Transcript Science 10 Unit 1: Sustainability of Ecosystems

• Brainstorm: What is science?
• Science is the study (or way of looking at) the
natural (or “not made by humans”) world
around us.
• There are many different types of science,
including biology (the study of life), chemistry
(the study of matter) and physics (the study of
matter & energy, and the interaction between
them)
• An ecosystem includes all organisms in an area
that interact with each other and with their
environment of energy and matter.
• In other words, all plants, animals, bacteria,
fungus, etc. in an area interact and connect
with each other AND with the environment.
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Swamps & marshes
Freshwater lakes, ponds & streams
Saltwater lakes & coastal ocean
Temperate forests
Highland forests
Unit Overview with Youtube Song
• The Sun is the ultimate source of energy for
most ecosystems
• Light energy from the Sun is converted by
plants into chemical energy
• Energy is channelled through the food chains
• Complete the handout and submit to your
teacher
• Introduction: The Importance of Respect
• Explanation of how student guide will be
assessed
• Work on Check Your Understanding (pg 2)
• Did not do this as of yet!!!!
Define the following terms:
• Herbivore
• Carnivore
• Omnivore
• Trophic level
• Primary producer
• Primary consumer
• Secondary consumer
• Tertiary consumer
• Decomposers
• Create a food web
• Check Your Understanding; pg 7; #1-5
• Food chains are often too simplistic and do
not provide a completely accurate picture of
an ecosystem. A better way to look at the
ecosystem is to make use of food pyramids.
• There are three types of food pyramids:
1. Pyramid of Numbers
2. Pyramid of Biomass
3. Pyramid of Energy (the best!)
1-2 top carnivores
Thousands or millions
of producers
• A pyramid of numbers shows that in most
ecosystems, there are more producers than
herbivores (or primary consumers) and more
herbivores than carnivores (secondary and
teritary consumers).
• But, this is not true for all ecosystems.
• Let’s take a look at the ecosystem within a
single oak tree:
• A pyramid of numbers does not take into
account the size of the organism, just the
number.
• A better way of looking at an ecosystem is to
use a pyramid of biomass. Biomass means
how much mass (or weight) is at each level.
• The best type of pyramid is a pyramid of
energy.
• A pyramid of energy flow measures the total
amount of food energy that flows through
each trophic (or feeding) level.
• Basically, there is always less energy available
for each level as you go UP the pyramid.
• Also, it is impossible to turn a pyramid of
energy upside down.
Pyramid of Energy of Flow
• Probably the most important thing to understand
about a food pyramid is that only about 10% of
the energy makes it from one level to the next.
• Why does this happen? Energy is lost because of
a variety of reasons, including:
1. Movement
2. Digestion
3. Thinking
4. Growing
5. Reproduction
• Check Your Understanding
• Pg 17; #1-5
OR
FINISH FOOD WEBS!!!
• Work on Bioaccumulation: The DDT Story
• Primary productivity is the average amount of
new plant material (or biomass) that is added
to an ecosystem per year.
• Primary productivity is measured as the
amount of energy per square metre per year
(or kJ/m2/year)
• The most productive ecosystems include rain
forests and salt marshes, while the least
productive would be deserts.
What goes in?
sugar
What goes out?
• All green plants & seaweed make food using a
process called photosynthesis
• Photosynthesis is a process used by plants to
convert (or change) light energy from the sun into
sugar. This sugar is used by the plants for energy.
• These sugars are made from water and carbon
dioxide (CO2). Oxygen is released as a waste gas.
• Photosynthesis provides oxygen to the
atmosphere and supplies most of the energy for
life on Earth.
• A chemical called chlorophyll makes this
reaction possible. Chlorophyll gives leaves a
green colour.
• The photosynthesis equation is probably the
most important reaction for all life on Earth!!!
These go into the plant cells.
These come out of the plant cells.
The MOST PRODUCTIVE
ecosystems are salt marshes,
swamps and
tropical rain forests.
The LEAST PRODUCTIVE
ecosystems are the tundra,
open ocean and deserts.
ARCTIC
TEMPERATE
FOREST
DESERT
RAINFOREST
ARCTIC
• Read the article
• Keep in mind that the Sun can only provide
the Earth with so much energy. And, the Earth
only has so much usable land.
• BTW, Earth grows 4.2 million hectares of
tobacco compared to 3.7 million hectares of
tomatoes. Is this a good use of land?
