Question 1
Which of these is an example of excretion?
- A dog passing faeces
- Removal of urea in urine
- Taking glucose into a cell
- Release of enzymes into the gut
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Answer: B (1)
Question 2
Define each of these characteristics of living organisms. (a) sensitivity (b) growth (c) excretion (d) nutrition
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- (a) the ability to detect and respond to changes in the internal or external environment (1)
- (b) a permanent increase in size and dry mass (1) reject increase in size alone
- (c) the removal of the waste products of metabolism and substances in excess of requirements (1)
- (d) the taking in of materials for energy, growth and development (1)
Question 3
A horse and a donkey can mate to produce a mule. A mule cannot produce offspring. Explain why a horse and a donkey are classified as different species.
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- a species is a group of organisms that can reproduce to produce fertile offspring (1)
- the offspring (mule) is sterile / infertile / cannot reproduce (1)
Question 4
The scientific name of the lion is Panthera leo. (a) State what the two words in a scientific name represent. [2] (b) State one reason why scientists use an internationally agreed system of naming. [1]
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- (a) the first word is the genus (1)
- the second word is the species (1)
- (b) so that scientists in all countries use the same name for an organism / avoids confusion caused by different local names / different languages (1)
Question 5
The table shows a dichotomous key for five animals. (a) Use the key to identify an animal with no feathers, no fur, no fins and moist skin. [1] (b) Name the animal in the key that has fins. [1] (c) A student wants to add a tortoise (dry scaly skin and a shell) to the key. Describe how step 4 should be changed. [2]
| Step | Feature | Result |
|---|---|---|
| 1a | Has feathers | Sparrow |
| 1b | Does not have feathers | Go to step 2 |
| 2a | Has fur | Rabbit |
| 2b | Does not have fur | Go to step 3 |
| 3a | Has fins | Trout |
| 3b | Does not have fins | Go to step 4 |
| 4a | Skin is dry and scaly | Lizard |
| 4b | Skin is moist and smooth | Frog |
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- (a) frog (1)
- (b) trout (1)
- (c) 4a (dry and scaly skin) now leads to a new step 5 instead of to lizard (1)
- step 5 is a contrasting pair such as 'has a shell' → tortoise and 'does not have a shell' → lizard (1)
Question 6
Supplement (what this means)
Supplement: only for the Extended papers (2 and 4). Core students can skip it. What the labels meanThe table shows how similar part of a gene is to the same gene in species X. The values are practice data. Using the table, identify the species that is most closely related to species X. Explain your answer.
| Species | Similarity to species X / % |
|---|---|
| P | 98 |
| Q | 82 |
| R | 71 |
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- P (1)
- its DNA base sequence is the most similar (1)
- so it shares a more recent common ancestor with X / is most closely related (1)
Question 7
Supplement (what this means)
Supplement: only for the Extended papers (2 and 4). Core students can skip it. What the labels meanWhich statement describes what modern classification systems aim to do?
- Group organisms only by where they live
- Reflect evolutionary relationships
- Group organisms by size
- Place every organism in a different kingdom
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Answer: B (1)