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Yr.12 Biology > evolution > Flashcards

evolution Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Evolution

A

the process of cumulative, inheritable changes in a population over many generations

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2
Q

Theory of ‘Transmutation of species’

A

organisms pass on to their offspring characteristics that they acquire during their lifetimes.

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3
Q

Theory of evolution

A

links all species to a common ancestor

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4
Q

Ancestor

A

species from which other species have evolved, and a common ancestor refers to an ancestor that is shared by different species.

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5
Q

Phylogeny

A

evolutionary relationship that exist between species.
Expressed in a tree-like diagram

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6
Q

evidence for theory of evolution

A

Biogeography
Comparative genomics (genetics)
fossil record (paleontology)
Comparative embryology (developmental biology)
Comparative anatomy

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7
Q

Geological time

A

Eons -> Eras -> Periods -> Epochs
Time expressed as mya (millions of years ago)

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8
Q

continental drift

A

Changes in the landmasses on Earth from one supercontinent called Pangea to the number of continents we have today, and their relative movements.

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9
Q

climate variation

A

Fossils track the climate variations through earth’s existence

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10
Q

significant events

A

First life 3500 mya
first reptiles and amphibians 299-251 mya
catastrophic mass extinction eliminates most life. First mammals. 251-200 mya
Pangea begins to break up 180 mya
africa breaks from Gondwana 160 mya
Dinosaurs extinct 66-23 mya

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11
Q

biogeography

A

Study of the distribution of organisms and ecosystems across the world and through geological time
by looking at the pattern of these distributions today, and that of the fossils, we are able to reconstruct its evolutionary history.

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12
Q

Genomics

A

study of the whole set of genes of a species and the interactions of the genes without a genome

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13
Q

Molecular homology

A

the identification of shared bimolecular elements - generally genes - used to test the closeness of relationships between organisms

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14
Q

Homology

A

similarity between a pair of structures, or genes in the case of molecular homology that links all life on Earth.

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15
Q

Clade

A

group of organisms that includes all the descendants of a common ancestor and the ancestor species itself.

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16
Q

Taxon

A

named group of organisms

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17
Q

Relatedness

A

uses taxon and clade
A measure of the evolutionary distance between two species

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18
Q

Comparative genomics

A

field of biological research in which researchers use a variety of tools to compare the genome sequences of different species.

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19
Q

DNA hybridisation

A

Method used to analyse relatedness
can be unreliable when comparing closely related species
DNA extracted from 2 organisms, purified and cut into fragments
It is unwound and hydrogen bonds joining the two sugar-phosphate backbones are broken.
resulting single strands of DNA from the 2 organisms are mixed
Some of the double-stranded DNA that forms contains DNA from each of the two species and is known as hybrid DNA.

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20
Q

Molecular phylogeny

A

the study of evolutionary relationships using comparative genomics

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21
Q

Phylogenetic tree

A

represents evolutionary relationships between groups.
Tip - end of the branch, where a species/taxon name is found
node - each point where two branches split
Root - the last node
branch - connects tip with node

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22
Q

paleontology

A

Study of fossils
Fossils show that there has been a clear change over time from simple to very complex organisms, which is evidence of evolution.

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23
Q

fossil

A

the preserved remains and traces of past life
They provide evidence of past life
these remains can be hard parts, such as teeth, bones and shells, or impressions in the rock where the organisms’ tissue has decayed.

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24
Q

Process of fossilisation

A

1. organic matter is quickly deposited and covered in sediments in an environment that lacks oxygen, preventing decomposition.
2. Minerals from sediments replace the natural bone/shell material, hardening the fossil.
3. Organisms covered with sedimentary materials. Materials consolidate to form sedimentary rock.
4. Long period of time.

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25
Q

Mineralisation

A

minerals from the sediment have replaced the natural bone or shell material.

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26
Q

Principle of superposition

A

States that oldest rock is found at the bottom of the rock, with each consecutive layer being relatively younger.

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27
Q

stratum

A

Each layer of rock in a profile
arranged in order in which they were deposited
Position of fossil in stratum allows for relative dating method
only allow palaeontologists to determine whether a fossil is older or younger than another fossil.

