10.3 Gene pools and speciation

1.How do the concepts of gradualism and punctuated equilibrium differ?

2. Which structure found in eukaryotes has a single membrane?

3. What can lead to reproductive isolation after just one generation?  

4. The genetic determination of dogs’ coats can be quite complex, with many different genes acting at the same time.

• The dominant allele E gives brown tones. The recessive allele e results in red tones. • The colour intensity is due to another gene. The dominant allele B gives a dark colour, whereas the recessive allele b results in a light colour.

What would be the genotype of a light brown dog produced from a cross between a dark brown dog and a light red dog?

5. The graph shows variations in beak size for the bird Geospiza fortis on an island in the Galápagos archipelago. What evidence from the graph indicates that disruptive selection is occurring?

6. Fossil records show that black bears increased in size during the Ice Age and decreased in size with warmer temperatures. What type of selection do these changes in size represent?