Unit 7: Natural Selection Flashcards

1
Q

natural selection

A

process by which organisms with traits better suited to the environment survive and reproduce more often

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2
Q

evolution

A

change in the gene pool

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3
Q

evolutionary fitness

A

measure of an organism’s ability to survive and reproduce

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4
Q

selective pressure

A

process by which organisms either live or die based on their traits

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5
Q

niche

A

organism’s role in an ecosystem

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6
Q

mutation

A

change in the nucleotide sequence of an organism

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7
Q

population

A

a group of same-species individuals located in the same area

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8
Q

speciation

A

formation of new species from one

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9
Q

genetic drift

A

change in allele frequences due to random chance event

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10
Q

bottleneck effect

A

change in allele frequencies due to clamactic event

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11
Q

founder effect

A

loss in genetic variation due small part of original population migrating

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12
Q

hardy-weinburg equilibrium

A

states that allele and genotype frequencies will remain constant in a population if there are no evolutionary forces acting on it

p^2 + 2pq + q^2 = 1
p + q = 1

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13
Q

nonrandom mating

A

sexual selection; female chooses mate

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14
Q

fossil

A

remains of a prehistoric organism captured in rock

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15
Q

vestigial structure

A

structures that we have that were once used by our ancestors but not used anynore

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16
Q

morphology

A

study of body structures and placements

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17
Q

phylogeny

A

evolutionary history of a kind of organism

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18
Q

phylogenetic tree

A

shows evolutionary relationships between organisms over time

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19
Q

cladogram

A

only shows the evolutionary relationships between organisms not with regard to time

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20
Q

outgroup

A

species that shares barely or not at all any similarities with the rest

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21
Q

lineage

A

descent from a common ancestor

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22
Q

reproductive isolation

A

barriers that prevent two species from reproducing

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23
Q

allopatric

A

different places

24
Q

sympatric

A

same place

25
Q

adaptive radiation

A

the exploitation of new niches by many organisms

26
Q

extinction

A

total elimination of a species

27
Q

convergent evolution

A

similar characteristics evolved in species without a recent common ancestor

28
Q

divergent evolution

A

similar characteristics due to a recent common ancestor

29
Q

species diversity

A

variety and abundance of species in a population

30
Q

ecosystem

A

a region as well as all the organisms and abiotic factors present in it

31
Q

RNA world hypothesis

A

idea that before cells, DNA, and the central dogma, RNA could form naturally and function like proteins

32
Q

molecular clock

A

technique in which the rate at which mutations occur is used to figure out when speciation first occurred

33
Q

What causes natural selection?

A

Overproduction
Variation
Selective pressure

34
Q

How does natural selection affect populations?

A

Natural selection applies selective pressure on populations based on traits that better suit the environment and increase reproductive fitness

35
Q

What is the importance of phenotypic variation in a population?

A

the more variation in a species, the less susceptible it as a whole is to disease, increasing reproductive fitness

36
Q

How can humans affect diversity within a population?

A

Via artificial selection, humans can choose the traits they want in a population over generations

37
Q

How do random occurrences affect the genetic makeup of a population?

A

genetic drift (random occurrences) leads to change in (may increase or decrease) allele frequencies of a population

38
Q

What is the role of random processes in the evolution of specific populations?

A

random processes like genetic drift lead to changes in allele frequencies which over time is evolution

39
Q

What is the change in the genetic makeup of a population over time called?

A

evolution

40
Q

What are the conditions under which allele and genotype frequencies will change in populations?

A
  1. small population sizes
  2. gene flow
  3. mutations
  4. nonrandom mating
  5. natural selection
41
Q

What will happen to the population if any of the conditions of Hardy- Weinberg are not met?

A

the population will evolve

42
Q

What types of data provide evidence for evolution?

A

Biogeography (distribution of species in different environment)
Fossils
Homologies (similar morphological structure)
DNA and proteins
Mathematical models (Hardy-Weinburg)

43
Q

How do morphological, biochemical, and geological data provide evidence that organisms have changed over time?

A

Morphological: organisms with homologous structures indicate a recent common ancestor implying that speciation has occurred.
Biochemical: mutations cause changes to the gene pool which is evolution
Geological: similar organisms changed due to being in different geographies (environments)

44
Q

What are the fundamental molecular and cellular features shared across all domains of life, which provide evidence of common ancestry?

A

The last universal common ancestor of all life had:

DNA, RNA, Proteins, ATP, lipid membrane, cell division

45
Q

What structural and functional evidence on cellular and molecular levels provides evidence for the common ancestry of all eukaryotes?

A

Membrane-bound organelles

Linear chromosomes

46
Q

How is evolution an ongoing process in all living organisms?

A

organism populations generally have genetic variation that natural selection can act on, which drives evolution.

47
Q

How can a phylogenetic tree and/or cladogram be used to infer evolutionary relatedness?

A

All organisms in the cladogram/phylogenetic tree are related via the recent common ancestor
Two species can be more closely related than others depending on how relatively recent speciation that created them occurred

48
Q

What are the conditions under which new species may arise?

A

reproductive isolation

49
Q

How does the rate of evolution and speciation differ under different ecological conditions?

A

Extinction can open up new ecological niches which can be rapidly exploited by organisms, leading to rapid evolution and speciation.

50
Q

What are the processes and mechanisms that drive speciation and evolution?

A

Natural selection
Genetic drift
Gene flow
Non random mating

51
Q

What factors can lead to the extinction of a population?

A
Abiotic factors (climate, asteroids, and comets, etc)
Biotic factors (humans, hunting, low fitness, etc)
52
Q

How can the risk for extinction increase due to changes in the environment?

A

Changes in the environment affect the ecological niches of organisms, which can lead to extinction if they can’t adjust to a new one.

53
Q

How can species diversity in an ecosystem change from speciation and extinction?

A

Speciation increases species diversity while extinction decreases species diversity

54
Q

How can extinction make new environments available for adaptive radiation?

A

Extinction clears up ecological niches that can be exploited by other organisms that survived the extinction event

55
Q

How does the genetic diversity of a species or population affect its ability to withstand environmental pressures?

A

The more diverse a species is the greater its ability as a whole to withstand environmental pressures.