Natural Selection and Evolution Flashcards

1
Q

Definition of evolution?

A

-change in gene frequencies over time

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2
Q

Definition of natural selection?

A

-sifting of variation to produce adaptations

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3
Q

Definition of genetic drift?

A

-random sampling of individuals over time

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4
Q

Definition of founder effect?

A

-small group of individuals ‘bud off’ or survive by chance

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5
Q

What are the different types of evidence for evolution?

A
  • fossil record
  • observations of similarities and differences between living species
  • natural selection acting within species
  • evolutions in action (observing changes in real time)
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6
Q

What are fossil records?

A
  • intermediate forms are present continuously in the fossil record
  • order of fossils suggests evolutionary perspectives
  • some species around today appear ‘unchanged’ from when their evolutionary history began
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7
Q

What are observations of similarities and differences between living species?

A
  • analogous
  • homologous (e.g. structure ends with 5 digits but is used for different purposes)
  • study of developmental patterns may illustrate evolutionary patterns
  • vestigial structures suggest evolutionary descent (limbs are no longer adaptive but remains are seen in skeleton)
  • phylogenetic approaches (understanding evolution by comparing features of extant species)
  • 2 changes are more likely to have occurred than 4 changes
  • problems with evolutionary classifications based on external features
  • universal homology is more reliable than looking at external features
  • phylogenetic approaches (aspects of species historical past and current ecology can explain…)
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8
Q

What is natural selection acting within species?

A
  • selection is a designing agent
  • only mechanism known to cause the evolution of adaptations that make individuals fitter
  • acts to sift variants of behaviour, favouring those that provide their bearer with greater representation in next generation
  • explains why individuals are well adapted to environment
  • selection for survival
  • selection for reproductive share (most adaptations are complex and have appearance of design that can’t arise via random processes)
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9
Q

What are evolutions in action (observing changes in real time)?

A
  • can be produced experimentally

- on small-scale evolution can be observed ‘in action’

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10
Q

What’s a phylogenetic tree?

A
  • a diagram showing inferred evolutionary relationships
  • any characteristic can be used to infer relationships and build a tree
  • the closer the branches are the more similar they are than those with sequences separated over longer evolutionary distance
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