Question
SLPaper 2
The image shows the wings of an insect, bird and bat.
1.[2]
Based on their structure, the insect and bat wings are analogous. Outline what is meant by an analogous trait.
Verified
Solution
- Analogous traits have a different evolutionary history/ancestry;
1 mark - Different structures are adaptations for flight;
1 mark - Selective pressure leads to a similar solution to the problem of flying;
1 mark
2.[1]
Cladistics and other evolutionary evidence suggest that mammals and birds have a more recent common ancestor than mammals and amphibians. Draw a cladogram to show the relationships between mammals, birds and amphibians.
Verified
Solution
What is important is that the proper relationships are shown not the style used.
3.[1]
The bird and bat wings share homologous bone structures whereas the insect wing does not. Outline the conclusion that can be drawn about the evolution of these wings, based on homologous structures.
Verified
Solution
- Bird and bat share a more recent common ancestor (than the insect);
1 mark - Bird and bat are more closely related than insect and bat / insect and bird;
1 mark - Bird and bat wings evolved from a common ancestor (by natural selection);
1 mark
4.[2]
Explain how cladistics can be used to investigate evolutionary relationships.
Verified
Solution
- (Cladistics) shows evolutionary relationships through a common ancestor;
1 mark - Cladistics uses DNA/protein/derived/shared anatomical characteristics/traits;
1 mark - Time of divergence is related to the number of differences in DNA (base sequence) / protein (sequence of amino acids);
1 mark - Homologous (versus analogous) traits are used to place an organism in a clade;
1 mark - More shared characteristics mean a more recent common ancestor;
1 mark
