Question 1: Natural selection is a process where organisms with advantageous traits are more likely to survive and reproduce, passing those traits to their offspring. Over time, this can lead to evolutionary changes within a species.

Answer: A process where beneficial traits increase an organism's chance of survival and reproduction, leading to evolution.

Question 2: Define the term 'adaptation' in the context of natural selection.

Answer: A characteristic that improves an organism's chance of survival and reproduction in its environment.

Question 1: List the four main conditions necessary for natural selection to occur.

Answer: Variation in traits, overproduction of offspring, limited resources leading to competition, and differential survival and reproduction based on traits.

Question 2: Explain how environmental changes can influence the direction of natural selection.

Answer: Environmental changes alter which traits are advantageous, thus shifting the selective pressures. As a result, different traits become beneficial, leading to changes in the traits that are selected for, and potentially causing evolution in the population.

Question 1: In a population of 500 rabbits, 100 possess a rare fur colour mutation that confers better camouflage. If 80% of these rabbits survive to reproduce, and only 50% of the rabbits without the mutation survive, calculate the relative reproductive success of rabbits with the mutation compared to those without. Use the formula: Reproductive success = (Number surviving with trait / Total with trait) ÷ (Number surviving without trait / Total without trait).

Answer: Relative reproductive success = (80/100) ÷ (250/400) = 0.8 ÷ 0.625 = 1.28

Question 1: A scientist studies a population of beetles, observing that darker-coloured beetles are more common in polluted environments. Describe a hypothetical experiment to test whether natural selection is responsible for this change, including the variables involved.

Answer: The scientist could compare beetle populations in polluted and unpolluted areas, recording the frequency of colour variants. The independent variable is pollution level; the dependent variable is beetle colour frequency. Controlled variables include habitat type, predator presence, and food sources. Data collection over multiple generations can show if darker beetles have higher survival rates in polluted areas, indicating natural selection.

Question 2: Interpret the following scenario: In a population of 1000 birds, a new beak shape appears due to mutation. Over several generations, the beak shape becomes more common. What does this suggest about the role of natural selection?

Answer: It suggests that the new beak shape provides a survival or reproductive advantage, and natural selection is increasing its frequency in the population.

Question 1: Explain how the development of antibiotic resistance in bacteria is an example of natural selection.

Answer: Bacteria with genes that confer resistance survive antibiotic treatment, reproduce, and pass on resistance genes, leading to a population of resistant bacteria, demonstrating natural selection.

Question 2: Discuss how understanding natural selection can help in conservation efforts of endangered species.

Answer: Understanding natural selection helps identify traits that increase survival. Conservation efforts can then focus on protecting habitats and conditions that favour advantageous traits, promoting adaptation and survival of endangered species.