Transcript Intro to Ecology Teacher Notes

Science 20 Unit D:
Changes in
Living
Systems
The
The Biosphere
Biosphere of
of Life
Life
POS Checklist:
•investigate and analyze an aquatic or a terrestrial local ecosystem,
distinguish between biotic and abiotic factors, describe how these
factors affect population size and
 infer the abiotic effects on life.
 infer biotic interactions.
 infer the influence of biota on the local environment.
It is the narrow zone around the
earth where life exists.
Atmosphere
The biosphere is made
up of three parts:
Hydrosphere
Lithosphere
There are two factors that affect any part
of the biosphere:
1.Biotic Factors: living organisms (life
forms).
2.Abiotic Factors: nonliving components
(geological and physical factors).
Question: what are some biotic and abiotic factors in a
lake?
When we study living systems, we will be
looking at the following:
1. Organism (the individual).
2. Population (group of individuals).
3. Community (one or more populations).
4. Ecosystem (community and abiotic
factors that interact).
*Using the Prairies, give examples of each of the 4 parts of a
living system.
Habitat
Habitat: abiotic and biotic factors
that encourage survival.
• Water is the most important abiotic factor
of an ecosystem.
• The habitat of an organism determines the
amount of water, sunlight and temperature
for growth and survival.
*What is your ideal habitat? Why?
Nutrients
• One component of habitat is
chemical nutrients.
• Nutrients are needed
compounds/elements used by
organisms to grow and
reproduce.
• Gardeners use fertilizers to give
all the needed nutrients to the
plants.
• The run-off from fertilizers can
cause problems with lakes and
algal blooms.
Fertilizers
- chemicals that contain nitrogen and phosphorus natural
fertilizer.
Manure: contains N which is ammonified first
in the soil, then nitrified to provide useful
nitrates.
Commercial Fertilizers: 3 numbers:
• The first number is the % nitrogen (by
weight)
• The second number is the % phosphorus
(by weight)
• The third number is the % potassium (by
weight)
This fertilizer contains 34%
___________ and 64% filler.
This fertilizer contains 25% _________ ,
3% _________ and 5% __________.
This diagram shows some of
the major, minor and micro
nutrients a plant needs.
Note that K, N and P are all
major nutrients.
Adding fertilizers to crops has
been good for society:
What are some advantages of using fertilizers?
However, there have also
been negative side effects.
While fertilizers help our crops grow, they also increase the
growth of some unwanted plant life.
Often, fertilizers run off into lakes, creating high concentrations
of chemicals.
The natural algae in
these lakes start to
grow uncontrollably:
resulting in a lake full
of algae.
This process is called eutrophication:
- a process in which nutrient runoff from
agricultural lands or livestock operations
causes photosynthetic organisms in ponds
and lakes to multiply rapidly
Human-caused
eutrophication wiped out
fisheries in Lake Erie in
the 1950s and 1960s.
LAKE EUTROPHICATION
High levels of P and N
containing compounds
(fertilizers/ detergents)
Low oxygen  other
organisms die out
Algal Bloom
(rapid growth of
algae)
Algae die  food for
decomposers 
population grows
Decomposers (bacteria) break down material
and use up oxygen in lake
•Water in which oxygen becomes too low to support animal life is
called eutrophic water.
•To protect Canadian lakes, ponds, and streams from
becoming eutrophic, some states no longer allow the sale of
detergents containing phosphorus compounds.
A surplus or lack of oxygen does occur in lakes naturally as well.
Oligotrophic lake: Nutrient-poor,
photosynthesis-limited, clear water,
O2 rich.
Eutrophic lake: Nutrient-rich, high
photosynthesis, murky water, O2
poor.
Hydrological (water) Cycle
• Water plays a critical role by:
– Maintaining global heat balance.
– Acting as a solvent in reactions.
• Movement of water through
environment: from atmosphere
to Earth.
• Volume of water remains
constant, specific amounts vary
in phases; water continuously
cycles.
The Hydrologic Cycle
The Hydrologic Cycle II
Biotic Factors
We have looked at some abiotic
factors so far, now we will look
at some biotic factors that
affect ecosystems:
Symbiosis = “living together”
Long lasting relationship that benefits at least one
organism of two different species.
Types of symbiosis:
– Mutualism: both species
benefit.
Read the paragraph on page 416 to determine the mutualism
between prairie dogs and bison.
- Commensalism: one organism
benefits, the other is
unaffected/unharmed.
Read the paragraph on page 417 to determine the mutualism
between cowbirds and bison.
- Parasitism: one organism
(parasite) benefits by harming the
other (host).
Read the paragraph
on page 417 to
determine the
mutualism between
cowbirds and the
yellow-rumped
warbler.
Predator-Prey Interactions
• This is NOT symbiosis; the two
organisms do not live together
and it is a short interaction.
• Predation: one organism
(predator) kills the other (prey).
– Mostly benefits the predator BUT
the prey community is left with fit
individuals.
Some
predatorprey
relationship
examples.
Competition
• Competition is where two or
more organisms compete for
the same resource.
• All organisms involved are
harmed; no one benefits.
• This is NOT symbiosis.
Assignment
• Please complete the following:
– Read and highlight the important
points on “biomes and habitats”
and “animal partnerships”.
– Complete #2,3 and 4 on page 412.
– Complete the Symbiosis Fact
sheet.
– Complete #2,3,5 on page 422.