Lec 13- Life History Flashcards
life history
description of major characteristics of an organism from birth to death
- body size
- survival
- age of reproductive maturity
- # of offspring produced
principle of allocation
amount of time and energy available to each organism is limited
- when energy and time is allocated to one function, it reduces energy and time available for other functions
energy budgets
need to allocate energy b/w and w/in parts of budget
- trade-offs w/in reproductive budget (offspring # and size)
( the small the offspring, the more produced)
- trade-offs b/w repro and other activities (survival and growth)
body size
length
height
weight
fecundity
offspring per episode
- harbor seal: 1 offspring
- lionfish: 30,000-40,000 offspring
- tulip: ~50-250
- amaranth ~1000-10,000
parity
of episodes for repro per life
- sockeye salmon 1 (anadromous)
- brown booby 16-20x
- rapeseed 1x
- apple tree up to 100x
maturity
age at 1st repro
- shrimp (4-6M)
- white shark (33 yrs)
- rapeseed (~3M)
- cherry tree (7-10 yrs)
aging/senescence
life span/survival
- ostracod (~40 days)
- bowhead wale (200 yrs)
- sunflower (~1 yr- annual)
- western redcedar (1000 yrs - perennial)
- glass sponge (10,000+ yrs)
- aspen (80,000+ yrs)
semelparity, semelparous
animals
one repro event
- salmon
iteroparity, iteroparous
animals
multiple repro events
- brown booby
monocarpic
flowers and sets seeds only 1x
- rapeseed
- plants
polycarpic
flowers and sets seeds multiple times
- trees
annual plants
completes life cycle in one growing season
- rapeseed
perennial
completes life cycle in multiple growing seasons
- trees
allometry
study of scaling b/w body size and various biological traits/fxns (shape, anatomy, physiology, behavior)
what does body size influence?
relationships with temp, energy, water, and nutrient acquisition
applications of allometry
estimating fish biomass in fisheries
- lionfish
- total length vs wet weight (+ correlation, exponential trend)
what are life history trade-offs result of?
evolutionary trajectories
offspring size vs number
freshwater darters
- the larger the fish, the higher number of eggs produced
+ correlation
linear
larger eggs means fewer eggs
seed size vs dispersal distance
larger seeds = less produced
negative correlation
larger seed mass = wider plants are dispersed
- many factors influence how far seeds disperse (plant height)
dispersal
permanent movement of individuals (propagules) usually from one population to another
- NOT migration
seed dispersal
spread of seeds from mother plant across space
offspring size vs gene flow
gene flow: transfer of genetic material from one population to another
- Turner and Trexler on diff species of darterfish
= smaller eggs means they are a larva for a longer time so they are able to move further away (more gene flow)
gene flow- smaller eggs
smaller and more eggs
- smaller larvae
- longer larval phase
drift far away
low genetic isolation
gene flow - larger eggs
larger and fewer eggs
- larger larvae
- short larval phase
do not drift far
higher genetic isolation
survival vs age at maturity
reproductive effort: allocation of energy, time and other resources to reproduction
- formation of eggs and offspring care
- costly for some
- early investment = less e for growth/survival
lizards and snakes (survival/maturity)
lizards and snakes have higher survival = mature at later ages
why is reproduction costly?
- organisms invest early in reproduction cannot allocate more E to growth and survival
- those that opt for higher survival rate reproduce at a later life stage
size vs maturity/behavior
variation within species also be substantial
- coho salmon “jack” vs “hooknose”
hooknose vs jack
2 groups must represent 2 alternative but successful evolutionary strategies
hooknose
fight among themselves to gain access to females
larger = later maturity
jacks
can hide and fertilize eggs w/o getting into fights with larger hooknose
r and K selection
MacArthur and Wilson
r selection
small and fast
- high r
- competitive ability not strongly favored
- rapid development
- small body size
- single, semelparity reproduction
- many, small offspring
K selection
large and slow
- low r
- highly favored competitive ability
- slow development
- late repro
- large body size
- repeated, iteroparity repro
- few, large offspring
Grime’s triangle
CSR
- competitive
- stress-tolerant
- ruderal
center: intermediate life history strategies
CR - disturbance
CS- competition
SR- stress
ruderals
best under high disturbance and low stress (weeds)
- rapid growth
- large amount of tiny seeds
- short life span (annuals)
- little maintenance and growth of large structures
amaranth
stress-tolerant plants
high stress and low competition (rock screes, saline marshes)
- slow growth
- physiological stress-tolerance rather than growth
wild tulips: bulb is storage for food and water so they avoid competition and cant allocate E for storage
competitive plants
low disturbance and high productivity
- grow fast
aspen
- strong competitors
E-P-O scheme
winemiller and rose
Fish
- equilibrium life history
- periodic life history
- opportunistic life history
PO- fecundity
EP- age of reproductive maturity
EO- juvenile survivorship
semi-triangular surface
theoretically possible adaptive space due to life history trade-offs
O
low survival
early maturity
low fecundity
- guppy
P
low survival
late maturity
high fecundity
- sturgeon
E
high survival
late maturity
low fecundity
- shark
guppy- O
enviro variable in space and time
- fast reproduction
sturgeon- P
seasonal environment: en masse reproduction
shark- E
stable environment, high competition
- juvenile survival so more E invested so less offspring produced
