In this topic you will learn about how characteristics are passed from parent to offspring.

A characteristic that is passed from parent to offspring is called an inherited trait. In corn, inherited traits include kernel color, plant height, and ear size. Heredity is the passing of these traits from one generation to the next. The word generation refers to parents and offspring. Parents are one generation. Their offspring are another.

Heredity applies to all organisms, including plants, animals, and even bacteria. Fur color is an inherited trait passed from cats to their kittens. Humans have inherited traits, too. Hair color, eye color, and dimples are examples of human inherited traits.

The study of how heredity works is called genetics. Gregor Mendel was the first person to count the numbers and types of offspring of pea plants to measure the inheritance of specific traits. He is now considered the father of genetics.

Mendel studied the pollination of pea plants. Pollination is the transfer of pollen from the male part of a flower to the female part. As a result of pollination, a cell is formed that develops into a seed. The seed can grow into an offspring plant, the next generation.

In one experiment, Mendel cross-pollinated purebred tall peas with purebred short peas. Cross-pollination takes place when pollen from one flower is transported to a different flower. All of the offspring resulting from the cross were tall. The offspring were hybrids. A hybrid is an organism produced by crossing parents that have two different forms of the same trait. In this case one parent was short, the other was tall.

Mendel hypothesized that the trait for shortness must have been present but was somehow hidden. In a second experiment he allowed the tall hybrids to self pollinate. Self-pollination occurs when the male parts of a flower pollinate the female parts of the same flower. This resulted in a second generation with both tall and short plants.

Mendel concluded that each tall hybrid in the first offspring generation carried both tall and short traits. He called tallness the dominant trait. A dominant trait is the form of a trait that appears in the hybrid generation. He called shortness the recessive trait. A recessive trait is a form of a trait that is hidden, or masked, in the hybrid generation.

Every time Mendel crossed two hybrids, he got the same result. For every three offspring that showed the dominant trait, one showed the recessive trait.