A variation of a gene. Some genes may have several different alleles. For
example, the gene for blood type has A, B, and O alleles.
Analogous to natural selection, except that humans control the differential
reproductive success of variations within a selected population. See more on
Amines that bind to the cell surface and act as hormones or
The neurological process of receiving information from a chemical signal.
Configurational key stimuli
A key stimulus (KS) composed of multiple stimuli that together
Members of the same species.
Twins born from the simultaneous fertilization of two different eggs by two
The study of the bodily secretions, namely hormones, that affect the
organism in which they are produced.
Neurological receptors that receive information from the environment external to
Any system that modifies operation based on the abundance or effects of its
Fixed action pattern (FAP)
A complex behavioral sequence that is indivisible and runs to completion. FAPs
are invariant and are produced by the innate releasing mechanism (IRM) that
responds to a key stimulus (KS).
Bundles of nerves, often found in invertebrates lacking a true brain.
Specific DNA or RNA sequences that comprise a functional unit.
The genetic makeup of an individual.
Steroids that target the reproductive organs.
The proportion of the total variance in phenotypes that is due to the
genetic variance of the trait in question.
When the two alleles of a gene on the two sets of chromosomes of an
individual are identical.
Substance produced within the body that produces a specific effect in its target
A region of the brain that collects and funnels information into the pituitary
Innate releasing mechanism (IRM)
The mechanism by which an organism responds to a key stimulus
(KS) with a
fixed action pattern (FAP).
Interactive FAP sequences
Chains of behavior where one fixed action pattern (FAP) acts as a key
Neurological receptors that receive information about the organism's internal
The stimulus that releases a fixed action pattern (FAP).
A system of vision in which excited neurons inhibit neighboring neurons to make
edges appear sharper.
Neurological receptors that receive tactile information through deformation of
Twins resulting from the division of a fertilized egg.
The mechanism by which evolution
population changes through the
differential survival and reproduction of members of a population.
Analogous to hormones, but produced by specialized neurons and carried
through the axons.
Chemicals released by the axon terminals of one neuron to stimulate another
neuron when it is picked up by its dendrites.
A peptide hormone that stimulates uterine contractions and milk secretion.
Chains of amino acids. In endocrinology, peptide refers to short-chain
hormones and neurotransmitters that bind to the cell surface.
The expressed characteristics of an individual.
A chemical secreted by an organism that affects conspecifics.
Neurological receptors that receive visual information.
The master endocrine gland located in the brain that controls the entire
endocrine system by targeting organs or other glands. The anterior pituitary
secretes growth hormones, and stimulates the thyroid and follicles. The
posterior pituitary stores hormones prior to their release and also produces
antidiuretics and oxytocin.
A continuous, rather than discrete, set of traits that are influenced by many
A peptide hormone that induces lactation and parental care.
Key stimuli used to find food and other resources.
17 carbon, 4 ring compounds.
Exaggerated stimuli that produce a distorted response.
The process in which the nervous system receives information about temperature.
A thin membrane that receives and transmits the vibrations of sound waves to the
nervous system for interpretation. Simple ears may consist of only a tympanic
membrane, simple receptors, and connective tissue. In more complex ears, the
tympanic membrane transmits information to the middle ear.
An antidiuretic that controls the amount of fluid in the body.