Transcript Chapter 1

Chapter 1
Science and the Environment
Understanding Our
Environment
 Environment: a complex web of
relationships that connects us with the
world we live in
 Environmental Science: the study of how
humans interact with the environment
Goals of Environmental
Science
 To understand and solve environmental
problems
 We must be able to identify causes and
describe solutions
Human Impact
 Humans live within the world’s
ecosystems and therefore change them
as a result of population growth,
technology, and consumption
 Problems: habitat destruction, pollution,
atmospheric changes, over fishing the
oceans, poaching, etc.
Consequences
 If environmental problems are not
addressed, ecosystems will be
irreversibly damaged
 Human populations NEED natural
resources in order to maintain and
improve their existence
Misconception
 News stories often focus on efforts to save
threatened or endangered species
 There can also be problems with
overpopulation of species within an ecosystem
 Ex: zebra mussels, house sparrows, European
starlings, fire ants, kudzu vine
Many Fields of Study
 Environmental science is an
interdisciplinary science (involves many
fields of study)
 ECOLOGY: the study of how living things
interact with each other and with the
nonliving environment
Major Fields of Study
 Biology: study of living organisms
 Earth Science: study of the Earth’s nonliving systems
and the planet as a whole
 Physics: study of matter and energy
 Chemistry: study of chemicals and their interaction
 Social Science: study of human populations
Scientists as Citizens
 Studying our environment is vital to
maintaining a healthy and productive
society
 Observations by nonscientists are often
the first step of addressing a problem
Our Environment Through Time
 Humans have always altered the
environment to suit their needs, often
without a regard for its long-term impacts
 Early humans were hunter-gatherers (H-G)
(they obtained food by collecting plants
and by hunting animals or scavenging
their remains)
Hunter-Gatherers (H-G)
 Early H-G groups were small and
migrated from place to place depending
on food abundance
 Some H-G societies today include
aborigines and tribes in New Guinea
Extinction
 Rapid climate change and over-hunting
of some species led to their extinction
 Examples: mastodons and mammoths
Conservation
 Some H-G groups were very aware of the need
for conservation
 Native Americans did not kill what they could
not use
 Although they hunted buffalo, it was the
American settlers who slaughtered them nearly
to the point of extinction
Agricultural Revolution
 H-G began collecting seeds to plant and
domesticating animals to raise food
 Agriculture began more than 10,000
years ago
Agricultural Revolution
 Through agriculture, an area of land was
able to support 500X as many people
 As populations grew, they began to
concentrate in smaller areas which
placed pressure on surrounding
environments
Slash-and-Burn Agriculture
 Causes many areas to become unusable
after a few years
 Common in rainforest areas
Industrial Revolution
 Mid 1700’s: shift from energy sources
such as animal muscle and running water
to fossil fuels (coal, oil, natural gas)
 Caused major changes in society
 Increased the efficiency of agriculture,
transportation, and industry
Industrial Revolution (I-R)
 Large-scale
production of goods
became common
 Farm machinery
decreased the
amount of human
workers needed
 Cotton picked by
slaves vs. cotton gin
Environmental Consequences
 Transportation rapidly
developed allowing
products to be
distributed over greater
distances
 As people experienced a
new standard of living,
the environment suffered
at our expense
Salt and Pepper Moth
(Biston betularia)
 H.G. Kettlewell’s study: both white and black
moths exist
 BEFORE I-R, white moths were more common
(camouflaged on white tree bark with lichens)
 AFTER I-R, black moths were more common
(camouflaged on soot covered tree bark)
Improving Quality of Life
 I-R introduced many changes that
improved human lives such as indoor
plumbing, nutrition, and medical care
 As human populations grow,
environmental problems increase
Rachel Carson
 By the 1900’s, pesticides were widely
used and caused many health problems
that were ignored
 Rachel Carson wrote Silent Spring
(1962) which called attention to the
misuse of pesticides and began the
environmental movement
Spaceship Earth
 Earth is compared to a ship traveling
through space that cannot dispose of
waste or take on new supplies
 Closed system: the only thing that enters
is solar energy and the only thing that
leaves is heat
Closed System
 Resources can be used up!
 Wastes are produced faster than we can
dispose of them
Environmental Problems
 Exist on three different scales: local,
regional, and global
 LOCAL: Columbiana County
 REGIONAL: Northeast Ohio
 GLOBAL: Affects the world
Main Environmental Problems
 Resource depletion
 Pollution
 Extinction
Resource Depletion
 Natural resources: any natural substance that
living things can use
 Examples: air, water, sunlight, soil, minerals,
plants, animals, forests, and fossil fuels
 When a resource is used up faster than it can
be replaced, it will become depleted!
Renewable Resources
 Resources that are
continually being
replaced
 Examples: solar energy,
water, soil, air, crops,
livestock, trees
 Can still be depleted if
not managed properly
Nonrenewable Resources
 Resources that cannot be
replaced…once depleted, they are gone
FOREVER!
 Examples: metals such as iron, copper,
and aluminum, minerals such as salt,
sand, and clay, fossil fuels
Pollution
 Contamination of our air, water, or soil that
affects the health, survival, or activities of
humans or other organisms
 Human byproducts are the main causes of
pollution
 Examples: pesticides, radiation, petroleum
products, PCB’s, mercury, CO2
Biodegradable Pollutants
 Pollutants that can be broken down by
natural processes
 Example: human sewage
Nondegradable Pollutants
 Pollutants that do not break down easily
 Accumulate in the environment at
dangerous levels
 Examples: pesticides, mercury, lead,
PCB’s
Loss of Biodiversity
 Biodiversity: the number and variety of
species that live in an area
 Many species become extinct due to
habitat destruction or polluted
ecosystems
Extinction
 Every last individual of a species has
died and the species is gone forever
 Examples: dodo, passenger pigeon,
great auk
 Animals and plants are natural resources
that we depend on to exist
Biosphere
 All life on Earth AND the physical environment
that supports it
 Damage to any part of an ecosystem can have
a ripple effect that can negatively impact the
entire biosphere
 What can YOU do to help protect the world?