Biodiversity

Question 1

Q6.The Amazonian forest today contains a very high diversity of bird species.
• Over the last 2 000 000 years, long periods of dry climate caused this forest to
separate into a number of smaller forests.
• Different plant communities developed in each of these smaller forests.
• Each time the climate became wetter again, the smaller forests grew in size and merged to reform the Amazonian forest.
(a) Use the information provided to explain how a very high diversity of bird species has developed in the Amazonian forest.

Answer 1

1. No interbreeding / gene pools are separate / geographic(al) isolation;
   Accept: all marks if answer written in context of producing increased diversity of plants
   1 Do not award this mark in context of new species being formed and then not interbreeding
   1 Accept reproductive isolation as an alternative to no interbreeding
2. Mutation;
   2 Accept: genetic variation
3. Different selection pressures / different foods / niches / habitats;
   3 Accept: different environment / biotic / abiotic conditions or named condition
   3 Neutral: different climates
4. Adapted organisms survive and breed / differential reproductive success;
5. Change / increase in allele frequency / frequencies;

Question 2

Suggest how this student would obtain data to give a more precise value for the index of diversity of this habitat.

Answer 2

Take more samples and find mean; Method for randomised samples described.