lecture 10 Flashcards
what are r-selected species?
species that are favoured for fast growth rates, often thought to be important in disturbed habitats
what are k-selected species?
species that are likely to have traits that favour efficient utilization of resources, rather than maximizing growth rates
what are traits of semelparity?
- a massive reproductive effort
- once in a life reproductive event (fatal)
- more so r species
what are traits of iteroparity?
- repeated episodes of reproduction
- more so k species
what is semelparity favoured by?
- low survival rate of adults between reproductive episodes
- high cost of surviving between reproductive episodes
what is iteroparity favoured by?
- high adult survival rates relative to juvenile survival rates
- wait longer to reproduce, fewer offspring, higher parental care per offspring
what is the grimes classification?
included environmental conditions to help explain life history strategies in plants
what does the grimes classification suggest about selective pressures?
that disturbance and abiotic stress are most important but so is competition
what are the three strategies of grimes classification?
- stress tolerant
- competitive
- ruderal
what are traits of the competitve strategy?
- grow fast
- great competitor for resources
- predominant under conditions of low disturbance and low stress
- high intensity of competition
- low intensity of disturbance
what are traits of the ruderal strategy?
- dominant under conditions of high disturbance and low stress
- grow fast
- short generation time
- often annuals
what are traits of the stress tolerant strategy?
- predominant under conditions of low disturbance and high stress
- grow slow
- nutrient detention
- low intensity of competition
what is disturbance?
events that cause temporary change in environmental conditions and results in plant destruction / mortality
what is stress?
environmental conditions that limit plant growth
what is the winemiller and roses classification?
life history strategy based on trade offs between juvenile survivorship, fecundity, and age of reproductive maturity
what are the three end points on the adaptive space surface?
- oppurtunistic
- equilibrium
- periodic
what are traits of the oppurtunistic strategy?
- low juvenile surivial
- low numbers of offspring per reproductiv event
- early reproductive maturity
- typical of small fishes
- tend to be r selected species
what are traits of the equilibrium strategy?
- high juvenile survival
- high numbers of offspring
- late reproductive maturity
- invest heavily in offspring, typically not large species
- typically k species
what are traits of the periodic strategy?
- low juvenile survival
- high numbers of offspring
- late reproductive maturity
- takes long time to grow, similar to stress-tolerant species
