Population Ecology Part 2 Flashcards
Violations of Assumptions of Mark Recapture Lab
Unequal Catchability Trap-Happiness Trap-Shyness Decreased Movement Increased Movement Changes in longevity
Life Table
Table that shows what the probability is that an individual of that age/stage/size will die before moving to the next age/stage/size
Why are Life Tables useful?
Clear and systematic picture of mortality and survival for a population
Used to project changes in population size given a certain age/stage/size population structure
Can be used to estimate the average individual birth and death rates for a population
Cohort
Following a group of individuals all born within a short period of time from birth of the first to the death of the last
What does investigating cohorts show?
Possible to asses fitness of an individual cohort
What makes investigating cohorts difficult?
Organisms that have overlapping generations
hard to follow individuals when they get mixed with individuals of other age classes
Static Life Table
Considers the survival and mortality of individuals of known age during a single time interval
Based on the age structure of a population at a particular time, or the age distribution of deaths
What does Static Life Tables assume?
Each age class is sampled in proportion to its numbers in the population and age at death Birth rates and death rates are constant over time
Dynamic-Composite
Takes as a cohort a sub-sample of a number of animals born/marked over a period of time periods
Combination of cohort/static life tables
Survivorship Curves
Log lx vs. age
Three types due to patterns of mortality/survivorship
Mortality Curves
qx vs age
Rate rather than numbers
Typically J shaped
Separated into two parts, juvenile phase, post-juvenile phase
lx
Survivorship, proportion of original cohort still alive
(number of alive individuals vs. original number of individuals)
Straight line = high survivorship
Steep line = low survivorship
qx
Age specific mortality, proportion of individuals that died during that age class of those that were alive at the beginning of that age class (amount that died vs. number of individuals that were originally alive in that age cohort)
Type I Survivorship
High survivorship when young, low survivorship when old
Type II Survivorship
Steady survivorship
Type III Survivorship
Low survivorship when young, high survivorship when old
Density Dependence
Regulation of population growth by mechanisms controlled by the size of the population
Effect increases as population size increases (logistic growth)
Density Independence
Population unaffected by population density
No effect from population size increases (exponential growth)
Biotic Factors regulate populations in which way?
Density-Dependent Factors
Abiotic Factors regulate populations in which way?
Density-Independent Factors
Density Dependent Factors
Disease, Predation, Competition
Density Independent Factors
Floods, Extreme temperatures
Climatic factors are most important
Population Fluctuation
Random
Population Cycle
Oscillation
More predictible
Dispersal
Movement of individuals through space
Involves the passive or active movement of juvenile or adult individuals
Generally describes the movement of individuals away from one another
Types of Dispersal
Emigration
Immigration
Emigration
Away from local subpopulation
Immigration
Into a local subpopulation
Population Dynamics
Behaviour of Populations
Study constancy and change in population size and structure
What influences Population Dynamics?
Dynamic balance between rates of birth, death, immigration and emigration
Logistic Growth
Density Dependence taken into account
Has carrying capacity = K
At higher densities of individuals there is:
Increased resource limitation
Increasing predator and disease pressure, increasing competition
Carrying Capacity
Maximum sustainable population size under the prevailing conditions and resources
