unit 3 populations vocab

generalist species

• varied diet/range of tolerance

• more adaptable because more likely to have things to eat

• more likely to be invasive

• often very competitive

specialist species

• narrow range of tolerance/diet

• more prone to extinction

population

A group of individuals of the same species living in a specific area at the same time, interacting and reproducing with one another.

K-selected

• few offspring

• lots of parental care

• long lifespan

• long time to sexual maturity = low biotic potential = slow population growth rate

  • more likely to be disrupted by environmental change/invasive species

r-selected

• many offspring

• little-to-no care

• may reproduce only once

• shorter lifespan

• quick to sexual maturity = high biotic potential = high population growth rate

• more likely to be invasive

• better suited for rapidly changing environmental conditions

life span

The duration of time an individual organism lives, which can vary significantly among different species.

biotic potential

the maximum reproductive capacity of a species under optimal environmental conditions.

low: hard to recover pop. after disturbance (k-selected) 

high: easier to recover pop. after disturbance (r-selected)

invasive species

non-native species that spread rapidly and cause harm to local ecosystems.

survivorship curve

a line that shows survival rate of a cohort in a population from birth the death

cohort

group of same aged individuals

• size (shape) indicates growth rate

  • larger 0-14: current and future growth (bc yet to have kids)

  • roughly equal 0-14 and 15-45: slight growth/stable (bc having only abt the same number of kids to replace them)

  • larger 15-45: population decline (bc having less than the number needed to replace them)

Type 1 curve

• high survivorship in early life due to high parental care

• high survivorship in midlife because of large size and defensive behavior

• rapid decline in survivorship in later life as old age sets in

• K-selected

type 2 curve

steadily decreasing survivorship throughout life

type 3 curve

• high mortality (low survivorship) early in life due to little-to-no parental care

• few make it to midlife, slow and steady decline in survivorship in midlife

• even fewer make it to adulthood

carrying capacity

the max. number of individuals in a population that an ecosystem can support (based on limiting resources)

exponential growth

A rapid increase in population size that occurs when resources are abundant, characterized by a J-shaped curve on a graph.

biotic potential = exponential growth

logistic growth

rapidly at first and then slowly as they approach carrying capacity and limiting factors come in, resulting in an S-shape curve 

overshoot

when a population briefly exceeds carrying capacity

consequence: resource depletion

resource depletion

the exhaustion of essential resources due to overuse by a population, leading to a decline in available supplies for that population

population growth

the increase in the number of individuals in a population over time, influenced by birth rates, death rates, immigration, and emigration.

population decline

the decrease in the number of individuals in a population over time, often due to high death rates, low birth rates, or migration

resource availability

the accessibility and abundance of resources essential for supporting a population's needs and well-being

fecundity

the potential reproductive capacity of an individual or population, typically measured by the number of offspring produced.

total fertility rate (TFR)

average number of kids a woman in a population will have

• higher = higher birth rate = population growth rate

replacement level fertility

the TFR required to offset deaths in a population and keep stable abt 2.1 in developed countries

• higher in developing countries bc higher infant mortality

infant mortality rate (IMR)

number of deaths of kids under 1 per 1000 people in a population

• higher = higher TFR (bc families having replacement kids) 

• higher in developing countries bc lack of access to food, healthcare, etc.

Malthusian theory

• earths has a human carrying capacity limited based on food production

• human population growth is happening faster than growth of food production

• didn’t account for tech advancement

density-independent factors

• tend to be abiotic

• have an effect on populations regardless of size or density

• natural disasters

• doesn’t matter how big/small a population is natural disasters limit them

density-dependent factors

• tend to be biotic 

• strong influence when number per unit are reaches a certain level 

• food, competition for habitat, water, light, disease 

• limit BASED ON SIZE

rule of 70

the time it takes (in yrs) for a pop. to double is equal to 70/growth rate

industrializing/developing

• modernization brings access to clean water, healthcare, etc.

  • IMR and CDR decrease

• TFR remains high bc lack of access of education for women and family planning

• need for child labor (agricultural) decreases

• generational delay (bc education and societal change take time)

• rapid growth bc high CBR and decreasing CDR

• shortish lives

pre-industrial economy

• high IMR & death rate

  • bc lack access to basics and health care

• high TFR bc lack of access to education for women and contraceptives

• need for kids for agricultural labor

• little to no growth bc high CBR and CDR balance

• VERY few countries in this stage

industrialized economy

• TFR declines

• increased family income

• more education for women 

• delayed age of 1st pregnancy and marriage 

• access to family planning and contraceptives

• slowing growth rate bc CBR drops closer to CDR 

• long lives

• low IMR

• high literacy rate

post-industrial economy

• highly modernized 

• affluent

• TFR declines

• more time for career and education 

• increased wealth  

• more use of family planning and contraceptives pushes age when 1st pregnant and how many kids had/needed

• CBR drops lower than CDR and growth becomes negative

• long lives

developed country

• stage 3/4

• lower TFR bc later age of 1st pregnancy, more education opportunities, more economic opportunities, less need for kids to provide income through agricultural labor, more access to family planning and contraceptives

developing country

• stage 1/2

• higher TFR due to earlier age of 1st pregnancy, limited education, and economic opportunities, reliance on agriculture, and less access to family planning and contraceptives.

limiting resource

limit pop. size (ex: food, water, habitat)

die-off/die-back

sharp decline in pop. size when resource depletion (overshoot) leads to many individual dying

size (N)

total number of individuals in a given area at a given time

• larger = safer from population decline

population size

(immigrations + births) - (emigrations + deaths)

density

number of individuals per area

• high density = higher competition, possibility for disease outbreak, possibility of depletion of food source

distribution

how individuals in a population are spaced out compared to others 

• random (trees) 

• uniform (territorial animals) 

• clumped (herd/group animals)

sex ratio

ratio of female to male

• closer to 50:50: more ideal for breeding 

  • die-off/bottleneck can lead to skewed sex ratio, limits population growth

rapid growth/stage 1 (pre-industrial)

slow growth/stage 2 (industrializing/transitional)

stable/stage 3 (industrialized)

declining/stage 4 (post-industrial)

growth rate

% increase in a population (usually per year)

• r

• (CBR-CDR)/10 = %/yr

crude birth rate (CBR)

births per 1000 ppl

crude death rate (CDR)

deaths per 1000 ppl