Population Ecology Flashcards
Define population ecology.
How populations change over space and time.
What factors influence population?
Density dependent forces.
Density independent forces.
What is an example of a density dependent force?
Competition for food.
What are examples of density independent forces?
Fires, floods etc.
What is the mark and recapture method?
- Capture animals.
- Mark/Tag the animals.
- Release.
- Return to site and recapture.
- Compare marked proportion to unmarked.
What are the pros/cons of mark and recapture?
You can assess other aspects of the population.
Very labour intensive.
What are life tables?
They use population census data to summarize birth/death rate of organisms at different life stages.
How many types of survivorship curve are there?
3
What organisms have a Type I survivorship curve?
Those with a high survival rate when young and a rapid decline when old.
What organisms have a Type II survivorship curve?
Those with a relatively constant death rate throughout life.
What organisms have a Type III survivorship curve?
Those with low survival rate when young but a high survival rate once mature.
What is the most basic form of population change?
Exponential increase/Unconstrained growth.
What factors are linked to population change?
Current population size and population growth rate.
What are life history traits?
An individual’s lifetime allocation of time and energy.
What are some examples of life history traits?
Growth, repair, defence and reproduction.
What are semelparous organisms?
Organisms that only reproduce once in their lifetime.
What are iteroparous organisms?
Organisms that reproduce multiple times during their life.
What is the life strategy of an r-selected species?
Live fast, die young, produce lots of offspring.
What is the life strategy of a k-selected species?
Slow to mature, slow to reproduce, high survival rate.
What is modular growth?
When a plant grows in modules that can be added intermittently.
Give some vertical module examples.
Leaves, buds, twigs, branches, flowers and fruits.
Give an example of a horizontal module example.
Clones.
Define genets.
Genetic individuals produced by sexual reproduction.
Define ramets.
Asexually produced individuals, derived from the same genetic parent.
What is a clone in terms of plant populations?
A group of ramets arising from a genet.
What is a ubiquitous species?
A species with a broad, widespread range made up of many populations.
What is an endemic species?
A species with a narrow range containing just a few populations.
What are the 3 dispersion patterns?
Random, clumped and uniform.
Which is the rarest dispersion pattern?
Random - it requires a uniform environment.
Which is the commonest dispersion pattern?
Clumped.
What are propagules?
Plant structures that detach from a plant and give rise to a new plant.
How can propagules be distributed?
By biotic or abiotic vectors or in other forms such as ballistically.
How are plant and animal populations structured differently?
Animal populations are usually age structured.
Plant populations are usually stage structured - based on size.
What aspect of a plant is used to determine its ‘stage’?
Size.
Define negative density dependence.
Plants responding to resource competition by slowing their growth.
Define self-thinning.
Progressive decline in density but an increase in biomass of the remaining individuals.
Define the Allee effect.
Increased reproduction/survival rate as a result of increased population density.
What are the 2 forms of reproduction in plants?
Monocarpic plants (semelparous). Polycarpic plants (iteroparous).
What are physiological stresses?
All external factors to a plant that limit growth.
What are the 3 points to Grime’s Triangular Model?
Stress tolerators, competitors and ruderals.
What is a stress tolerator plant?
Slow growing species found in unfertile areas. They conserve captured resources.
What is a competitor plant?
Fast growing species that inhabit highly fertile areas. They maximise resource capture.
What is a ruderal plant?
Fast growing species that inhabit highly fertile areas. They have high seed production.
What is the rate of living theory?
The faster an organism’s metabolism, the shorter its lifespan.
What is the mutation accumulation theory?
The severity of inbreeding depression increases with age.
