The alignment of chromosomes at the metaphase plate, a plane halfway between the poles of the meiotic spindle, during meiosis I.

OBSOLETE. A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of a flagellum, a long thin projection from a cell, used in movement.

The directed movement of a motile cell or organism in response to a temperature gradient. Movement may be towards either a higher or lower temperature.

The contraction and relaxation movements of the pharyngeal muscle that mediate feeding in nematodes.

Posterior movement of an organism, e.g. following the direction of the tail of an animal.

Self-propelled movement of a cell or organism from one location to another along an axis.

Anterior movement of an organism, following the direction of the head of the animal.

Maintenance of a nematode during the facultative diapause of the dauer (enduring) larval stage of nematode development.

Exit from the facultative diapause of the dauer (enduring) larval stage of nematode development.

Entry into the facultative diapause of the dauer (enduring) larval stage of nematode development.

The hardening, enlarging and rising of the penis which often occurs in the sexually aroused male and enables sexual intercourse. Achieved by increased inflow of blood into the vessels of erectile tissue, and decreased outflow.

The narrow gap that separates the presynaptic and postsynaptic membranes, into which neurotransmitter is released.

The nucleus of a plant egg cell. This nucleus is found at the micropylar end of the embryo.

The nucleus of a megasporocyte, a diploid cell that undergoes meiosis to produce four megaspores, and its descendents.