LIFE HISTORY PATTERNS

1. LIFE HISTORY PATTERNS

2. LIFE HISTORY PATTERNS: is a genetically inherited pattern of resource allocation (= investment)to that optimizes the passing of genes to the next generation Different investment patterns

3. FOR REST OF TERM – LIFE HISTORY PATTERNS: is a genetically inherited pattern of resource allocation to that optimizes the passing of genes to the next generation EGG AND SPERM PRODUCTION FERTILIZATION PATTERNS SPERM COMPETITION TYPES OF DEVELOPMENT LARVAL DISPERSAL STRATEGIES SETTLEMENT PATTERNS

4. Spawing and Fertilization

5. Evolution of Anisogamy Imagine some Precambrian creature G. Parker Produces undifferentiated gametes Fertilization

6. Gametes produced come in a variety of sizes Large Medium Small Number produced Mitotic competence

7. Size distribution of gametes produced Gamete size Number produced

8. External fertilization Which ones are the most likely to produce offspring?

9. Combinations Very high Very high Very high Moderate Very high Very low Moderate Low Low High Very low Very high Competence Frequency of contact

10. After several generations Selected against Gamete size Number produced

11. Anisogamy

12. Spermatogenesis is the process by which spearmtids are produced from male germ cells via mitosis and meiosis Spermiogenesisis the final stage of spermatogenesis in which spermatids add tails and become motile

14. FERTILIZATION TYPES OF SPERM AND EGG RELEASE AND FERTILIZATION 1. Broadcast spawners (= free spawners) -eggs and sperm are released into the water column - fertilization is external 2. Spermcastspawners -sperm are released into the water column and taken in by the female -fertilization is internal 3. Copulators -sperm placed in the body of the female usually with some intromittentorgtan -fertilization is internal

15. SPAWNING 1. BROADCAST SPAWNING

16. SPAWNING 1. BROADCAST SPAWNING Problems for broadcast spawners How does an animal ensure fertilization by dumping eggs and sperm in the open ocean? 1. Proximity 2. Timing 3. Currents 4. Sperm/egg contact

17. Boradcastspawners suffer a dilution effect Quinn and Ackerman. 2011. LimnolOceanogr. 2011: 176

18. Boradcastspawners suffer a dilution effect

19. How to get around this problem 1. Proximity oysters mussels

20. How to get around this problem 2. Timing and synchrony Haliotisasinina Counihan et al. 2001. Mar.Ecol.Prog.Ser.213:193

21. How to get around this problem 2. Timing and synchrony Haliotisasinina Counihan et al. 2001. Mar.Ecol.Prog.Ser.213:193

22. How to get around this problem 2. Timing and synchrony Haliotisasinina Counihan et al. 2001. Mar.Ecol.Prog.Ser.213:193

23. How to get around this problem 2. Timing and synchrony Haliotisasinina Counihan et al. 2001. Mar.Ecol.Prog.Ser.213:193

24. How to get around this problem 2. Timing and synchrony Haliotisasinina Conclusions (Counihanet al. 2001) 1. Spawning season is determined by water temperature 2. Precise time of spawning is influenced by tidal regime 3. Both sexes spawn in response to an evening high tide 4. Males spawn 19 mins before high tide: females 11 mins after 5. More animals spawn in presence of opposite sex. Counihan et al. 2001. Mar.Ecol.Prog.Ser.213:193

25. 3. Currents

26. 3. Currents Patterns of flow – move gametes unpredictably Advection – mean direction and velocity of a gamete cloud Diffusion –rate of gamete spreading Main problem – production of eddies (vortices) – unpredictable and ephemeral

27. 3. Currents

28. 4. Sperm-egg contact a. Dilution -is it sperm concentration or egg:sperm ratio? If sperm and egg are at similar concentrations -sperm :egg ratio is important Sperm concentration is imporant Sperm:egg ratio important

29. Sperm concentration and fertilization 1) Fertilization success more sensitive to sperm concentration Reduction in egg concentration Reduction in sperm concentration Same reduction in fertilization success Reduction in egg concentration Reduction in sperm concentration

30. Final problem Egg and sperm longevity Horseshoe crabs Sea urchins Sea stars Ascidians hydroids Sperm live less than a few hours Sea urchins Sea stars Ascidians Eggs live about 3x longer than sperm

31. How can sperm and egg increase the chances of contact? a) Chemical attractants

32. How can sperm and egg increase the chances of contact? a) Chemical attractants L- Tryptophan in abalone Tryptophan ‘cloud’

33. How can sperm and egg increase the chances of contact? b) Jelly coat Jelly coat increases the size of the egg and acts as a sperm‘trap’

35. Fertilization Spermcast spawning -mating “by releasing unpackaged spermatozoa to be dispersed to conspecifics where they fertilize eggs that have been retained by their originator.” Bishop and Pemberton.2006. Integr.Comp.Biol. 46:398

36. Fertilization Spermcast spawning most sponges many hydroids some corals (Cnidaria) some polychaetes (Annelida), some bivalve Mollusca, Entoprocta, some articulate Brachiopoda, all Ectoprocta, most or all pterobranchs(Hemichordata), most ascidians (Chordata: Tunicata)

37. Fertilization Spermcast spawning In most spermcasters- Sperm release Intake by female Fertilization and brooding Storage of sperm Release of competent larvae

38. Fertilization Spermcast spawning Factors influencing spermcasters 1. Longevity of sperm Retain ability to fertilize longer than free spawners

39. Fertilization Spermcast spawning Factors influencing spermcasters 2. Conservation of energy Sperm release Sperm are inactive or periodically active Intake by ‘female’ Consequence: Fertilization can happen with fewer sperm at greater distance Sperm consistently active

40. Fertilization Spermcast spawning Factors influencing spermcasters 3. Sperm storage -allows accumulation of a number of allosperm Diplosomalisterianum- 7 weeks Celleporellahyalina- Several weeks

41. Fertilization Spermcast spawning Factors influencing spermcasters Diplosomalisterianum 4. Egg development Sperm release Intake by ‘female’ Celleporellahyalina Triggering of vitellogenesis Consequence: Investment in eggs is not wasted.