Science 10

1.
2.
3.
4.
5.
6.
The Silence of the Frog (1.1)
Ecosystems
Food chains
Producers
Consumers
Herbivores
Omnivores
Sustainable Ecosystems
Unit 1 2010
7. Carnivores
8. Detritus
9. Decomposers
10. Habitat
11. Indicator species
Notes Section 1.1
In recent years biologists have become award of the disappearance of frogs, toads and
salamanders at extremely high rates.
Frogs have been around for a long time, with their ability to withstand droughts, floods, and
winter ice it is surprising that they are now disappearing so fast. Why?
Frogs can be found in most ecosystems that include water.
Ecosystem  describes the relationship between the living organisms in an environment
and the relationship between those organisms and the non-living parts of the environment.
Why all the concern?
Frogs are excellent bio-indicators, which means they can tell us how healthy the environment in
which they live is. How?
The first part of their life is spent in the water (aquatic environment) and the second part of
their life is spent on land (terrestrial environment). This means that they are exposed to
hazards both in water and on land.
They also are part of two very important and separate food chains
Food Chain  Step-by-step illustration linking organisms that feed on each other starting
with a producer and continuing with animals that feed on plants and other animals (consumers).
Food chain #1 – As an adult
Food chain #2 – As a juvenile
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Sustainable Ecosystems
Unit 1 2010
Why are they disappearing?
1. Loss of Habitat
Growth of cities, extensive farming, and cutting down trees are a few of the human
activities which have lead to the loss of viable frog habitat.
2. Air and water quality
Because frogs do not have any protective coat over their skin they are more susceptible
to pollution.
Acid rain also damages the frog eggs and lowers the amount of tadpoles which will hatch.
3. Ultraviolet Light
Just like humans, the thin skin of frogs will burn easily when exposed to UV sunlight for a
short period of time.
4. Climate change
Global warming is causing the temperatures to rise and if the climate becomes drier,
frogs will not be able to survive.
 Canada’s Endangered Species(1.2)
o Classification of Species at Risk
1. Extinct-no longer exists
2. Endangered- at risk of becoming extinct
3. Extirpated- no longer exist in certain areas
4. Threatened-declining numbers concerns of endangerment
5. Vulnerable-declining numbers
Notes
Extinction  a species that is no longer alive anywhere on earth
Ex. Tasmanian Tiger, Dinosaurs, Dodo bird, Wooly
Mammoth, Passenger pigeon.
Species  is a group of organisms that are capable of breeding and producing offspring that
are also able to breed.
Ex. a horse and a donkey are both species, however, if we were to mate a
horse with a donkey we get a mule. A mule is sterile (unable to breed).
Therefore a mule is not a species.
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4 Main causes of extinction:
1. Major catastrophes
Ex. asteroids, volcanoes, fire, earthquakes
2. Climate change
Ex. ice age
3. Competition
Competition with other species for food and space to live
4. Human activity
 Ecology (1.5)
Pest :
an organism that people consider harmful or inconvenient in a particular situation
or place. Examples may include : rats , cockroaches , mice , lice , etc.
Abiotic :
is the non-living part of the environment that affects an organism. Examples
include: sun light, rain , rocks, wind , temperature, etc.
Biotic :
is the living part of the environment . Examples include : grass , frog, human ,
bear.
Ecology :
is the study of the interaction of living things with each other (biotic) and with
the non-living (abiotic) factors in their environment.
Ecotone :
is a transition area between two eco-systems that includes members of both ecosystems and therefore has the greatest bio-diversity.
Population:
a group of organisms of the same species living in the same ecosystem
Community:
consists of all populations of species that live in an ecosystem.
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 Energy in the Ecosystem (1.10 and 1.11)
1. All energy begins with photosynthesis.
2. State the equation
We categorize organisms in a food chain by their trophic level which describes how they get
their energy.
Let’s look at the energy flow through some food chains
Every food chain starts with a producer of some kind. They get energy from the sun and
transform it into chemical energy (C6H12O6) for consumers.
When these primary consumers eat producers energy is transferred from the producer to
the consumer.
Then the energy is transferred to the secondary consumer and it continues.
However not all the energy captured by the prey is getting transferred to the predator?
Why?
Each organism in the food chain needs some energy to maintain life!
Thermodynamics (Energy Flow and Transformations)
First law of thermodynamics
Energy cannot be created nor destroyed on transformed from one form to another.
Second law of thermodynamics
Whenever energy is transferred some energy is lost in the form of heat
This means that the amount of energy at each step in the food chain is less then the step
before.
Example:
Grass  Dear  Wolf
Ecological Pyramids
Pyramid of Energy – measure amount of energy at each trophic level
Pyramid of Numbers – measures number of organisms in each trophic
level
Pyramid of Biomass – measures the dry mass of all organisms at each
trophic level.
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FOOD WEBS, CHAINS
Food Chain
A food chain is a single pathway of feeding relationships among organisms in an ecosystem that
results in energy transfer.
Food Web
Since the feeding relationships in an ecosystem are often too complex to be represented by a
single food web, the individual food chains interlink to form a food web. Many consumers eat
more than one type of food and more than one species of consumer may feed on the same
organism.
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TROPHIC LEVELS-An organism’s trophic level indicates the organism’s
 Cycling of Matter in the ecosystem (2.1)
Organic- living and inorganic- non living material
 The Carbon cycle (2.5)
Carbon is the key element in all living things.
Every year about 50 to 70 billion tonnes of carbon dioxide is turned into the organic carbon
compound know as sugar through the process of photosynthesis.
The chemical equation for photosynthesis is summarized below:
6CO2
+
Carbon dioxide +
REACTANTS
6H2O +
Light
water + light energy

