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biology > topic 5 - evolution > Flashcards

topic 5 - evolution Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what is evolution?

A

a change in the allele frequency of a population’s gene pool over successive generations

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2
Q

what is Lamarck’s theory of evolution?

A

species change via habitual use and disuse (ex. giraffe stretches its neck to reach leaves in tall trees, so giraffe’s neck becomes extended from constant use and its offspring inherit its long neck)

rejected, as acquired traits do not have a genetic basis (can’t be inherited)

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3
Q

what is Darwin (and Wallace)’s theory of evolution?

A

species change via natural selection

(ex. giraffe with a longer neck can reach leaves in tall trees, so it will get enough food to survive and reproduce so it has more offspring that inherit a long neck)

reinforced by our understanding of modern genetics

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4
Q

what is a fossil

A

preserved remain or trace of a past organism

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5
Q

what is the fossil record

A

totality of all fossils

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6
Q

how can fossils be dated

A

by determining the age of the rock layer (strata) in which te fossil is found

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7
Q

what is the law of fossil succession

A

the chronological sequence of complexity by which characteristics appear to develop (basically changes have occured in organisms and changes occured in consistent sequence of development)

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8
Q

what are transitional fossils

A

intermediary forms within the evolution of a genus and demonstrate species connections

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9
Q

what is an example of a transitional fossil

A

archaeopteryx links evolution of birds (wings and feathers) to dinosaurs (jaws and claws)

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10
Q

what is selective breeding

A

form of artificial selection

mating of animals with desired characteristics (driven by human intervention)

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11
Q

selective breeding promotes phenotype extremes: T or F?

A

true

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12
Q

example of selective breeding?

A

draf horses (power) vs racing horses (speed)

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13
Q

what are homologous structures

A

anatomical features that are similar in basic structure despite being used in different ways

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14
Q

Species A: 5 digit limbs
Species B: 6 digit limbs
Species C: 3 digit limbs
Species D: 5 digit limbs

Which two species are most closely related? RANDOM SITUATION

A

A + D

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15
Q

what is adaptive radiation?

A

Describes the rapid evolutionary diversification of a single ancestral line

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16
Q

what is an example of a homologous structure in a variety of animals?

A

pentadactyl limb of mammals, birds, amphibians and reptiles

mammals: tool manipulation
bird/bat wings: flying
horse hooves: galloping
whale/dolphine fins: swimming

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17
Q

what type of distribution curve does genetic variation typically follow?

A

normal distribution curve as the rate of change is gradual and cumulative

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18
Q

what is speciation

A

evolutionary process by which two related populations diverge into separate species

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19
Q

how does speciation occur?

A

populations become isolated, and hence the level of genetic divergence gradually increases the longer the populations remain separated (since genetic compatibility decreases)

populations will reach a point where they can no longer interbreed and produce fertile, viable offspring

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20
Q

what is an example of evolution in melanistic insects?

A

peppered moths

exist in two forms (light and dark colouration)

in polluted environments, SO2 kills the lichen on trees and soot blackens the bark, which provides camouflage for dark moths

before the industrial revolution, the lighter moth had a survival advantage (lichen is white)

after the industrial revolution, the dark moth has a survival advantage

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21
Q

what is biogeography

A

distribution of species across an area (related species will usually be found in close proximity)

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22
Q

what are vestigial structures

A

functionless or reduced remnants of organs that were once present in ancestors

ex. whales have a pelvic bone (ancestors were terrestrial)

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23
Q

how can the time of evolutionary divergence be estimated? (molecular clock) –> think of conditions

A

gene must have a stable mutation rate

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24
Q

what are the three main mechanisms by which genetic variation within a population is maintained?

A

mutations (changes to the gene sequence)

sexual reproduction (new gene combinations)

gene flow (immigration and emigration)

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25
Q

how can population variety be altered? (biodiversity down)

A 
random chance (genetic drift)
directed intervention (natural / artificial selection)
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26
Q

is the impact of a change greater on a large or small population?

A

SMALL (may occur via population bottle necks or founder effect)

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27
Q

why does natural selection occur? (list potential reasons)

A
  • genetic (inheritable) variation within a population caused by mutations, meiosis, and sexual reproduction
  • there is competition for survivale as species tend to produce more offspring than the environment can support
  • environmental selection pressures give rise to differential rates of reproduction
  • organisms with beneficial traits are likely to survive and reproduce while those less adapted produce less offspring
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28
Q

ICEAGE?

A

key components to the process of natural selection

Inherited variation, Competition, Environmental selection, Adaptations, Genotype frequency changes, Evolution occurs

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29
Q

what are examples of environmental selection pressures?

