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Biology Yr 12 > Evolution > Flashcards

Evolution Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Define evolution.

A

The scientific explanation for the mechanisms that drive species to change over time.

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2
Q

What does the fossil record provide?

A

A significant source of evidence for evolution.

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3
Q

What does the modern evolutionary synthesis do?

A

Combines evidence from the fossil record with our relatively modern knowledge of how genes are inherited and how changes to genes arise to give a complete picture of the mechanisms of evolution.

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4
Q

What are the measures of time in which evolution has occurred?

A

Periods, eras, epochs and eons.

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5
Q

What does continental drift cause?

A

The significant movement of tectonic plates over time.

Explains current biogeography.

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6
Q

What provides evidence for continental drift?

A

The fossil record.

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7
Q

Give examples of continents that once existed.

A

Gondwana and

the supercontinent Pangaea.

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8
Q

Describe the association between Oxygen levels and organisms.

A

Around 300 my, Oxygen level of Earth’s atmosphere rose sharply.
Corresponds with an increase in organisms’ body size in the fossil record.
Corresponds with the Carboniferous period and the rise of photosynthetic plants.

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9
Q

What are the five major lines of evidence supporting evolution?

A

Palaeontology
Biogeography
Developmental biology
Morphology

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10
Q

Define palaeontology.

A

The study of prehistoric life, particularly the fossil record.

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11
Q

Define biogeography.

A

The study of the distribution of species over time.

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12
Q

Define developmental biology.

A

The study of the process by which organs develop.

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13
Q

Define morphology.

A

The study of the form and structure of organisms.

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14
Q

Define genetics.

A

The study of genes, heredity and variation in living organisms.

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15
Q

Give examples of further evidence supporting evolution?

A

Comparative genomics
Comparative biochemistry
Bioinformatics

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16
Q

Define comparative genomics.

A

The comparison of genomic features of organisms.

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17
Q

Define comparative biochemistry.

A

The comparison of proteins of organisms.

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18
Q

Define bioinformatics.

A

Analysis of large data sets (such as the genomic sequences of different organisms).

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19
Q

Define fossils.

A

Preserved remains of organisms and their traces.
Commonly hard parts such as teeth, bones and shells. Also include impressions left after soft tissue has decayed, or footprints, burrows or preserved faeces (coprolites).

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20
Q

How does fossilation occur.

A

Fossilisation requires the absence of oxygen.
Organisms can be covered with sediment such as silt or sand. This can protect the remains from scavengers and slow the decay long enough for fossilisation to occur.
Mineralisation: hard parts of organisms are replaced with minerals and makes fossilisation more likely.
Can be formed as a result of freezing and subsequent dehydration, by soft material such as ash falling on impressions, or from impressions made in sandstone and mudstone.

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21
Q

Where are fossils found?

A

Not usually found in volcanic rock, as molten lava solidifies at 1000°C.
Not usually found in metamorphic rock as the pressure and heat of metamorphism is likely to destroy fossils.

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22
Q

Define transitional forms.

A

Show important intermediate states between an organism’s ancestral form and that of its descendants.

23
Q

What is an example of a famous transitional form?

A

Archaeopteryx, the dinosaur/bird transitional form.

24
Q

Why is the probability of a specimen being captured in the fossil record low?

A

Transitional forms usually did not remain in their state for long periods.

25
Q

Define gradualism.

A

The concept that assumes that evolution of species occurs at a slow, steady pace.

26
Q

Define the theory of punctuated equilibrium.

A

States that evolution occurs in bursts and between the bursts are periods of relative stasis.

27
Q

What are the two types of fossil dating?

A

Comparative and absolute.

28
Q

Describe comparative dating.

A

Gives an idea of how old a rock (perhaps containing a fossil) is in relation to surrounding rocks since we know that sedimentary rock is formed by gradual deposition of sediments.
Lower rock is assumed to be older than the rock that is higher
Rock may have tilted or even rotated, so this method requires careful observation.

29
Q

Describe absolute dating.

A

Involves the use of techniques that can assign a numerical age to a fossil or rock.

30
Q

What are the three techniques used in absolute dating?

