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DSST Anthropology as a Discipline

Mendels first principle of genetics states that the

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Mendel's first principle of genetics states that the sex cell of a plant or animal may contain one factor (allele ) for different traits but not both factors needed to express the traits. In essence, each parent's sex cell contributes one factor for a trait. The trait (i.e. eye color) cannot be expressed without the sex cells from both parents, which combine to give the required two genes in a genotype. A variation of a gene is known as an allele. For example, the gene for eye color has several alleles--blue, brown, black, hazel, etc.. Mendel's second principle of genetics states that characteristics are inherited independently from other characteristics.
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For example, a trait for blue eyes is not dependent on the trait for height within an individual organism. A person gets genes which determine eye color, as well as genes which help determine height--they are independent of each other. Mendel's third principle states that each inherited characteristic is determined by two heredity factors/genes, one from each parent, which determines whether a gene will be dominant or recessive . Also known as the law of Dominants and Recessives (Mendel's third principle). Certain genes are dominant, and others are recessive. If a child receives a brown eyed gene from one parent, and a blue eyed gene from the other, he will have brown eyes. Why? Because brown eyes is a dominant gene, and blue eyes are recessive. It would take two blue eyed genes (one from each parent) to have blue eyes. In biology, adaptation is the process by which an animal or plant becomes fitted to its environment ; it is the result of natural selection acting upon heritable variation. Even the simpler organisms must be adapted in a great variety of ways: in their structure, physiology, and genetics; in their locomotion or dispersal; in their means of defense and attack; in their reproduction and development; and in other respects. Accurate adaptations may involve migration to, or survival in, favorable conditions (i.e. temperature). Alternatively, organisms may partly manufacture their own adaptations . An example are mammals, which produce their own optimum body temperature. To be useful, adaptations must often occur simultaneously in a number of different parts of the body. A change from a more carnivorous to a more vegetarian diet necessitates alterations not only of the teeth, digestive juices, and length of the digestive tract but also in habit and defense mechanisms. Even in humans and other mammals, the blood is chemically quite closely related to seawater. Some of the most fundamental biological adaptations are chemical and genetic. The conditions in which the cells of the body can live are restricted and have changed very little since life first arose in the sea. Natural selection is an essential mechanism of evolution proposed by Charles Darwin , and is the process by which those members of a particular species that are better adapted to their environment survive longer and produce more offspring than the poorer adapted.
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