1 / 42

IB 362 lecture 6

IB 362 lecture 6. Reproduction, Dispersal and Migration in Marine Organisms. Reproduction. Behavior Regulation/effect of hormones Allocation of resources i.e. somatic vs. non-somatic tissue growth Method/frequency of fertilization Parental Care.

yagil
Download Presentation

IB 362 lecture 6

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. IB 362 lecture 6 Reproduction, Dispersal and Migration in Marine Organisms

  2. Reproduction Behavior Regulation/effect of hormones Allocation of resources i.e. somatic vs. non-somatic tissue growth Method/frequency of fertilization Parental Care

  3. dominant/large males select best shelters • females select dominate male’s shelter and moves in • female will molt and then mate • after mating, female waits for shell to harden then moves out • other females in waiting move into shelter with olfactory cues Reproduction Behavior North Atlantic Lobster – Homarus americanus

  4. Reproduction • no active searching for mates or pre-spawning behavior • females secrete pheromone after molting and any nearby male is attracted Behavior Opossum Shrimp

  5. Reproduction Behavior Regulation/effect of hormones Allocation of resources i.e. somatic vs. non-somatic tissue growth Method/frequency of fertilization Parental Care

  6. Lifetime Reproduction-two basic strategies • Iteroparous: • spawning possible more than once • most fishes and invertebrates • Semelparous: • spawning only once, followed by death • pacific salmon, some eels, lampreys

  7. Lifetime Reproduction-two basic strategies • Iteroparous: • spawning possible more than once • most fishes and invertebrates • Semelparous: • spawning only once, followed by death • pacific salmon, some eels, lampreys

  8. Lifetime Reproduction What are benefits and potential risks of each strategy? • Iteroparous • Semelparous

  9. Advantages / Disadvantages • Iteroparous: +several opportunities + environment unpredictable - longevity expected • Semelparous: + maximum investment - unfavorable conditions

  10. Mating Systems number of mating partners an individual has during a breeding season • Promiscuous: little or no mate choice • Polygamous: one sex has multiple partners • Polyandry: one female, several males - rare • Polygyny: one male, several females - common • Monogamous: mates stay together, exclusively

  11. Mating Systems • Promiscuous • organisms that live in large groups • organisms with high fecundity • sedentary organisms

  12. Mating Systems • Polygamous – Polyandry / Polygyny • none to some parental care • nest guarding • relatively rare in marine organisms, especially beyond egg stage

  13. Mating Systems • Monogamous • defense of territory / resource • parental care by both parents • relatively rare in marine organisms

  14. Extreme/Atypical Mating Systems • Monogamous Males rely on females for nutrition - internal organs degenerate with exception of testes

  15. Gender Roles • Gonochoristic:gender fixed, determined early • Hermaphrodites:either both, or sex change • Simultaneous: eggs & sperm at same time Hamlets

  16. Gender Roles • Gonochoristic:gender fixed, determined early • Hermaphrodites:either both, or sex change • Simultaneous: eggs & sperm at same time • Sequential : sex change during life

  17. Sequential – common in several marine fishes (most common in wrasse family – Labridae) Lyretail Coralfish: • Large aggregations • Sex-ratio 36F:1M • If x M removed, x F change sex

  18. Sex Change Clownfish – 30 species • Two large and several small fish • largest = female • 2nd largest = male • rest = immature(even if same age as mature fish) but hiearchal by size • Body size maintained until change

  19. Parental Care very diverse across fishes Trade-off in resource allocation: • few, but high-quality • many, but low-quality ? 7 300,000,000

  20. Fertilization InternalExternal Transfer of sperm in many invertebrates is via a spermatophore • Can be stored internally or attached externally • May provide nutrients to female • May prevent subsequent matings by other males • Decreased surface area

  21. Fertilization Transfer of sperm in many invertebrates is via a spermatophore • Successful system, why not more common?

  22. Fertilization Transfer of sperm in many invertebrates is via a spermatophore • Successful system, why not more common? Metamerism – serial repetition of body regions = more opportunity for appendage specialization

  23. Fertilization • Rare in invertebrates • Becomes more common in “higher” vertebrates Internal (in body cavity)External

  24. Open spawners Brooders External pelagic benthic • More common in marine fishes • Also known as broadcast spawners • Some benthic fishes will do it • high fecundity

  25. Open spawners Brooders External benthic pelagic • gametes released into current • settle to substrate after fert.

  26. Open spawners Brooders • gametes can be stored internally • fertilization is external • fert. eggs carried (usually by females) • until hatching • more common in invertebrates External

  27. Open spawners Brooders External • parental care of juveniles after hatching • does occur but is rare, mostly in fishes Cardinal Fish

  28. Occurs via splitting, budding or fragmentation • Generally rare, but more common in colonial organism at • the cellular level of organization Asexual Reproduction

  29. Dispersal egg >> larvae >> juveniles >> adults • Most marine organisms have a larval stage

  30. Dispersal egg >> larvae >> juveniles >> adults • Most marine organisms have a larval stage • Most freshwater organisms do not • Why the difference?

  31. Dispersal

  32. Dispersal

  33. Dispersal

  34. Development - Larvae

  35. Hatch – egg to larvae • not tied to specific developmental stage • water temp and oxygen content • tide conditions, time of day, seasonal current changes Hatching occurs at sunset of night of strongest ebb tide Coral Reef Flat Damselfish

  36. Larval stage Duration of larval stage dependant on resource needs in relation to currents • Food, habitat • 1 week to 18 months

  37. Two main types • Lecithotrophic –with yolk sac, no digestion • Planktotrophic – feed while larvae, digestion Larval stage • Name different across taxonomic groups Zoea – Crustaceans Amphiblastula - sponges Veliger – some molluscs Leptocephalus – some fishes Hard corals - planula

  38. Larva – unknown for many species

  39. Migration – a directed movement

  40. Migration – a directed movement

  41. Migration – a directed movement

  42. Migration – a directed movement

More Related