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Systematics > Species Concept and Mechanics of Speciation > Flashcards

Species Concept and Mechanics of Speciation Flashcards

1
Q

making of species

A

speciation

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2
Q

species diverge gradually over time in small steps

A

gradual speciation model

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3
Q

a new species changes quickly from the parent species and then remains largely unchanged for long periods of time afterward

A

punctuated equilibrium model

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4
Q

all species on earth thought to share a single __ __

A

common ancestor

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5
Q

when did life arise

A

3.8 billion years ago

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6
Q

speciation is the generation of __ __ __

A

species level diversity

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7
Q

what processes lead to genetic differences sufficint to create a new species

A
  1. Natural selection
  2. Mutation
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8
Q

external

A

natural selection

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9
Q

internal

A

mutation

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10
Q

may have occured billions of times in the last 3.8 billion years

A

speciation

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11
Q

all cultures recognize different forms (species) and name them

A

naming

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12
Q

different species in groups

A

classifying

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13
Q

the challenge of scientists is to name and classify species in a testable way

A

system

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14
Q

number of living species may be as great as ____

A

100 million

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15
Q

is the evolutionary biology subfield that deals with taxonomy, understanding speciation, describing species, inferring phylogenies, and similar endeavors

A

systematics

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16
Q

what is a species

A

smallest independently evolving unit

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17
Q

When does independent evolution occur

A
  • mutation
  • selection
  • gene flow
  • genetic drift
    operate indpendently in different populations
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18
Q

change in the DNA sequence of an organism

A

mutation

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19
Q

process in nature by which organisms better adapted to their environment tend to survive and reproduce more than those less adapted to their environment

A

Natural selection

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20
Q
  • transfer of genetic material from one population to another
  • can take place between two populations of the same species through migration, and is mediated by reproduction and vertical gene transfer from parent to offspring
A

Gene flow

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21
Q
  • change in frequency of an existing gene variant in the population due to random chance
  • may cause gene variants to disappear completely and thereby reduce genetic variation
  • cause initially rare alleles to become much more frequent, and even fixed
A

Genetic Drift

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22
Q

Four basic species concept

A
  1. Biological Species Concept
  2. Morphological Species Concept
  3. Ecological Species Concept
  4. Evolutionary Species Concept
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23
Q
  • defines a species taxon as a group of organisms that can successfully interbreed and produce fertile offspring
  • a species’ integrity is maintained by interbreeding within a species as well as by reproductive barriers between organisms in different species
A

Biological Species Concept

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24
Q

Problems with Biological Species Concept

A
  • is irrelevant to allopatric speciation
  • inapplicable to:
    (1) fossil species
    (2) organisms reproducing asexually or with extensive self-fertilization
    (3) sexual organisms with open mating systems (species that freely hybridize)
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25
Q

defines species as groups of individuals that are morphologically similar to one another and are morphologically distinct from other such groups

A

morphological species concept

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26
Q

advantages of morphological species concept

A
  1. traditional and simple
  2. applicable for living and extinct
  3. applicable for asexual and sexual
  4. on-spot (ready to use as reference)
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27
Q

disadvantages of morphological species concept

A
  1. cryptic species (comprise two or more taxa under single name)
  2. does not address genetic differences
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28
Q
  • concept of species in which a species is a set of organisms adapted to a particular set of resources, called a niche, in the environment
A

ecological species concept

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29
Q

describes the role an organism plays in a community

A

niche

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30
Q

species integrity in ecological species concept is not so much maintained by __ __, but by selection to adapt to each species to its niche

A

reproductive isolation

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31
Q

disadvantages of ecological species theory

A
  • Too many decisions on how much difference between individuals is too much variation
  • Nearly the entire are made up of non-identical individuals
32
Q
  • is a single lineage of ancestor-descendant populations of organisms
  • maintains its identity from other such lineages (in space and time)
  • has its own evolutionary tendencies and historical fate
A

evolutionary species concept

33
Q

advantages of evolutionary species concept

A
  • conceptually clear
  • applies to asexual species, through time, and allopatric species
34
Q

population or species that is physically isolated from other similar groups by an extrinsic barrier to dispersal

