Population Dynamics Flashcards
What is a population?
A population is a group of organisms of the same species occupying a particular space at a particular time
Describe a local population
A local population or deme, comprises individuals that are interbreeding, with individuals sharing a common gene pool
What does population ecology focus in on?
Concerned with the measurement of the following population attributes
-Primary Parameters:
-Density
-Birth rate
-Death rate
-Immigration
-Emigration
What are secondary population attributes?
-Age distribution
-Sex ratio
-Genetic composition
What factors affect population density?
Immigration +
Natality (births) +
Emigration -
Mortality (deaths) -
What determines the birth and death rate of a population?
Potential fecundity vs. realised fecundity
Potential longevity vs. Realised longevity
What is biotic potential?
-The maximum rate at which a population could increase
-Can be reached when conditions are ideal, with maximum birth rates (potential fecundity( and minimum death rates (potential longevity)
What is environmental resistance?
-Factors in the living and non-living environment that limit population growth
-Includes space, food availability, predation pressure
-These factors can increase death rate and decrease birth rate
What are mathematical calculations used for?
Are used to describe and project changes in population size
What is population ecology applied to?
-Management of harvested populations (fisheries)
-Control of pest species
-Conservation of endangered species
-Planning for projected human population growth
What is population age structure?
-Refers to the numbers of individuals alive at each age
-Can make population size predictions using age structure and age specific birth and death rates to make predictions about population
What are life tables?
-Collects data describing numbers at each age and numbers dying at each age
-Can combine with a fertility schedule showing average number of offspring produced by an individual of each age (fecundity)
What can we calculate from life table data?
The populations reproductive rate and if it increasing or decreasing
What is a cohort life table?
A cohort of organisms is tracked from year of birth to year of death for the oldest survivor
What is a static life table?
Presents mortality data for a cross section of the population at a specific point in time. Records numbers of individuals and the number of deaths in each age class
What species is an example of type 1 survivorship curves?
Humans - large numbers survive until old age
What species is an example of type 2 survivorship curves?
Squirrels
What species is an example of type 3 survivorship curve?
Fish- large numbers die off quickly
What aspects of turtle conservation exist?
-Protection of nesting sites
-Artificial rearing of juveniles
-Reducing fishing related mortality of adults
What did life table analysis show in relation to the common snapping turtle? (Congdon et al 1994)
-Life table data showing that increasing adults’ or juvenile survival would have a bigger impact on population stability than improvements in nest survival
What is elasticity?
Is the proportional contribution of each vital rate (age-specific survival and fecundity) to the annual population multiplication rate
