Evolution of Sexuality
C
Concealed Ovulation
Concealed ovulation refers to the biological trait where females show no obvious external signs when they are most fertile during their menstrual cycle, making it difficult for others to detect when ovulation occurs. This is a characteristic shared by humans and some other primates, in contrast to many other mammals who display clear physical or behavioral signs during their fertile period.
Coolidge Effect
The Coolidge Effect is a biological phenomenon observed in many species, including humans, where males show renewed sexual interest if introduced to new receptive sexual partners, even after exhaustion or satiation with a previous partner. This effect is named after U.S. President Calvin Coolidge, due to an anecdote about him and his wife visiting a chicken farm.
M
Mate-guarding
Mate-guarding refers to behaviors and strategies employed by individuals to maintain their romantic or sexual relationship by preventing their partner from engaging in sexual or emotional relationships with others. This behavior is rooted in evolutionary psychology and can manifest in various ways, from subtle actions to more overt displays of possessiveness or jealousy.
Mating Systems
Mating systems refer to the patterns of sexual relationships between individuals within a species or society. These systems describe how individuals pair up for reproduction and the social structures that support these pairings. In humans and other animals, mating systems can vary widely, influenced by factors such as environment, resources, and cultural norms.
P
Pair-bonding
Pair-bonding refers to the formation of a close, long-term emotional and physical attachment between two individuals, typically in a romantic or sexual relationship. This biological and psychological process involves the development of strong emotional ties, often accompanied by behaviors that promote closeness and intimacy. Pair-bonding is believed to have evolved as a survival strategy in humans and some other species, encouraging cooperative child-rearing and resource sharing.
Parental Investment Theory
Parental Investment Theory is an evolutionary concept that explains differences in mating strategies between sexes based on their relative investment in offspring. Proposed by Robert Trivers in 1972, this theory suggests that the sex that invests more in offspring (typically females in mammals) will be more selective in choosing mates, while the sex that invests less (typically males) will compete more intensely for mating opportunities.
S
Sexual Dimorphism
Sexual dimorphism refers to the physical differences between males and females of the same species, beyond the differences in their sexual organs. In humans, this includes variations in size, shape, color, or structure that distinguish the two sexes. These differences are often the result of evolutionary processes and hormonal influences.
Sperm Competition
Sperm competition is a biological process where sperm from two or more males compete to fertilize a single egg. This evolutionary mechanism occurs in many species, including humans, and can influence male anatomy, physiology, and sexual behavior. In essence, it's nature's way of ensuring that the fittest sperm succeeds in fertilization.