biodiversity + soil + water + primary productivity Flashcards
population ecology studies what
the # of individuals of a species that are found in an area. It looks at how and why those numbers increase and decrease.
population density
looks at the number of individuals of a species per unit of area or volume at a given time and incorporates how organisms are distributed
growth rate
rate of change in a population’s size
what is growth rate determined by
birth rate & death rate (r=b-d)
populations __ in size as long as the number of ____ is greater than the number of _____
increase, births, deaths
what does it lead to if deaths outpace number of births
extinction
emigration is
the number of individuals leaving an area
immigration is the number of individuals ____ an area
entering
biotic potential
maximum reproductive rate of an organism; doesn’t usually happen bc of limited factors
examples of limiting factors
food, water, shelter, mates, nutrients, etc
how do species increase and how do they maintain their carrying capacity?
developing adaptations and migrating to other areas
what is density-dependent factors?
regulate pop growth by affecting a larger proportion of the population as population density rises
predation, disease, competition
what is density independent factor?
limit pop growth but are not influenced by changes in pop density
hurricanes, fires
generalist
lives in a broad niche
able to withstand a wide range of ecological conditions
ex:
coachroaches
mice
humans
specialists
lives in narrow niches
sensitive to environment
prone to extinction
ex: giant panda
in stable conditions, specialist excel due to little or no competition
competition exclusion principle
no two organisms can occupy the same niche at the same time
what are key stone species
a species whose presence contributes to the diversity of life and whose extinction would lead to extinction to other forms of life
what characterizes a new species
when offspring from the ancestor species can no longer reproduce
what do mutations do
random change in genetic code
natural selection is…
the environmental conditions determine what traits are useful
artificial selection…
human determine which individuals breed and what traits are beneficial
what is the bottle neck effect?
a drastic reduction in the size of population can lead to change in the pop’s genetic composition (fire)
what is founder effect?
a small number of individuals colonize a place. The future generations will have similar genetic composition to the founders
geographic isolation
a large population is separated into two smaller populations as geo barriers change
