Transcript hunter-gatherers

Introduction to Environmental Science
What is Environmental Science?
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Environmental Science – the study of the impact of humans
on the environment.
Many Fields of Study
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The foundation of Environmental Science is ecology.
Ecology the study of how living things interact with each other
and with their nonliving environment.
Some other major fields of study in environmental science
include zoology, botany, geology, climatology, hydrology,
geochemistry, sociology and many others.
Our Environment Through Time
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Manhattan – before and after
Hunter-Gatherers
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For most of human history, people were hunter-gatherers.
Hunter-gatherers – people who obtain food by collecting
plants and by hunting wild animals or scavenging their
remains.
The Agricultural Revolution
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Hunter-gatherers began to collect seeds and domesticate
animals. This change to how human societies behaved is
known as the agricultural revolution.
Agriculture- the practice of growing, breeding, and caring for
plants and animals that are used for food, clothing, housing,
transportation, and other purposes.
The Industrial Revolution
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The change during the 1700’s that occurred as humans moved from animal
and running water power to fossil fuels is known as the industrial
revolution.
This included large-scale factory production of goods and machinery to
reduce human labor. Motorized vehicles meant food and goods could be
moved great distances more easily.
Population Effects
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One reason there are so many environmental problems today
is that the agricultural revolution and industrial revolution
allowed the human population to grow more rapidly than
before.
Environmental Problems
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There are three general categories of environmental
problems:
1. Resource Depletion
2. Pollution
3. Loss of Biodiversity
Resource Depletion
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Natural Resource – any natural material that is used
by humans.
Renewable resources are resources that can be
replaced reasonably quickly by natural processes.
Nonrenewable resources are resources that form at a
much slower rate than the rate that it is consumed.
Pollution
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Pollution – an undesired change in air, water, or soil that
adversely affects the health, survival, or activities of humans
or other organisms.
Pollution can be biodegradable or non-degradable.
Loss of Biodiversity
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Biodiversity – the numbers and variety of species that live in
an area.
Many species have become extinct.
“The Tragedy of the Commons”
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In 1968, ecologist Garrett Hardin published an essay
titled “The Tragedy of the Commons”. This essay
addressed the problem of sharing common
resources.
Commons were areas of land that belonged to a
whole village. These were often overgrazed until
individuals owned their own land.
Supply and Demand
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The law of supply and demand states that the greater the
demand for a limited supply of something, the more that
thing is worth.
Developed vs. Developing
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Developed countries have higher average incomes, slower population
growth, diverse industrial economies, and stronger social support systems.
Developing countries have lower average incomes, simple and agriculturebased economies, and rapid population growth.
Population and Consumption
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Most environmental problems can be traced back to two root
causes.
1. Population growth – in some areas the human population is
growing too quickly for the local environment to support it.
2. Consumption – people are using up, wasting, or polluting
many natural resources faster than they can be replaced or
cleaned up.
Ecological Footprints
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An ecological footprint shows the productive area of Earth needed to
support one person in a particular country.
It includes the land used for crops, grazing, forest products, and housing.
Also includes the ocean area used for harvesting seafood and forest
needed to absorb air pollution.
A Sustainable World
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Sustainability – the condition in which human needs are met
in such a way that a human population can survive
indefinitely.