生殖與遺傳：練習題

A specific species of plant has a diploid number of \(2n = 24\). Which of the following statements correctly describes the outcome of asexual reproduction in this species compared to the formation of a zygote through sexual reproduction?

In humans, the allele for brown eyes (B) is dominant over the allele for blue eyes (b). A brown-eyed man whose mother had blue eyes marries a blue-eyed woman. What are the genotypes of the parents and the probability that their first child will have blue eyes?

A scientist observes that a population of rabbits has developed thicker fur over many generations in a cooling climate. According to Darwin’s theory of evolution by natural selection, which sequence of events most accurately describes this process?

An insect-pollinated flower is likely to have which combination of structural adaptations compared to a wind-pollinated flower?

In a monohybrid cross between two pea plants that are heterozygous for purple flowers (Pp), where purple (P) is dominant over white (p), a total of 1200 offspring are produced. Calculate the expected number of offspring that would possess a homozygous dominant genotype.

Compare the structural adaptations of a wind-pollinated flower to an insect-pollinated flower, specifically explaining why the position of the stamens and the type of pollen produced differ.

Describe the sequence of events that occurs after a pollen grain lands on a stigma, leading to the formation of a seed and fruit.

Predict the probability of a child being born with a recessive phenotype if both parents are heterozygous for a specific gene, and explain your answer using the concept of alleles.

Flowering plants can reproduce sexually through pollination. Flowers are adapted depending on whether they are pollinated by insects or the wind.

(a) Describe two structural differences between an insect-pollinated flower and a wind-pollinated flower. (2)

(b) Explain the process that occurs after a pollen grain lands on a stigma, leading to the formation of a seed. (3)

Charles Darwin proposed the theory of evolution by natural selection to explain how species change over time.

(a) Explain the steps involved in the process of natural selection. In your answer, refer to variation, competition, and the role of alleles. (5)

(b) Define the term phenotype and explain how it differs from a genotype. (2)