Studied by 6 people
Introduced species
Species transferred by humans from native to new habitat
Native species
A species that occurs in an area naturally, without intervention
Cryptogenic
Of obscure or uncertain origin
Invasive species
An introduced species that harms its new environment
K-selected species
Those species present in stable and predictable environments that produce fewer offspring, have longer gestation periods, and provide long-term care after birth, are larger, live longer
r-selected species
Those species that produce a large number of offspring and contribute few resources to each individual offspring, smaller, short-lived
Survivorship curves
Graphs that show the proportion of a population that survives from one age to the next
Cohort
A group of individuals from the same population who are born at the same time
Type I survivorship curves
Represent populations whose organisms tend to survive beyond their young and middle-ages and die when elderly (small # of offspring, lots of parental care ) (ex. whales, humans)
Type II survivorship curves
Represent populations with a constant proportion of individuals dying at each age interval, steadily decreasing chance of surviving (ex. squirrels, birds)
Type III survivorship curves
Represent populations that have a high death rate among the young, but a relatively low death rate for those who survive into middle and old age (lots of offspring, not much parental care) (ex. fish, bugs)
Type I survivorship curve graph
Type II survivorship curve graph
Type III survivorship curve graph
Population growth formula
P(n)= Initial population * growth rate ^n
p= population, n= # of unit of time (ex. 3 of months or years (example, initial pop of 500, growth rate of 10% and 5 years 500×1.1^5)
Logistic growth
The s-shaped curve which contains exponential growth then hitting a carrying capacity
Exponential growth
growth whose rate becomes ever more rapid in proportion to the growing total number or size
Malthusian limit
The human carrying capacity as said by Thomas Malthus
Overshoot
When a population briefly exceeds carrying capacity
Die-off/dieback
Sharp decrease in population size when resource depletion due to overshoot leads to individuals dying
Density-dependent factors
Factors that influence population growth based on size (food, competition for habitat, water, light, disease, food)
Density-independent factors
Factors that influence population growth independent of their size (natural disasters like flood, hurricane, tornado, fire)
Biotic potential
Maximum potential growth rate, with no limiting resources
Population size formula w/ immigration
Population size = (Immigrations + births) - (Emigrations + deaths)
Size (N)
Total # of individuals in a given area at a given time
Density
Number of individuals/ area
Distribution
How individuals in population are spaced out compared to each other (ex. random, uniform, clumped)
Population sex ratio
The ratio of males to females in a population
Population pyramid (age structure diagram)
Shows the distribution of age and sex in a population
Rapid growth
Large proportion of young people and small proportion of older people, high birth, high death
Slow growth
higher proportion of young people as compared to older people, but not as extreme as in rapid growth
Stable population
Relatively similar proportions of young, middle age, and older people (declining birth rates, low death rates)
Declining population
Relatively few younger individuals
Doubling time
The time it would take for a population to double
Rule of 70
Doubling time can be approximated by taking 70 and dividing it by growth rate (% , not decimal)
Demographic transition model
Shows the shift from high birth and death rates to low birth and death rates
Demographic transition model stage 1
Pre-Industrial
Pre-Industrial
High birth rates, high death rates, population stays the same
Demographic transition model stage 2
Transitional/Early Industrial
Transitional/early industrial
Decreasing death rates, industrializing, population increases
Demographic transition model stage 3
Industrial
Industrial
Decreasing birth rates, small population growth
Demographic transition model stage 4
Post-Industrial
Post-Industrial
Birth rates low, death rates low, population stays the same
Note 
Flashcard (35)