BIOL2040: Evolution - Lecture 14: Sex & Sexual Selection

This set of flashcards covers key concepts and vocabulary related to sexual reproduction and sexual selection, as presented in BIOL2040 Lecture 14.

Sexual reproduction

The process by which organisms combine genetic material from two parents, leading to genetic diversity.

Adaptive significance of sex

The advantages of sexual reproduction in enhancing survival and adaptation in changing environments.

Muller’s Ratchet

The irreversible accumulation of deleterious mutations in asexual populations due to lack of genetic recombination.

Fisher–Muller hypothesis

The theory that sexual reproduction accelerates adaptive evolution by combining beneficial mutations from different individuals.

Red Queen hypothesis

The idea that sexual reproduction provides an evolutionary advantage by allowing hosts to stay ahead of rapidly-evolving parasites.

Gamete size

The size of reproductive cells (sperm and eggs), which can influence mating strategies and reproductive success.

Anisogamy

A reproductive system characterized by the production of two different sizes of gametes, typically large eggs and small sperm.

Intersexual selection

A form of sexual selection where individuals of one sex choose their mates from individuals of the other sex.

Intrasexual selection

A form of sexual selection where members of one sex compete with each other for access to mating with the opposite sex.

Direct benefits model

A model of sexual selection suggesting that females choose mates based on tangible resources that enhance their fecundity or survival.

Handicap principle

A concept where costly traits serve as reliable indicators of an individual's fitness and genetic quality.

Fisherian sexual selection

The process by which female preference for certain male traits reinforces the evolution of those traits in males.

Sensory bias model

A model suggesting that pre-existing preferences in one sex can lead to the evolution of traits in the other sex.

Sperm competition

A form of postcopulatory sexual selection where sperm from different males competes to fertilize eggs.

Sexual dimorphism

The differences in appearance between males and females of the same species, often resulting from sexual selection.

Costly signals

Honest indicators of genetic quality that are expensive to produce, revealing the health and fitness of the signaler.

Male-male competition

Aggressive interactions among males to gain mating access to females, often leading to the evolution of combat traits.

Sexual conflict

The differing and often opposing reproductive strategies of males and females that can lead to antagonistic evolution.

Mate-guarding

A strategy used by males to remain close to females before or after copulation to prevent other males from mating with them.

Evolution of anisogamy

The process explaining the emergence of different sizes of gametes (large eggs vs. small sperm) in sexual reproduction.

Natural vs sexual selection

The distinction between evolution driven by survival advantages (natural selection) and advantages in mating success (sexual selection).

Good genes hypothesis

A theory proposing that females select mates based on traits indicating the male's genetic quality.

Runaway sexual selection

A scenario where the preference for an extravagant trait in males becomes stronger over generations, leading to extreme versions of that trait.

Postcopulatory sexual selection

The competitive process occurring after mating, affecting the success of sperm and offspring.

Visual and auditory signals in mate attraction

Traits like bright colors or calling songs that serve to attract mates, often selected through intersexual competition.

Intrinsic factors in sexual selection

Internal attributes like health, fertility, and genetic quality influencing mating success.

Extrinsic factors in sexual selection

External environmental traits that may affect reproductive success and mate selection.

Bet hedging

A reproductive strategy where variability in offspring increases the odds that some will survive in unpredictable environments.

Genetic variation

Diversity in gene frequencies within a population that can lead to adaptation and evolution.

Environmental unpredictability

The unstable nature of habitats that can influence selection pressures on organisms.

Spermatogenesis

The process of sperm production, which can vary in quality and quantity among different male reproductive strategies.

Female choice

The preference exhibited by females in selecting mates based on specific traits or behaviors.

Male ornamentation

Extravagant traits in males, such as bright colors or long tails, often evolved for attracting females.

Cuckoldry

A reproductive strategy where males raise offspring that are not genetically their own due to female infidelity.

Phenotypic diversity

The range of different physical traits exhibited by offspring from sexual reproduction.

Zygote survival

The likelihood of a fertilized egg developing successfully, which can be influenced by gamete size.

Territoriality in mating

The behavior of males defending specific areas to attract and secure mates.

Fecundity

The reproductive capacity of an organism, referring to the potential number of offspring.