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Grade 11 bio > Evolution > Flashcards

Evolution Flashcards

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Biology 101 flashcards
1
Q

What is Darwin’s theory of evolution

A

All species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual’s ability to compete, survive, and reproduce

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2
Q

what did John Ray introduce

A
  • classification system for plants and animals based on anatomy and physiology
  • introduced the term species
  • said that a species was: 1. similar in structure and shape
    2. reproduced with one another
    3. the offspring must be able to reproduce
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3
Q

what did Buffon learn

A

Noticed similarities between humans and apes
Thought that maybe apes were our common ancestor that we developed from a long time ago

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4
Q

What did mary anning discover

A
  • fossil hunter
  • found a giant aquatic reptile
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5
Q

what did George Cuvier discover

A
  • developed science of paleology
  • studied fossil in sedimentary rock
  • found some species completely disappeared in more recent layers
  • first to notice extinction
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6
Q

what was Hutton’s theory of geological change

A
  • Idea known as Gradualism
  • Changes in earth’s curst due to slow continuous processes
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7
Q

what did Charles Lyell discover and therorize

A
  • proposed theory of uniformitarianism
  • uniform rates building and wearing down earth’s crust
  • proposed that earth’s crust was millions of years old and not thousands
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8
Q

what did Lamarck theorize

A
  • stated that changes are adaptions to environment acquired in an organism’s lifetime
  • said acquired traits were passed to offspring (not true)
  • idea of use and disuse
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9
Q

what did Thomas Malthus observe

A
  • economist
  • Observed babies being both faster than people were dying
  • Population size limited by resources such as the food supply
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10
Q

Darwin’s 5 key observations

A
  1. why are similar organisms clustered in the same region
  2. why are living and fossilized organisms found in the same region
  3. why did island organisms look like those from the nearest mainland
  4. why was there a lot of biodiversity on such small islands
  5. did nature have a selection process
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11
Q

what was Darwin’s idea on natural selection

A
  • used natural selection to describe the process that only the offspring fittest for the environment would survive
  • now it is defined as different levels of survival and reproduction of individuals due to differences in phenotype
  • in his book, he describes how populations underwent decent with modifications due to natural selection
  • didn’t use the word evolve since he thought it indicated progress or improvement towards a goal
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12
Q

natural selection concepts

A
  • the struggle for existence
  • survival of the fittest
  • descent with modification
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13
Q

survival of the fittest

A
  • fitness; ability of an individual to survive & reproduce
  • adaption; inherited characteristic that increases an organisms chance for survival
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14
Q

descent with modifications

A
  • all species, living & extinct were derived from common ancestors
  • implies that all living organisms are related; single tree of life
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15
Q

what are the three features of the fossil record

A
  1. Fossils appear in chronological (time) order in layers of sedimentary rock
  2. Fossils in young layers of rocks are more similar to species alive today. The oldest fossils are in the deepest layers of rocks
  3. Different fossils appear in layers of rocks of different ages
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16
Q

what are the four main fossilization processes

A
  1. mineralization: minerals in water permeate bones, wood, or shells
  2. preservation: amber, tar pits and permafrost can keep all parts of the organism intact
  3. molds; the shell or bones take a long time to dissolve and leave a hollow sedimentary rock
  4. compression: common for leaves and ferns inder sedimentary pressure
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17
Q

transitional fossils

A
  • show intermediary links between groups of prehistoric organisms
  • help scientists better understand relationships between groups of organisms alive at different times
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18
Q

vestigial structures

A
  • reduced forms of structures that were once useful in ancestors but no longer are needed
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19
Q

the 5 evidences to support evolution

A
  1. fossils
  2. biogeography
  3. anatomy
  4. comparative embryology
  5. molecular biology (DNA & proteins)
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20
Q

biogeography

A
  • study of past and present geographical distribution of species
  • Geographically close environments are more likely to be populated by related species
  • Animals on islands often closely resemble animals on the closest continent
  • Geology of rocks and fossils form the previously connected continents supports the Theory of Evolution
  • Found fossils from Pangea era in different continents that are now miles apart from each other
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21
Q

Anatomy

A
  • Anatomical similarities and differences are used to determine how closely related species are
  • Homologous structures
  • Analogous structures
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22
Q

homologous structures

A

structures that have similar parts and a common ancestry or origin but now have different functions

