Science 421
Ecology
The
study of the interaction of
living things & their environment
What else does it mean these
days?
Ecology is...
Chapter 1 - Diversity in
Ecosystems

The Earth’s regions differ in their:
◦
◦
◦
◦
◦
◦
Temperatures
Light intensity
Water availability
Weather
Species
Read pages 8 & 9 and complete
question 1.
1.1 The Silence of the Frogs





Amphibians are found
almost everywhere there is
water on the planet.
Amphibians have two lives
and live within two
ecosystems:
1. Eggs laid in water grow
into a tadpole;
2. Froglet (lose their tail
and adapt to living on land
and breathing air).
Croaking Frogs...
Over 30% of North American frogs and
toads are in trouble. A change in either of
their ecosystems can result in a decline in
amphibian population.
 Amphibians are an
species,
meaning if they start to die off, it is a
sign that the ecosystem is in trouble.
 Complete questions 1 - 6 on page
13.

Factors Affecting Frog
Populations

1. Loss of Habitat – Road construction,
deforestation, etc.

2. Air and Water Quality - Frogs are able to breath
through their thin skin, therefore pollutants are able
to pass through their skin.

3. Ultraviolet Radiation – Causes skin damage to
amphibians.

4. Climate Change - Global warming increases
temperatures and reduces wetlands/habitats.

Planet Earth Frogs...
Use your text & define the following
terms in your notes:
Ecosystem
 Decomposers
 Herbivores
 Food Chain
 Detritus
 Carnivores
 Producers
 Omnivores
 Consumers

1.2 Canada’s Endangered
Species

Canada has over 250 species of plants and
animals that are at risk. There is a
classification system to describe the risk
to each species.
Classification

Vulnerable

Example:
Description/Example
At risk due to declining
numbers in some areas.
Grey Fox – Ontario
Classification

Threatened
Description/Example
Likely to become endangered if
factors are not reversed. Ex.Wood Bison
Classification

Extirpated
Description/Example
No longer exists in specific
areas, but can be found in
others.(Black bear no longer
on PEI since 1930.)
Classification

Description/Example
Endangered
Close to extinction in all parts of
Canada. Ex.-Eastern Cougar
Classification
Description/Example

Extinct
A species that does not exist
anywhere. Ex.-Passenger
Pigeon

Complete questions 1, 2 and 4 on
page 15.
Humans have influenced the process
of extinction for many species over
the past 50 years.
Extinction Timeline

1600 - 1900 -An average of one
species every 4 years.

1980 –present - An average of over
10,000 per year.
Causes of Extinctions

Asteroids - Asteroids impacted with the Earth &
caused a large cloud of dust
blocked light
from the sun, & set off many volcanoes.

Climate Change - A change in a
species’ environment forces them to
adapt or die.

Pressure of Competition- 2 species may
compete for the same food sources and/or
habitat. One wins, the other adapts or dies.

Human Factors - Logging, oil exploration,
expanding cities, expansion of agriculture,
introduction of new species (purple loosestrife)
Effects of Extinction
is the variety of life on Earth.
It is the number of species in an
ecosystem. The loss of one species
impacts the entire food chain &
ecosystem.
 YouTube - Official video of the
International Year of Biodiversity 2010
Restoring Balance

Due to the effects on a food chain, it is
extremely difficult to restore the balance
once an a species has been removed

Questions 1-5, 6a; pg. 19
are organisms that cause problems for humans.

Why are pests such as mosquitoes, termites, caterpillars
and weeds needed?

Mosquito larvae provide food for fish and adult
mosquitoes are food for birds.
Some insect “pests” are needed by plants for
pollination, while others, such as wasps, help decompose
tissues of dead plants and animals.
Weeds: source of food for animals, & can help anchor
the soil, preventing erosion.


Define the following Ecology Terms:
Abiotic
 Biotic
 Population
 Community

-the study of how organisms interact
with each other.
non-living things in an
ecosystem. Ex:- light, soil, wind, temperature
-living things in an ecosystem
-all of the members of the same
species living in an ecosystem.
- all of the populations of species
in an ecosystem.

