- 업종: Education
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Founded in 1946, Palomar College is a public two-year community college in the city of San Marcos, located in north San Diego County, California. Palomar offers over 300 associate degree, certificate programs and is designated by the U.S. Department of Education as an Hispanic-Serving Institution ...
Severe deficiency of calories in the diet. Prolonged undernourishment can result in marasmus which is a wasting away of the body. See malnourishment.
Industry:Anthropology
Sequences of three nucleotide bases on a transfer RNA molecule that can pair with a specific messenger RNA Codon.
Industry:Anthropology
Selection for or against one extreme of a trait. In the case of polygenic traits that are expressed as a continuum of phenotypes, such as human stature, it would be selection for people who are either very tall or very short. The result would be a progressive increase in the form of the trait that is being selected for and a reduction in the form that is being selected against. In the case of a trait controlled by only two alleles, it would be selection against one of the alleles. When that allele is recessive, it is usually selection against the recessive homozygote and for the dominant homozygote and the heterozygote. An example is selection against people who have a fatal genetically inherited disease that only shows up in homozygous recessive people. The result would be a progressive reduction of the recessive allele in the gene pool of the population and, subsequently, a reduction in the number of people who have the disease. Continuous directional selection can result in evolution. See disruptive selection and stabilizing selection.
Industry:Anthropology
Selection for both extremes of a trait and against the middle. In the case of polygenic traits that are expressed as a continuum of phenotypes, such as human stature, it would be selection for both very tall and very short people and against those who are average in height. The result would be a progressive increase in both of the extreme forms of this trait and a reduction in the middle range. In the case of a trait controlled by only two alleles, it would be selection for both recesssive and dominant homozygotes and against heterozygotes. The result would be a progressive reduction in the number of people who are heterozygous for the trait in the population. See directional selection and stabilizing selection.
Industry:Anthropology
Selection against extreme forms of a trait. In the case of polygenic traits that are expressed as a continuum of phenotypes, such as human stature, it would be selection for people who are in the middle of the range and against those who are very tall or very short. The result would be fewer people who are at the extremes in height. In the case of a trait controlled by only two alleles, it would be selection against both homozygotes and for the heterozygote. An example is nature selecting for people who are heterozygous for the sickle cell allele in a malarial environment. See directional selection and disruptive selection.
Industry:Anthropology
Seeing with two eyes that have an overlapping field of view. This is essential to stereoscopic vision.
Industry:Anthropology
Sections of DNA molecules that do not code for proteins but still perform important functions. Apparently, some are enhancers or suppressors of genes. About a fourth of DNA consists of introns. The remaining "junk" DNA, that makes up three fourths of a DNA molecule, very likely also has subtle functions. For instance, It helps determine the shape of chromosomes and also buffers against change by absorbing the mutagenic effect of radiation and viruses. See exons.
Industry:Anthropology
Rock formed from sediments usually eroded from older rock or inorganic remains of organisms (e.g., shells and skeletons). Examples: sandstone, shale, and limestone.
Industry:Anthropology
Remains of a plant or animal of a species that is known to have lived only during a specific time period. The discovery of such a fossil in an archaeological site is circumstantial evidence of the approximate time period that it was occupied. Fossil bones of horse and elephant related species are often used to relatively date fossils of our ancestors. Index fossils are used for biostratigraphy.
Industry:Anthropology
Relationships that are recognized between individuals based on family ties. Among humans, those ties are created by marriage and shared descent from ancestors. Among non-human primates, they are due to descent.
Industry:Anthropology
