Chang In Populations Flashcards
What are Four Processes that Change Population (N)
Births (b)
Deaths (d)
Immigration (i)
Emigration (e)
What is the equation to calculate Change in Population Size?
AN = [birth + immigration] - [mortality + emigration]
AN = (b+i) - (d+e)
What is the equation for Growth Rate? What is it used for?
no. Of individuals in a pop. / a specific time frame
AN gr = ———-
At
It used to measure increases or decreases in population size over time
Negative values are okay - they show a decrease in population
What is the equation for calculating Per Capita Growth Rate? What is it used for?
Change in no. of individuals in a pop. / original no. of individuals
cgr = AN/N
It’s use to compare populations of the same species that are different sizes or live in different habitats
What is the equation that calculates Population Density?
No. of individuals/ area or volume
Dp = N/A Dp = N/V
What are the two factors that limit the growth of a population?
Biotic and Abiotic
What is a species’ Biotic Potential (r)?
The highest possible per capita growth rate for a population
What are four factors that determine biotic potential?
No. of offspring per reproductive cycle
No. of offspring that survive long enough to reproduce
Age of reproductive maturity & no. of times the individual reproduces in a life span
The life span of the individuals
Exponential Growth Pattern - J shaped curve specs
Populations growing at near biotic potential
Brief lag phase, followed by a steep increase in the curve
What is a carrying capacity?
Th max no. of individuals in a population that a habitat can support
What is a Lag Phase?
Initial stage - birth rate is greater than death rate
Pop. size increases rapidly (exponential)
What is a Stationary Phase?
Competition of resources and other limiting factors will slow the rate of growth
ie. Lack of food
At this stage, birth & death are equivalent
Logistic Growth Patten specs - S shaped curve
Populations that will reach a carrying capacity and then hover around carrying capacity
Carrying Capacity (K) - the theoretical maximum population size that the environment can sustain over
The no. of individuals in a population that can live in a given environment without depleting the resources
What is Environmental Resistance?
Combines effects of various interacting limiting factors
Prevents a population from growing at its biotic potential and determines carrying capacity of the habitat
What are Limiting Factors?
Predation and disease are examples of LFs that apply environment resistance to population growth