Do # 1-5 on pg. 23.
Example: A pond ecosystem

Consists of a habitat with
of aquatic plants,
waterside plants, micro-organisms (in the mud at the
bottom of the pond), fish and birds. The organisms
together make up a
of living things.
DO NOT COPY DOWN
Ecologists can study:



- A population and how it interacts in the ecosystem.
(Coyotes)
- A community and how all species interact (biotic
factors).
- An ecosystem including all biotic factors and the
physical environment, or abiotic factors.
Quiz!
1.
Identify each of the following as either
biotic or abiotic.
Temperature
Soil
Grass
Worms
Marsh
Identify each
of the following as either a
The Mallard
All fish in
ducks in a
The whiteor
species,
a
population,
community
The trees, birds,
the stream
marsh
spruce trees
Brookvale
insects, mammals,
behind the
ecosystem.
Demonstration
plants and
2.
Woodlot
amphibians in the
forest
school

An
is a transition area between
two different ecosystems where species
from each can interact. There is often
greater diversity in the ecotone than in
either of the two ecosystems bordering it.

An area with greater biodiversity is less fragile
consumers have more food sources; don’t have to
rely on only 1 source. An ecotone guards against
extinction.

Artificial ecosystems -human made. (Ex. farms,
parks)

A natural ecosystem - made by nature. Species
are able to interact with their surroundings
freely. Humans will still have an impact on the
ecosystem but they do not control it.
Albedo effect - % of light an object reflects. The higher
the Earth’s albedo, less energy is absorbed and therefore
less energy is available for maintaining the Earth’s
temperature.
30%
Photosynthesis:
0.023%
70%

Energy is constantly moving within our ecosystems. To
understand how living things gain their energy we must
look at trophic levels (position in the food chain).

Most ecosystems only contain about three trophic levels
consisting of:

1. Autotrophs - make their own food - producers.

2. Heterotrophs - can’t make their own food –
consumers (can be broken down into sub-levels)

Fourth Trophic Level Tertiary Consumers
◦ Eat secondary and primary consumers.
(Heterotroph)
◦ Bear, cougar

Third Trophic Level
Secondary Consumers
◦ Eat primary consumers and producers.
(Heterotroph)
◦ Eagles, wolves

Second Trophic Level
Primary Consumers
◦ Eat producers for food. (Heterotroph)
◦ Deer, mice, bugs

First Trophic Level
Producers
◦ Make their own food from basic nutrients and
sunlight. (Autotrophs)
◦ Grass, berries, trees

A food web is graphical representation of the feeding
relationships between organisms in an ecosystem. In reality a
single organism can be a part of many food chains
.
DO NOT COPY

Ecosystems with the greatest
biodiversity are the most stable
they have complex food webs and
therefore the removal of one
consumer or one producer may
have only a small impact on the
ecosystem and the overall web.
Sunlight
Source of all energy on earth
 Less than 1% is used for photosynthesis (conversion of
solar energy into chemical energy sugar molecules)

Energy Transfer


Each time energy is transferred from one organism to
another, there is a change of form. (i.e. plant used most
of the sun’s energy to grow
only a small
fraction of sun’s energy is passed onto an animal that
eats the plant)
As you move through a food chain, less energy is
available to each organism.
LAWS OF THERMODYNAMICS

1st Law – Energy is not created nor
destroyed, only changed from 1 form to
another

2nd Law – During an energy transfer,
some of the energy is converted into
thermal energy or heat which is released
to the environment
Energy use by organisms:
- Growth, repair and survival
 - Given off as heat and used in respiration.
 - Excretion (although decomposers actually
use this energy in a different food chain).
 - Transport of materials in the body, and for
movement.


All the energy used in these ways returns to
the environment, and is not available to the
next trophic level.
Human Use of the Energy in
Ecosystems
 Two main revolutions have increased our
energy demands on ecosystems and have
reduced the amount of energy available to
other organisms.

