Module 4 - Species and taxonomy

Question 1

2 marks

During courtship males of a bird species vibrate their wings which produces a sound.
Explain how this sound helps to ensure that the female mates only with a male of the same species.

Answer 1

• Female recognises own species sound
• Respond to that soundy only
• Courtship sequence continues

Question 2

1 mark

Define phylogenetic classification

Answer 2

Grouped according on evolutionary orgins.

Question 3

1 mark

Define heirachy

Answer 3

Smaller groups within larger groups with no overlap

Question 4

2 marks

Explain why biologists use protein structure to investigate the realtionship between different species of cranes.

Answer 4

1. More closely related species have more similarities in amino acid sequence
2. In same protein
3. Amino acid sequence is related to DNA base/triplet sequence;

Question 5

2 marks

Explain why temperatures could be used to find the % of DNA hybridisation

Answer 5

Higher temperature= more energy required= the higher the percentage DNA hybridisation = more bases are similar
Correct reference to breaking hydrogen bonds / more/less hydrogen bonds being present;

Question 6

2 marks

Describe how organisms are grouped in a phylogenetic classification system.

Answer 6

1. Heirachy (smaller groups within larger groups) with no overlap
2. Grouped according to evolutionary origins

Question 7

2 marks

Give 2 ways in which courtship increases the probability of successful mating

Answer 7

1. Attracts / recognises same species
2. Attracts / recognises opposite sex
3. Indication of sexual maturity
4. Stimulates release of gametes
5. Form pair bond

Question 8

2 marks

The biologists analysed the amino acid sequences of the blood protein samples from these hummingbirds. Explain how these sequences could provide evidence as to whether the crimson topaz and the fiery topaz are different species

Answer 8

1. Different species would have different amino acid sequences
2. Amino acid sequence is the result of DNA base sequence

Question 9

1 mark

Cytochrome c is more useful than haemoglobin for studying how closely related different organisms are. Suggest one reason why.

Answer 9

All organisms respire / have cytochrome c

Question 10

1 mark

Define genetic diversity

Answer 10

Number of different alleles of each gene.

Question 11

3 marks

Explain the principles which biologists use to classify organisms into groups

Answer 11

1. Large groups are divided into smaller groups
2. Members of a group have features in common based on anatomy, fossils, DNA
3. Reflects evolutionary history

Question 12

2 marks

Suggest how information on amino acid sequences is used to construct a phylogenetic tree.

Answer 12

1. Those with similar sequences put in same groups =more closely related
2. The greater difference in amino acid sequence the longer ago the groups
   diverged

Question 13

2 marks

Suggest one advantage and one disadvantage of using cytochrome c to construct a phylogenetic tree

Answer 13

Advantage- present in all eukaryotic species- quantifiable
Disadvantage- Extinct species not considered, cant include prokaryotic species

Question 14

1 mark

Cytochrome c is more useful than haemoglobin for studying how closely related different organisms are. Suggest one reason why.

Answer 14

All organisms have cytochrome C

eukaryotes

Question 15

2 marks

During courtship, vibration of the wings creates a sound. The sound is different in the two species of fruitfly. Explain how this prevents mating between members of different species.

Answer 15

1. Acts as sign stimulus
2. Responds only to species-specific sound

Question 16

2 marks

The male birds were selected because they were very similar to each other to measure % of courtship behaviour. Suggest two reasons why it was important that they were of similar age.

Answer 16

1. So age not a factor in female choice
2. So will attract a mate
3. So similar sexual maturity
4. So have the correct feathers