brainstorm please list 3 abiotic and 3 biotic factors that affect population growth and decrease in...

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