chapter 53- pop ecology Flashcards
What is ecology
the scientific study of interactions between organisms and the environment
- many levels of ecology
What is population ecology
the study of how species populations change over time and how those pop. interact w the environment
what is community ecology
how specific interactions affect overall community and what influences diversity
what is a population
ind. of same species living in same overall area
what are 3 areas of study
density, dispersion and demographic
what is density
number of individuals per area
what is dispersion
pattern of spacing among individuals
what is a demographic
birth and death rates, composition of population.
What is the best way to calculate density
through mark-recapture studies
what is the mark recapture study
technique used estimate the size of a pop where it is impractical to count every individual
# of butterflies marked X # captured/ # captured a second time
Clumped dispersion is
the most common type bcs species congregate in preferred habitats
Uniform dispersion
often involves direct interactions between ind.
What is random dispersion
position of one ind. is independent of others, there are no strong attractions or repulsions
what do demographics show
vital stastitics of pop. ( birth and death rates) in form of a LIFE TABLE
What is a survivorship curve
a graph showing the number of ind in a population and their drop offs w time
- basically # of cohort alive at each age
what is a reproductive rate
reproductive tables determine reproductive rate, measures which generations are replaced.
Birth and Immagration _ to a pop.
add ind.
death and emmigration _ to a pop.
remove ind from a pop.
What is semelparity and iteroparity
both are reproductive statergies available to living organisms
What is semelparity strategy
sinfle reproductive episode before death, and utilied in an unstable enviornemnt where survival of parent is not clear
What is iteroparity strategy
multiple reproductove cycles over course of lifetime
beneficial in more stable enviornments
What are K selected species
Only produce few offspring, but offspring is large and has long lifespan, exhbits logisitc growth
What are R selected species
where they produce as many as possible, but have shorter lifespans and echbity exponential growth
what is ecological foot print
summarizes the aggregate land and water needed to sustain the ppl of a nation, can be calulctaed using energy growth
