Lecture 14 - Reproduction Flashcards
What is iteroparity?
Breeding several times during a life cycle.
What is semelparity?
Breeding once and then dying.
Describe semelparity in ragworms.
- Lose all muscle, digest body tissue, stop feeding (put all of energy into reproductive event)
- Swim out of burrows and burst, releasing sperm and eggs into the water.
- Pick the time they reproduce depending on the risk level of the environment that they are living in.
What is semelparity favoured by?
- High population growth rate
- Low adult survivorship
- Longer intervals between reproductive episodes
- Early senescence
What is epitzoky?
Partial or complete transformation in order to swim into the water column for reproduction.
Give an organism where epitoky is a semelparous strategy.
In Nereidae, where the whole worm becomes the epitoke.
Describe the reproduction strategies of the palolo worm (Palola viridis).
Semelparous.
Use cues from moon, temperature and daylight hours to tell them exactly when to reproduce, via swarming in vast numbers, for reproductive success.
What is broadcast spawning?
Throwing eggs and sperm into the environment.
What is the ancestral reproduction strategy?
Broadcast spawning
What is predator satiation?
Mass spawning of multiple species in synchronisation; too many eggs are produced for the fish to eat in one day, avoids predation/ensures some reproductive success.
How do fertilisation rates vary over distance from males in broadcast spawners?
Decline, due to sperm dilution.
How is fertilisation success altered by turbulence that is
a) Mild or moderate?
b) Extreme?
a) Mild or moderate turbulence enhances fertilisation success by gamete mixing.
b) Gametes are diluted in extreme turbulence, and egg-sperm interaction is disrupted, reducing fertilisation success.
Describe the work of Campbell et all (2016).
Studying sperm competition under future conditions of ocean acidification.
OA always reduced sperm fitness.
Sperm switch in genotypes in what makes them best in different environments.
What does it mean if a cleavage is
a) Holoblastic?
b) Meroblastic?
a) Holoblastic = the whole embryo
b) Meroblastic = partial cleavage.
What is cleavage under control of?
Proteins and mRNAs stored in the oocyte by the mother (before the sperm arrives).