1. Which process leads to changes in the base sequence of a gene that could increase genetic diversity within a species ?
a) Crossing over during meiosis
b) Independent segregation of chromosomes
c) Mutation
d) Random fertilisation
Answer
c) Mutation
2. When scientists carry out a diversity investigation, what method could they use to select areas at random ?
a) Choosing areas with the highest species density
b) Using random number generator
c) Selecting areas based on visible plant cover
d) Picking areas closest to the researcher's location
Answer
b) Using random number generator
3. Cytochrome C is a protein present in all eukaryotes and is involved in aerobic respiration. The table below shows the amino acids in one section of cytochrome C in several animals. Using this information, give the animal to which humans are most closely related.
Answer
In this case, humans are most closely related to rabbits because there are only four amino acid differences in the sequence, which is the least number of differences among the species compared. Amino acid sequences are coded for by DNA sequences. The more similar the base sequence, the more closely related the animals are.
4. A scientist compared DNA and mRNA base sequences between organisms from different species. The mRNA sequence for a particular gene was the same, but the DNA sequence for this gene differed. Why ?
a) DNA is unstable compared to mRNA
b) DNA possesses introns which are removed during splicing on mRNA
c) mRNA contains non-coding regions absent in DNA
d) DNA and mRNA always have identical sequences
Answer
b) DNA possesses introns which are removed during splicing on mRNA
5. It is more useful to use genes related to respiration when studying evolutionary relationships, rather than genes that code for physical characteristics such as hair colour or skull type. Suggest why.
Answer
All organisms respire, so all must possess the gene for a protein involved in respiration. This allows comparison across a wider range of organisms.
6. The table below shows some features of Anole lizards. Suggest how the features of Anole lizards living in the bush and on blades of grass are adapted to their habitat.
Answer
Body length small enough to hide from predators. Long limb length in order to run from predators. Tail length extremely long to help balance on blades of grass.
7. Give some ways in which lizards that live on trunks and those that live on the lower trunk and ground are adapted to their habitat.
Answer
Trunk anoles: grey helps with camouflage, smaller body length to be able to climb trunk.
Ground anoles:
long leg length to run away from predators, brown to be camouflaged against ground.
8. The Anole lizards that live on trunks and on the lower trunk and ground are believed to have evolved from a common ancestor. Describe how this might have occurred.
Answer
Those individuals better adapted to living on the ground tended to remain there, while those better adapted by chance to living on trunks tended to stay in that environment. Different selection pressures in each habitat led to different phenotypes being favored. Random mutations introduced further variation and adaptation, eventually resulting in reproductive isolation between the groups.