Question 1
Unit 2 style
Which feature describes a cell of a bacterium rather than an archaeon?
- Cell wall containing peptidoglycan
- Ether-linked lipids in the membrane
- Linear DNA associated with histones
- 80S ribosomes
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Question 2
Unit 2 style
State what is meant by the term species and give one reason why the species concept cannot be used to classify all organisms.
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Question 3
Unit 2 style
Explain how new molecular evidence led to the three-domain system of classification and why the scientific community evaluates new data critically.
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Question 4
Unit 2 style
State what is meant by the terms biodiversity and endemism.
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Question 5
Unit 2 style
Describe how human activities are threatening the variety of life on Earth.
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Question 6
Unit 2 style
Researchers sampled a small, isolated population of a rare plant and determined the genotype at one gene locus for each plant. The results are shown in the table. Calculate the heterozygosity index. Show your working.
| Genotype | Number of plants |
|---|---|
| RR | 25 |
| Rr | 6 |
| rr | 9 |
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Question 7
Unit 2 style
The table shows the number of individuals of each species found in a survey of a woodland. Use the formula D = N(N − 1) ÷ Σn(n − 1) to calculate the index of diversity. Show your working.
| Species | Number of individuals |
|---|---|
| A | 20 |
| B | 10 |
| C | 5 |
| D | 3 |
| E | 1 |
| F | 1 |
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Question 8
Unit 2 style
A pond has 8 species and a stream has 8 species. The index of diversity of the pond is 6.4 and of the stream is 2.1. Explain how the two habitats can have the same species richness but different indices of diversity.