1. Marine Invertebrate Zoology
Reproduction and Development
Reproduction & Development

2. Reproduction & Development
Asexual reproduction
Reproduction in the absence of fertilization (without union of gametes)
Reproduction & Development

4. Reproduction & Development
Parthenogenesis
Parthenogenesis – eggs develop to adulthood in the absence of fertilization (some arthropods, and rotifers)
Reproduction & Development

5. Reproduction & Development
Parthenogenesis
Reproduction & Development

6. Reproduction & Development
Sexual Reproduction
Patterns of Sexuality
Gonochoristic or dioecious
The parents are of 2 different sexes
Hermaphroditism – both male and female sex organs
Simultaneous or sequential
Protandric
Protogynous
Reproduction & Development

7. Getting the “Boys” to the Party
Internal fertilization
Direct
Indirect
Methods of transfer vary across phyla
Reproduction & Development

8. Reproduction & Development
Sexual Reproduction
Reproduction & Development

9. Broadcast Spawning & External Fertilization
Requires the precise timing of gamete release
Successful fertilization is dependent on:
Reproduction & Development

10. Reproduction & Development
Larval Forms
The product of external and some internal fertilization usually results in a free-living, swimming larvae that grows and differentiates in the plankton
Most larvae are ciliated for locomotion, and food collection
Reproduction & Development

11. Advantages for Free-living Larvae
Transitions between phases of complex life cycles usually requires metamorphosis (abrupt morphological, physiological, and ecological changes)
Reproduction & Development

12. Cost of Delaying Metamorphosis
Reproduction & Development