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28
Q

Gradualism

A

assumes that evolution occurs as a steady, slow divergence of lineages at an even pace.

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29
Q

Punctuated equilibrium

A

states that the apparent burst of evolution are not an illusion, but real.

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30
Q

Fossil dating methods

A

comparative dating (relative dating)
Absolute dating

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31
Q

Comparative dating (relative dating)

A

used to determine the age of a rock or a fossil contained in the rock, relative to other rocks or fossils nearby.
Relies on our understanding of how sedimentary rock is formed.

32
Q

Absolute dating

A

Any technique that assigns a numerical age in years to a fossil or rock.
based on physical or chemical properties of materials in the rock.

33
Q

Theory of evolution

A

states that all organisms have developed from previous organisms and that all living things have a common ancestor.

34
Q

Mechanisms for evolution

A

mutation
Natural selection
genetic drift
Migration (gene flow)

35
Q

mutation

A

A source of new alleles in a population’s gene pool.
permanent change in the DNA sequence of a gene.

36
Q

Selection pressure

A

an abiotic or biotic environmental factor that enhances the survival and reproduction of those individuals in a population who possess a beneficial trait, and reduces the survival and reproduction of those individuals without that trait.

37
Q

population

A

Group of individuals of the same species that live in the same geographic area and interbreed to produce the same offspring.
members have variation in their genotypes that causes variation in their phenotypes.

38
Q

Gene pools

A

Total collection of alleles within a population

39
Q

natural selection

A

Occurs when selection pressures in the environment confer an advantage on a specific phenotype and enhance its survival and reproduction.
this results in changes in allele frequencies in the gene pool of a population.

40
Q

Natural selection steps

A

1. Variation
2. Overproduction
3. Competition and survival of the fittest
4. Higher reproductive rate
5. Heritability
6. Change in allele frequencies over generations

41
Q

Artificial selection

A

intentional breeding or reproduction by humans of individuals with desirable traits, resulting in changes in allele frequencies in gene pools over time.

42
Q

Sexual selection

A

selection by males and females of a population for an inherited trait that assists in copulation or in the winning of a mate.
Links to mating behaviours in animals
over generations, frequency of advantageous alleles increases.
Leads to fixation of advantageous alleles and extinction of disadvantageous alleles

43
Q

sexual dimorphism

A

Species in which males and females have different appearances or size.
two sexes of the same species display two different forms.
Two sexes of the same species display two different forms

44
Q

biological fitness

A

The capacity of an individual to survive and produce viable, fertile offspring.

45
Q

genetic drift

A

Mechanism of evolution in which allele frequencies of a population change over generations due to chance.
Effects strongest in small populations, faster fixation of alleles and extinction of others.
occurs when a random, non-representative sample from a population produces the next generations. Thus, over time the proportion of an allele can ‘drift’ up or down.
Random fertilisation
random assortment.

46
Q

Bottleneck effect

A

caused by catastrophic event or period of adverse conditions which drastically reduces the size of a population
If some portion of population survives, OG gene pool cannot be recovered.

47
Q

founder effect

A

Happens when there is a dramatic decrease in genetic diversity caused by the development of small colonies of individuals, sourced from OG population, that remain isolated from other colonies.

48
Q

gene flow

A

Transfer of alleles, and it results from the migration of individuals from one population to another.
immigrants may add new alleles to gene pool and emigrants may completely remove some alleles or significantly change their frequency.
Migration of individuals from population to population results in changes in the allele frequencies in populations.

49
Q

variable traits

A

A trait that varies in the population due to difference in alleles carried by different individuals
must be inherited.

50
Q

Micro-evolution

A

change in the gene pool below species level
Change within a species

51
Q

macro-evolution

A

Evolutionary changes above the species level.

52
Q

speciation

A

Evolution of one or more new species from an ancestral species.

53
Q

biological species concept

A

Wether members can interbreed to produce fertile offspring.

