Population Ecology 1 & 2 Flashcards
Describe a population
- Group of individuals of a single species living in same general area
- Populations are described by their boundaries and size
What are the 5 Ds of population ecology?
- Density
- Distribution
- Dispersion (pattern of spacing)
- Dispersal (av distance an individual moves from where it was born to where it reproduces)
- Demographics
what factors influence spacing of individuals ?
- Environmental and social factors
Describe demographics
- Demographics: the statistical study of the structure of a population &
the changes that occur over time. - Incorporates:
- birth rates & death rates
- age structure
- sex ratios
What is Semelparity?
Single event (ollowed by death)
What is Iteroparity? what two types?
Repeated reproductive events =>
Seasonal iteroparity: e.g. birds, perennial plants
Continuous iteroparity: e.g. primates, tropical species
Population diagrams - how do they look when population is growing?
pyramid
Describe a mark-recapture survey
a method of population estimation in which
researchers capture and mark a subset of a
population from an area, return it to the area,
and capture a second sample of the population
after time has passed.
How is population size estimated:
What two life tables can we have?
Age specific summary of survival pattern of a population =>
1. Cohort Life Tables - follows an age group from birth to death
2. Time specific (static) - quantifies survival`::fecundity of ALL individuals at one time interval
What important stats for life history?
- age
- No alive each year
- survival
-Deaths - Mortality rate
- Mean expectation of further lfie at age x
What are the patterns of survivorship: intermediate types?
Type II/III intermediate
- High young mortality
* - then constant adult mortality rate
(e.g. many birds, mud turtles)
Type I/II intermediate
- Low mortality in young,
* - then steady adult mortality rate
Use of population models?
help understand complex real ecological
systems in simple terms.
- Test theories, enables predictions to be made & help in decision making for managing & conserving populations of species
why is it helpful to study population growth ?
in an idealized situation to help us
understand the capacity of species to increase and the conditions that
may facilitate this growth.
Population dynamics modelling?
Express mathematically population growth ?
How can births and deaths be expressedN
as an average number of births and deaths PER INDIVIDUAL during the specified time interval
What is the per capita rat of increase aka intrinsic growth rate?
(R) = b-m
r=0?
zero population growth
r>0 ?
population increases
r<0 = ?
population decrease
How can we now write the change in population size?
When does exponential population growth happen?
under idealized conditions
What is the equation for exponential population growth?
think of N as money in bank account and r as interest
