Biodiversity and Evolution Flashcards

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1
Q

what is the narrow, more formal definition of evolution

A

the genetic changes in a population over generations

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2
Q

what is the broad definition of evolution?

A

change in populations over time

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3
Q

what do genetic changes lead to

A

modifications in appearance, function or behavior of organisms

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4
Q

what is one of the best supported theories in science

A

theory of evolution

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5
Q

what is the foundation for modern biology

A

evolutionary theory

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6
Q

why is evolutionary theory the foundation for modern biology

A

Knowing how organisms adapt and respond to environments over time is vital for understanding history of life

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7
Q

what does biological evolution result from

A

RANDOM genetic changes

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8
Q

natural selection

A

Process where traits that enhance survival and reproduction pass on more frequently to future generations than those that don’t

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9
Q

what can natural selection alter

A

the genetic makeup of an ENTIRE population

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10
Q

what is the mechanism for evolution

A

natural selection

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11
Q

what is natural selection based on

A

unique characteristics seen in the SAME species

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12
Q

does natural selection target a single species or multiple at a time

A

single species

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13
Q

is natural selection universal for ALL animals

A

NO - some traits that are beneficial for one species might be disadvantageous for other species

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14
Q

what do species evolve into over time due to natural selection

A

posses characteristics that lead to better and better success in their given environment

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15
Q

adaptive trait aka adaption

A

a trait that promotes success

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16
Q

maladaptive trait

A

a trait that reduces success

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17
Q

what were three observations found by Darwin and Wallace that contributed to natural selection theory

A
  1. Organisms produce more offspring than can survive and some are more likely to survive and reproduce than others
    - this also insights competition for food, mates, space…
  2. Organisms face a constant struggle to gain enough resources to survive and reproduce
  3. offspring might inherit the characteristics that give individuals an advantage in surviving and reproducing, and the traits woudl then become more prevalent in the population for future generations
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18
Q

what must a trait be for natural selection

A

heritable (genes in the DNA code for the trait and its passed along generations)

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19
Q

sources of genetic variation in populations

A
  1. mutations (changes in nucleotides in DNA)
  2. sexual reproduction (recombination)
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20
Q

three ways natural selection can act on genetic variation

A
  1. directional selection
  2. stabilizing selection
  3. disruptive selection
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21
Q

directional selection

A

selection that drives a feature/trait in one extreme or the other (not the intermediate)

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22
Q

stabilizing selection

A

selection that produces the intermediate trait

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23
Q

disruptive selection

A

selection were traits diverge from their starting condition in BOTH extremes

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24
Q
A

Stabilizing Selection

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25
Q
A

Directional Selection

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26
Q
A

Disruptive selection

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27
Q

Selective pressures

A

an evolutionary force that causes a particular phenotype to be more favorable in certain environmental conditions.

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28
Q

are all selective pressures the same for each environment

A

NO

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29
Q

divergent evolution vs convergent evolution

A

divergent evolution ; two populations of the SAME species, which are geographically separated or reproductively isolated, evolve different traits over time because of adaptation to selective pressures from different environments or habitats.

convergent evolution ; Completely unrelated species develop similar traits because of adaption to selective pressure that are similar in their respective environments

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30
Q

what type of evolution results in speciation

A

divergent evolution

31
Q

why does divergent evolution result in speciation

A

the characteristics of the populations eventually become so different that they are no longer of the same species.

32
Q

Selective breeding

A

allowed humans to exaggerate particular traits that we want and “shape” organisms into the desired phenotype (dog breeds)

33
Q

biodiversity

A

Total variety of all organisms in an area

34
Q

what does biodiversity encompass

A
  • species
  • genes
  • populations
  • habitats
  • communities
35
Q

species

A

a population (or group of populations) of a particular type of organism whose members share certain traits and can interbreed successfully to produce fertile offspring

36
Q

what is a key aspect of organisms being considered species

A

the ability to interbreed successfully and produce fertile offspring

37
Q

Population

A

A group of individuals of a particular (same) species that live in the same area

38
Q

Allopatric speciation

A

Emergence of a new species because of the physical separation of populations over some geographical distance

39
Q

why does allopatric speciation result in new species

A

The separation of once one population into more than one results in them unable to breed together and over time the populations will independently form their own genetic variation

40
Q

what is the test whether speciation has actually occurred

A

Once the populations become different enough where breeding does not produce viable offspring

41
Q

when can speciation ONLY occur

A

if the populations remain isolated for an extended amount of time (if they come back together and breed speciation has NOT occurred)

42
Q

Sympatric speciation

A

When two species form from populations that become reproductively isolated, occupying a new ecological role within the SAME geographical area.

