Unit 3 Flashcards
- narrow niche
- less adaptable b/c of specialized needs
- more likely to become extinct
- use a specific set of resources
- easily affected by changing conditions
- have an advantage when conditions are more constant
specialists
- broad niche
- adaptable to many environments
- less likely to become extinct
- use a variety of resources
- high range of tolerance
- have an advantage when conditions change
generalists
- factors that affect the size of a population depending on the size and density of the population
- the greater the size/density of population the greater the impact of these resources on population size
- ex. food, water, shelter, disease, predation, competition, mates
density-dependent factors
- factors that influence population size, regardless of the population density
- ex. hurricanes, tornadoes, floods, fires, climate change, volcanic eruptions, drought, deforestation
density-independent factors
- this model shows rapid growth of a population when it is not limited by resources
- more births occur with each step in time
- population growth line on a graph is a J shaped curve
- unlimited resources
exponential growth
- this model initially shows exponential growth, but then population size slows as it reaches the carrying capacity of the environment
- determined by density-dependent limiting factors
- creates an S-shaped curve on a graph
- limited resources
logistic growth model
the number of individuals the environment can sustain/support
carrying capacity (k)
every population has a maximum potential for growth if conditions are ideal and resources are unlimited
biotic potential/intrinsic growth rate
overshoot
population is over its carrying capacity and has a lot of resources
die-off
population is below its carrying capacity and has a decrease in resources
- a species with a low intrinsic growth rate that causes the population to increase slowly until it reaches carrying capacity
- specialists
- type 1
- logistic growth model
Life Span = long
Time to Reproductive Maturity = long
# of Offspring = few
Size of Offspring = large
Parental Care = present
Population Growth Rate = slow
Population Regulation = density-dependent
Population Dynamics = stable, near k
Ex = elephants, primates, redwood trees, bald eagles, humans
k-selected species
- a species with a high intrinsic growth rate and often leads to population overshoots and die-offs
- invasive species and generalists
- type 3
- exponential growth model
Life Span = short
Number of offspring = many
Time to Reproductive Maturity = short
Size of Offspring = small
Parental Care = absent
Population Growth Rate = fast
Population Regulation = density-independent
Population Dynamics = highly variable
Ex = mice, insects, tuna, dandelions, bacteria, small fishes
r-selected species
- these species have a high survival rate throughout most of their life span, but increased mortality as individuals get older
- typical of K-selected species
type 1
- the individuals die at equal rates no matter their age
- relatively constant in survivorship throughout most of their life
type 2
- these species have low survivorship early in life with few individuals reaching adulthood
- typical of r- selected species
- large % of population dies early in life
type 3
the number of individuals per unit area at a given time
population density
the number of births per 1,000 individuals per year
birth rate
the number of deaths per 1,000 individuals per year
death rate
equals the birth rate minus the death rate divided by the initial population size
growth rate
the difference between immigration and emigration in a given year per 1,000 people in a country
net migration rate
the movement of people into a country or region, from another country or region
immigration
the movement of people out of a country or region
emigration
a country with relatively high levels of industrialization and income
developed country
a country with relatively low levels of industrialization and income
developing country
- total fertility rate required to offset the average number of deaths in a population in order to maintain the current population size
- maintains a stable population
- higher in developing countries because mortality among young people tends to be higher
replacement level fertility
an estimate of the average number of children that each woman in a population will bear throughout her childbearing years
total fertility rate
continued population growth after reduction measures have been implemented
population momentum
a visual representation of the number of individuals within specific age groups for a country, typically expressed for males and females
age structure diagram
group of individuals of the same age
cohort
the average ecological footprint of an individual in a given country or area
per capita
theory that as a country moves from a subsistence economy to industrialization and increased affluence it undergoes a predictable shift in population growth
demographic transition
- developing
- stable population
- no family planning
- women are not working
- no health care
- high birth and death rates
phase 1
- end of the phase is developed
- death rates drop b/c health care increases
- birth rates high
- population grows
phase 2
- stable
- birth rates drop
- death rates low
phase 3
- developed
- birth and death rates low
- no growth since birth and deaths are the same
- population stops growing
phase 4
the practice of regulating # or spacing of offspring through the use of birth control
increase in this:
- women’s education
- advertising campaigns
- increased income
family planning
The average number of years that an infant born in a particular year in a particular country can be expected to live, given the current average life span and death rate in that country
life expectancy
the number of deaths of children under 1 year of age per 1,000 live births
infant mortality
the number of deaths of children under age 5 per 1,000 live births
child mortality
thomas malthus
said humans can exceed their carrying capacity
- is the entire set of environmental conditions under which a species can survive and reproduce itself
- there are no limiting factors on the environment or the resources the organism can use
- AKA pre-competitive niche
fundamental niche
- this is where the species actually lives
- the set of environmental conditions actually used by a species after interactions with competitors and predators are taken into account
- AKA post-competitive niche
realized niche
