Question 1

Which of the following best explains why sexual reproduction is considered an evolutionary advantage in changing environments?

Accepted Answer

It increases genetic variation among offspring, enhancing adaptability.

Question 2

A starfish loses one of its arms, and that arm grows into a new starfish. Which process is primarily responsible for this phenomenon?

Accepted Answer

Fragmentation followed by regeneration

Question 3

Which of the following statements about internal and external fertilization is CORRECT?

Accepted Answer

Internal fertilization involves eggs being retained within the female, with investment in fewer, higher quality gametes.

Question 4

Which of the following is a disadvantage of asexual reproduction in rapidly changing environments?

Accepted Answer

It limits genetic diversity, reducing adaptability.

Question 5

In bluehead wrasse fish, if the dominant male dies, the largest female transforms into a male. This phenomenon is an example of:

Accepted Answer

Sex reversal

Question 6

Which embryonic layer forms the nervous system in vertebrates?

Accepted Answer

Ectoderm

Question 7

A certain insect species can produce offspring from unfertilized eggs, resulting in clones of the mother. This process is called:

Accepted Answer

Parthenogenesis

Question 8

Which of the following correctly matches the embryonic germ layer with the structure it forms?

Accepted Answer

Mesoderm – muscles and body wall

Question 9

During fertilization, which mechanism acts as the fast block to polyspermy?

Accepted Answer

Depolarization of the egg membrane

Question 10

Which of the following best describes the process of gametogenesis in animals?

Accepted Answer

Gametes are produced by meiosis; spermatogenesis is continuous and prolific, oogenesis is usually prolonged.

Question 11

Which of the following equations best represents the genetic outcome of sexual reproduction?

Accepted Answer

$$n + n \rightarrow 2n$$

Question 12

A researcher observes an animal that produces offspring by splitting into two individuals of approximately equal size. This is an example of:

Accepted Answer

Fission

Question 13

Which of the following is a direct consequence of the cortical reaction during fertilization?

Accepted Answer

Prevention of additional sperm from entering the egg (slow block to polyspermy)

Question 14

Which of the following is TRUE regarding hermaphroditism?

Accepted Answer

Hermaphrodites possess both male and female reproductive organs and may self-fertilize.

Question 15

In vertebrate development, the mesoderm splits into somites. Which of the following structures does NOT arise from somites?

Accepted Answer

Lining of the gut

Question 16

Which of the following best explains why sexual females have half as many daughters as asexual females, yet sexual reproduction persists?

Accepted Answer

Sexual reproduction increases genetic recombination, which can enhance survival in changing environments.

Question 17

Which of the following is a real-world example of parthenogenesis?

Accepted Answer

A lizard species where females lay unfertilized eggs that develop into offspring identical to the mother.

Question 18

Which of the following is a disadvantage of external fertilization compared to internal fertilization?

Accepted Answer

It exposes gametes to unstable environmental conditions and predation.

Question 19

Which process is responsible for the formation of gametes in animals, and what is the chromosome number of these gametes compared to somatic cells?

Accepted Answer

Meiosis; gametes are haploid ($$n)$$

Question 20

A scientist observes that after fertilization, the egg's membrane rapidly changes its electrical charge, followed by a slower chemical change at the surface. What is the biological significance of these two events?

Accepted Answer

They prevent multiple sperm from fertilizing the egg (block to polyspermy).

Chapter 18: Reproduction and Development: Mechanisms and Evolutionary Implications

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