5.1 (Evidence for evolution)

Adaptive radiation

the diversification of several new species from a recent ancestral source, each adapted to utilize or occupy a vacant adaptive zone ( or niche)

Artificial selection

the human intervention in animal or plant reproduction to ensure that certain desirable traits are represented in successive generations. Also called 'selective breeding'

Continuous variation

the variation in phenotypic traits, such as body weight or height, in which a series of types are distributed on a continuum rather than grouped into discrete categories.. - Is easily influenced by the environment.

Discontinuous variation

the variation in phenotypic traits in which types are grouped into discrete categories with few or no intermediate phenotypes. (Ex: blood types). Is not influenced by the environment.

Evolution

the change in the genetic composition of a population during successive generations, as a result of natural selection acting on the genetic variation among individuals, and resulting in the development of new species.

Fossil

a remnant, or representation, of an organism that existed in a past geological age, or of the activity of such an organism, occurring in the form of mineralized bones, shells, etc., as casts, impressions, and moulds.

Divergent evolution

the change in the genetic composition of a population during successive generations, as a result of natural selection acting on the genetic variation among individuals. -- when two separate species have a similar structure, but use it in different ways because of their environment.

Heritable characteristics

characteristics that are capable of being passed from one generation to the next through the genes.

Homologous structures

structures derived from a common ancestor or same evolutionary or developmental origin but not necessarily in function: the wing of a bird and the foreleg of a horse are homologous.

Melanism

an increased amount of black or nearly black pigmentation (as of skin, feathers, or hair) of an organism, resulting from the presence of melanin.

Pentadactyl limb

a limb with five digits, such as a human hand or foot, which is found in many amphibia, reptiles, birds, and animals, which can allow us to deduce that all species in these categories derived from one common ancestor.

Population

a group of organisms of one species that interbreed and live in the same place at the same time (e.g. deer population).

Selective breeding

the intentional breeding of organisms with desirable traits in an attempt to produce offspring with similar desirable characteristics or with improved traits.

Species

an individual belonging to a group of organisms (or the entire group itself) having common characteristics and been capable of mating with one another to produce fertile offspring.

Macroevolution

occurs on a large scale leading to the development of new species.

transitional fossils

records of very important links that show evolutionary transitions. These fossils are called _____________ fossils and display common characteristics between ancestral groups showing evidence for macroevolution

Breed

group of animals within a species that have specific and similar characteristics.

Microevolution

occurs on a small scale within a species.

Analogous structure

performing a similar function but having a different evolutionary origin, such as the wings of insects and birds.

Convergent evolution

when organisms that are not closely related evolve similar structures that are used for similar purposes

Speciation

the process by which new species form,

industrial melanism

The process of this change in the melanin-producing allele frequency due to environmental pressures from industries

Transient polymorphism

is the gradual change in the allele frequency of a population due to the slow replacement of one gene of another.

Balanced polymorphism

is a balance between both forms of the allele variations within a population.