1. Agricultural Revolution
 2. Industrial Revolution


End of Chapter 1 – class test on Tuesday,
June 2nd.
Section 2.1

Cycling of Matter in Ecosystems
Please answer the following questions in your notebooks. Please use your
textbook and provide complete answers.
Define matter.

What is an organic compound?

What is an inorganic compound?

What does the term cycling (or recycling) mean?

What do we mean when we say that matter is recycled?

Is food organic or inorganic? Explain the “cycling” of organic matter within
living things.

Decay is a process involved in the cycling of matter. Please explain this
process.

Using the information in this section make a diagram (or drawing) to show
how matter is cycled within an ecosystem. Please use the following terms
and organisms in your explanation: plants, inorganic molecules, inorganic
nutrients, soil bacteria, fecal matter, rabbit, fox, decomposing bodies. Please
ensure that your diagram looks like a cycle.

Please complete Questions 1, 2, 4-6 on page 51.
Chapter 2
Cycling of Matter in Ecosystems


Matter – anything that has mass & takes up space
Organic substances contain:
◦
◦
◦
◦
carbon
Hydrogen
Sometimes nitrogen
sometimes oxygen

Example: proteins, sugars, and fats.

Inorganic substances
Do not contain the combination of carbon
AND hydrogen. Ex: carbon dioxide (CO2),
water (H2O) and ammonia (NH3).
Cycling of Organic Matter
Continuously being recycled.
 Limited amount of materials found on the
Earth means they must be recycled for life
to continue.


Example: Carbon molecules are recycled over and over .
some part of your body may contain a carbon molecule
which was part of a dinosaur over 70 million years ago!
Cycling of Organic Matter


(Eaten by)
Plant
(Eaten by)
Rabbit
(Turns it into)

soil bacteria
plant
(Eaten by)
Fox (feces)
(Eaten by)
inorganic molecules
plant roots
2.2 Pesticides

Pests are
organisms
considered to be
harmful or
inconvenient (e.g.
weeds, insects,
fungi or rodents.)
Pesticides are chemicals designed to kill pests.
Why use pesticides?
◦ 30% of the annual crop in Canada is lost to
pests (i.e weeds, rusts, moulds, insects, birds
and small mammals). This may increase the
cost of food.
◦ Malaria (causes fever and can lead to death) is
transmitted by a mosquito.
◦ Increases the yield of crops.
 Prevents allergies from mold and mildew
First Generation Pesticides




500 BC sulfur was used to repel insects
15th century arsenic, lead and mercury
were applied to crops as insecticides
2 Problems: substances killed insects but
were also highly poisonous to people AND
these pesticides remained in the soil for a
long time.
1763 - gardeners began to use natural plant
extracts ( uses the plants’ own chemical
defenses) to kill insects.
Second Generation Pesticides
Made in the laboratory
DDT first used in 1939 as an insecticide.
DO NOT COPY:
 Now more than 500 chemical pesticides
registered for use in Canada.
 Worldwide approximately 2.3 million tonnes of
pesticides are used yearly (0.4 kg for every
person on earth)
 Pesticides are added to shampoos, carpets,
mattresses, paints, and even wax on produce.
 More than 25% of pesticides are used to get rid
of pests in homes, gardens and parks.


Pesticides are classified into 4
groups:
Insecticide - targets insects
Example: DDT
 Persistence: high - stays in ecosystem for 2 - 15 years
Herbicide - targets weeds
Example: Roundup
 Persistence: mostly low - stays in ecosystem for days to weeks
Fungicide
-targets moulds and fungi
 Examples: Captan
 Persistence: low - stays in ecosystem for days
Bactericide- targets bacteria
 Examples: penicillin, vancomyecin
 Persistence: mostly low
Modern Chemical Pesticides





New pesticides are now water soluble and
do not build up in the tissues of animals.
They are safer but still have negative effects
such as:
-They break down quickly so they have to be
spread more often.
- They are not selective so they can also kill
birds, reptiles, amphibians, and fish.
- Animals that do not die immediately may
still put others at risk through
bioamplification.
Pests –can develop resistance to pesticides
Bioamplification


Some toxins, such as pesticides, buildup in
the fatty tissues of animals; they are not
soluble in water.
Pesticide

primary consumer (grasshopper)

secondary consumer (shrew)
(eats several prey so the amount of toxin in its body
will be larger.)

