The Physical Anthropology - Assignment Example

Question Allele This is an alternative version of a gene located in a particular position on a specific chromosome carrying genetic distinct traits passable from parents to offspring through the process of sexual reproduction. A good example is allele for skin pigmentation. Recessive allele This allele is masked in the presence of a dominant allele. Its prevalence is physically manifested if an organism has a pair of the recessive alleles. A typical example is blue eyes allele that is only manifested in an individual if he/she has two copies of this allele. Dominant allele This is an allele whose trait is physically manifested in an individual and does not have to occur as a pair for the trait to be visible. An example is the brown eyes allele that is dominant over blue eye allele. An individual with both blue and brown eyes alleles would have brown eyes. Homozygous The term describes an organism that possesses a pair of identical alleles for a trait at a specific locus. An example is a garden pea with wrinkles whose pair of alleles would be RR. Heterozygote The term describes an organism that has two different alleles for a certain trait at a specific locus. The two alleles are represented with the lower and upper case of the same letter. A good example is a plant with a pair of alleles that determine whether it would have smooth or serrated margin. The pair would be written as (Ss) to denote the different genetic information carried. Genotype This is the genetic make-up of an organism that describes the genetic information contained by alleles in the cells of the organism. A good example is a gene that would define an individual as vulnerable to a particular disease. Phenotype This is the physical manifestation of the genotype in the form of observable trait. Typical examples are the color of the eyes of a person, hair color, and presence of serrated leaves on a plant. Principle of segregation The principle asserts that, allele pairs representing a certain trait in an organism separate during the formation of gametes and randomly unites after the process of fertilization. This is as based on the following proponents; a particular gene can exist in different forms, new organisms inherit a pair of alleles for each trait from parents, and meiosis result to cells where each acquire a single allele for a given trait. A pair of different alleles results to dominant and recessive alleles that are expressed differently phenotypically. A typical question is the color of seeds in peas. Formations of gametes lead to separation of alleles that determine color in the seeds. They randomly unite during fertilization. Seed color in the peas become a question of which allele is dominant; either the green color allele or yellow color allele. Yellow color allele is dominant over green color allele. Presence of both alleles in a pea results to yellow pees. (YY) and (Yy) genotypes result to yellow seeds. (yy) genotype results to green peas. Principle of independent assortment The principle states that, for genes located on different chromosomes, pairs of alleles segregate independently during the formation of gametes such that, specific traits are transmitted to the offspring in a manner that is independent of one another. For example, the alleles that depict color in peas would be transmitted independently to the offspring. They would eventually appear green or yellow depending on the dominant allele. Mendelian vs. Polygenic Traits Mendelian traits are those determined by one gene. For instance, the color traits in pea plant’s flower are determined by one gene. The flower can be purple or white. On the other hand, polygenic traits are those determined by more than one gene. For example, the hair color is determined by more than one gene. Question 2 Dominant allele: T Recessive alleles: t Number of resulting genotypes: 4 Number of resulting phenotypes: 4 Homozygous dominant genotype: TT Heterozygous genotype: Tt Homozygous recessive genotype: tt Question 3 Evolution This is the gradual change in inheritable traits of living organisms over a given period of time leading to variations across various taxonomic levels and individual living organisms as manifested by genetic and phenotypic structure (Jurmain 31-35). For instance, man evolved through various stages to reach Homo sapiens sapiens. Natural selection This is the process by which living organisms acquire new traits due to interaction with the environment such that their chances of survival and reproduction are enhanced in their successive generations (Jurmain 31-35). A good example is the long necked giraffe. They once had shorter necks but their attempt to reach out for food higher on the trees saw their necks become longer. This trait was passed to their successive generations. Gene flow This is the successive transmission of genes from one population to another as attributed by such factors as migration and immigration resulting to resultant variations in a given gene pool of a given group of living organisms. For example, the dominant gene of skin color among Caucasians is a result of the gene flow in the population that was once black. Genetic drift This is the process where the frequency of a gene variant changes in a given population as a result of random sampling of the organisms. It has an effect of disrupting genetic variation resulting to organisms with unfavorable traits for example poorly developed body organs. Question 4 Comparing evolutionary systematics with cladistics Evolutionary systematics depicts a traditional approach to classification and interpretations of evolutionary relationships. The ancestors and descendants in question are traced through analysis of homologous characters (Robert Jurmain 111). A good example is analyzing of ancestors. On the other hand, Cladistics is an approach that is based on vigorous evolutionary interpretations in analysis of certain types of homologous characters. This approach considers only a group that shares a common ancestor. Question 5 Biological species concept This is a concept that describes a species a group of living organisms whose members can freely interbreed to produce fertile organisms, while being isolated reproductively from other groups of living organisms. A good example is the lion species Panther leo. Lions can freely interbreed to produce fertile offspring. Sexual dimorphism This is the phenotypic distinctiveness between male and female members of a certain species (Robert Jurmain 120). Examples of such features include sexual organs and observable differences like body strength and structure. Taphonomy This is a keen study of decomposing and decaying organisms to establish how they become fossilized. The study of how bones are buried in the earth and preserved as fossils is a good example (Robert Jurmain 123). Another example is the study of the process that leads to creation of fossil assemblages. Adaptive radiation Organisms change rapidly showing expansion and diversification into new forms due to changes in the environment in form of resources, needs, and challenges by this process. For example, man has transformed from one to another being to exploit different situation in the environment. Epoch This is a particular geological time chosen in history as a point of reference in measurement of time in the context of evolution (Robert Jurmain 127). Paleocene is a typical example. Endothermic This element describes an organism that generates heat internally to maintain the body temperature. Man is an endotherm. Birds are also warm blooded. Heterodont This organism has more than one tooth morphology. The teeth include incisors, canines, premolars, and molars. Man is a heterodont. Microevolution These small evolutionary changes lead to altered allele frequencies within a species through mutation, natural selection, gene flow, and gene drift. Macroevolution These are evolutionary changes across various gene pools beyond the levels of a species or population. It results to such changes as physical appearance in levels above the species. Works Cited Jurmain, Robert, Lynn Kilgore, and Wenda Trevathan. Essentials of physical arthropology. Belmon, CA: Wadsworth/ Cengage, 2013. Robert Jurmain, Lynn Kilgore, Wenda Trevathan & Russell Ciochon. Introduction to Physical Anthropology, 2013-2014 Edition. Belmont, CA: Wadsworth/Carnage, 2014. Read More