brainstorm please list 3 abiotic and 3 biotic factors that affect population growth and decrease in...
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Brainstorm
Please list 3 Abiotic and 3 Biotic factors that affect population growth and decrease in size.
Old Bio StuffAbiotic vs. Biotic FactorsThat limit population growth
Not living Sunlight Temperature Climate Chemical
environment
Living factors Reproduction rates Food supply Habitat Resistance to
disease Ability to adapt to
change
Abiotic Biotic
POPULATION SIZE
Growth factors(biotic potential)
Favorable lightFavorable temperatureFavorable chemical environment (optimal level of critical nutrients)
Abiotic
BioticHigh reproductive rateGeneralized nicheAdequate food supplySuitable habitatAbility to compete for resourcesAbility to hide from or defend against predatorsAbility to resist diseases and parasitesAbility to migrate and live in other habitatsAbility to adapt to environmental change
Decrease factors(environmental resistance)
Too much or too little lightTemperature too high or too lowUnfavorable chemical environment (too much or too little of critical nutrients)
Abiotic
BioticLow reproductive rateSpecialized nicheInadequate food supplyUnsuitable or destroyed habitatToo many competitorsInsufficient ability to hide from or defend against predatorsInability to resist diseases and parasitesInability to migrate and live in other habitatsInability to adapt to environmental change
Biotic potential = growth
Environmental resistance = decrease
How come this doesn’t happen
Population Dynamics
Bus Analogy
What is the bus a symbol of?
As the # of people on the bus increases, what is the impact on…
The people trying to get on
The people already on The bus itself
Population Dynamics
Studying the change in size, density, and distribution of a population.
Population Dynamics
Size: number of individuals
Density: how many individuals are in a certain area
Distribution: How many individuals are in a certain group (gender, age, etc.) and where the population lives
Size
Increases in population: through birth or immigration
Decreases in population: through death or emigration.
Change in Population
Births + Immigration
Deaths + Emigration
Note: You should know difference between Immigration & Emigration!
Turkey Trending
NY State population = 300,000
500,000 births, 25,000 immigrate
450,000 deaths, 50,000 emigrate
= (B + I) – (D + E)
Two Types of Growth
No limiting factors
Shown in r-species
Boom, then bust
Limiting factors present
Shown in K-species
Stable populations
Exponential (Bacteria) Logistic (Turkeys)
Exponential or Logistic Growth Curve?
“Boom and Bust” “Boom then stable”
Logistic Growth
Will see exponential growth at first introduction to new environment.
Then, growth will be limited by environmental factors and will follow carrying capacity
S shaped P
op
ula
tion
siz
e (N
)
Time (t)
Carrying capacity (K)
Environmentalresistance
Bioticpotential
Exponentialgrowth
Clearer view of “J” and “S”
Going up…
Intrinsic rate of increase (r) is the rate the population would grow if it had unlimited resources.
Can be seen as the “boom” of the population.
Coming down…
Overshoot occurs when the population “booms” and is too great for the resources to support
Overshoot is followed by dieback, or the sudden decrease in population
What species are you?N
um
ber
of
ind
ivid
uals
Time
Carrying capacity
K species;experienceK selection
r species;experiencer selection
Species
Reproduce early in life Reproduce frequently Large numbers of
offspring Little to no parental care Boom and bust
populations Examples:
Frogs Cockroach Dandelions Mice Most insects
Reproduce later in life Reproduce less frequently Have less offspring at one
time Lower infant mortality Logistic graph (stable at
top) Examples:
Humans Elephants Whales Long-living plants
r-selected Species K-selected Species