A 
Predator / prey dynamics 
Abiotic factors (ex climate)
Nutrient supply (food source)
Diseases / pathogens 
Available resources (ex. light)
Space requirements (habitat)

PANDAS

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30
Q

how does genetic variation occur through mutations?

A

new alleles are formed

can be beneficial, detrimental or neutral

beneficial: change the gene sequence –> new variations of a trait (missense mutation)

detrimental mutations: truncate the gene sequence (nonsense mutations) to abrogate normal function

neutral: no effect (silent mutation)

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31
Q

how does meiosis promote variation?

A

produces new gene combinations through either crossing over or independent assortment

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32
Q

what is crossing over

A

exchange of segments of DNA between homologous chromosomes during prophase I between nonsister chromatids at chiasmata

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33
Q

what is independent assortment

A

orientation of homologous chromosomes towards the opposing poles is random when they line up in metaphase I

orientation of each bivalent occurs independently, meaning different combinations of maternal/paternal chromosomes can be inherited when bivalents separate in anaphase I

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34
Q

how does sexual reproduction promote variation

A

random fertilization by egg and sperm generates different zygotes

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35
Q

what did Malthus identify?

A

Malthusian dilemma: populations multiply geometrically (exponential progression) while food resources only increase arithmetically (linear progression)

SPECIES TEND TO PRODUCE MORE OFFSPRING THAN THE ENVIRONMENT CAN SUSTAINABLY SUPPORT

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36
Q

what are adaptations

A

features of organisms that aid their survival by allowing them to be better suited to their environment

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37
Q

how can adaptations be classified?

A

structural: physical differences in biological structure (ex. giraffe neck)
behavioural: differences in patterns of activity (ex. opossums feigning death)
physiological: variations in detection and response by vital organs (ex. colour perception)
biochemical: differences in molecular composition of cells and enzyme functions (ex. blood groups)
developmental: variable changes that occur across the life span of an organism (ex aging)

38
Q

do biological adaptations have a genetic basis? why or why not

A

yes, organisms with beneficial adaptations are more likely to survive and reproduce

39
Q

what is an ecological niche

A

functional position of an organism in the environment

40
Q

how are adaptive radiation and ecological niches related?

A

when members of a species occupy a variety of different ecological niches, it leads to the rapid diversification of the original ancestral line (adaptive radiation)

ex. beaks of finches on Daphne Major

41
Q

is the variation that exists within a population heritable? if so, how is it determined?

A

yes, determined by the presence of alleles

42
Q

how does the proportion of different alleles change due to natural selection?

A

beneficial alleles improve reproductive prospects and are more likely to be passed onto future generations

detrimental alleles result in fewer offspring and are less likely to be present in future generations

43
Q

what is Daphne Major

A

volcanic island part of the Galapagos (native habitat of Darwin’s Finches)

44
Q

how can bacteria develop antibiotic resistance via gene mutation?

A

resistant bacteria survives and reproduces by binary fission

flourishes in the absense of other strains of bacteria (that are killed b bacteria)

introduction of antibiotic caused the antibiotic resistant gene to become more frequent (evolution)

45
Q

what is the binomial system of naming

A

globally recognized classification scheme developed at a series of congresses, proposed by Carl Linnaeus in 1735

46
Q

how are organisms named according to the binomial system?/

A 
two part name:
Genus species
genus is first + capitalized
species is second + lower case
must be underlined when handwritten
47
Q

what are the three domains of life?

A

Eukarya
Archaea
Eubacteria

48
Q

what are eukarya?

A

eukaryotic organisms that contain a membrane-bound nucleus

49
Q

what are archaea

A

prokaryotic cells lacking a nucleus and consist of extremophiles

50
Q

what are eubacteria

A

cells lacking a nucleus and consist of the common pathogenic form

51
Q

T or F? Archaea and Eubacteria were always two separate domains

A

F. Initially both considered part of Monera

reclassified after biochemical differences were noted

52
Q

what is taxonomy?

A

science involved with classifying groups of organisms on the basis of shared characteristics

53
Q

what does it mean when organisms share a lot of taxa

A

the more taxa organisms share, the more similar they are

54
Q

what are the taxa used?

A 
kingdom
phylum
class
order
family
genus
species

Katy Perry Comes Over For Grape Soda

55
Q

what are the two main classification schemes used to identify living organisms?

A

artificial classification

natural classification

56
Q

what is artificial classification? (w/ one advantage + one disadvantage)

A

arbitrarily selecting unifying characteristics first and then grouping organisms accordingly

advantage: easy to develop + stable
disadvantage: do not show evolutionary relationships

57
Q

what is natural classification (+ one advantage + disadvantage)

A

grouping organisms based on similarities first and then identifying shared organisms

advantage: can be used to predict characteristics shared by species within a group
disadvantage: highly mutable (may need to reclassify groups when new information/evidence arises)

58
Q

characteristics of bryophyta?