43
Q

examples of sympatric speciation

A
  1. the same species mating during different seasons
  2. species having different mating rituals
  3. occupying different niches in the same area
44
Q

What makes each species unique

A

organisms physical makeup and genetic makeup

45
Q

Fossils

A

Preserved remains of organisms (in sedimentary rock) that lived long ago

46
Q

why are fossils important

A

tell us about the behaviors, physiology and habitats of dead organisms

47
Q

how can we figure out how old a fossil is and when the organism lived

A

by dating the age of the rock where the fossil was found

48
Q

Fossil record

A

Cumulative body of fossils world wide, spanning most of geologic time

49
Q

five things the fossil record shows

A
  1. life has existed on earth for 3.5 billion years
  2. modern organis,s developed from earlier ancestral organisms
  3. number of species existing at any one time has increased through time
  4. species alive today are tiny fraction of all species ever lived with the vast majority being extinct
  5. five major mass extinction events
50
Q

what determines biodiversity

A

the appearance (speciation) and disappearance (extinction) of species

51
Q

Extirpation

A

disappearance of a species from one part of its normal range

52
Q

Extinction

A

Complete disappearance of a species from earth

53
Q

what can cause extinction

A

environmental conditions change rapidly or severely enough that a species cannot adapt genetically to the change

54
Q

are big or small populations MORE vulnerable to extinction

A

SMALL - fluctuations in their size (by chance) could bring pop to zero

55
Q

what are some examples of species more susceptible to extinction

A
  • small populations
  • species dependent on a specific niche or resource
  • endemic species
56
Q

endemic species

A

species that occur in only one location on earth, no where else

57
Q

Background extinction rate

A

the rate at which extinction of one species occurs

58
Q

Mass extinctions

A

Events that killed off massive number of species at once

59
Q

what do mass extinctions represent

A

times when biological diversity dropped drastically in short period of time (50%-90%)

60
Q

what provides the stage for evolution

A

ecology

61
Q

levels of hierarchy that ecologists study

A

ORGANISM level ——> POPULATION level —–> COMMUNITY level ——-> ECOSYSTEM level

62
Q

organism level

A

Describes relationships between organisms and physical environment

63
Q

Population level

A

Quantitative dynamics of how individuals of the same species interact with one another

64
Q

Community level

A

Interactions among species, from one to one interactions to complex interrelationships with entire communities of organisms

65
Q

Ecosystem level

A

Focus on patterns of energy and nutrient flow by studying living and nonliving components of systems in conjunction

66
Q

Habitat

A

Consists of both living and nonliving elements (rocks, soil, leaves…) as well a other organisms around it

67
Q

what do motile organisms use in relation to habitats

A

habitat selection ; actively select habitats from among the range of options they encounter

68
Q

Niche

A

A species’ niche reflects its use of resources and its functional role in a community
(habitat use, consumption of foods, role in flow of energy and matter, interactions with other organisms)

69
Q

Specialists vs Generalists

A

Specialists ; Species that can survive in only narrow range of habitats that contain very specific resources (Koala or panda)

Generalists ; Species with broad tolerances and can use a wide array of habitats or resources (rats, coyotes…)

70
Q

Benefits and disadvantages of specialists

A

Benefit ; Can be successful over evolutionary time by being extremely good at the things they do

disadvantage ; Are vulnerable when condition change and threaten the habitat or resource they have specialized

71
Q

Benefits and disadvantages of generalists

A

Benefit ; Succeed by being able to live in a wide variety of places and weather variable conditions

Disadvantage ; May not survive in any one situation to the degree that a specialist would
(Wouldn’t have the specialized skill set that the specialists would have but a more general skill set)

72
Q

what is important to note about the five mass extinction events

A

they all have different presumed causes (some my volcanic eruptions, some by climate change, some by asteriods…)

73
Q

true or false
we may be in a six great extinction because of human affects

A

TRUE

74
Q

important ecological concepts

A
  • habitat
  • niche
  • specialization