Tertiary consumer (hawk)
◦ (higher level predator gets all of its toxins plus those of all the other
prey it eats.)
Concentration of toxin becomes greater
at each level of the food chain.
 The higher the trophic level, the greater
the concentration of toxins.
 This process is referred to as
bioamplification

2.5 The Carbon Cycle

Carbon is an essential element for living things. The
cycling of carbon is conducted through 2 processes:
photosynthesis & cellular respiration.

Photosynthesis - the process in which plants use
solar energy, carbon dioxide from the atmosphere,
and water from the soil to make food (sugar).


Carbon Dioxide + Water +
6CO2
+
6H2O
Light Energy
+
light
Sugar (glucose)
C6H12O6
+
+
Oxygen
6O2

Cellular Respiration -uses sugar and
oxygen for energy and releases carbon
back into the environment.

Glucose
+ Oxygen
Water

C6H12O6
+
6H2O
6O2
+
Carbon Dioxide
+
6CO2
CO2 is removed from the atmosphere by
photosynthesis and returned to the atmosphere by
cellular respiration.
NASA How Carbon Works...
The carbon cycle usually works on
an equal balance, however, the
increase in the burning of fossil
fuels(i.e. oil, gas) has caused the
amount of CO2 in the atmosphere
to increase, causing an increase in
the Earth’s temperature
known
as the Greenhouse Effect.
 Carbon Cycle Game

Human Impact on the Carbon
Cycle ...do not copy

Humans have modified the carbon cycle
by releasing large quantities of organic
carbon from reservoirs faster than they
normally would.

Example: mining coal, burning fossil fuels and
burning forests ( less vegetation
less
photosynthesis
less carbon dioxide is being
absorbed)
Complete #1-4 on pg. 65
(understanding concepts)
1. What is limestone?
 2. How can volcanic activity contribute to
the release of CO2?
 3. What is peat?
 4. How do coal and oil form?


Effects:
◦
◦
◦
◦
◦
◦
Melting ice caps
Sea levels to increase – flooding
Change in climate patterns
More/less rainfall
Large impact on agriculture
Natural vegetation could change
Questions…

Please do questions 1,2,3,4,5 on page 65
of your textbook.
The Nitrogen Cycle…
Nitrogen – needed for the production of
proteins and nucleic acids (DNA)
 79% of atmosphere – N2 gas…but is not
usable. Nitrogen is very stable and does
not react with many things. Therefore, it
must be in the ion form (NO3 - nitrate) to
be used by organisms.
 Most plants and animals cannot capture
nitrogen from the atmosphere.
 Nitrogen Cycle video clip…

Nitrogen Fixation
Process of converting atmospheric N2 into
nitrates, the nitrate ion (NO3-)…2 methods:
 1. Nitrogen-fixing bacteria: found on plant
roots in nodules and in soil. Bacteria provide
the plant with a built-in supply of usable
nitrogen, while the plant supplies the nitrogenfixing bacteria with sugar to make the nitrates.
Excess nitrates move into soil.
 2. Lightning – causes N2 to react with O2 to
create nitrates (can dissolve in H2O)

Denitrification

Denitrifying bacteria break down nitrates
and nitrites into N2 gas gas re-enters
atmosphere
◦ Maintains balance between soil nitrates and
atmospheric nitrogen
Nitrogen Cycle
1. Atmospheric pool of N2
2. N2-fixing bacteria in root
nodules of legumes
3. Fertilizers
4. Soil nitrate
5. Nitrate take up by plant
roots
6. Plant and animal proteins
7. Dead organisms
8. Decomposers
9. Nitrate bacteria
10. Nitrate bacteria
11. Denitrifying bacteria
12. Lightning
Long term cycle
Short term cycle
The Phosphorous Cycle


Phosphorous cycles in two ways:
Long term - in rocks in the Earth’s
crust
◦ phosphates eroded from the rock are carried
away by rivers and lakes and end up in the ocean
where they enter the food chain.

