distant ancestors
- example: white fur that identifies polar bears as monophyletic group within bears

76
Q

what are the disadvantages of phylogenetic concept

A
  • only available for tiny subset of populations
  • tends to recognize many more species than the other concepts
  • complicates naming of species

Biology 2 Lecture (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions