Lecture 1: Intro & Basics of Life Histories Flashcards
Give some examples of life history traits.
- Age at first reproduction (age to maturity)
- realised lifespan
- fecundity (no. offspring produced)
- viability of offspring
- mode of reproduction (sexual vs. asexual)
- frequency of reproduction (only once vs. more than once).
Define ‘semelparous’.
An animal which reproduces more than once.
Define ‘iteroparous’.
An animal which only reproduces once.
Define ‘annual plants’.
Go from seed to seed within a year.
Define ‘biennial plants’.
A plant which takes two years to complete its life cycle.
Define ‘perrennial plants’.
A plant which lives for more than two years.
Define ‘Darwinian Demons’.
The idea of organisms which possess unlimited fitness.
Why do Darwinian Demons not exist in nature?
Due to life history constraints.
Give examples of life history constraints.
• amountofenergy anorganismcanharvestisfinite
andbiologicalprocessestaketime!
• trade‐offs betweenlifehistorytraitsareunavoidable!
• variationinlife‐historiesareduetodifferencesinthe
allocationofresources(i.e.energy,time,essential
amino‐acids)
• Organismsthatfind“optimalbalance”betweencosts
andbenefitsarefavouredbynaturalselection.
What does an intrinsic rate of increase (r) population select for?
Highpopulationgrowthratesinuncrowded
environments,newlydisturbedhabitats,etc.
What does a carrying capacity (K) population select for?
• Slowergrowthratesinpopulations
thatareatornearK (carrycapacity)
• incrowdedconditions,efficient
reproductionisfavoured.
Define ‘stress’.
Anyfactorthatreducesvegetativegrowth.
Define ‘disturbance’.
Anyprocessthatdestroysplantbiomass.
What can life history traits be used for?
- Predict species demography & threats of extinction
(population management and conservation biology) - better our understanding of species adaptation to the environment.
Define ‘life history theories’.
They seek to explain the differences in how organisms grow, mature, reproduce and senesce.
