heredity: Quick Facts

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Carolus Linnaeus.

Black and white portrait of Jean-Baptiste Lamarck, French naturalist, shown from the chest up wearing a high-collared shirt, cravat, and jacket.

Mendel's law of segregationCross of a purple-flowered and a white-flowered strain of peas; R stands for the gene for purple flowers and r for the gene for white flowers.

Mendel's law of independent assortmentCross of peas having yellow round seeds with peas having green wrinkled seeds. A stands for the gene for yellow and a for the gene for green; B stands for the gene for a round surface and b for the gene for a wrinkled surface.

Diagram illustrating sex-linked inheritance of white and red eye color in Drosophila fruit flies, showing genetic crosses between white-eyed and red-eyed males and females, with chromosomes and resulting eye color traits mapped through two generations.

A step-by-step diagram shows the stages of mitosis in a somatic cell, illustrating chromosome duplication, alignment, separation, and the formation of two identical daughter cells, with labeled cell structures and brief descriptions of each phase.

A step-by-step diagram of meiosis, showing the stages of sex cell division. Illustrated cells depict chromosome behavior, cell membrane changes, and the formation of four daughter cells, each with half the chromosome number of the original cell. Labels and brief descriptions explain key processes such as homologous chromosome pairing, crossing over, and separation of chromatids.

Behaviour of chromosomes at meiosis.

The initial proposal of DNA structure

Four kittens with different fur patterns-three tabby and one black-and-white-lying together in a box, illustrating genetic variation among offspring.

What are chromosomes?

Witness a living plant cell's chromosomes carrying genetic material duplicate during the process of mitosis

Gregor Mendel's discovery of heredity laws

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Topics

cytoplasmic inheritance principle of segregation preformation theory population genetics principle of independent assortment genetics Lamarckism DNA RNA gene Metabolism death Biological development Growth Reproduction extinction environment cell Biology coloration

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Key People

Gregor Mendel

Gregor Mendel

botanist

Thomas Hunt Morgan

Thomas Hunt Morgan

American biologist

Weismann, August

August Weismann

German biologist

Karl Pearson

Karl Pearson

British mathematician

Ernst Haeckel

Ernst Haeckel

German embryologist

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Edith Rebecca Saunders

British botanist and geneticist

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Muriel Wheldale Onslow

British biochemist

Bateson, William

William Bateson

British biologist

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Sir Cyril Burt

British psychologist

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Bernard Ogilvie Dodge

American botanist

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Charles Benedict Davenport

American zoologist

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Wilhelm Ludvig Johannsen

Danish botanist and geneticist

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Cyril Dean Darlington

British biologist

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Clarence E. McClung

American zoologist