ESS grade 10 test 2 Flashcards
Population
all the individuals of a species that live together in an area
demography
the statistical study of populations allows predictions to be made about how a population will change
three key features of a population
size
density
dispersion
size
number of individuals in an area
density
measurement of the population per unit area/volume
density equation
number of individuals / unit of space
types of dispersion
- clumped = schools of fish, herds, flocks of birds
- random = weeds, spread out, no order
- uniform = rows of corn, vineyards (usually only with human involvement)
Other key features of a population
growth rate
- birth rate (natality) - death rate (mortality) = natural growth rate
- + natality + immigration - mortality - emigration = actual growth rate
How is density affected
- immigration
- emigration
- density dependent factors
- density independent factors
immigration
movement of individuals into a population
emigration
movement of individuals out of a population
density dependent factors
biotic factors in the enviornment that have an increasing effect as the population size increases (disease, parasites, competition)
density independent factors
abiotic factors in the environment that affect populations regardless of their density (temperature, weather)
how is population size measured
- population density
- size (count all individuals in a population)
- estimate by sampling
- mark - recapture method
explain estimate by sampling
lincoln index
- find a group of species year one and tag them
- in year two collect another group randomly
- in year two group, the group will have some from year one and some new ones
- use the math formula to estimate the change in population
explain mark recapture method
mark an animal and follow it for a while
carrying capacity + the other name for it
the max population size that can be supported by the available resources. there can only be as many organisms as the environment’s resources can support
- called the booms and busts
exponential vs logistic growth
exponential (up curve)
logistical (up and then curves off)
factors limiting growth rate (declining growth rate or increasing death rate)
limited food supple
buildup of toxic wastes
increased disease
predators
bioaccumulation
the more tainted food an organism eats, the more the toxic substance accumulates in the body. causes infertility
for example, mercury
biomagnification
amount of toxic substances builds up with the food chain.
ship = 1
fish eats 3 shrimp
fish = 3
big fish eats 3 fish
big fish = 9
etc
r strategists
focus on reproducing
- short lifespan
- small body size
- reproduces quickly
- many offspring
- little to no parental care
- ex mosquitos, flys, weeds, bacteria, cockroaches
k strategists
focus on maintaining the carrying capacity (not reproducing)
- long life span
- large body size
- reproduces slowly (gestation period)
- have few offspring
- provides parental care
- ex humans, elephants, cows, etc
neither k nor r strategists
some species are neither or a bit of both
- dogs
- cats
- birds
- squirrels
reproductive strategy organisms on survivorship graphs
time on the x
percentage of organisms alive on the y
- r = L shape
- k = upside down L shape
- neither = in the middle
population pyramids
- shows when events occur in time which affect population size
- shows where countries need to improve in elderly care, natality rates
- shows the age range of the population
biodiversity
measure of how different species live in an ecosystem
high vs low biodiversity in ecosystems
high - many different species of organism
low - not many different species of organism
ecosystem stability
the higher the biodiversity, the more stable the ecosystem will be
how will a species going extinct affect an ecosystem with high biodiversity
it wont make much of a difference since there are still other options for organisms to feed on
how will a species going extinct affect an ecosystem with low biodiversity
one small change will cause several organisms to go without food
what organisms are more likely to go extinct
organisms with specialized habit or diet
ex pandas, koalas
invasive species
non native species in an ecosystem that reproduce quickly and have no/few natural predators
- they decrease biodiversity by taking over food sources, space, causing competition and pushing out native species
ex of invasive species
zebra mussels, kudzu plant, brown tree snake, wild hogs/boars
survivorship curve
graph which shows when a population is most likely to die
what do all types of growth start out as
exponential growth
total fertility rate
average number of children a female has in her lifetime
biotic potential
max ability to produce offspring
estimate of humans carrying capacity
10-15 billion
ecological footprint
how many resources a human requires to live
life history
a record of all events in an organisms life including growth, development reproduction, and survival
will a population level off the same year it reaches zero population growth
no, because the parents live on for years, meanwhile their children are having children and so on
Limiting factors + examples
factors that limit (slows or stops) a population from growing further.
ex. food, water, space, disease, mates, natural disasters, predation
mutualism, commensalism, predation, parasitism, competition
mutualism - both benefit
commensalism - one benefits, one doesnt care
predation - one benefits the other doesnt
parasitism - parasite benefits, host doesnt
competition - neither benefits
negative feedback loop
when a process occurs which allows conditions to stay the same
delayed density dependance
predator prey relationship
- prey increases
- this causes predators to decrease due to abundance of food
- abundance of predators cause the prey to die out
- lack of prey causes predators to starve and they die out
- lack of predators causes prey to grow
etc, etc