A

allopatric species

35
Q

disdvantages of evolutionary species concept

A
  • difficult to know the future
  • asexual species have too many indepent lineages
36
Q
  • practical approach of dealing with the more philosophically grounded evolutionary species concept
A

phylogenetic species concept

37
Q

two-step process to define species in phylogenetic species concept

A
  1. grouping taxa
  2. ranking groups by the criterion of finding the smalles diagnosable monophyletic groups
38
Q

disadvantage of phylogenetic species concept

A
  • almost any population can be diagnosed
  • gene trees may not follow species trees
39
Q

logic of phylogenetic species concept is that traits can only distinguish populations on a phylogeny if the populations have been

A
  • isolated in terms of gene flow
  • have diverged genetically and/or morphologically
40
Q

a population of organisms that is considered distinct for purposes of conservation

A

evolutionarily significant unit (ESU)

41
Q

The “classic” process of speciation

A
  1. isolation
  2. divergence
  3. sometimes secondary contact
42
Q

isolation

A
  • physical barriers
  • allopatry
  • dispersal
  • vicariance
43
Q

division of the population due to the appearance of a new geographical barrier

A

vicariance

44
Q

divergence

A
  • drift
  • natural or sexual selection
45
Q

sometimes secondary contact

A
  • hybridization
  • reinforcement
  • fusion
46
Q

grouping that includes a common ancestor and all the descendants (living and extinct) of that ancestor

47
Q

what can be an isolating factor

A

anything that causes a reduction in gene flow between two potential species

48
Q

physical (geographic) isolation resulting in speciation

A

allopatric speciation

49
Q

alloparty can be due to…

A
  • dispersal (movement)
  • vicariance (encroaching physical feature)
50
Q

= separation of species by physical barriers like water forms, oceans, mountains, etc

A

Geographical isolation

51
Q

heritable condition of possessing more than two complete sets of chromosomes

A

polyploidy

52
Q

speciation without any physical isolation

A

sympatric isolation

53
Q

how does polyploidy happen

A

non-disjunction during meiosis

54
Q

mechanism that keeps species from mating with other

A

Reproductive isolation

55
Q

two types of reproductive isolation

A
  1. prezygotic isolation
  2. postzygotic isolation
56
Q

separation of different species to keep them from creating offspring by preventing the gametes from forming a zygote

A

prezygotic isolation

57
Q

What are the different prezygotic barriers

A
  1. temporal isolation
  2. habitat isolation
  3. behavioral isolation
  4. gametic barrier
  5. mechanical barrier
58
Q

differences in breeding schedules

A

temporal isolation

59
Q

populations of a species move to a new habitat and overimte, forces of natural selection, mutation, and genetic drift will likely result in divergence

A

habitat isolation

60
Q

presence/absence of a specific behavior prevents reproduction from taking place

A

behavioral isolation

61
Q

differences in gamete cells prevent fertilization from taking place

A

gametic barrier

62
Q

reproductive structures simply do not fit

A

mechanial barrier

63
Q

isolation occurs after members of two different species have mated and produced a zygote

A

Postzygotic isolation

64
Q

What are the different postzygotic barriers

A
  1. hybrid inviability
  2. hybrid sterility
65
Q

hybrid individuals cannot form normally in the womb and simply do not survive past embryonic stages

A

hybrid inviability

66
Q

reproduction leads to birth and growth of a hybrid that is sterile and unable to reproduce offspring of their own

A

hybrid sterility

67
Q

biotic factors

A
  • competition
  • predation
  • prey
68
Q

abiotic factors

69
Q

phenomenon in which two or more species with effective defenses share a similar appearance or signaling

A

Müllerian mimicry

70
Q

example of animal that were influenced by their habitats in terms of their mating preferences

A

cichlid fish

71
Q

emphasizes the importance of the environment in shaping perception and thus preferences

A

Sensory drive

72
Q

Speciation via sensory drive in cichlid fish:

A
  • higher frequency of red LWS allele and more red males found in deeper waters
73
Q

the evolutionary process by which many species originate from one species in an area and radiate to different species

A

Adaptive radiation

74
Q

Any of a group of different types of individuals of the same species in a population

A

morphotype

75
Q

what drives diversification

A
  • larger range size
  • more opportunity to get into new habitats

Systematics (17 decks)

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