Question 1: Explain the primary biological mechanism responsible for determining the sex of an individual in humans.

Answer: In humans, sex is determined by the presence or absence of the Y chromosome, with males typically having XY chromosomes and females XX.

Question 1: Name two other organisms that use environmental factors, such as temperature, for sex determination, and briefly describe how this mechanism works.

Answer: Some reptiles, like turtles and crocodiles, use incubation temperature to determine sex; higher or lower temperatures during critical periods influence whether the offspring develop as males or females.

Question 2: Multiple Choice: Which of the following best describes the role of the Y chromosome in human sex determination?

Answer: It determines maleness by carrying the SRY gene.

Question 1: Calculate the probability (as a percentage) that a son will inherit an X chromosome from his mother, given that the mother has XX chromosomes. Show your working.

Answer: 50%

Question 1: Describe a basic experimental setup to investigate the effect of temperature on sex determination in reptile eggs. Include variables to control, variables to measure, and safety precautions.

Answer: An experiment would involve incubating reptile eggs at different controlled temperatures, ensuring consistent humidity and egg placement. Variables to control include egg size, species, and incubation duration. Variables to measure include the sex of hatchlings. Safety precautions include handling eggs carefully, using heat-resistant gloves, and ensuring proper lab ventilation.

Question 1: In a study of 100 reptiles incubated at two different temperatures, 60% of the hatchlings at higher temperature were males, while only 20% at the lower temperature were males. What does this suggest about the effect of temperature on sex determination?

Answer: It suggests that higher incubation temperatures increase the likelihood of male hatchlings, indicating temperature-dependent sex determination.

Question 1: How is knowledge of sex determination used in the poultry industry to manage breeding programmes?

Answer: The poultry industry uses genetic and environmental methods to determine the sex of chicks early, allowing for selective breeding and efficient resource allocation, such as producing more females for egg laying.

Question 1: Discuss potential ethical issues associated with techniques that manipulate sex ratios in wild or domestic animal populations.

Answer: Manipulating sex ratios may disrupt natural populations, affect biodiversity, and raise ethical concerns about human intervention in wildlife. It could lead to unforeseen ecological consequences and welfare issues for animals if used irresponsibly.