Short term - in living organisms
◦ In the short cycle, phosphate in dead organisms is
recycled by decomposers, which break it down
and release the phosphates back to the
ecosystem.
Nutrient Cycling
◦ Rate depends on the rate of
decomposition.
◦ In warm moist areas process is rapid.
In colder and dry areas process is
slow.
◦ Soil chemistry and frequency of fire also
affect the rate of cycling.
Please do the following questions
from your text…
#’s 1,2,3,4,7,8,9,10, 11,12
 Page 69

Population Growth Patterns…
The 4 factors involved in population growth are:
 Natality: the number of offspring of a species
born in one year

Mortality: the number of individuals of a
species that die in one year

Immigration: the number of individuals of a
species moving into an existing population

Emigration: the number of individuals of a
species moving out of an existing population
Pop. Growth =
(Births +immigration) - (Deaths + emigration)


Open / Closed Populations

Open Population: when all 4 factors
are acting on the population of each
organism.

Closed Population: when only
natality and mortality affect their
population size. (Example: human
population, since people do not emigrate
to other planets)
2.10

Limits on Populations
Biotic potential is the maximum
number of offspring that a species can
produce, if resources were limited.
◦ Example: Black bears have 1 or 2 cubs; takes at
least 2 years to mature.
◦ Mice give birth to six or more pups; can
reproduce every 6 weeks. It also only takes six
weeks for mice to reach sexual maturity (i.e. can
start reproducing).
Biotic potential is limited by four
factors:
◦ Birth potential: maximum number of
offspring per birth
◦ Capacity of survival: number of
offspring that reach reproductive age.
◦ Procreate: number of times a species
reproduces each year.

Length of reproductive life: the age of sexual
maturity and the number of years the individual
can reproduce.
Chapter 3

A biome is a collection of ecosystems
that are similar or related to each other,
usually in the type of plants that they
support.

Canada can be organized into 4 major
biomes: tundra, boreal forest, temperate
deciduous forest, & grassland
The tundra biome









Canada’s northernmost biome
is a cold desert - receives very little precipitation (10-12 cm/year)
support s only a small number of organisms
short growing season (limits the types of plants that can survive)
plants must deal with permafrost - a layer of soil that never thaws.
active layer - the soil layer above permafrost that thaws in summer
to allow the uptake of water and minerals by plant roots.
cycling of matter is slow and there is only a small amount of
organic matter in the thin soil
Caribou have been present (eat lichens and mosses) but their
population is in decline.
See Table 1 -Page 89 for abiotic and biotic factors
The Boreal Forest Biome









immediately south of the tundra, also called the taiga biome
dominated by conifers (trees with needle-shaped leaves)
boreal forest is found in every province and makes up
approximately 80% of the forested areas
harsh climate with rapid changes in temperature
more precipitation than the tundra
no permafrost layer - soil thaws every summer and this
permits the growth of plants with deeper root systems
organic matter decomposes faster because of higher temps.
Only 50 species of birds - only those birds with special beaks
(for prying seeds out of cones or cracking cones)
See abiotic and biotic factors in Table 2 on Page 90
Temperate Deciduous Forest
Temperate Deciduous Forest