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23
Q

analogous structures

A

structures that perform a similar function now but do not have a common ancestry

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24
Q

comparative embryology

A
  • study of structures that appear during embryonic development
  • similarities in development are indicative of common ancestry
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25
Q

molecular biology

A
  • By comparing DNA of different organisms, scientists can determine their degree of relatedness
  • also compare amino acid sequences that make up the proteins in different organisms
  • Amino acid sequence of protein depends on nitrogen base sequence in the DNA
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26
Q

microevolution

A
  • process that results from genetic changes over a small number of generations
  • caused by changes in allele frequencies in a population; changes occur to help populations better adapt to their environment
  • Results in adaptations as a result of natural selection of the fittest offspring
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27
Q

alleles and gene pool

A
  • phenotype depend on the genotype or alleles
  • Species with more genetic variation are more likely to survive when there are challenging selective pressures in the environment like climate change
  • A gene pool describes all the alleles of all the genes in a population
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28
Q

what are the 4 types of natural selection

A
  1. Directional selection
  2. Diversifying selection
  3. Stabilizing selection
  4. Sexual selection
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29
Q

natural selection

A
  • process by which individuals with favourable traits that make them better suited for their environment are more likely to survive reprocure
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30
Q

directional selection

A

One extreme of the phonotype is favoured resulting in a shift in phenotype distribution over time

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31
Q

stabilizing selection

A

middle phenotype is favoured and extremes phenotypes are rarer over time

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32
Q

disruptive selection

A
  • both extremes of phenotype are favourable for survival over time
  • Results in loss of intermediate phenotype
  • Might eventually form two different species
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33
Q

sexual selection

A
  • Evolutionary trend is for females to have large ovum with lots of stored energy for zygote growth
  • Males have immense numbers of small mobile sperm
  • Lead to huge variety of sexual behaviours and attractants
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34
Q

sexual dimorphism

A
  • a strategy where one sex displays different physical characteristics to show fitness for mating
  • Most often male is brightly coloured to show his fitness
35
Q

what does sexual selection usually involve

A
  • competition between males
  • mate choice by females
  • leads to enhanced reproductive success
36
Q

5 microevolution mechanisms

A
  1. natural selection
  2. mutations in gametes
  3. genetic drift (bottleneck and founder effect)
  4. gene flow
  5. non-random mating or artificial selection (in-breeding, assortative mating)
37
Q

mutations in gametes

A
  • Only important to evolution if mutation is in a gamete and is passed on to offspring
  • New mutation might provide an advantage for natural selection
38
Q

genetic drift

A
  • change in allele frequencies due to small population size
  • Smaller the population the less likely all the alleles in parent gene pool will be reflected in offspring gene pool
39
Q

genetic drift - bottleneck effect

A

reduction in alleles in a population resulting from a disaster that drastically reduces population size

40
Q

genetic drift - founder effect

A
  • when a few individuals separate from a large population and establish new population in new location
  • New population allele ratios can be very different and some alleles can be missing in the new population
41
Q

gene flow

A

gain or loss of alleles from a population by the movement of individuals by immigration or emigration

42
Q

non random mating

A
  • when individuals choose a mate based on a particular phenotype
  • two types:
    1. in-breeding
    2. assortative
43
Q

non-random mating: in-breeding

A
  • Between closely related partners results in fewer heterozygotes and more homozygotes thus changing allele frequencies
44
Q

non-random mating: assortative

A

Where a similar partner is chosen
- Ex. Same sized hermaphroditic land snails. Having the same size bodies allows better alignments of genitals for mating

45
Q

speciation

A
  • the splitting of one species into two different species as a result of a reproductive isolating mechanism
46
Q

reproductive isolation

A
  • once gene flow stops, genetic divergence occurs between two populations and they become genetically different
  • lacking gene flow will cause the mutations in the two populations to be independent
  • natural selection & genetic drift within the 2 populations will be different
  • allele frequencies will change differently in separated populations
47
Q

what are the two mechanisms for reproductive isolation

A
  1. pre-zygotic
  2. post-zygotic
48
Q

pre-zygotic

A

barriers prevent mating or fertilization

49
Q

post-zygotic

A

barriers occur when sperm enters the egg but sometimes prevents the zygote from developing into a fertile offspring

50
Q

what are the 5 pre-zygotic barriers

A
  1. behavioural barriers
  2. time or temporal barriers
  3. habitat barriers
  4. mechanical barriers
  5. gamete barriers
51
Q

behavioural barriers

A

special signals or behaviours that are species-specific and prevent interbreeding with closely related species
- ex. courtship rituals, bridsong variations, pheromones

