Question 33 — The Human Story (25 marks) (a) Complete the information missing in cells of the table marked (1), (2) and (3) - HSC - SSCE Biology - Question 33 - 2003 - Paper 1

Absolute dates provide a specific age or date for a fossil, usually obtained through methods like radiometric dating. In contrast, relative dates place fossils in a sequence but do not assign a specific age, often determined by the position of the fossil in sedimentary layers.

1. Incomplete fossil records can lead to gaps in understanding evolutionary transitions, resulting in question marks in the diagram.
2. The potential for re-evaluation of fossil dates due to new dating techniques can also contribute to uncertainty.

The variation in the frequency of blood group B among different populations can be attributed to genetic drift, historical population migrations, and adaptation to local environmental factors, which influence allele distribution.

The limited variation in blood groups among these populations may result from their relatively small population sizes and limited gene flow with outside groups, leading to a higher prevalence of certain blood types due to genetic isolation.

I organized the information by categorizing it into themes and patterns, used graphical representations to visualize changes in human populations, and compared historical records with recent studies to identify trends.

I evaluated the reliability by cross-referencing multiple sources, checking for peer-reviewed publications, and considering the methodologies used in the research to ensure credibility and accuracy.

I will evaluate the 'Out of Africa model', which posits that modern humans originated in Africa and migrated out. Evidence includes genetic studies showing that non-African populations have less genetic diversity, supporting the idea of a recent common ancestry traced back to Africa.