south of the boreal forest in Eastern and central Canada
dominated by deciduous trees such as maples and oaks
conifers gradually give way to deciduous trees (less obvious shift
than from tundra to boreal forest)
broad leaves of deciduous trees maximize light capture for
photosynthesis
higher temps allow faster decomposition and the organic matter
available from fallen leaves provides the basis for the formation of a
richer soil.
light can reach forest floor so more plants grow under large trees this includes small trees , shrubs and ferns.
presence of many types of plants allows deciduous forest to
support many animals & insects (mice, deer, shrews, birds)
Have three levels that support animals (the canopy, the understory
and the litter)
See Table 3 on Page 92.
Grassland
Grassland Biome












found at approximately same latitude as deciduous forest;extends from
Manitoba to the Rocky Mountains
abiotic factors of grassland mirror those of deciduous forest (because of
similar latitude). One exception - grassland receives less moisture
not enough rainfall to support trees except near rivers, lakes and ponds
fires periodically sweep through preventing growth of trees and also acting
as decomposers, speeding the return of nutrients to the soil
black earth of grasslands is most fertile soil in the world
short-lived grasses provide a great biomass for decomposition and high
summer temps promote rapid decay ensuring high concentration of
nutrients and organic matter in the soil
length of grasses regulated by rain - more rain the longer the grasses
now much of the grassland is devoted to growing grain
grassland ecosystems have only one layer that supports animals so
biodiversity is limited
grasses of this biome once supported herds of migrating bison
See abiotic and biotic factors in Table 4 Page 93
Complete Questions #1-3,5,8-10 on Page 93.
Section 3.3 Soil and Its Formation
Do not copy
 The quality and amount of soil available
are crucial factors in determining the size,
and health, of the plant community and
therefore the biodiversity of local
ecosystems.

Soil Layers:
Litter layer (upper layer) –made of partially decomposed
leaves or grasses. Acts as an insulator limits temperature
variations & reduces water loss by evaporation.
 Topsoil (beneath litter) -made up of small particles of rock
mixed with decaying plant and animal matter (humus).
Humus is black, so topsoil is often dark.

Subsoil (below the topsoil) -usually contains more stones,
mixed with only small amounts of organic matter. (Lighter in
colour because of the lack of humus; may contain large
amounts of minerals such as iron, aluminum, and
phosphorous.
 Bedrock (beneath the soil) is a layer of rock which marks
the end of the soil.


Figure 2 in your textbook - page 98 draw
this diagram into your notebooks
Formation of Soil
Soil begins as bedrock and is formed
through the erosion of rock by water,
wind, ice, or living things.
 Particles are broken off and mixed with
organic matter to form the first soil (a
thin layer).
 Process may take hundreds or thousands
of years.

Water Beneath the Soil

Surface water is precipitation that collects and flows
above the ground. Lakes, ponds, and rivers are all
surface water.

Ground water is the water found in the soil or rock
layers of the Earth’s crust. It may flow into bodies of
surface water.
Percolation the process in which ground
water, pulled by gravity, flows downward
through the soil.
 (The larger the particles that make up the
soil, the larger the spaces between
particles and the faster the percolation
rate.)


Water table is the boundary, found either in
the soil or the bedrock, between the area
where ground water is percolating down and
a layer that is saturated with water. In
general, wherever rainfall is great, the water
table will be higher (closer to the surface).
See figure 3 on Page 98.

Leaching is a process in which nutrients such
as organic matter and minerals are dissolved
in percolating water and carried into lower
layers of bedrock.
What determines the pH of the
soil?
The nature of the rock from which it was formed
 The nature of the plants that grow in it
 the acidity of the rain and snow and therefore the
ground water that enters the soil
 humans by burning fossil fuels such as coal, oil and
gasoline contribute to higher levels of acidity.


Acid deposition is a term used to describe the
falling of acids from the atmosphere to the
ground. Example: acid rain
Section 3.3 Soil and Its Formation

Soil can be viewed as a series of layers. List and explain each of these layers.

Explain how soil is formed.

Define surface water and give examples of surface water.

What is ground water?

Define percolation and explain what increases percolation rate.

What is the water table?

Explain leaching.

What determines the pH of the soil?

What is acid deposition?
Questions 1-3, 5,7,8 Page 99.
