Lecture 11 –
LIFE HISTORY
STRATEGY
Life History Strategy
A suite of traits that improve an
individual's chances of surviving and
reproducing in a particular environment
COST/BENEFIT ANALYSIS
1.
Energy committed to one function is not available for
others.
Growth
Respiration
Reproduction
Predator Defense
Growth
Respiration
Reproduction
Predator Defense
COST/BENEFIT ANALYSIS
1.
Energy committed to one function is not available for
others.
2.
Every evolutionary ‘choice’ has costs and benefits
Settles on wave exposed shore
Costs
Benefits
-energy in holding on
-less exposure to predators
-restricted movement for food
gathering
-more food delivery
-size restriction
-less energy directed to
growth
COST/BENEFIT ANALYSIS
1.
Energy commited to one function is not available for others.
2.
Every evolutionary ‘choice’ has costs and benefits
3.
Every organism represents a compromise of a number of
evolutionary ‘choices’
Periclimenes yucatanicus
Colour - bright & obvious to predators
- disruptive
Hides in anemone – restricted foraging
but has protection
Exoskeleton – restricts movement but
offers protection
Macarthur and Wilson (‘70’s) - Theory of Island Biogeography
r strategists
Opportunistic
-rapidly colonizing, fast
growth
K strategists
R.H. Macarthur
E.O. Wilson
Equilibrium
-slower colonizing, slow
growth
Attributes of r and K - selected organisms
r - selected
Climate
Mortality
Population Size
K - selected
Variable, unpredictible
Consistent, predictible
Density independent,
uncertain adult survival
Density dependent,
uncertain juvenile survival
Variable, below K
Consistent
More species, no
recolonization
Community Characteristics
Few species, recolonization
Lifespan
Short
Individual Attributes
Rapid development, early
reproduction, high rate of
increase, small body size
Slow development, late
reproduction, low rate of
increase, larger body size
Allocation of Energy
Greater % to reproduction
Greater % to growth and
maintenance
Long
Attributes of r and K - selected organisms
r - selected
K - selected
Climate
Variable, unpredictible
Consistent, predictible
Mortality
Density independent,
uncertain adult survival
Density dependent,
uncertain juvenile survival
Population Size
Variable, below K
Consistent
Community Characteristics
Few species,
recolonization
More species, no
recolonization
Lifespan
Short
Long
Individual Attributes
Rapid development, early
reproduction, high rate of
increase, small body size
Slow development, late
reproduction, low rate of
increase, larger body size
Allocation of Energy
Greater % to
reproduction
Greater % to growth and
maintenance
Productivity
Attributes of r and K - selected organisms
r - selected
K - selected
Climate
Variable, unpredictible
Consistent, predictible
Mortality
Density independent,
uncertain adult survival
Density dependent,
uncertain juvenile
survival
Population Size
Variable, below K
Consistent
Community Characteristics
Few species,
recolonization
More species, no
recolonization
Lifespan
Short
Long
Individual Attributes
Rapid development, early
reproduction, high rate of
increase, small body size
Slow development, late
reproduction, low rate of
increase, larger body size
Allocation of Energy
Greater % to
reproduction
Greater % to growth and
maintenance
Productivity
Efficiency
Look at our original energy allocation graphs
Growth
Growth
Respiration
Respiration
Reproduction
Reproduction
Predator Defense
More r - like
Predator Defense
More K - like
r - K continuum
r-strategist
Frequent disturbance
K-strategist
Less frequent disturbance
Aclonal Life History
recruitment
Sexual reproduction
Death
Clonal Life History
Sexual reproduction
recruitment
Fission
Fission
Fission
Death
Life history pattern -- a genetically inherited pattern of
resource allocation to that optimizes the passing of genes
to the next generation
EGG AND SPERM PRODUCTION
FERTILIZATION PATTERNS
TYPES OF DEVELOPMENT
LARVAL DISPERSAL STRATEGIES
SETTLEMENT PATTERNS
Fertilization Patterns
1. External (no copulation)
Fertilization Patterns
1. External (no copulation)
Problems
Gamete output
Synchrony
Gamete dispersal
Gamete dilution
Fertilization Patterns
1. External (no copulation)
Problems
Gamete output
Synchrony
100
%
success
Gamete dispersal
Gamete dilution
0.5 m
Distance between individuals
Fertilization Patterns
1. External (no copulation)
Allee Effect
Reproductive
rate
Number or Density
Fertilization Patterns
2. Internal (no copulation)
Fertilization Patterns
2. Internal (copulation)
Fertilization pattern
Costs
External Fertilization
-large gamete output
Benefits
-takes advantage of medium
-need for synchrony
-unpredictable dispersion
-gamete dilution
Internal Fertilization
(no copulation)
-large gamete output
-takes advantage of medium
-unpredictable dispersion
-gamete dilution
Internal Fertilization
(copulation)
-energy in mate searching
-less gamete wastage
-energy in courtship
-greater efficiency in
reproduction
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
Overview – Life History Patterns
1) Fertilization patterns ✓
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
4) Settlement patterns
Developmental Patterns
-Kinds of eggs
Isolecithal
• ••
• •• • • ••
• • •• ••
• •• • •
Telolecithal
••••••••••• ••
•
•
•
•
•
•••••••••••••••••• •••
• •• • •
yolk
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
Developmental Patterns
-Kinds of eggs
4) Settlement patterns
Isolecithal
• ••
• •• • • ••
• • •• ••
• •• • •
Cleavage through
entire egg
Telolecithal
••••••••••• ••
•
•
•
•
•
•••••••••••••••••• •••
• •• • •
Cleavage not through
entire egg
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
Developmental Patterns
