Population and population ecology Part 1

Population and population
ecology Part 1
The Basics
2010 Env Sci
Essential Question:
• How do populations affect resources? How
does the growing population of humans affect
Earth’s resources? How can humans begin to
live sustainably on Earth?
Warm Up! 9/6/11
• Read the short article and then answer the
questions in your journal.
• What happens when a population reaches
carrying capacity?
• What would happen to a population when it
goes above carrying capacity?
What is a
Populations are defined as
• A group of individuals of the same species that
live in the same geographic area at the same
Characteristics of Populations
Birth and death rates
Growth rates
Age structure
Population density is defined as:
• Number of individuals of a
species within a given area
• Usually referred to in terms of
human populations
– For example, Canada's
population of 33 million,
divided by the land area of
3,559,294 square miles
• Can you do the math??
9.17 people per square
mile in Canada
• However,
population density
also defines all
Population Density
How might population growth affect
the density of a population?
As population size
increases, so does the
population density.
• As population size
decreases, so does the
population density.
Where do we all live?
World Population
Biodiversity and Populations…
• The variety of life on Earth, its biological
diversity is commonly referred to as
– The number of species of plants, animals, and
microorganisms, the enormous diversity of genes in
these species, the different ecosystems on the planet,
such as deserts, rainforests and coral reefs are all part of
a biologically diverse Earth.
We will get more into
Biodiversity and resources in
the next unit…
Why Is Biodiversity Important?
• Biodiversity boosts ecosystem productivity where
each species, no matter how small, all have an
important role to play.
• For example,
– A larger number of plant species means a greater variety
of crops
– Greater species diversity ensures natural sustainability
for all life forms
– Healthy ecosystems can better withstand and recover
from a variety of disasters, such as hurricanes.
Activity: A World of Difference
• Clear your desks.. Keep out a pen/pencil to
take down data as you go through the activity.
• When you’ve completed the activity, complete
the all the questions asked.
Answer the following discussion questions from
the activity A World of Difference.
• How would you feel if all the lions, tigers and bears in
the world went extinct? IF all slugs, snails and worms
went extinct? Which would have a greater effect on
your life? On the health of the other animals and
• A group of neighbors wants to plow the fields that
contain the last of a species of plant that several
animals need for a golf course. What would your
arguments be for or against plowing the fields? Would
your arguments be different if, instead they wanted to
build low income housing, factory or retirement home?
Why or why not?
Exit Ticket – In your journals
• In your own words, define what a population
• Be sure to include the characteristics of a population.
• How does biodiversity and populations affect
each other?