3.1 Describe the process of natural selection - NSC Life Sciences - Question 3 - 2020 - Paper 2

Hominidae

Cultural evidence such as tools, weapons, language, and artifacts demonstrates advances in human development, which supports the idea that humans have evolved over time. These cultural markers provide insights into the cognitive and social complexities of early hominins and how these traits have developed across generations.

The most recent common ancestor of H. erectus and H. heidelbergensis existed approximately 3 million years ago.

H. ergaster is placed between A. afarensis and H. heidelbergensis because it represents a transitional species that exhibits characteristics of both groups. It showcases evolutionary traits that link early Australopithecines to later Homo species.

Fossils of organisms from 4 million years ago support the 'Out of Africa' hypothesis by providing evidence that early Homo species originated in Africa. These fossils indicate a movement of populations out of Africa, which contributed to the genetic diversity of modern humans in other parts of the world.

(a) Species-specific courting behavior.

(b) Length of the (male long-tailed widowbird's) tails.

Using 27 long-tailed widowbirds instead of only 3 ensures a larger sample size, which increases the reliability of the results. A larger sample better represents the population and allows for more accurate statistical analysis.

Group 3 was included as a control group so that comparisons could be made with the other groups. This helps determine if the changes in tail length significantly affect mating success, thus validating the findings.

To represent the results, a bar graph should be created with the average number of nests produced on the Y-axis and the groups on the X-axis, showing Group 1 (0.5), Group 2 (2.5), and Group 3 (1). Each bar should be clearly labeled.

The results indicate that the longer the male long-tailed widowbird's tail, the higher the mating success. Conversely, shorter tails influence lower mating success.

Continental drift could have led to the separation of land masses, which resulted in the common ancestor being split into different groups on separate continents. As each group faced different environmental conditions, they would have undergone divergent evolution.

Pottos and lemurs, originating from a common ancestor, became geographically isolated due to the separation of land masses. They adapted to their unique environments in Africa and Madagascar, leading to genetic divergence and the formation of distinct species due to different ecological pressures.