54
Q

morphological species concept

A

Defines species by its structural features

55
Q

Macro-evolution steps

A

1. Population change over time as their gene pools accumulate small changes in response to natural selection - micro-evolution
2. Eventually a population accumulates so many changes that a new species can be identified - speciation
3. Sometimes a rapid series of speciation event leads to the development of a whole collection of new species, or even genera, families, or higher classification groups - macro-evolution

56
Q

Mechanisms of speciation

A

Reproductive isolation
adaptive radiation
Divergent evolution

57
Q

reproductive isolation

A

When a single population and becomes 2 seperate populations that are unable to interbreed due to changes that produce physical, biological or behavioural barriers.

58
Q

pre-reproductive isolating mechanisms

A

A mechanism that prevents organisms from being able to interact to reproduce.
biological and ecological mechanisms: temporal (time) mechanisms, behavioural mechanisms, morphological mechanisms.

59
Q

Post-reproductive isolating mechanisms

A

(Post zygotic)
A mechanism that prevents fertilisation occurring or an embryo developing into viable offspring if fertilisation occurs.
mechanisms include: gamete mortality, zygote mortality, hybrid sterility

60
Q

Allopatric speciation

A

speciation that occurs due to physical or geographic isolation
Seperations include: water, land, mountains, continental drift, rising sea levels, climate change.

61
Q

sympatric speciation

A

Speciation that occurs without physical or geographical isolation.

62
Q

mass extinction

A

Period when rate of extinction is very high
extinction of many species over a relatively short geological period of time.

63
Q

Radiometric dating

A

method of absolute dating
Uses known rates of decay of naturally occurring radioactive isotopes present in rock or fossil.
time taken for the OG amount to decay to the present amount.
The older the object, the larger the margin for error.
Carbon-14 dating not always useful for fossils as: carbon-containing tissue has been chemically altered or replaced, process of fossilisation generally takes longer to occur than the maximum age of accuracy for carbon-14.

64
Q

Comparative anatomy

A

the study of similarities and differences in structure between different organisms

65
Q

Embryology

A

study of the anatomy or embryos and how they develop over time until the adult stage.

66
Q

Embryology

A

study of the anatomy of embryos and how they develop over time until the adult stage.

67
Q

Comparative embryology

A

used to establish evolutionary relationships and common ancestry on the basis of the similarities and differences in anatomy and development between embryos of different species.
Embryos show conserved homologous features that are not observed or obvious in adults of different vertebrate species. The longer the embryos remain structurally similar during development, the more closely related they are.

68
Q

comparative anatomy

A

Shows how seemingly disparate kinds of organisms are derived from a common ancestor

69
Q

homologous structures

A

Structures that show the same structural plan but perform different functions due to different species living in different environments with different selection pressures.

70
Q

adaptive radiation

A

The process by which a species rapidly diversifies into many taxa with differing adaptations
when adaptive radiation occurs, organisms retain many of the same basic structures because they have the same genetic history.
(Eg. Lizards have scales, scaled vary in colour)

71
Q

Vestigial structures

A

biological structures that have lost most, if not all, of their original function in the course of evolution.
Homologous structures stemming from a common descent.

72
Q

Analogous structures

A

features of organisms that have the same function but a different basic structure that evolved independently
eg. Bat wings and insect wings.

73
Q

Divergent evolution

A

pattern of evolution in which differences between groups of organisms accumulate to a critical point that leads to speciation, (development of new species).
Usually result of the dispersal of a single species to different environments, that is groups from the same species become isolated from one another. Homologous structures indicate that there has been divergent evolution, because new species have the same fundamental structural plan, but the structure may perform a different function.

74
Q

Adaptive radiation

A

as members of a population develop adaptations, by natural selection favouring certain mutations over successive generations, they may diverge enough to become new species.
Occur particularly when environmental changes trigger the availability of new resources and environmental niches.

75
Q

convergent evolution

A

Pattern that occurs when distantly related organisms evolve similar adaptations in response to living in the same environment
results of convergent evolution often show up as analogous structures.
Eg. Anteaters: echidnas, numbats, pangolins.

Yr.12 Biology (6 decks)

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