Population and population ecology Part 1

The Basics2010 Env Sci

Neubert

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 population?

Populations are defined as

• A group of individuals of the same species that live in the same geographic area at the same time.

Characteristics of Populations

• Density• 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??

• However, population density also defines all species!!!

9.17 people per square mile in Canada

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

Biodiversity and Populations…

• The variety of life on Earth, its biological diversity is commonly referred to as biodiversity. – 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 plants?

• 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 is. • Be sure to include the characteristics of a population.

• How does biodiversity and populations affect each other?