Lesson 2.2 Population Growth Flashcards
How is population growth determined?
By factors like birth, death, immigration, and emigration. These factors influence the number of individuals added (birth or immigration) or removed ( death and emigration).
What is the equation for positive population growth?
B + I > D + E
What is the equation for no growth population growth?
B + I = D + E
What is the equation for negative population growth?
B + I < D + E
What is exponential growth model?
How populations grow when there’s lots of resources and no constraints.
What is logistic growth model?
How populations grow when resources become limited and carrying capacity is apparent
What does an exponential growth model graph look like?
Steep to show how fast growth is when population is without constraints
What does a logistic growth model graph look like?
Curved with halfway to carrying capacity the highest that the population can reach
What are the variables in the model?
N/ N(t) = population size
t = time
dN/dt = population growth rate
r = maximum per individual growth rate
N(0) = constant representing initial population size
K = carrying capacity
What is the equation for exponential growth?
dN/dt = rN
What is the equation for logistic growth?
dN/dt = rN( ( K-N)/K))
What happens to exponential and logistic models when (r) changes ?
Exponential - When r increases the population grows at a faster rate and vice versa.
Logistic - Higher (r) leads to faster initial growth and population reaches K sooner.
What happens to What happens to exponential and logistic models when (N) changes ?
Exponential - Affects how long populations has been growing.The longer the time the more impact population size.
Logistic - Affects how long population will reach K. The longer the time, the more gradually population approaches K.
What happens to exponential and logistic models when (K) changes ?
Exponential - Affects the speed of population growth
Logistic - Affects time that maximum population stays.
What is carrying capacity?
The maximum population size that the environment can support with no degradation of habitat.
