Why Y Chromosomes Might Disappear

In most mammals, what combination of sex chromosomes results in a female offspring?

• XY

• XX

• ZW

• ZZ

Why is genetic diversity important for a species?

• It makes all individuals identical.

• It helps some individuals adapt to changing environments.

• It reduces the number of offspring.

• It ensures all individuals have the same traits.

What significant discovery did Nettie Stevens make regarding sex determination?

• She discovered that temperature determines sex in some animals.

• She found that male humans are a product of excess heat.

• She identified the Y chromosome as being related to sex.

• She proved that all animals have the same sex determination system.

In some birds and reptiles, which parent's sex cells typically determine the sex of the offspring?

• The male parent's sperm.

• The female parent's egg.

• Both parents equally.

• Neither parent, it's determined by temperature.

What is the primary factor that determines sex in animals that use Temperature-Dependent Sex Determination (TSD)?

• Genetic material inherited from parents.

• The temperature of the environment during development.

• The nutritional content of the parents' food.

• The presence or absence of specific sex chromosomes.

For European pond turtle eggs, what temperature range during incubation typically results in the development of female turtles?

• Below 25 degrees Celsius.

• Between 25 and 30 degrees Celsius.

• Above 30 degrees Celsius.

• Any temperature below 30 degrees Celsius.

How do some marine worms, like Bonellia viridis, determine their sex?

• Based on the temperature of the water.

• Based on the nutritional content of their food.

• Based on whether larvae land on the ocean floor or re-enter the parent's body.

• Based on a fixed set of sex chromosomes.

What does it mean when scientists say that sex determination systems are not permanent?

• Individual animals can change their sex at any time.

• The system a species uses can change over long periods of evolutionary time.

• Scientists can genetically engineer animals to change their sex determination system.

• All animals eventually lose their sex chromosomes.