Unit 2: Life History Strategies Flashcards
Adaptation is apparent at
every stage of the life cycle
* embryo
* juvenile
* adult
embryo stage
time to and size at hatching or birth
juvenile stage
- time to and size at metamorphosis (if applicable)
- time to and size at sexual maturity
adult stage
- number of breeding events
- number and size of offspring per breeding event
- parental investment
- longevity
Life history adaptations tend to trend toward
overal short or long lifespan, with some exceptions
greater number of offspring =
- shorter lifespan
- faster growth
- earlier reproduction
- earlier sexual maturation
- smaller parental investment
fewer offspring =
- longer life span
- slower growth
- delayed reproduction
- later sexual maturation
- greater parental investment
life history traits tend to fall on a [–]
continuum of environmental factors
the principle of allocation
- organisms have finite amounts of energy and resources to overcome environmental challenges so compromises or trade-offs are made
for plants, trade-offs involve
- seed size
- number
- distribution method
studies have demonstrated the trade-offs between
clutch size and reproductive success
fledging
leaving nest = difficult to keep track of them
tropical and temperate birds have different strategies for
provisioning offspring
temperate birds tend to
make more trips but have higher mortality
tropical birds tend to
make more trips per nestling, increasing their reproductive success because of increased offspring survival
Kestrels could raise more chicks, but it would
decrease parental survival
what happended during clutch manipulation for kestrels
- when more egges are added, more offspring survive
- increasing clutch size also increased mortality for parents
studies have also show trade-offs between [–] and [–] to immune function
parental effort and allocation of resources
black capped chickadees use [–]
torpor to conserve energy
black-capped chickadees to what to their body weight
in the fall, they increase their body weight ~4% to stave off effects of water foraging
flycatchers with larger broods also demonstrated higher rates of
malarial parasite infection
in high predator environments, guppies
allocate more resources to producing quickly
higher predator environments =
mature male guppy size is small = % of reproduction of allocation is higher
freshwater snails, conversely, delay reproduction in the
“presence” of predators to grow larger and produce large egg masses
semelparity
- reproduction that is done only once
- reproduce and then die
- no point in surviving once they reproduce
ex) bamboo, agave, salmon
iteroparity
- multiple reproduction events
- repeated reproduction
- fewer offspring per time
ex) birds, humans
Senecence
- occurs in both iteroparous and semelparous species
- the condition of process of deterioration with age
