Dating different fossil technique
artifact: An object made by humans that has been preserved and can be studied to learn about a particular time period.artificial selection: The process by which humans breed animals and cultivate crops to ensure that future generations have specific desirable characteristics.The diameter of the aperture determines the intensity of light admitted. archeology: The study of human history and prehistory through the excavation of sites and the analysis of physical remains, such as graves, tools, pottery, and other artifacts.The pupil of a human eye is a self-adjusting aperture. archetype: The original form or body plan from which a group of organisms develops.acquired trait: A phenotypic characteristic, acquired during growth and development, that is not genetically based and therefore cannot be passed on to the next generation (for example, the large muscles of a weightlifter).adaptation: Any heritable characteristic of an organism that improves its ability to survive and reproduce in its environment.amphibians: The class of vertebrates that contains the frogs, toads, newts, and salamanders.
The eggs are soft and vulnerable to drying, therefore reproduction commonly occurs in water.amino acid sequence: A series of amino acids, the building blocks of proteins, usually coded for by DNA.Exceptions are those coded for by the RNA of certain viruses, such as HIV.Allometric relations can be studied during the growth of a single organism, between different organisms within a species, or between organisms in different species. amino acid: The unit molecular building block of proteins, which are chains of amino acids in a certain sequence.allopatric speciation: Speciation that occurs when two or more populations of a species are geographically isolated from one another sufficiently that they do not interbreed. There are 20 main amino acids in the proteins of living things, and the properties of a protein are determined by its particular amino acid sequence.