Behaviors that conform to an individual‚was sex category. See Play fighting (or rough-and-tumble play), Sex-typing, Sexual orientation
Category Archives: Uncategorized
Sex chromosomes
The genetic material that determines whether one develops male or female reproductive structures. It humans, it is typically XX for female and XY for male. The short squat Y chromosome, containing only 20 genes compared to more than 1000 for the X chromosome, has been depicted as doing little more than determining the sex of …
Sex ratio
Refers to the proportion of males to females in a given population, usually expressed as the number of males per 100 females. Three types of ratios are distinguished: primary sex ratio (assessed immediately after fertilization), secondary sex ratio (assessed at birth or hatching), and tertiary sex ratio (assessed at maturity, and giving a ratio in which …
Sex category
Dichotomous classification as either male or female . See Sex role, Sex typing
Sex-typing
Behaviors that are associated with either males or females. See Fantasy play, Play fighting (or rough-and-tumble play), Sex roles
Sex
In biology, it takes on two meanings: 1. heterogametic sex: the gender that has two different sex chromosomes (e.g., in humans, the male is heterogametic because he has an X and a Y chromosome, while in avian species , the female is heterogametic because she has a W and a Z chromosome); 2. homogametic sex: the …
Sevenless
A receptor tyrosine kinase involved in signalling the fate of a photoreceptor. See Boss (or bride of seven less), Developmental genetics, Ras, R7 and R8 photoreceptors, Tyrosine kinase receptor/pathway
Serial ordering
First raised by Karl S. Lashley (1890-1958), it is a major issue in the study of motor control, and also in the development of movement coordination. It can be defined as the sequencing or stringing together of a number of movements into an efficient pattern in order to achieve a particular outcome (e.g., reaching ‚aa …
Serotonin (5-hydroxytryptamine, or 5HT)
An indoleamine found in plants and animals, and that with dopamine, norepinephrine, epinephrine, acetylcholine and histamine, it is one of the biogenic amine neurotransmitters or neuromodulators. They are widely dispersed through the brain, but are particularly dense in the cortex. There are at least seven different types of serotonin receptors in the brain, the majority of …
Serial homology (or homonomy)
Originally termed a homotypy by Ernst H. Haeckel (1834-1919) that great coiner of neologisms, it refers to similarities in repetitive or serial structures within the same organism. Examples include the arms and legs of humans or among the branches and leaves of a tree. A more complex example is the jointed appendages of anthropoids. In …