Fish Reproduction/Conservation (11)

Flashcards covering key concepts related to fish reproduction, sex determination, variations in reproductive strategies, and conservation threats.

Chromosomal sex determination

A type of sex determination observed in fishes where the sex is determined by chromosomes, typically X-Y for males and X-X for females.

X-Y heteromorphic system

A chromosomal system where males have one X and one Y chromosome (X-Y), making them heterogametic, while females have two X chromosomes (X-X).

Z-W system

A sex determination system where females are the heterogametic sex with a Z-W chromosome pairing, while males have two Z chromosomes (Z-Z).

Gonochoristic

Refers to species in which individuals are distinctly male or female throughout their lives.

Juvenile Hermaphroditism

Occurs when some fish species possess both male and female reproductive structures during their juvenile stage.

Asynchronous Hermaphroditism

A condition in which hermaphrodites can produce functional eggs and sperm at different times.

Synchronous Hermaphroditism

A rare reproductive strategy in which individuals can produce both male sperm and female eggs simultaneously.

Successive Hermaphroditism

A process where individuals typically begin life as one sex, then change to the other as they age or grow larger.

Gynogenesis

A reproductive strategy where fertilization occurs when sperm is required for egg development, but it does not contribute to the offspring's genome.

Parthenogenesis

A form of asexual reproduction where an organism develops from an unfertilized egg, requiring no male.

Environmental pressures on freshwater habitats

Factors such as pollution, habitat alteration, and human activities that threaten the species living in freshwater ecosystems.

Overfishing

An unsustainable fishing practice that depletes fish populations faster than they can reproduce, posing a threat to marine ecosystems.

Coral reef fishes

Fish species that live in coral reefs, facing threats from pollution and climate change-related ocean warming.