A
  • no vascularization
  • no true leaves, roots, or stem
  • reproductive stalks
  • short
  • ex. mosses, liverworts
59
Q

characteristics of fiicinophyta?

A
  • vascular
  • no flowers
  • triangular fonds
  • reproduce through spores
  • ex. ferns
60
Q

characteristics of coniferophyta?

A
  • vascular
  • woody stems
  • needles and scales
  • reproduction through non-motile gametes (cones)
    ex. cedar, juniper, fir, pine trees
61
Q

characteristics of angiospermophyta?

A
  • vascular
  • flowering plants
  • flowers and fruits
62
Q

how is the kingdom Animalia subdivided?

A

invertebrates (no backbone)

vertebrates (backbone)

63
Q

characteristics of porifera

A
  • no body symmetry
  • no mouth or anus
  • pumping water in/out to filter out food
  • stuck in place
  • ex. sea sponges
64
Q

characteristics of cnidaria

A
  • mouth but no anus
  • stinging cells
  • tentacles
  • ex. sea jellies
65
Q

characteristics of platyhelminthes

A
  • bilateral symmetry
  • mouth but no aanus
  • flattened body shape (SA:vol ratio up)
  • nonsegmented
  • ex. tapeworms
66
Q

characteristics of annelida

A
  • segmented
  • mouth + anus
  • ex. earthworm
67
Q

characteristics of mollusca?

A
  • mouth + anus
  • non segmented
  • shell reinforced with calcium
  • ex. snails, clams, octopus
68
Q

characteristics of arthropoda

A
  • hard exoskeleton made of chitin
  • segmented
  • mouth + anus
  • ex. insects, spiders
69
Q

characteristics of chordata

A
  • mouth + anus
  • notochord + hollow, dorsal nerve
  • ex. mammals, birds, reptiles
70
Q

characteristics of fish?

A
  • gills to absorb oxygen
  • scales made of bony plates
  • ecothermic
  • external fertilization
71
Q

characteristics of amphibian

A
  • moist skin
  • external fertilization
  • start lives underwater (adults develop lungs)
  • ectothermic
72
Q

characteristics of reptiles

A
  • scales made of kertain
  • internal fertilization
  • lungs with extensive folding
  • ectothermic
73
Q

characteristics of birds

A
  • bipedal
  • covered in feathers made of keratin
  • internal fertilization + lay eggs
  • endothermic
  • light weight
  • high heartbeat + breathing rates
74
Q

characteristics of mammals?

A
  • hairy bodies (hair made of keratin)
  • females can produce milk in specialized glands
  • endothermic
75
Q

what is a dichotomous key?

A

method of identification whereby groups of organisms are divided into two categories repeatedly

76
Q

what is cladistics?

A

method of classifying organisms into groups of species called clades

77
Q

what is a clade

A

group of organisms that evolved from a common ancestor (share common characteristics)

78
Q

what are cladograms

A

tree diagrams where each branch point represents the splitting of two new groups from a common ancestor

79
Q

what is a node

A

branch point which represents a speciation event by which distinct species are formed via divergent evolution

80
Q

what is phylogeny

A

evolutionary history

81
Q

what does it mean when the number of nodes between two groups is small

A

they are expected to be more closely related

82
Q

what type of relationship do cladograms show

A

evolutionary

83
Q

features of a cladogram

A

root: initial ancestor
nodes: common ancestor that speciated
outgroup: distantly related species in cladogram
clades - common ancestor

84
Q

how are molecular sequences used to determine how closely related two species are?

A

the more similar the base sequences of two species are, the more closely related the two species are expected to be

85
Q

what are amino acid sequences typically used to compare?

A

different taxa

86
Q

what are DNA/RNA base sequences often used to compare?

A

closely related organisms

87
Q

what is the molecular clock + how does it work? (think of conditions)

A

when the rate of change (of mutations) of change is reliable / at a constant rate, scientists can calculate the time of divergence according to the number of differences

88
Q

what are two limitations to using morphological differences as a basis for classification?

A

closely related organisms can exhibit very different structural features due to adaptive radiation

distantly related organisms can display very similar structural features due to convergent evolution

89
Q

what is convergent evolution

A

independent evolution of similar features in species with distinct lineages

90
Q

what are homologous structures

A

traits that are similar because they were derived from common ancestry

91
Q

what are analogous structures

A

traits that are superficially similar but were derived through separate evolutionary pathways

92
Q

how was the figwort family reclassified using cladistics?

A

many of the figwort plants were too dissimilar ins tructure to function as a meaningful grouping

the chloroplast gene was examined in figworts

figwort family was diveded into five clades

biology (11 decks)

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