Chapter 10, Problem 33A

Summary Introduction

To summarize:

The importance of the given rule for the success of Mendel’s experiments.

Introduction:

The study of heredity is called genetics. Gregor Mendel was a mathematician who studied how some characteristics are passed from parent to offspring while others do not. Mendel carefully controlled his experiments and the pea plants that he used. He studied one trait at a time to control variables and analyzed the data mathematically.

Answer to Problem 33A

Mendel made a rule for his experiments according to which he said that the hybrids of his plants muse be protected from the influence of all foreign pollen during the flowering period. Mendel was referring this rule to his experiment on F₁ plants that were heterozygous for a particular trait. He wanted to protect his plants from cross pollination. He wanted them to self- pollinate so that he can understand how traits are passed down from parents to offspring.

Explanation of Solution

Mendel chose garden pea plants for his experiments mainly because pea plants reproduce sexually and are self-pollinating. Both male and female sex organs are located on the same flower.

Mendel crossed pure breeding tall pea plants with pure breeding short pea plants and produced new plants that were hybrids. The hybrids he got in first generation (F₁) were all tall pea plants. He allowed these tall plants from F₁ generation to self- pollinate.

Mendel made a rule for this experiments according to which he said that the hybrids of his plants muse be protected from the influence of all foreign pollen during the flowering period. He wanted to obtain seeds from these hybrids plants and then plant them to get second generation of pea plants.

By ensuring that the hybrids of his plants are protected from the influence of all foreign pollen during the flowering period, he made sure that the first generation tall pea plants did not cross pollinate. By doing so, he concluded that the alleles for the trait were passed down from the parent pea plants.