Topic 10: Reproduction Flashcards
E production
growth and reproduction
What is the ultimate goal of managing an energy budget?
to have energy remaining for reproduction
Life History Theory
every species has a pattern of growth, development, reproduction, and death shaped by natural selection
- success in the past helps shape life history traits
Environment affects LH traits by influencing energy budgets through:
amount of light
food sources
shelter
wind
precipitation
Maximizing reproductive success involves __________ due to _________
tradeoffs; fixed energy budgets & selective pressures
Fitness vs. number of seeds
increasing slope
Fitness vs. seed size
increasing slope
number of seeds vs. seed size
decreasing slope
2 types of growth:
determinate & indeterminate
Indeterminate growth:
growth continues through lifespan (ectotherms)
Determinate growth:
growth ceases when ‘adult’ state is reached (endotherms)
Reproduction (2 types)
asexual and sexual
Asexual reprodution produces:
clones
- prokaryotes replicate genome and divide by binary fission
- eukaryotes replicate genome and divide by mitosis
Sexual reproduction produces
recombinants
- genomes are halved into gametes and combined with other gametes
(only eukaryotes)
Life History Traits (7)
growth rate
parental care
fecundity
size/age @ sexual maturity
mortality rate
frequency of reproduction (parity)
size & survivorship of offspring
Passive care
pre birth energy investment (seed development, gestation, etc.)
Active care
post birth energy investment (raising, dispersing seeds, etc.)
Tradeoff: Growth rate & reproduction
decreasing slope
Tradeoff: Fecundity & survivorship of parent
decreasing slope
- both low = extinct
- both high = not enough energy for both
Tradeoff: Reproduction & Survival of Parent
reproducing at too young or high age = high mortality rate bc it is costly for young and old
- mortality rate would increase as reproduction increases
Tradeoff: ______ mortality rate would favour early age of maturity
high
Semelparity
can reproduce only once
Iteroparity
can breed/reproduce multiple times in its lifetime
Fecundity
ability to make many offspring
Fecundity _______ as body size increases
(when is this an advantage?)
increases
- advantage of delaying sexual maturity until larger size of parent
Tradeoff: Mating vs. Lifespan
decreasing slope, as mating increases rate of mortality
more predation = _______ population size @ reproduction
less
Age structure pyramids
zero, negative, rapid growth
r-selected
- small size
- early sexual maturity
- high fecundity
- low parental investment
- low juvenile survivorship
- short lifespan
- semelparous
K-selected
- large size
- late sexual maturity
- low fecundity but can reproduce many times
- high parental investment
- high juvenile survivorship
- long lifespan
- iteroparous
as mammal size increases, ______ energy is involved
more
What do life history traits allow us to do?
- to determine if r- or k- selected
- to predict how a population will change
- useful in manipulating crops & lifestock, to control pests/weeds, and for conservation efforts
When R0 > 1…
population is increasing
When R0 < 1…
population is decreasing
When R0 = 1
population is the same
sx =
survival rate
lx =
survivorship (fraction of original cohort still alive)
mx =
fecundity
nx =
number of organisms in cohort
x =
usually time/age
Survivorship curves: type 1
upside down L curve
- exponential decrease
- low mortality rate
- large animals
- high parental care
- high juvenile survivorship
- k-selected
Survivorship curves: type 2
- constant mortality rate - decreasing slope
- mix of r & k selected
Survivorship curves: type 3
- L shaped curve
- exponential decrease
- high mortality rate
- small animals
- low parental care
- low juvenile survivorship (mortality decreases with A)
- r-selected
How to detect constant mortality rate (type 2)? What would it look like on a regular survival vs. age graph?
- on a linear scale, it looks like type 3 graph ( L shaped curve)
- on log transformed scale, it looks normal (linear decrease)
