Life Histories Flashcards
life history
adaptations, its survival and size and age of reproductive maturity
- evolutionary scale (fixed) or common ecological scales (plastic/not fixed)
offspring size vs number
organisms have limited access to energy and resources so there is a trade-off between the number and size of offspring; those that produce larger offspring are constrained to produce fewer
adult survival and reproduction allocation
where adult survival is lower, organisms begin reproducing at an earlier age to invest greater proportion of their energy budget to reproduction; where adult survival is higher, organisms defer reproduction and allocate less resources to reproduction
other trade offs
growth vs reproduction and present vs future reproduction
parity
how many times you breed
- semelparous or monocapric: once (more resources to reproduction)
- iteroparous or polycarpic: multiple
life history classification
the great diversity of life histories can be classified on the basis of a few population characteristics: fecundity, survival, relative offspring size and age of reproductive maturity
r selection
opportunistic
favours higher population growth. is the strongest in disturbed habitats
- high rate increase, competitive ability not favoured, rapid development, early reproduction, small body, many small offspring, type III
k selection
equilibrium
refers to the carrying capacity in a logistic growth curve and is a form of natural selection favouring efficient utilisation of resources (Type I or II)
- low increase rate, competition, slow development, more constant and predictable environment, late reproduction, large bodies, iteropathy, few large offspring
plant life histories
- low disturbance - low stress (lots of resources) = competitive
- low disturbance - high stress = stress tolerant
- high disturbance - low stress = ruderal
life cycle
the successive stages through which an organism passes from a zygote of one generation to zygote of the next generation
