Fish reproduction

What are the two types of sex determination?

Genetic (sex determined by genetic code at fertilization), or environmental.

What is sex differentiation?

The development of anatomical features that belong to one sex or another.

What is maturation?

The production of functional gametes.

What is the result of gametogenesis?

Four haploid daughter cells.

What is the process for oogenesis?

Primary oocyte → Secondary oocyte and polar body → ovum, second polar body.

What is the result of oogenesis?

3 polar bodies, and 1 ovum

What is the result of spermatogenesis?

4 spermatids

What is lecithotrophy?

The provisioning of nutrients from mother to egg via yolk.

What is matrotrophy?

The provisioning of nutrients to embryo directly from mother, usually by a placenta (placentotrophy).

What is iteroparity?

Reproducing multiple times in one lifetime.

What is semelparity?

Reproducing only one time in life and then dying.

What are the three types of polygamy?

Polyandry (one female, many males), Polygyny (one male with many females), Polygynandry (both sexes have multiple mates).

What is a harem?

One male guarding many female mates.

What is a lek?

Several males congregating to present to females.

What is intersexual selection?

When the limiting sex (typically females) prefers certain characteristics in the other sex.

What is intrasexual selection?

When the members of the less limiting sex (typically males) compete with each other for for access to the limited sex.

Why does sexual dimorphism usually evolve?

Inter- and intrasexual selection.

What is a common form of sexual dimorphism in fish?

Sexual dichromatism, differences in coloration between sexes (usually males are more distinct).

What are primary sexual characteristics?

Structures used directly for reproduction (testes, ovaries, external genitalia).

What are secondary sexual characteristics?

Features specific to only one sex that is not involved in reproduction (as a result of sexual selection).

What is role switching?

When males participate in the incubation of young.

What is sexual plasticity?

Flexibility in sex determination.

What is sexual plasticity so common in fishes?

Only 10% of fishes have distinct sex chromosomes, the rest have the sex-influencing genes spread throughout the genome.

What are common environmental characteristics of sex determination?

Temperature, pH, body size (in comparison to others).

What sex is associated with larger body sizes?

Females.

What sex is associated with colder temperatures and why?

Females, they are born earlier in the season (colder) and thus get more time to grow.

What sex is associated with lower (more acidic) pH?

Males

What are gonochores?

Individuals that function as one sex in their lifetime.

What are hermaphrodites?

Individuals that function as more than one sex in their lifetime.

What is protogyny?

When an individual matures as a female and then changes into a male later in life.

What is protandry?

When an individual matures as a male and then changes into a female later in life.

What fish family has simultaneous hermaphroditism and participates in mating with other individuals?

Hamlets (Serranidae)

What fish species has simultaneous hermaphroditism and participates in self fertilization?

Kyrptolebias marmoratus

What is parthenogenesis?

Female reproduction without males.

What genus is associated with parthenogenesis?

Poecilia

What is gynogenesis?

A form of parthenogenesis where triploid (3n) females reproduce asexually (eggs are activated by other species sperm) to create only other 3n daughters.

What is hybridogenesis?

A form of parthenogenesis where diploid (2n) females produce haploid (1n) female eggs that are fertilized by other species sperm, all offspring are (2n) females.

What is the sexy sons hypothesis?

Females will want to mate with males that have many female partners.

In what family is sexual parasitism seen?

Anglerfish (Lophiiformes)