population ecology Flashcards
what is ecology?
study levels of organization ranging from individuals organisms to the biosphere
study of the interactions between organisms and their environments
what do the mathematical models do?
allow computer models to simulate natural events and large scale experiments
what are the steps in Mark-Recapture study?
- capture a random sample of individuals that are marked
- release marked individuals back into population
- capture a second random sample if individuals, some of whom are marked
- calculate initial population size using the formula n1/x=n2m/n2
what is geographical range?
overall spatial boundaries within which a population lives
what is a habitat?
specific environment in which a population live as characterized by its biotic and abiotic features
what is spatial distribution?
individuals within the geographical range
doesn’t tell the population
what is dispersion patterns influenced by?
distribution of resources in environment/ landscape
habitat requirements of each individual
social structure of species
dispersal capacity of reproduction of species
presence of other species
what is random distribution?
distance between individuals is random with respects to each other’s location
rarest type of destitution
found in homogeneous environments
what is uniform distribution?
maximal distance between and two individuals
- found in many lants due to competition for resources
- also can result from territorial behaviour
what is a clumped distribution?
most common form of distribution
- resources rare
- poor dispersal capacity
- benefits to group living
what are population characteristics?
population age structure
sex ratio
proportion reproduction
generation time
can have dramatic effects on capacity for future growth
what is demography?
statistical study of processes that change a population’s size and density through time
what is a life table?
summarize demographics of a population
what are the different types of survivorship curves?
type 1: high survivorship until late life
type 2: constant rate of mortality in all ages classes
type 3: high juvenile mortality, followed by low mortality after critical age and size
what is life histories?
the schedule frequency and duration of events in an organisms’ lifetime
what is the evolution of life histories?
influenced by organism’s physical and ecological environment
- development age
- age of sexual maturity
- number of offspring
- level of parenting investment
- senescence and death
what is passive parental care?
before offspring born
what is active parental care?
offspring is born
many young = little care
few young = more care
what are the 2 types of breeding?
semelparity
iteroparity
what is semelarity?
one reproductive episode
devotes all stored energy
maximal fecundity
death after reproduction
what is iteroparity?
multiple reproductive episodes
only some energy devoted in each even
what does early reproduction favor?
adult survival rates low
animals do not grow more fecund with age
what does later reproduction?
if sexually mature adults likely to become older
if organisms grow larger with age
if larger organisms have higher fecundity
can have more offspring, natural selection favours this
what is life history evolution?
trade offs reflect differences strategies to maximize fitness
what is LH characteristic 1?
male displays
probability of being predated increases brightness/ number of spots
attractiveness vs survival tradeoff
what is LH character 2?
body size
probability of being predated decrease with body size
effect on time for first reproduction
what is LH character 3?
many stimuli offspring, produce more frequently vs. fewer better provisioned offspring produce more occasionally
what is LH character 4?
trade-off for parasite tolerance
life history traits and population?
the specific of a species life history characteristics can have important consequences for
- population growth
- population fluctuations
- nature of interactions with other species
what is population growth?
organisms often have the capacity to produce more offspring than are needed to replace themselves in the next generation
the study of population growth is central to ecology
what is the exponential growth model
by expressing per capita birth and death rates, education describes unlimited population growth
when there is no limits on population growth, it follows exponential pattern
what is rMAX?
intrinsic rate of increase (maximum per capita growth rate)
fast maturation = high rMAX
more offspring = high rMAX
what is bacterial population growth?
bacteria reproduction by binary fission; their population in size each generation
- short generation time
- small body size
- large rMAX
what is the logistical growth model?
most population growth is not exponential - limited in some fashion
carrying capacity (K): maximum population size that environment can sustain (theoretical but not fixed value)
per capita population growth rate (r) decrease in N approached K
what are the prediction effects of N on r?
when N < K, r > 0
when N = K, r = 0
when N > K, r < 0
what is density dependent factor?
crowding decreases individual growth rates, adult size and survivorship
what is fecundity is density dependent
more competition between species in same environment
what are density dependent factors?
reduced population growth regardless of population size
what are density independent factors?
may interact with density dependent factors
- food shortage caused by high population density may lead
- malnourished individual may be more likely to succumb to stress of extreme weather
what is cyclic fluctuations?
some animal populations exhibit cyclic fluctuation in size
what is intrinsic control?
hormonal and behavioural changes
what is extrinsic control?
relationships between a cycling species and other factors (food or predators)
