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Mendel and His Peas. 3-1. INTRODUCTION. Heredity , or the passing of traits from parents to offspring. Gregor Mendel. Gregor Mendel was born is Heinzendorf, Austria in 1822 on a farm where he learned about flowers and fruit trees. When he was 21 he entered a monastery.
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INTRODUCTION • Heredity, or the passing of traits from parents to offspring
Gregor Mendel • Gregor Mendel was born is Heinzendorf, Austria in 1822 on a farm where he learned about flowers and fruit trees. • When he was 21 he entered a monastery. • The monks taught science and performed many scientific experiments. • Mendel discovered the principles of heredity in the monastery garden.
Unraveling the Mystery • From working with plants, Mendel knew that the patterns of inheritance were not always clear. • For example, sometimes a trait that appeared in one generation (parents) was not present in the next generation (offspring). • Mendel decided to study garden peas to learn what caused the pattern of the peas in each generation.
Why PEAS? • Pea plants grow quickly (in a garden). • Pea plants are cheap. • Many different kinds (of traits or characteristics). • No ethical questions. • Can self-pollinate.
Self-Pollinating Peas • A self-pollinating plant has both male (pollen) and female (ovule) reproductive structures. • Because the peas were self-pollinating, Mendel was able to grow a true-breeding plant.
True -BreedingPlant • When a true-breeding plant self- pollinates, the offspring will have the same trait as the parent. • For example, a true-breeding plant with purple flowers will always have offspring with purple flowers.
Characteristics • A characteristic is a feature that has different forms in a population. • Mendel studied only one characteristic at a time. • The different forms (such as round peas and wrinkled peas) are called TRAITS.
Mix and Match • Mendel decided to see what would happen if he crossed two plants that had different traits of a single characteristic. • He removed the anthers of purple flowered plant so that it could not self-pollinate, and cross-pollinated it with a white flowered plant.
Traits • A dominant trait is the trait observed in the first generation when parents that have different traits are bred. • A recessive trait is a trait that reappears in the second generation (after disappearing in the first generation) when parents with different traits are bred. • To recede means “to go away or back off.” • The “hidden” trait.
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Gone but Not Forgotten • In 1865, Mendel published his findings, however, it wasn’t until 30 years after he had died that his work was widely recognized.
