Sexual Reproduction and Selection

These flashcards cover the key vocabulary and concepts from the lecture regarding sexual reproduction, sexual selection, and related biological strategies.

Syngamy

The process of fertilization where gametes from two different individuals unite.

Anisogamy

The condition of producing two distinct types of gametes, typically larger eggs and smaller sperm.

Isogamous

Organisms that produce gametes of similar size, leading to no defined sexes.

Dioecious

Species in which individuals are either male or female.

Hermaphroditic

Species that possess both male and female reproductive organs.

Outcrossing

Mating process between individuals from different genetic backgrounds.

Selfing

Reproduction occurring when an organism fertilizes its own gametes.

Asexual reproduction

Reproduction without the fusion of gametes, often through methods like vegetative propagation.

Parthenogenesis

A form of asexual reproduction where an egg develops into an individual without fertilization.

Cost of sex

The disadvantages of sexual reproduction, such as breaking up successful gene combinations.

Sex ratio

Proportion of males to females in a population.

Intrasexual selection

Competition among the same sex for mating opportunities.

Intersexual selection

Mate choice whereby one sex selects partners based on certain traits.

Male-biased operational sex ratio

A situation where there are more males than females available for mating.

Bateman gradient

Relationship indicating that male mating success varies more than female success.

Sperm competition

Competition between sperm from different males to fertilize an egg.

Male mating tactics

Strategies used by males to increase their chances of reproduction.

Mate guarding

Behavior by one partner to prevent the other from mating with others.

Sexual dimorphism

The difference in appearance between males and females of the same species.

Fisher’s runaway model

Theory explaining how preferences for certain traits can lead to exaggerated characteristics through sexual selection.

Adaptive plasticity

Traits that can change based on environmental conditions for better survival or reproduction.

Sensory bias

Preference of mates that evolves based on existing sensory traits.

Runaway selection

Theory in sexual selection where traits become exaggerated due to preference feedback.

Good genes hypothesis

Theory suggesting that individuals choose mates based on signals of genetic quality.

Compatible genes

Genetic makeup that enhances survival and reproductive success of offspring.

Secondary sexual characteristics

Traits evolved in males or females to attract mates, such as colorful plumage in birds.

Sperm scrubbing

A mechanism where females have adaptations to remove less favorable sperm from their reproductive tract.

Coercion

A tactic used by some males to increase reproductive success by forcefully mating with females.

Amplexus

Mating behavior in frogs where males cling to females during the breeding process.

Harem

A social structure in which a male mates with multiple females, often seen in polygynous species.

Directional selection

A process in evolution leading to a shift in population traits favoring one extreme.

Alternative mating tactics

Different strategies within a sex that individuals may adopt to enhance mating success.

Copulatory plugs

A male’s substance deposited in the female's reproductive tract to prevent other males from mating.

Competitive variance

The differences in reproductive success among individuals competing for mates.

Mate choice copying

A phenomenon where individuals are influenced by the mate choices of others.

Sensory trap

A situation where mate signaling exploits an existing sensory bias in the chooser.

Variance in fitness

Differences in the reproductive success of individuals in a population.

Historical selection pressures

Factors that have influenced the evolution of species due to historical contexts.

Sexual selection

The natural selection arising through preference by one sex for particular characteristics in another sex.

Chick survival rates

Percentage of chicks from a particular mating strategy that survive to a given age.

Seychelles warbler

A species known for its unique mating and mate-guarding behaviors.