unit 3 Flashcards
carrying capacity
K
exponential vs logistic growth models
exponential growth model (impossible): Occurs when there are no limits on resources, has idea conditions. Creates a J shaped curve because populations can growth rapidly
logistic growth model (realistic): Factors in carrying capacity (K), and creates an S-shaped curve. Used to predict populations affected by density dependent limiting factors
intrinsic growth rate
Maximum potential growth of a population under ideal conditions
overshooting
u know
k selected vs r selected species
K-selected: Has a low intrinsic growth rate, thus low biotic potential. Be larger organisms. Have populations close to the carrying capacity. Produce few offspring that are well cared for (expensive offspring). Reach maturity later in life, reproduce later in life
R-selected: Have a high intrinsic growth rate, thus high biotic potential, Are smaller bodied. Have a lot of young and provide little care (cheap offspring). Reach maturity early, reproduce early. Rarely exist close to the carrying capacity, Overshoot then die off
survivorship curves (type 1-3)
Type 1: Species have a high survival throughout most of its life. However, they start to die off rapidly once they start reaching old age. EXCLUSIVELY k-selected species
Type 2: Species have a relatively constant decline in survivorship as time moves on, Also K- selected species
Type 3: Species have low survivorship early on in life
As time goes on, survivorship increases (but at this point few individuals remain). Produce a lot of offspring, R-selected species
age structure (diagram)
banana chips (what are those called)
(i figured it out its plantains)
types of age structure diagrams (kinda self explanatory)
expanding rapidly, wide base and narrow peak. Expanding slowly, similar shape but slope is steeper. stable, relatively even/rectangle like but old might form a peak. declining, higher proportion of the population in the post reproductive group, base is narrower than the top.
levels of complexity in nature
u know
demographic transition stage 1
High death rate
High birth rate
Low but stable population
stage 2
high birth rate
stabler death rate
lotsa growth
stage 3
stabler death and birth rate
population starts to stabilize
stage 4
low birth and death rate
stable population
popul;ation density
Population / Area
birth/death rate
Births or Deaths / Population
Multiply by 1000 for crude
population growth rate
crude Births - Crude Deaths) / 10 = r%
(Births - Deaths) / Population x 100 = r%
Population Change w/ Emigration and Immigration
(Births + Immigration) - (Deaths + Emigration) / Population x 100
Doubling Time
70/growth rate
population distribution
How individuals are distributed with respect to one another.
Random distribution: no particular pattern
Uniform distribution: evenly spaced, usually bc of territorial animals or manmade
Clumped distribution: where living in large groups helps individuals survive
density dependent vs density independent factors
i feel like u know this
total fertility rate and replacement fertility rate
Total fertility rate (TFR): The average number of children born per woman of childbearing age
Replacement fertility rate (RFR): The number of children a couple must produce to replace themselves. Mathematically speaking 2.1 children per couple in DEVELOPED nations, nations with high infant mortality have higher RFR
factors that influence total fertility rate
The age which females have their first child, Education and employment opportunities for women , Access to family planning
Governmental policies, Importance of children in the workforce (esp. True in rural/poorer areas), More children meant more earning power for the family , Cost of raising and educating children. The more expensive children are, the fewer children couples have, Pension systems: kids can support parents if there is no system, so there is an incentive to have more of them, Urbanization: things become more expensive in cities
signs of a healthy population
life expectancy: the average number of years a person born in a particular year can be expected to live
infant mortality: the best metric tbh. the number of babies out of 1000 who die before their first birthday. Usually, lower infant mortality rates mean lower total fertility rates. Areas with high infant mortality tend to have larger families bc replacement fertility rate ykyk
Malthusian theory
Human population will grow exponentially, but resources grow arithmetically.
This means that resource availability has to be a check on population growth.
If population grows beyond resource production, famine, disease, and war will bring the population back in check
