Unit 5 Human Population DynamicsPresentation Transcript
Mathematics of Population Growth
Determinates and Demographics
World Population Growth
Population Growth and Environment
People consume resources such as:
Over-consumption uses up or severely depletes supplies of both
renewable and non-renewable resources faster than they can replenish
People emit wastes as a product of our consumption including:
Some wastes, such as untreated sewage and many pollutants, threaten
Economies tend to become more high-polluting during early stages of
economic development because they first adapt inexpensive
technologies that are relatively inefficient-simple manufacturing
systems and basic consumer goods such as cars.
Urbanization and Megacities
Consequences of Demographic
What is Demographic Change?
Demographic change is the calculable shift in
the characteristics of a geographically-defined
population. These include changes in
population age profile, racial makeup or family
What are the Consequences?
“The environmental consequences of
population growth are a subset of broader
interactions between population and national
The ratio of
retirees) to workers
in a human
population: the higher
the ratio, the greater
the dependency load.
A rise in the rate of economic growth due to a
rising share of working age people in a
Demographic Convergence and
Human Lifespan Trends
Demographic convergence is the narrowing of the
difference between developed and developing countries for
things like fertility rates and life expectancy.
1950 life expectancy difference from developed and
developing countries was 25 years.
Now the gap has increased to 12 years.
What’s Slowing the Progress
Many factors hinder the
development of impoverished
● AIDS pandemic/malaria
● Bad agricultural conditions
● Geographic/economic isolation
Ideas to Improve
Some economists think that if wealthy countries doubled
their foreign aid from $80 billion to $160 billion then poverty
could be eliminated by 2025.
Many people in wealthy countries are living longer healthier
lives than were ever possible before. Life expectancy is
expected to rise and could potentially reach almost 100 by
the end of the century.
Population Growth &
Human Population Change
Reasons some populations grow
slower than others:
● hormone regulation
● body size
● food and habitat accessibility
● predator populations
Population Growth Key Terms
Density-dependant limitations: A limiting factor of a population
wherein large, dense populations are more strongly affected than
small, less crowded ones.
Density-independent limitations: A factor that affects the size of a
population independent or regardless of the population density
Environmental resistance factors: Things that lower population
density and growth.
Logistic Growth: When a population’s growth rate changes to
match it’s local conditions.
Logistic Growth Equation
K is the environment’s carrying capacity, N
is population size,
is the change in
population size over time, and (rN) is
exponential growth over time.
Factors in Human Population Change
Emigration - population movement from a place
Immigration - population movement to a place
Replacement birth rate - the number of kids a
couple has to replace them in a population
Death rate - population death due to many
5 Steps To A 5: 138-139
● Isolated Population- POpulation with very little genetic mixing.
● Things that barely disturb a diverse population can destroy an
● In order for recessive traits to balance out, a certain number of
individuals with dominant and healthy traits needs to reproduce.
● With limited numbers of breeding pairs on an island, a mutation
would be passed on through generations unequally.
● When a species is isolated long enough, loss of genetic diversity
may affect reproduction.
● EX: Grizzly Bear Pop. in 1800 was 100,000 but today there are less
Impacts of Population Growth
● Land Use- Land overuse results from economic
circumstances, poor land laws, and cultural customs.
● Resource Distribution- People that redistribute food
from growers, food processors, and distributors and
then make the food available to the needy.
● Population Control- Efforts to control population include
birth control and education.
5 Steps Key Terms Dani Beck
Do the key terms at the beginning of the 5
Steps Chapter 11 as well as the key terms in
the Habitable Planet.