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BIO 1411 > Chapter 16 | Speciation > Flashcards

Chapter 16 | Speciation Flashcards

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Biology 101 flashcards
1
Q

what are species?

A

groups of organisms that mate with one another

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2
Q

what do each species represent?

A

an independent unit of biodiversity

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3
Q

what’s a good analogy to compare species with?

A

puzzles–pieces that fit are related, others not so much

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4
Q

how does Linnaeus describe species?

A

based on appearance

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5
Q

define the morphological species concept

A

individuals with unique morphology in comparison with other groups are identified as distinct species

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6
Q

why do members of species look alike?

A

they are genetically related through a common gene pool

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7
Q

define cryptic species

A

organisms that look similar but do not interbreed

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8
Q

what are some common examples of cryptic species?

A

species of frogs and fish

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9
Q

define sexual dimorphism

A

organisms can be of the same species but may have differing physical characteristics

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10
Q

define morphological differences

A

variations in the physical form, structure, or appearance of organisms within or between species

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11
Q

define the lineage species concept

A

species are terminal monophyletic branches on the tree of life

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12
Q

what is the lifeline of the history of a each species?

A

starts at a speciation event and ends at extinction or another specification event

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13
Q

what is a speciation event?

A

one species splits into two or more daughter species, which thereafter evolve as distinct lineages

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14
Q

a group of organisms that includes a common ancestor and all of its descendants

A

monophyletic or distinct clade

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15
Q

define the biological species concept

A

groups of actually/potentially interbreeding populations which are reproductively isolated from other such groups are defined as species

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16
Q

what are exceptions or constraints to the biological species concept?

A

it does not apply to asexually reproducing organisms and is limited to a single point in evolutionary time

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17
Q

list the types of reproductive isolating mechanisms

A

(1) prezygotic reproductive barriers
(2) postzygotic reproductive barriers

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18
Q

define prezygotic reproductive barriers

A

barriers that act before ferritization which prevent mating

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19
Q

what are some examples of prezygotic reproductive barriers?

A

(1) habitat
(2) timing
(3) behavior (i.e songs)
(4) mechanics (structure compatability)
(5) gametes

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20
Q

define postzygotic reproductive barriers

A

barriers that act after ferritization that prevent the development of viable offspring or lower their fertility

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21
Q

what is an example of an animal that is infertile as a result of cross-organism mating?

A

mules/donkeys

22
Q

what is necessary for lineages to remain distinct through evolutionary time?

A

reproductive isolation

23
Q

what happens if reproductive isolation does not occur for lineages?

A

the exchange of genes maintain a common gene pool

24
Q

define the Dobzhansky-Muller model

A

(1) a single ancestral population is divided into two and they evolve independently
(2) in each lineage, new alleles become fixed at different loci. these new alleles at the two loci work fine with other alleles within their own gene pool

25
Q

if two separated populations come back together, what could they still be able to do?

A

hybridize/interbreed

26
Q

what are Dobzhansky-Muller genetic incompatibilities

A

new alleles of hybrid offspring are inferior or lethal, reducing viability and/or fertility

27
Q

as pairs of species diverge genetically, they become

A

increasingly reproductive isolated

28
Q

occurs when populations are separated by a physical barrier

A

allopatric or geographic speciation

29
Q

as populations accumulate genetic differences

A

they increasingly become incapable of successful reproduction

30
Q

for marine organisms that experienced allopatry, if a random species on both sides shared a gene pool, what would that imply?

A

the gene pool is air dispersed or organisms found a way to cross the barrier

31
Q

if marine organisms experienced divergence before a barrier was present, what does that suggest?

A

the barrier had no effect on their gene flow and was already in the process of splitting

32
Q

what are two main kinds of allopatric speciation?

A

organisms are separated by a barrier or organisms cross a barrier to form new isolated populations

33
Q

when a small group of individuals becomes isolated from the main population and establishes a new population in a different geographic area

A

founder event

34
Q

a partition of a gene pool without physical isolation

A

sympatric speciation

35
Q

what’s an easy way to describe sympatric speciation?

A

populations aren’t separated, but something occurred that made them split/evolve into separate species

36
Q

what are some concepts that could cause sympatric speciation?

A

(1) behavioral changes
(2) genetic mutation
(3) adaptation to ecological niches

37
Q

what’s a real-life example of sympatric speciation?

A

fruit flies used to lay eggs on hawthorn fruits, but some flies now lay their eggs on apples when Europeans brought them over

38
Q

sympatric speciation most commonly occurs by

A

polyploidy

39
Q

duplication of whole sets of chromosomes

A

polyploidy

40
Q

chromosome duplication in a single species

A

autopolyploid

41
Q

combination of chromosomes from two species and duplicating them

A

allopolyploidy

42
Q

how does a tetraploid individual come about?

A

accidental autopolyploid of two diploid gametes combining

43
Q

polyploidy can result in ______ in two generations

A

complete reproductive isolation

44
Q

how can interbreeding occur?

A

if differentiated populations in sympatry do not completely discriminate in choice of mate

45
Q

how will gene pools be mixed and such that no speciation occurs?

A

if hybrid offspring are fit and interbreed with both parental populations

46
Q

strengthening of prezygotic barriers

A

reinformcement

47
Q

if hybrid offspring survive or reproduce poorly

A

natural selection may favor prezygotic barriers

48
Q

what are some characteristics that influence speciation rates?

A

(1) in plants, rates are higher in animal-pollinated than wind-pollinated plants
(2) sexual selection
(3) specialized diets
(4) faster in species with poor dispersal abilities

49
Q

the proliferation of a large number of species from a single ancestor

A

evolutionary radiation

50
Q

resulting species live in a wide array of environments

A

adaptive radiation

BIO 1411 (3 decks)

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