Extreme CH 10- Reproductive strategies

Interesting Reproductive Biology in the Ocean

Learning Goals

  • Understand the diverse reproductive strategies in the ocean

  • Define key terminology related to marine reproductive biology

  • Examine specific species presented in the chapter

Taxonomic Classification and Symmetry

  • Overview of various animal phyla and their key features:
      - Porifera (Sponges)
        - No ciliary combs
        - No defined body cavities
        - No tissues
        - Lack bilateral or radial symmetry
      - Cnidaria (Cnidarians)
        - Possess tissues
      - Ctenophora (Comb Jellies)
        - Have ciliary combs
      - Platyhelminthes (Flatworms)
      - Nemertea (Ribbon Worms)
        - No segmentation
      - Mollusca (Mollusks)
        - Foot and mantle present; no jointed legs
        - Bilateral symmetry
        - Many have a body cavity and circulatory systems
      - Chaetognatha (Arrow Worms)
      - Annelida (Segmented Worms)
        - Exhibit segmentation
      - Arthropoda (Arthropods)
        - Jointed legs
        - Ventral nerve cord or ganglion
      - Phoronida (Phoronids)
      - Ectoprocta (Bryozoans)
      - Brachiopoda (Lamp Shells)
      - Echinodermata (Echinoderms)
        - Possess radial symmetry
      - Hemichordata (Hemichordates)
        - No notochord or lophophore
      - Chordata (Chordates)
        - Have a notochord and may exhibit varied characteristics including presence of lophophores and segmentation.

Sequential Hermaphroditism

  • Clownfish (Amphiprion spp.)
      - Approximately 30 species in genus Amphiprion
      - All clownfish are born as males
      - Behavior:
        - Multiple immature males share a sea anemone
        - Largest and most dominant male becomes female
        - The next largest male develops functional testes
        - When one of the mated pair dies, the next in rank replaces them
      - Features a hierarchy of size and strength in breeding pairs
      - Symbiosis with sea anemones: Close bond essential for survival & reproduction.

Sexual Dimorphism

  • Definition: Significant physical differences (size & appearance) between males and females besides reproductive organs

  • Anglerfish:
      - Exhibit pronounced sexual dimorphism
      - Males are significantly smaller than females, yet possess strong sensory organs
      - Male anglerfish bites and fuses to the female's body, leading to:
        - Dissolution of his body organs except testes
        - Female produces chemical signals to stimulate sperm release from the fused male organs
        - A female can host multiple males' testes simultaneously.

Metamorphosis

  • Definition: Change in body shape and anatomy during different life phases

  • Palolo Worm (Palola viridis):
      - Belongs to Kingdom Animalia, Phylum Annelida, Class Polychaeta
      - Reproduction occurs once a year, linked to specific lunar phases
      - Process:
        - Intestines dissolve
        - Gonads mature
        - Development of epitokes (the reproductive segments)
      - Spawning event:
        - Individuals collectively release eggs and sperm simultaneously.

Reproductive Interest in Marine Species

  • Seahorses: Unique reproductive roles and features

  • Sergeant Major Damselfish: Noteworthy reproductive behaviors or strategies

  • Giant Octopus Moms: Fascinating maternal traits and reproductive strategies