Question 1: Natural selection is a process where organisms better adapted to their environment tend to survive and produce more offspring. This leads to changes in the characteristics of a population over time. Explain in your own words how natural selection contributes to evolution.

Answer:

Question 1: Define 'natural selection'.

Answer: A process where organisms with advantageous traits are more likely to survive and reproduce, passing these traits to their offspring.

Question 2: List three environmental factors that can drive natural selection.

Answer: Predation, climate change, availability of food or water.

Question 3: Explain why genetic variation within a population is important for natural selection to occur.

Answer: Genetic variation provides different traits, some of which may give an advantage in survival, allowing natural selection to act upon these differences.

Question 1: In a population of 1000 birds, 200 have a genetic trait that confers resistance to a new disease. After several generations, 400 birds possess this trait. Calculate the percentage increase in the resistant trait.

Answer: 100%

Question 1: Describe a simple experiment to investigate how predators might influence natural selection in a bird population.

Answer: Introduce a predator to a bird population with varying beak sizes and observe which beak types survive better over time, indicating selection pressure.

Question 2: Identify two variables in the above experiment that need to be controlled to ensure valid results.

Answer: Availability of food, habitat conditions.

Question 3: State two safety precautions that should be considered when conducting experiments involving living animals.

Answer: Ensure humane treatment of animals, obtain necessary ethical approvals.

Question 1: A population of beetles shows a variation in shell colour: 60% are green, and 40% are brown. After exposure to a new predator, the proportion of brown beetles increases to 70%. Suggest a possible explanation for this change based on natural selection.

Answer: Brown beetles may be less visible to predators, leading to higher survival rates and more offspring with brown shells, increasing their proportion in the population.

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

Answer: Bacteria with genetic mutations that confer resistance survive antibiotic treatment and reproduce, passing resistance traits to their offspring, leading to a resistant population.

Question 2: Discuss one way humans can influence natural selection in domesticated animals or plants.

Answer: Selective breeding by choosing animals or plants with desirable traits to reproduce, thereby increasing the frequency of those traits in the population.