C6H12O6
 Sugar (glucose)
PRODUCTS
+
6O2
+ oxygen
All living things release carbon dioxide as a by product or cellular respiration. The chemical
equation for cellular respiration is summarized below:
C6H12O6 +
Sugar (glucose)
REACTANTS
PRODUCTS
6O2

6CO2 +
6H2O
+ oxygen  Carbon dioxide + water
Because photosynthesis and cellular respiration are complimentary processes, carbon is
continually passing from one process to another.
This is called the Carbon Cycle.
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Sometimes the change from organic to inorganic carbon compounds takes many years, such
as when carbon is trapped under ground as oil, coal or diamonds.
Carbon is present in many places in and on the earth. The atmosphere is made of 0.03%
carbon
Humans have impacted the carbon cycle because we have released large amounts of carbon
that would have normally either been turned into rock (trees being turned into coal) or
stayed as in the earth (oil removed from earth and burned).
Due to these reasons, the amount of carbon in the atmosphere has been
steadily increasing for the past number of years.
The Carbon Cycle:
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 The Nitrogen cycle (2.6)
Like water and carbon, nitrogen and phosphorus are cycled through ecosystems
Most nitrogen is found in the atmosphere as N2(g), an unusable form.
We will look at how nitrogen gas is converted to nitrates and nitrites, the kind which can be
used by living things).
What do we use nitrogen for? DNA!
The process of transferring atmospheric nitrogen into nitrites is called nitrogen fixation, and it
can happen in the following ways:
 Lightning
 Bacteria on the roots of legumes (clover, soybeans, peas or alfalfa).
 Bacteria decaying detritus also produce nitrites.
These nitrites are further converted to nitrates again by bacteria.
The nitrates are used by plants (the producers in the food webs).
These nitrates can also be converted back to atmospheric nitrogen by denitrifying bacteria
through a process called denitrification.
These bacteria need an environment which lacks oxygen, this is why people aerate their lawns in
the springtime.
Soils that have a high amount of water (ex bogs) have a low oxygen level and therefore low
nitrates. This is why not many plants live on bogs.
Specialized plants have adapted to find their own nitrates (pitcher plant).
Phosphates are important for living things in many ways: cell membranes, energy production,
making DNA, and bones
Most phosphates are found in rocks. These phosphates are released by weathering and are
taken in by plants (the producers in the food webs).
Animals eat the plants and get the phosphates that way. Once the animals die, the phosphates
are returned to the rocks.
The speed of the cycle depends on the temperature and the amount of oxygen in an ecosystem.
A warm tropical rain forest has a rapid cycle but the cool tundra would have a slow cycle.
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Science 10
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1.
2.
3.
4.
Sustainable Ecosystems
Unit 1 2010
Monitoring Changes in the Population (2.9)
Rate of change of a population *Equation = (birth + imm.) –(death + emigration)
Factors that effect the rate of change of a population
Closed population / open population
Growth curve, phases of the growth curve
 Limits on the Population (2.10)
1. Biotic Potential
2. Four factors
o Birth potential
o Capacity for survive
o Reproduce
o Length of sexual maturity
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Limiting factors
Abiotic vs biotic
Carrying capacity
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