What are the 5 different scopes of ecological research?
- global ecology
- landscape ecology
- ecosystem ecology
- community ecology
- population ecology
How do community and population ecology differ?
Community - Interspecific
Pop - intraspecific
What factors influence the distribution of a species?
- dispersion/reproduction
- abiotic factors (climate-light, fire, moisture, temp; salinity, o2)
- biotic (predation, herbivory, competition, pathogens, disease)
Define population
inter or intra specific?
group of organisms of the same species occupying a particular space at the same time.
genetic and ecological units in which a species’ members interact with one another.
Intra
Define metapopulation
spatially separated, disjunct population which is distributed in patches across a heterogeneous landscape and interconnected by immigration (dispersal).
By which mechanism are meta metapopulations connected?
dispersal
What are advantages are dispersal?
- range expansion
- increased gene flow
- inbreeding avoidance
- reduced resource competition
What are 3 patterns of dispersal?
- natal dispersal
- presaturation dispersal
- saturation dispersal
What conditions affect the decision/ability to disperse?
age
condition
carrying capacity reached?
despite dependent/independent
Describe natal dispersion
- who is this most common with in mammals?
The dispersion from birth place before the first breeding/before sexual maturity.
in mammals - usually males disperse
Describe presaturation dispersal
animals in good condition
dispersal before the carrying capacity is reached
density independent
Describe saturation dispersal
animals in poor condition
young/small
carrying capacity has been reached or exceeded
density dependent
Dispersal is from ____ to _____ - _____ filled by _______
Dispersal is from source to a sink- empty habitat filled by immigration
Have you done the required reading on UMLearn?
- determinants of habitat selection
Yes
What are the determinants of habitat selection?
Genees and environment
Tradition
What are properties of populations that help in measuring them?
density dispersion sex ratios age structure mortality natality
How is density used to measure a population?
1 - count all individuals in a population
2 - estimate using sampling
3 - mark-recapture method depends on likelihood of recapturing the same individual
Define density
number of organisms occupying a defined unit of space
Define crude density
of individuals per unit area
Define ecological density
measured in terms of useable habitat
rarely estimated - very difficult to measure what portion of habitat represent living space
List 3 patterns of spatial dispersion.
What are they strongly influenced by?
- uniform
- random
- clumped
- strongly influenced by landscape and interactions among members of the population
What type of dispersion are the most even? why?
uniform - infraspecific comp.
(ex. territoriality)
Define random dispersion
position of each individual is independent of others or the occupation of each is equally likely
is random dispersion common or rare? when does it occur?
rare!
envr uniform
resources equally available all year
interactions among members of pop produce no patterns of attraction or avoidance
what is the most common type of distribution pattern?
clumped
- habitat differences
- daily and seasonal changes
- reproductive patterns and social behaviour
What are some reasons that clumped distribution patterns can occur?
poor dispersal capability of young
patchy distribution of resources
social organization
Define sex ratios
proportion of males to females - 1:1 in most sexually reproducing organisms
1degree sex ratio
ratio at conception
2degree sex ratio
ratio at birth
- usually weighted towards males in mammals
Demographics
population dynamics
what is a life table?
what can it be used for?
an age-specific summary of the survival pattern of a population.
producing survivorship curves
Describe exponential growth model
uncontrolled growth
applicable to only initial growth after colonization of an unexploited habitat
not biologically realistic or sustainable
Two examples of exponential growth
St Paul reindeer herd
Rabbits
Describe the logistic growth model
idealized model of growth, slowed by limiting environmental factors
reach K - carrying capacity
give two examples and boom and bust cycles
hares and lynx
snowy owls and lemmings
give two examples and boom and bust cycles
hares and lynx
snowy owls and lemmings
What is Life History and what do these traits include?
series of events from birth to reproduction, to death - age @ first repro. - freq. of repro. - # offspring amount of parental care given energy cost of repro.
What are the 2 major life history strategies?
r-selection
k-selection
Describe r-selection
“live fast, die young”
- reach sexual maturity early
- large # offspring
- litte/no parental care
- generally short lived
Describe k - selection
“live long and prosper”
- reach sexual maturity late
- small # offspring
- parental care
- generally long-lived
What are r-selected species usually limited by? What about k-selected species?
r = density-independent factors
–> can easily colonize new habitats
k= density-dependent factors
When is population ecology more important?
applied research
- endangered species
- manage wildlife populations
- human pop. growth
- SARA
What are the 2 steps to in the SARA process?
- scientific evaluation
2. listing by government
define mutualism
both organisms benefit
define commensalism
one benefits, other with no loss/no gain
define amensalism
one no effect, one negative
how could a community be controlled bottom-up?
nutrients
how could a community be controlled top-down?
predators
how does production efficiency range between birds/mammals, fish, and insects?
birds/mammals = 1-3% (endothermy) fish = 10% insects = 40%+
required reading on bison??
Yes
how are bisons suggestion to shift ecosystem functions?
graze so intensely they they freeze plants in early spring for weeks at a time, preventing them from maturing. This forces them to continuously produce young shoots
- increases nutrients in plants by 50-90% by end of summer
- extra food
- prolongs growing season
- accelerates growth
What are properties of a population
density dispersion sex ratio age structure mortality natality
What are some reasons for a clumped distribution?
poor dispersion of young
patchy distribution of resources
social organization
Example of a mammal discussed in class that displayed exponential growth?
St. Paul Reindeer