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Biology > Origin Of Species > Flashcards

Origin Of Species Flashcards

1
Q

What is the difference between genotype and phenotype?

A

Genotype you cannot see, where traits come from. Phenotype looks or appearance of the genotype.

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2
Q

What is the definition of Species?

A

share similar physical traits, free interbreed and produce fertile offspring

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3
Q

What is population?

A

any group of individuals, usually of a single species, occupying a given area at the same time

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4
Q

Critics of biological species concept examples?

A
  • Successful reproduction between two different species
  • Unknown if populations that are geographically separated (allopatric) in nature can interbreed
  • Many organisms are asexual and do not mate
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5
Q

What is the biological species concept defines species as?

A

“groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups.”

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6
Q

What is a sub-species?

A

within a single species, individuals in populations that occur in different areas may be distinct from one another
–ex. orange, grey, black, and calico cats

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7
Q

What is considered sympatric in a population?

A

When two different species exist in the same geographic area and thus encounter one another.

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8
Q

What happens if sympatric species commonly exchange genes?

A

Their gene pools should become homogenized.

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9
Q

Distinctiveness of sympatric species are?

A

–Sympatric species are distinctive entities that are phenotypically different, utilize different parts of the habitat, and behave separately.
–Two species that occur together and appear to be nearly identical are termed sibling species.

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10
Q

Individuals that cannot produce fertile offspring are termed?

A

reproductively isolated, and thus members of different species.

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11
Q

What is speciation?

A

process by which new species arise, by either:
–transformation of one species into another
–splitting of one ancestral species into two descendant species

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12
Q

What is Cladogenesis?

A

one ancestral species divides into two descendant species.

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13
Q

What is allopatric speciation?

A

differentiation of populations separated geographic by area into separate species.

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14
Q

What is sympatric speciation?

A

differentiation of populations within a common geographic area into separate species

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15
Q

What is reproduction isolation?

A

populations whose members do not mate with each other or who cannot produce fertile offspring
•Reproductive isolating mechanisms are barriers to successful reproduction

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16
Q

What is the prezygotic isolation?

A

Prevents zygote formation.

Ex. geographic, ecological, behavioral, temporal, mechanical, gamete fusion prevention

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17
Q

What is postzygotic isolation?

A

Prevents proper function of zygote after formation.

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18
Q

What is geographic isolation?

A

–not in the same location (allopatric); do not encounter each other
–Can occur in populations after a natural disaster or anthropogenic disaster

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19
Q

What is ecological isolation?

A

–two species in the same area, but they utilize different portions of the environment
–do not hybridize because they do not encounter each other.
lions and tigers in India
TIGLON lol

20
Q

What is behavioral isolation?

A

–Many birds differ in courtship rituals which tends to keep species distinct
sympatric species avoid mating with members of the wrong species in a variety of ways, including differences in:
visual signals
sound production
chemical signals = pheromones
electrical signals = electroreception

21
Q

What is temporal isolation?

A

species reproduce in different breeding seasons or at different times of day.

22
Q

What is mechanical isolation?

A

Reproductive structures differences prevent mating.

23
Q

What is gamete fusion prevention?

A

gametes of one species functions poorly with the gametes of another species or within the reproductive tract of another species.

24
Q

What is the result of postzygotic isolation?

A

–Hybridization often produces embryos that die during early development.
–hybrid sterility
–abnormal sex organ development
–chromosome alterations

25
Q

Dobzhansky: Genetics and the Origin of a Species is?

A

–Combination of natural selection and population genetics

Evolution is the alteration in a population’s gene pool over time

26
Q

What is gene pool?

A

All available genes in a population.

27
Q

Gene or allelic frequency is ?

A

percent that an allele is represented in a population

28
Q

What is gene flow?

A

movement of genes into/out of a population:
–movement of individuals or gametes between populations
Flow between two populations causes loss of genetic distinctiveness
decrease speciation (as in incompletely isolated populations)

29
Q

What is genetic drift?

A

changes in a population’s gene pool and gene frequencies by chance
–is a greater force in smaller populations

30
Q

What is the founder effect ?

A

Rare alleles and combinations become more prominent when population founded by few individuals
–population bottlenecks; may increase speciation

31
Q

Who said you could stop evolution? How?

A

Hardy-Weinberg
–Population size needs to be large to buffer any chance alterations in the gene pool
–No emigration; no immigration
–Reproduction is at random
–No genetic mutations
–Symbolized by the equation: p2 + 2pq + q2 = 1

32
Q

What is adaptation?

A

change in genes that increases likelihood of survival and reproduction
•Adaptation will increase speciation
–Natural selection produces differences in physiological and sensory traits
–Promotes ecological and behavioral isolation

33
Q

Example of adaptation?

A

–Adaptations in dewlap color produced behavioral isolation in Anolis lizards; increasing speciation
Ability to see dewlap (to attract mate and defend territory) depends on color and environment
Light color reflects light in dark forest conditions
Dark color more visible in bright glare of open habitats

34
Q

What is stabilizing selection?

A

Nature favors “average” phenotype.

35
Q

What is directional selection?

A

Nature favors one extreme phenotype .

Gradualism. Starts slow then hits extreme.

36
Q

What is oscillating selection?

A

Nature favors one set of traits over time then reverses to a previous trait. Oscillation.

37
Q

What is disruptive selection?

A

Nature favors both extreme phenotype, eliminating intermediate.
–Increase speciation: become different species over multiple generations, assuming the two phenotypes evolve reproductive isolating mechanisms

38
Q

What is polyploidy?

A

More then two complete sets of chromosomes.

Tetraloid 4n plants can survive. But not fertilized Diploids. Humans are Diploids.

39
Q

What is autopolyploidy?

A

All chromosomes arise from a single species.

40
Q

What is allopolyploidy?

A

Two species hybridize. Two species breed with one another. Have chromosomes from both parents.
Hybrids often do not develop into adults and Are infertile.

41
Q

What is reinforcement in speciation?

A

genes naturally selected to prevent hybridization until complete reproductive isolation
–ex. pied flycatcher and collard flycatcher appear similar when isolated, but when close, they evolve different color patterns to avoid hybridization

42
Q

What is adaptive radiation?

A

process producing a cluster of species, occupying a series of similar habitats, all evolving from a recent ancestor.

43
Q

What is character displacement?

A

Divergent of adaptions or other characteristics in two similar species in a location where they share habitation. Spurred by competition when there habitat overlap.

44
Q

What is key innovation?

A

Evolves within a species allowing it to use resources or other aspects of the environment that were previously inaccessible.
- Evolution of lungs in fish
- wings in birds and insects.
Allows diversity in descendant species.

45
Q

What is stasis?

A

Long periods of little or no evolutionary change.

Caused by stabilizing selection and oscillating isolation.

46
Q

Does speciation have to occur which substantial phenotype change?

A

No.
–Do not need to develop new behaviors or morphology for speciation to occur
•Phenotypic change can occur within species in the absence of speciation
–Not all phenotypic changes will lead to speciation
–May form only subspecies

47
Q

How long after an extinction would speciation need?

A

10 my.

  • ecosystems must recover.
  • speciation and adaptive radiation require time to occur.

Biology (3 decks)

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