The classification of organisms according to their evolutionary relationships.

Anterior portion of the forebrain.

The final stage of mitosis or meiosis during which the chromosomes uncoil, nuclear membranes reform, and cytokinesis occurs.

A molecule that directs the synthesis of another molecule by acting as a model or pattern (ei. mRNA is the template for protein synthesis).

A fibrous connective tissue that connects a bone to a muscle.

A cross between an organism showing a dominant trait and an organism showing a recessive trait, to determine whether the former organism is homozygous or heterozygous for that trait.

The male sperm producing organ; also secretes testosterone.

A sustained muscle contraction that results from continuous stimulation.

A pair of homologous chromosomes synapsing during prophase I of meiosis; each chromosome consists of two sister chromatids, thus each tetrad consists of four chromatids.

A large ovoid mass of gray matter that forms the larger dorsal subdivision of the diencephalon and is located medial to the internal capsule and to the body and tail of the caudate nucleus. It functions in the relay of sensory impulses to the cerebral cortex.

The largest lymph vessel in the body, which collects lymph from the left side of the body above the diaphragm and from all parts below the diaphragm. Also called left lymphatic duct.

The level that must be reached for an effect to be produced, as the degree of intensity of a stimulus that just produces a sensation, or the concentration that must be present in the blood before certain substances are excreted by the kidney.