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IB Biology HLA4.1 Evolution and speciationQuestion Bank

A4.1 Evolution and speciation

Question 1

[Maximum number: 4]

Analysis of the genome of primates reveals many DNA segments that have been duplicated. It is possible to deduce the stage in evolution at which segmental duplications (SDs) occurred by comparing human and other primate genomes. Human-specific SDs occurred after humans and chimpanzees diverged. Human-chimpanzee shared SDs occurred after the common human-chimpanzee ancestor diverged from gorillas and so on. It is possible to estimate the rates at which SDs occurred during evolution using knowledge of when the primates changed. In the chart the bars indicate numbers of shared SDs and the line shows estimates of the rate of SDs per millions of years (Myr).

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Question 1(b)

(a)

Outline the trends in the rate of SDs occurring since the separation of orangutans from other primates.

[ 2 ]

Question 1(c)

(b)

Explain how the number of human-chimpanzee shared SDs can be the lowest despite the rate of SDs per millions of years being the highest.

[ 2 ]

Question D2

Question D2(b)

(a)

Outline how isolation of a gene pool can lead to evolution.

[ 2 ]

Question 2

Question 2(b)

(a)

Compare allopatric speciation and sympatric speciation.

[ 2 ]

Question 2

Question 2(a)

(a)

Distinguish between allopatric speciation and sympatric speciation.

[ 1 ]

Question D2

Question D2(a)

Question D2(a)(ii)

(a)
(i)

State two examples of barriers between gene pools.
1.
2.

[ 1 ]

Question 2

Question 2(c)

(a)

Distinguish between sympatric and allopatric speciation.

[ 1 ]

Question 2

Question 2(c)

(a)

Wings have evolved in both birds and insects enabling them to fly. State with a reason whether this is due to convergent or divergent evolution.

[ 1 ]

Question D2

Question D2(c)

(a)

Distinguish between analogous and homologous structures.

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Question 3

[Maximum number: 6]

Explain how speciation can occur due to polyploidy.

Question D3

[Maximum number: 6]

Explain the conclusions about evolution that can be drawn from the universality of DNA and protein structures, and variations in specific molecules.

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