-Kinds of eggs
4) Settlement patterns
Holoblastic
Isolecithal
• ••
• •• • • ••
• • •• ••
• •• • •
Cleavage through
entire egg
Telolecithal
••••••••••• ••
•
•
•
•
•
•••••••••••••••••• •••
• •• • •
• •
•• • •• •
• ••• ••••• ••• ••••
• ••• •• ••• •
• •• • ••
Meroblastic
Cleavage not through
entire egg
••••
••
••••••• •••••••••
•• •• •
•
• • ••
Developmental Patterns
-Kinds of eggs
Isolecithal - Holoblastic
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Telolecithal - Meroblastic
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
Developmental Patterns
-Kinds of eggs
Isolecithal
• ••
• •• • • ••
• • •• ••
• •• • •
Telolecithal
••••••••••• ••
•
•
•
•
•
•••••••••••••••••• •••
• •• • •
4) Settlement patterns
Holoblastic
•• ••
••• • ••• •
• • ••••• • ••••
• ••• •• ••• •
• •• • ••
Planktotrophic larvae
Meroblastic
••••
••
••••••• •••••••••
•• •• •
• •
• ••
Lecithotrophic larvae
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
Kinds of Development Patterns
4) Settlement patterns
Free spawning
Weakly
isolecithal egg
Indirect
Maturation
Free spawning
Planktotrophic,
free-swimming
larvae
Settlement and
metamorphosis
Indirect
Maturation
Juvenile
Mating
Brooding of
embryos
Direct
Maturation
Settlement and
metamorphosis
Juvenile
Mating
Strongly telolecithal
egg
Planktotrophic,
free-swimming
larvae
Strongly/moderately
telolecithal egg
Hatch as juveniles
Moderately
telolecithal egg
Maturation
Juvenile
Brooding of
embryos
Mixed
Hatch as freeswimming larvae
Settlement and
metamorphosis
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
Larval Settlement – Large Scale
4) Settlement patterns
0.2 %
recovery
0.2 %
recovery
0.18 %
recovery
Scheltema ‘71
Larval Settlement – Large Scale
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Scheltema ‘71
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
Larval Settlement – Large Scale
4) Settlement patterns
1012
1010
Frequency
of dispersal
108
106
104
102
102
104
106
108
1010
1012
Population size
Scheltema ‘71
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
Larval Settlement – Large Scale
4) Settlement patterns
Volume of water (m3)
Total number of larvae
North Atlantic Drift
2.45 x 105
3.31 x 1011
North Equatorial Current
3.43 x 105
4.63 x 1011
South Equatorial Current
2.26 x 105
3.05 x 1011
Equatorial Undercurrent
0.98 x 105
1.32 x 1011
Scheltema ‘71
Larval Settlement
Large Scale
Point Conception
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
Larval Settlement
Large Scale
4) Settlement patterns
Point Conception
Current Patterns
Larval Settlement
Large Scale
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Point Conception
Current Patterns
Biogeographical Zones
Embayment Flushing (Gaines & Bertness, ‘92)
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Wind & Tidal Currents
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Associated with internal
waves
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
Settlement - Behaviour of Larvae
4) Settlement patterns
Metamorphosis to
postlarva
Drifts in plankton
(days/weeks)
Lobster hatches
-photopositive-
Preference
switches to
photonegative
Lobster settles and
undergoes
metamorphosis
3. Benthic/Surface Phenomena
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
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
3. Benthic/Surface Phenomena
4) Settlement patterns
Pawlik et al, ‘91. Science 251:421
No ‘sampling’
#
settling
Current
Erosion
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
Early models
4) Settlement patterns
Larvae in water column
Settle randomly
Differential mortality
Adult distribution
More recent view
Larvae in water column
Passive deposition
Testing substrate
Not settle
Settle
Adult distribution
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
Passive Deposition
-due to
1) sedimentation rate
2) swimming behaviour
3) 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
Change in angular velocity
x
xx x x
Experiment on settling and flow
Botman et al 1998
Capitella
rich muds
Mercenaria
coarse sand
Experiment on settling and flow
Flow
Glass beads
Mud
Experiment on settling and flow
Still
water
Mud
Capitella
Mercenaria
Flow
Beads
yes
no
Conclusion
Mud
beads
no
yes
no
yes
No
preference
No
preference
- choice is species specific
- Mercenaria couldn’t ‘sample’
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
General Model
4) Settlement patterns
Free swimming larva
Alternating photonegative & photopositive behaviour
Passive deposition and contact with surface
Surface texture
Chemical cues
Attachment
Contact with conspecifics
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
Larval Settlement
4) Settlement patterns
1. Conspecifics
Free fatty acids
Larval settlement
Phragmatopoma
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
Larval Settlement
4) Settlement patterns
2. Bacterial films
Polysaccharides,
Glycoproteins
Increased searching
or metamorphosis
Larval Settlement
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
4) Settlement patterns
3. Prey species - herbivores
Settlement induced by
GABA
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
Larval Settlement
4) Settlement patterns
3. Prey species - herbivores
Gigartina
Abalone larva
In field
Porphyra
-not found on either
-not induced to settle
on whole fronds
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
Larval Settlement
4) Settlement patterns
3. Prey species - carnivores
Onchidoris bilamellata
Induces settlement
1) Fertilization patterns
2) Development patterns
3) Dispersal patterns
Larval Settlement
4) Settlement patterns
3. Prey species - carnivores
Phestilla
Induces settlement
< 500 Da protein
(< 10 mM)