Population Ecology
what happens in a population with exponential growth?
K has not been reached, growth is only limited by the reproductive speed of the species
what are survivorship curves?
a graph that shows the mortality rate in a population
what is a population?
a group of organisms in an area that are able to reproduce together and belong in the same species
describe a type 3 survivorship curve
a large percentage of the young die fast but if they survive until maturity they live for a long time, organisms reproduce fast
what are the types of dispersion that can occur among populations?
clumped, uniform, random
what are life tables used for?
comparing the chances of survival of various ages and genders in a population
what does population ecology study?
composition of populations
what are the environmental factors that influence population growth?
density-independent and density-dependent factors
what are examples of species that have uniform distribution?
desert plants, territorial organisms (lions)
what are density-dependent factors and some examples?
factors that have a greater effect when population density is higher ex: food source, space
what are examples of organisms with type 1 survivorship curves?
humans, large mammals like lions or bears
how can the number of number of individuals change in a population (increase or decrease)?
immigration increases the population emigration decreases the population birth rate increases the population death rate decreases the population
what are examples of organisms with type 2 survivorship curves?
mice, rats, ladybugs, bearded lizards, spiders
describe random distribution
organisms are dispersed randomly
describe uniform distribution
organisms are evenly spread out, resources are scarce and must be divided up
describe a type 2 survivorship curve
organisms have an equal chance of dying at any age
describe a type 1 survivorship curve
organisms reach maturity in large numbers, they survive to old age and die in old age, take care of their young and reproduce slowly
describe clumped distribution
organisms that live in packs, flocks, herds, or schools
what are examples of species that have clumped distribution?
packs of wolves, flocks of geese, schools of fish
what are density-independent factors and some examples?
regardless of density these factors affect individuals to the same extent ex: volcanic eruption, hurricane
what are techniques used to study how many individuals are in a population?
sampling, counting, catching, and marking individuals
what is K selection?
species reproduce slowly, take care of their young
what is r selection?
species reproduce very fast but many die at a young age
what is carrying capacity?
the number of individuals the environment can support in a given area at a given time
what is population density?
the number of organisms in a given area or volume
what happens in a population with logistical growth?
the population reached the K and environmental conditions determine their growth rate
what are examples of organisms with type 3 survivorship curves?
trees, clownfish, frogs
what are examples of species that have random distribution?
wind blown seeds
