Download Grade 7 Science Unit 1

Grade 7 Science
Unit 1
Interactions Within
Ecosystems
Chapter 3
The Changing Ecosystem
Succession...
A natural change of the
ecosystem.
It is the process by which a
biological community changes
over time. These changes may be
slow and hard to see over short
time periods.
Pioneer species: the first species
to inhabit an ecosystem
undergoing succession. Examples
include lichens.
Climax community: the final
community in the process of
succession that remain
unchanged for many years. The
balsam fir is an example
2 Types of Succession...
Primary Succession
Takes place in areas lacking soil
(bare rocks, sand dunes, and
cooled lava for example)
Secondary Succession
The process by which an
ecosystem changes after it has
been disturbed by a fire for
example.
The re-growth of a community.
Discussion...
Read p. 70-1
Succession can have
environmental changes such as...
1. Soil composition
2. Plant types
3. Animal types
4. Amount of light
Explain
Core STSE
“The Two Centimeter
Forest”
The Human Impact...
How do you think we have impacted
our environment?
1. Harvesting resources
2. Habitat loss/ destruction
3. Introduced species
4. Pollution
Harvesting Resources
The demand for natural
resources has increased due to
the increase in the human
population.
Our technologies have enabled
us to remove the resources we
need.
Habitat Loss/ Destruction
Removing vegetation and soil
removes shelter and food for
animals.
Changes on land alter drainage of
water which affects rivers and
lakes.
See table 3.1 on p. 77
Endangered Species of
Newfoundland & Labrador
Pine marten
Wolverine
Piping plover
Eskimo curlew
Long’s braya
Barrens willow
Choose one of the above and “tell
its story”.
Habitat Conservation
Pros
Cons
Sustainability of
Artificial habitats
resource
Preservation of
biodiversity
Eco-tourism
Economic loss
(job loss, etc.)
Limited human
use
Introduced Species
Species that have spread beyond
their natural range into new
locations as a result of human
activities.
Also called alien, exotic or nonnative species.
Can have negative impacts on the
environment and affect
ecological processes.
Ex. Of Introduced Species in NL
 Moose 1904
 Eastern chipmunk 1962
 Coyote
 Snowshoe hare 1860
 American mink 1934
 Deer mouse
 Norway rat
 Masked shrew
 American res squirrel
1963
 Bank vole
 Purple loosestrife
 English ivy
 Scotch broom
Pollution
Substances that cause harm to
the air, soil, water, or living
things are called pollutants.
Can have direct and indirect
impacts on the environment.
P. 82
Groups Interested in
Protecting the Environment...
Local Examples:
Protected Areas Association
Conservation Corps
Newfoundland & Labrador
Shane Mahoney
National Examples:
Parks Canada
Canadian Native Federation
Nature Conservancy of Canada
David Suzuki
International Examples:
Friends of the Earth
World Wildlife Fund
Ducks Unlimited
Some environmental problems
are not so easy to solve.
The Decline in Cod Stocks
Reasons?
New fishing technology
2. More demand
3. Lack of conservation
4. Unsustainable harvesting
1.
p. 80-1
Oil Slicks/ Spills
Acid Rain
•Caused by pollutants combining with
water vapour in the atmosphere to
produce acids.
•The acids fall as acid precipitation.
•NL is mostly granite rock. (unable to
neutralize the acid)
Managing the Ecosystem
Ecosystems must be monitored to
detect any changes. Methods may
focus on the:
Physical
Chemical
Biological
Atmospheric
Long-term Monitoring
Occurs over a period of many
years.
Important in managing species as
it helps determine if the
environment is changing in a
significant way.
Predicting Change
A goal of environmental monitoring.
(ex. Climate change)
Important for planning future
developments.
Environmental impact assessments
are used to help make decisions prior
to new development.