Evolution Evidence (5.1) Flashcards

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1
Q

Define biological evolution

A

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

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2
Q

Define microevolution

A

Small changes that occur over a short period of time and lead to the formation of new breeds or bacterial strains.

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3
Q

Define macroevolution

A

Large changes that occur over a long period of time and lead to the formation of new species and even phylum.

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4
Q

What provides evidence for evolution and how?

A

The fossil record because it reveals the features of an ancestor which can be used to compare against living descendants.

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5
Q

The Fossil Record

A

The totality of fossils, both discovered and undiscovered.

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6
Q

The Law of Superposition

A

Within a sequence of layers of rock, the oldest layer is at the base and the newest layer is at the top.

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7
Q

How does The Law of Superposition help us?

A

It allows us to relatively figure out the age of different fossils by dating the rock that it is fossilised in.

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8
Q

The Law of Fossil Succession

A

The ordered succession of fossils. It suggests that newer species likely evolved as a result of changes to ancestral species.

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9
Q

What are transitional fossils?

A

Intermediary forms that establish links between species by exhibiting traits common to both the ancestor and its predicted descendants.

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10
Q

How do fossils provide evidence for evolution?

A

By comparing hominin skeletons. Australopithecus first appeared in the fossil record approx. 4 million years ago. We can compare this fossil with the bone structure of homo sapiens today and see marked developments.

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11
Q

What is selective breeding?

A

Selecting specimens to breed based on the desirability of their traits. Artificial selection.

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12
Q

Outline two potential harms of selective breeding

A

Less genetic variation and inbreeding (this can cause health problems).

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13
Q

Define homologous structures

A

Structural similarities in groups of organisms that suggest they all share a common ancestor.

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14
Q

Define adaptive radiation

A

A type of divergent evolution. A common ancestor evolves into a large number of species to occupy distinct niches with different environmental conditions.

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15
Q

Give an example of homologous structures

A

The pentadactyl limb is seen in a variety of animals indicating a common ancestor. Mammals, birds, amphibians and reptiles all share similar appendage structures. However, these are all used for different forms of locomotion. Their common ancestor was early amphibians.

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16
Q

Define analogous structures

A

Features of different species that are similar in function but not necessarily in structure and do not derive from a common ancestral feature. They are the result of convergent evolution.

17
Q

Define convergent evolution

A

When species occupy similar ecological niches and adapt in similar ways in response to similar environmental pressures.

18
Q

Define divergent evolution

A

When two or more species evolve/diverge from a common ancestor.

19
Q

Define vestigial structures

A

Functionless and reduced remnants of organs that were once present in their ancestors. Changes to the environment have meant they have lost their functionality.They demonstrate the evolutionary divergence of a species.

20
Q

Define biogeography

A

The distribution of lifeforms over geographical areas.Related species are usually found in close physical proximity. This suggests that closely distributed species share a common lineage, providing evidence for evolution.

21
Q

Define comparative embryology

A

The study of the growing embryo in animals and plants.Closely related species go through similar stages of development. This suggests that the organisms shared a common evolutionary pathway, providing evidence for evolution.

22
Q

Define speciation

A

The evolutionary process by which two related populations diverge into separate species.

23
Q

When are populations of species considered to be ‘separate species’?

A

When the two populations can no longer interbreed and produce fertile, viable offspring.

24
Q

Define reproductive isolating mechanisms

A

Factors that prevent populations from reproducing successfully with one another. Eg. geographical separation, and behavioural isolation.