52
Q

time or temporal barriers examples

A
  • timing of mating might differ for similar species occupying the same habitat or geographical range
    -ex. different time of day for breeding
  • ex. different breeding seasons
53
Q

habitat barriers examples

A
  • specific habitats might differ for similar species with the same geographical range
  • ex. one type of snake prefer to live in the meadows while another likes to live near the water
54
Q

mechanical barriers examples

A
  • anatomical incompatibility of two species that attempt to mate
  • ex. “lock and key” genitals of some insects
  • ex. left & right coiling snails
55
Q

Gamete barriers example

A
  • inability of gametes that do meet to fuse and form a zygote
  • ex. sperm of one species unable to survive the reproductive tract of another species
56
Q

what are the 3 post-zygotic barriers

A
  1. hybrid sterility
  2. hybrid inviability
  3. hybrid breakdown
57
Q

hybrid sterility

A
  • hybrid offspring is sterile since meiosis fails to form normal gametes in hybrid due to different chromosome number or structure of the two parent species
  • ex. mule (horse x donkey)
  • ex. liger (male lion & tigress)
58
Q

hybrid inviability

A
  • genetic incompatibility prevents normal mitosis after fusion
  • ex. hybrid zygote of a tiger & leopard
59
Q

hybrid breakdown

A
  • hybrid offspring are viable and fertile but the second generation are often sterile or weak
  • ex. rice hybrids, cichlid fish
60
Q

what are the 3 human effects on speciation

A
  1. habitat destruction
  2. hunting
  3. invasive species
61
Q

examples of habitat destruction

A

farms, wetland drainage, roads, and cities destroy or fragmented ecosystems

62
Q

examples of hunting

A

a lot of people hunt animals to keep a part of them as a trophy which causes them to become endangered

63
Q

examples of invasive species

A

often out-compete native species for resources

64
Q

what is the name of the current era

A
  • Anthropocene era
  • described as era where human activity has the main influence on the environment
65
Q

what can species be defined with

A
  • morphology
  • phylogeny
66
Q

morphology

A

similarities in body shape, size and other structural features

67
Q

phylogeny

A

similarities in evolutionary history

68
Q

what are the 2 types of speciations

A
  1. phyletic speciation
  2. divergent speciation
69
Q

phyletic speciation

A
  • happens when an ancestral species changes over time to become a new descendent species
  • also called anagenesis
70
Q

divergent speciation

A

happens when species diverge- one species branches off into 2 or more species
- also called cladogenesis

71
Q

what are the 2 types of divergent speciation

A
  1. allopatric
  2. sympatric
72
Q

sympatric

A

populations within the same geographical areas diverge and become reproductively isolated
- most common in plants than animals

73
Q

what are the two scenarios of sympatric speciation

A
  1. polyploidism
  2. Hybridization
74
Q

what happens in polyploidism

A
  • parent plants produce offspring that are polyploid if there are mistakes in meiosis
  • offsprings are reproductively incompatible with parent population
75
Q

what happens in hybridization

A
  • two species can interbreed to produce a sterile offspring
  • asexual reproduction results in the formation of a separate population
  • sterile hybrids, through mistakes in meiosis become fertile polyploids which forms a new fertile species
76
Q

allopatric

A
  • population is split into 2 or more isolated groups by geographical barrier
  • gene pool of split populations diverge cause of natural selection, genetic drift, gene flow, or mutation
  • if enough time passes by 2 populations become so distinct that they are unable to interbreed if they are brought back together
77
Q

adaptive radiation

A
  • a form of allopatric
  • a diversification of a common ancestral species into a variety of a differently adapted species
78
Q

divergent evolution

A
  • pattern of evolution in which species from a common ancestor become increasingly distinct
  • eg. adaptive radiation is a form of divergent evolution: finches
79
Q

convergent evolution

A

pattern of evolution in which two unrelated species have different traits that have arisen as adaptations to similar environmental conditions

80
Q

what are the two types of speed of evolutionary change

A
  1. phyletic gradualism
  2. punctuated equilibrium
81
Q

phyletic gradualism

A

the idea that evolution occurs at a slow but steady pace

82
Q

punctuated equilibrium

A

the idea that for most of the time species are stable. but every now and then there is a disruptive event that prompts rapid change

83
Q

How long was Darwin’s voyage of discovery and where and what did he discover

A

— Left England in 1831 and returned in 1836
-stoped at the Galápagos Islands west of South America
-discovered very different climates and unique animals on the islands (finches, tortoises, iguanas)

Grade 11 bio (16 decks)

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