Unit 3: Populations Flashcards
smallest to biggest ecological levels
- individual
- population
- community
- ecosystem
If People Care Enough
population
all the individuals of a PARTICULAR SPECIES(10 bunnies)
individual
a singular type of species(1 bunny)
community
all the species interacting (2 bunnies, 2 bears, 2 birds)
ecosystem
community + abiotic factors(animals/plants + dirt, sand, air)
Things we look at in a population
- size
- density
- pop. distribution
size doesn’t penis-dick
what factors affect population
- reproduction rate
- resources
how to calculate density
of indiv/area
density dependent factors
impact size of population as a response to how dense the pop is(the more dense, the greater impact on size of pop) EX: disease(the more dense, the faster the disease can spread)
density independent factors
would happen regardless of how dense pop is
EX: natural disasters
population distribution
how spread out people are within the area
types of population distribution
- nearly uniform (everyone equidistance) —– evidence of ppl trying to est. territory/hunting ground
- random (not as common, no benefit, ex: weeds/generalist species)
- clumped (schools of fish, hunting packs)
k selected v r selected SPECTRUM(species in between)
k= quality care, few offspring r= quantity(no care) care, many offspring
k selected
-reproduce many times(give birth many seperate times)
-long lifespan
-SLOW population growth rate
-SLOW sexual maturity
-more likely TO BE DISRUPTED
EX: mammals, birds
r selected
-reproduce once
-short lifespan
-QUICK sexual maturity(high biotic potential)
-FAST population growth rate
-more likely TO BE INVASIVE
-better suited for fast changing env conditions
EX: insects, fish, plants
survivorship curves
show patterns of survival/lifespan
-fast drop in line=quicker die off
-slow drop in line=longer avg. lifespan(live till old age/die of old age)
(doesn’t have years on bottom j cuz all have diff lifespans)
type 1 survivorship curve
Ex: humans w access to medicine (most of the time will see species w same curve BUT depends on location, develop v nondevelop countries)
-rapid decrease at the end(die of old age)
type 2 survivorship curve
constant death rate(linear negative line down)
-equally likely to die at any age
EX: squirrels
type 3 survivorship curve
EX: weeds
-die alot
what type of curve do K species have
type 1 (good parental care makes sure they live long)
what type of curve do R species have
type 3(bad parental care doesn’t help them live)
carrying capacity(K)
maximum population that a habitat can support over a given period of time
what pushes exponential growth forward
biotic potential
What keeps a population from exponentially growing infinitely
environmental resistance, keeps the carrying capacity down
