Flashcards in Lecture 1: Intro & Basics of Life Histories Deck (19):
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).
An animal which reproduces more than once.
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.
• amount of energy an organism can harvest is finite
and biological processes take time!
• trade‐offs between life history traits are unavoidable!
• variation in life‐histories are due to differences in the
allocation of resources (i.e. energy, time, essential
• Organisms that find “optimal balance” between costs
and benefits are favoured by natural selection.
What does an intrinsic rate of increase (r) population select for?
High population growth rates in uncrowded
environments, newly disturbed habitats, etc.
What does a carrying capacity (K) population select for?
• Slower growth rates in populations
that are at or near K (carry capacity)
• in crowded conditions, efficient
reproduction is favoured.
Any factor that reduces vegetative growth.
Any process that destroys plant biomass.
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.
What are the life history pattern classifications?
- annual, biennial, perennial
- r selection, K selection
- fast, slow pace of life
- stress, disturbance (plants) 'Grime'
- survival, fecundity, maturity (animals).
What are the main life history events?
Birth, maturity, reproduction, senesence, death.
What are the most important life history events and why?
Reproduction and death - they determine an organisms fitness and therefore its likelihood of success.