True-breeding parental plants are the P...

This preview shows page 1 - 3 out of 9 pages.

Biology Lecture Notes – Content Outline and Key Terms Chapter 9 I. Introduction A. Dogs are one of man’s longest genetic experiments. 1. Over thousands of years, humans have chosen and mated dogs with specific traits. 2. The result has been an incredibly diverse array of dogs with distinct a. body types and b. behavioral traits. II. Mendel’s Laws A. The science of genetics has ancient roots 1. Pangenesis, proposed around 400 B.C. by Hippocrates, was an early explanation for inheritance that suggested that a. particles called pangenes came from all parts of the organism to be incorporated into eggs or sperm, and b. characteristics acquired during the parents’ lifetime could be transferred to the offspring. 2. Aristotle rejected pangenesis and argued that instead of particles, the potential to produce the traits was inherited. 3. The idea that hereditary materials mix in forming offspring, called the blending hypothesis, was a. suggested in the 19 th century by scientists studying plants but b. later rejected because it did not explain how traits that disappear in one generation can reappear in later generations. B. Experimental genetics began in an abbey garden 1. Heredity is the transmission of traits from one generation to the next. 2. Genetics is the scientific study of heredity. 3. Gregor Mendel a. began the field of genetics in the 1860s, b. deduced the principles of genetics by breeding garden peas, and c. relied upon a background of mathematics, physics, and chemistry. 4. In 1866, Mendel a. correctly argued that parents pass on to their offspring discrete “heritable factors” and b. stressed that the heritable factors (today called genes), retain their individuality generation after generation. 5. Heritable features that vary among individuals, such as flower color, are called a character . 6. Each variant for a character, such as purple or white flowers, is a trait . 7. True-breeding varieties result when self-fertilization produces offspring all identical to the parent. 8. The offspring of two different varieties are hybrids . 9. The cross-fertilization is a hybridization, or genetic cross .
10. True-breeding parental plants are the P generation . 11. Hybrid offspring are the F 1 generation 12. A cross of F 1 plants produces an F 2 generation C. Mendel’s law of segregation describes the inheritance of a single character 1. A cross between two individuals differing in a single character is a monohybrid cross . 2. Mendel performed a monohybrid cross between a plant with purple flowers and a plant with white flowers. a. The F 1 generation produced all plants with purple flowers. b. A cross of F 1 plants with each other produced an F 2 generation with ¾ purple and ¼ white flowers. 3. The all purple F 1 generation did not produce light purple flowers, as predicted by the blending hypothesis. . .

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture