life history strategy (part 2). overview – life history patterns 1) fertilization patterns 2)...
TRANSCRIPT
LIFE HISTORY STRATEGY (PART 2)
Overview – Life History Patterns
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
✓
From last lecture
Fertilization pattern
Costs Benefits
External Fertilization -large gamete output
-need for synchrony
-unpredictable dispersion
-gamete dilution
-takes advantage of medium
Internal Fertilization(no copulation)
-large gamete output
-unpredictable dispersion
-gamete dilution
-takes advantage of medium
Internal Fertilization(copulation)
-energy in mate searching
-energy in courtship
-less gamete wastage
-greater efficiency in reproduction
Developmental Patterns-Kinds of eggs
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Isolecithal
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Telolecithal
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yolk
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Developmental Patterns-Kinds of eggs
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Isolecithal
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Telolecithal
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Cleavage through
entire egg
Cleavage not through
entire egg
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Developmental Patterns-Kinds of eggs
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Isolecithal
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Telolecithal
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Cleavage through
entire egg
Cleavage not through
entire egg
Holoblastic
Meroblastic
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Developmental Patterns-Kinds of eggs
Isolecithal - Holoblastic Telolecithal - Meroblastic
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Developmental Patterns-Kinds of eggs
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Isolecithal
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Telolecithal
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Holoblastic
Meroblastic
Planktotrophic larvae
Lecithotrophic larvae
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Kinds of Development Patterns
Free spawning
Planktotrophic, free-swimming
larvae
Settlement and metamorphosis
Juvenile
Maturation
Weakly isolecithal egg
Indirect
Free spawning
Planktotrophic, free-swimming
larvae
Settlement and metamorphosis
Juvenile
Maturation
Strongly/moderately telolecithal egg
Indirect
Mating
Brooding of embryos
Hatch as juvenilesMaturation
Strongly telolecithal egg
Direct
Mating
Brooding of embryos
Hatch as free-swimming larvae
Juvenile
Maturation
Moderately telolecithal egg
Mixed
Settlement and metamorphosis
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Larval Settlement – Large Scale
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
0.2 % recovery
0.18 % recovery
0.2 % recovery
Scheltema ‘71
Scheltema ‘71
Larval Settlement – Large Scale
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Scheltema ‘71
Larval Settlement – Large Scale1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
102 104 106 108 1010 1012
1012
1010
108
106
104
102
Population size
Frequency of dispersal
Scheltema ‘71
Larval Settlement – Large Scale1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
North Atlantic Drift
Volume of water (m3) Total number of larvae
North Equatorial Current
Equatorial Undercurrent
South Equatorial Current
2.45 x 105
3.43 x 105
2.26 x 105
0.98 x 105
3.31 x 1011
4.63 x 1011
3.05 x 1011
1.32 x 1011
Point Conception
Larval SettlementLarge Scale
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Point Conception
Larval SettlementLarge Scale
Current Patterns
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Point Conception
Larval SettlementLarge Scale
Current PatternsBiogeographical Zones
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Embayment Flushing (Gaines & Bertness, ‘92)
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Wind & Tidal Currents
Associated with internal waves
Wind & Tidal Currents
Associated with internal waves
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Settlement - Behaviour of Larvae
Lobster hatches-photopositive-
Drifts in plankton(days/weeks)
Preference switches to
photonegative
Lobster settles and undergoes
metamorphosis
Metamorphosis to postlarva
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
3. Benthic/Surface Phenomena
Pawlik et al, ‘91. Science 251:421
- settlement of reef-building worm
Current Speed
-low-medium-high (>15 cm/sec)
Phragmatopoma
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
3. Benthic/Surface Phenomena
Pawlik et al, ‘91. Science 251:421
# settling
Current
No ‘sampling’ Erosion
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Early models
Larvae in water column Settle randomly Differential mortality
Adult distribution
More recent view
Larvae in water column Passive deposition Testing substrate
Settle
Adult distribution
Not settle
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Passive Deposition
-due to1) sedimentation rate2) swimming behaviour3) bottom flow patterns
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Bottom flow patterns
Laminar flow
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Bottom flow patterns
xxx xx
Change in angular velocity
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Experiment on settling and flow
Botman et al 1998
coarse sandrich muds
Capitella Mercenaria
Experiment on settling and flow
Glass beads Mud
Flow
Experiment on settling and flow
Still
water
Flow
Mud Beads Mud beads
Capitella yes no yes no
Mercenaria no yes
No preference
No preference
Conclusion - choice is species specific- Mercenaria couldn’t ‘sample’
General Model
Free swimming larva
Alternating photonegative & photopositive behaviour
Passive deposition and contact with surface
Surface texture Chemical cues Contact with conspecifics
Attachment
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Larval Settlement
1. Conspecifics
2. Microbial films
3. Prey species
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Larval Settlement
1. Conspecifics
Free fatty acids
Larval settlement
Phragmatopoma
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Larval Settlement
2. Bacterial films
Polysaccharides, Glycoproteins
Increased searchingor metamorphosis
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Larval Settlement
3. Prey species - herbivores
Settlement induced byGABA
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Larval Settlement
3. Prey species - herbivores
Gigartina
Porphyra
Abalone larva
In field-not found on either-not induced to settle on whole fronds
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Larval Settlement
3. Prey species - carnivores
Onchidoris bilamellata
Induces settlement
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Larval Settlement
3. Prey species - carnivores
Phestilla
Induces settlement
< 500 Da protein(< 10 mM)
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns