Population Ecology Flashcards
What is ecology?
study of interactions of organisms with their environment
What are the 2 components in the environments?
Biotic and Abiotic
What are the biotic components?
Living organisms
What are the abiotic components?
Non- living things
From Greek words oikos (house) + logos (study): originally, study of _________________________-
organisms in their natural “homes”
___________ is where organism lives
habitat
population: a group of individuals of the ____________________________________.
same species occupying a given area
____________: number of individuals per unit area (e.g. no./hectare or no./m2)
Density
_________________: three possibilities: uniform (or even), random, or clumped
Distribution in space
What are the population characteristics?
Distribution in space and Density
What are the spatial distribution?
uniform; random; clumped
Which of the spatial distribution is the most common?
clumped
What factors affect the size of the population?
natality (births)
mortality (deaths)
immigration (movement of individuals into a population
emigration (movement out of a population)
What is the equation for the growth rate?
Growth rate = (births + immigration) - (deaths + emigration)
In the growth rate equation, if these two sets of factors are ________, population size is stable: ______________
equal; zero population growth
What would happen to a pair of sexually reproducing organisms in an ideal habitat with no limitations on food or space?
Exponential growth would take place
What type of curve is exponential curve?
“J-shaped curve”
Exponential growth does not occur for ______________
very long in nature
What is the equation for exponential growth?
G = rN
G = growth rate
r = net productive rate
N = number of individuals in population
What are the examples of limited resources?
food, space, etc.
other factors may also regulate population density: _____________________________
weather extremes, disease, competition, predation, etc.
populations actually level off at some size, “K”, defined as the ________________________
environmental carrying capacity
In exponential growth, number of individuals that the environment _______________________
is able to support indefinitely
What are the 2 types of growth?
Logistic growth and exponential growth
What is the equation for logistic growth?
G = rN(K-N/K)
G = Growth Rate
r = net productive rate
K = carrying capacity
N = # of individuals in a popl.
What factors limit the carrying capacity?
density-dependent factors and density-independent factors
What is and are the density-dependent factors?
depend on the density of organisms
e.g.: nutrient supply: the more plants, the more nutrients taken up; supply becomes limiting — reduces population growth
What is and are the density-independent factors?
limits on growth that act independently of density
e.g. late spring freeze, volcanic eruption
What is competition for resources?
individuals may compete for limited resources
What are examples of competition for resources?
birds set up territories, and males chase away all others of same species
Predation, parasitism, disease can be __________, especially if _________- increases
powerful factors; density
What are density-dependent population controls?
competition for resources and predation, parasitism, disease
human growth over the last several hundred years has become _____________
exponential
_______________, ___________, and _____________&___________ have raised carrying capacity
agriculture, technology, and medicine & sanitation
for thousands of years, population was limited by _______________, _____________, and ___________
food resources, water supplies, and disease
The human population still increasing ____________
overall growth rate is __________
exponentially; decreasing
Survivorship curves graphically represent the _________________________
death rates of a population over a generation
What are the different types of survivorship curves?
types I, II, and III
What is survivorship curve type 1?
high survivorship through most of life; most deaths late, after reproduction
What is survivorship curve type 2?
constant rate of death throughout lifespan
What is survivorship curve type 3?
high early death rate; only a few make it to old age
What population will have survivorship curve type 1?
typical of human populations with good health care
What population will have survivorship curve type 2?
songbirds, lizards, small mammals, etc.
What population will have survivorship curve type 3?
insects, marine invertebrates, many fishes