A

Radiometric dating
Electron spin resonance
Luminescence techniques

31
Q

Describe radiometric dating.

A

Takes advantage of known rates of atomic decay.
Isotopes break down at a steady rate over time.
Relative proportions of carbon-14 and nitrogen-14 can give an indication of the degree of decay that has to occur and thus the age of the material.

32
Q

Describe error margins for radiometric dating.

A

Error margins for radiometric dating grow in magnitude the older an object is.
Most of the organic (carbon-containing) material is replaced or altered over time.
Process of fossilisation occurs over a larger time period than then maximum accuracy for carbon dating (12,000 years).

33
Q

Describe electron spin resonance.

A

Electrons trapped in a material gain magnetic force as a result of exposure to environmental radiation over time.

34
Q

Describe luminescent techniques

A

Measures light emitted from a material when it is heated or exposed to visible light.

35
Q

What evidence does the geographical distribution of species provide?

A

Now isolated locations were once close.
Differences between species in different locations can give an indication of how much time has passed since they were co-located.

36
Q

What does Wallace’s line mark?

A

The boundary between the location of Asian fauna and Australian fauna.

37
Q

Define divergent evolution.

A

Occurs as groups of organisms change over time, accumulating enough changes that they become different species.

38
Q

How does divergent evolution occur?

A

Usually happens when groups of a single species disperse to different environments which then become isolated, preventing individuals from moving between the groups.
A group of organisms with a recent common ancestor may evolve different adaptations in response to a range of environmental pressures.

39
Q

Examples of divergent evolution.

A

Koalas, Tasmanian devils and marsupial moles, which shared a common ancestor in the Eocene epoch.
Big cats have diverged into grasslands, African forests and Asian forests.

40
Q

Define adaptive radiation.

A

Occurs when new environments or environmental niches become available to species, such as following a mass extinction.

41
Q

Example of adaptive radiation.

A

When marsupials reached Australia, they diversified to fill many different environmental niches.

42
Q

Define convergent evolution.

A

When different species evolve similar adaptations in response to similar environmental demands or opportunities.

43
Q

Examples of convergent evolution.

A

Adaptation of ant-eating structures in ant-eating species.
Australian mammals of many families have evolved similar behaviours (feeding at dawn and dusk, resting in the shade during the height of daytime temperatures) and structures (long back feet for hopping, grey colour to make detection by prey difficult at dawn and dusk).

44
Q

Define comparative anatomy.

A

Used to establish evolutionary relationships on the basis of structural similarities and differences.

45
Q

Define embryology

A

Comparative study of vertebrate embryos, which share similarities across a large range of species even with relatively distant common ancestors.

46
Q

Example of embryology.

A

The similarities observed between embryos of fish, humans and many other organisms.
Suggestive of a shared ancestor from which all these species have evolved.

47
Q

Define homologous structures?

A

Features that were present in common ancestors and have evolved to perform different functions in descendent species.

48
Q

Example of homologous structures.

A

The pentadactyl limb. In each species, the limb has been modified to suit a variety of different ways of life, demonstrated by the different bone lengths and coverings of the limbs.

49
Q

Define vestigial structures.

A

Homologous structures that no longer have a function in the descendent species.
They are usually rudimentary or atrophied.

50
Q

Example of vestigial structures.

A

The human appendix-the remains of the caecum that is found in the digestive tract of herbivorous primates.

51
Q

Define analogous structures.

A

Features that serve the same purpose but do not have the same structure.
May arise by convergent evolution.

52
Q

Describe molecular homology.

A

All living organisms share the same genetic code.
Suggests that it is a very successful way of transmitting hereditary information and is highly conserved.
Proteins are often conserved if their structure is well suited to their function, even while species evolve.

53
Q

Example of molecular homology.

A

Histone proteins, whose function is the same across different species.
Comparing the number of mutations in a DNA sequence can give an estimation of the time since two species diverged.

54
Q

Comparative genomics uses bioinformatics to do what?

A

To analyse genome sequences of different species for sequence conservation and mutation frequencies.
Can help to trace the evolutionary history of the divergence of the two genomes.
Can help to build a branching phylogenetic tree in the technique of molecular phylogeny.

Biology Yr 12 (8 decks)

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