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A group of birch trees living on a hill
A colony of 2,146 ants
All of the spruce trees in a forest
All of the cod fish in the Bras d’Or Lake
Frogs living in a pond
• A population is a group of organisms of the
same type (or same species) living in the same
area.
• A population is usually the actual number of
individuals in an area that are all the same
type.
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More births than deaths
Moving into an area from somewhere else
Lots of food & water
No disease
Good weather
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More deaths than births
Moving out of an area
Disease & sickness
Severe weather, droughts & storms
Starvation or lack of food
• NO!!! The largest population that an
environment can support is called the
carrying capacity.
• For example, a forest ecosystem may only be
able support a few dozen deer.
1. Materials & energy (sunlight, water, fertilizer,
etc.)
2. Food chains (the amount of food lower in the
food chain)
3. Competition (between same species or
different species)
4. Overcrowding (leading to not enough space,
disease, less births, more deaths, etc.)
5. Natural disasters (such as forest fires, storms)
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Natality
Mortality
Population size
Population density
Immigration
Emigration
Intraspecific competition
Interspecific competition
1. What is meant by the term “carrying capacity”?
2. How might overcrowding lead to a reduction in
population size?
3. How might an increase in population of plants
in an area lead to an increase in the population
of hawks?
4. How might an increase in the population of
hawks in an area lead to an increase in the
population of plants?
• Work on the activity in class
• This is an in-class assignment worth 10 points
• You will be evaluated on how well you work
and on getting some good numbers!!
What are nutrients?
Nutrients are chemicals used by organisms
(plants, animals, fungus, bacteria) to operate
their bodies. Nutrients include non-living
nutrients (oxygen, water, carbon dioxide,
minerals). Organic (or “living nutrients”)
include carbohydrates, fats & proteins.
What is a nutrient cycle?
A nutrient cycle is the cycling (or recycling) or
a nutrients through the environment.
What is carbon?
Carbon is the key chemical or element upon which all life is
based. Carbon is one of the most important chemicals in all
living things.
What is the carbon cycle?
Simply put, plants take in carbon dioxide (CO2) from the air
during photosynthesis and make carbohydrates (or sugars).
Animals and other consumers then eat the carbohydrates
for energy and growth. Also, animals give off carbon
dioxide in their breath (as a waste gas). And the cycle
continues.
Video
1. Plants take in carbon dioxide during a process called
photosynthesis.
2. During photosynthesis, plants change carbon dioxide
to sugar/carbohydrates and oxygen with the help of
sunlight and water.
3. Consumers eat plants (and other animals) for food.
These consumers take in sugar/carbohydrates (from
plants) during a process called cellular respiration.
4. During cellular respiration, consumers change sugar
and oxygen into energy. Carbon dioxide and water
are given off as waste products.
5. The cycle repeats. Plants use carbon dioxide during
photosynthesis.....
Photosynthesis
Cellular Respiration
• Carbon cycle webquest and nitrogen cycle
webquest
Plants and animals could not live without
nitrogen. It is an important part of
many cells and processes such as amino
acids, proteins, and even our DNA. It is also
needed to make chlorophyll in plants, which
plants use in photosynthesis to make their
food and energy.
• Around 78% of the atmosphere is nitrogen.
However, this is mostly not usable by animals and
plants.
• Nitrogen is used in fertilizer to help plants grow
faster.
• Nitrous oxide is a greenhouse gas. Too much of it
can also cause acid rain.
• Nitrogen has no color, odor, or taste.
• It is used in many explosives.
• About 3% of your body weight is nitrogen.
• Nitrogen is used by organisms to carry out many of the
functions of life. This element is especially important to
plant life. Yet, nitrogen in its gaseous form is almost
entirely unusable to organisms. It must first be
converted or “fixed” into a more usable form. The
process of converting nitrogen is called fixation.
• There are specialized bacteria whose function it is to fix
nitrogen, converting it, so that it can be used by plants.
There are still other bacteria who do the reverse. That
is, they return nitrogen to is gaseous form. This
process is called denitrification.
• After nitrogen is fixed, it can be absorbed and used by
plants, and then eventually by animals.
• The process of nitrogen being fixed, used by plants and
animals, and later returned to the atmosphere is
referred to as the nitrogen cycle.
Unfortunately, human activity has altered
the cycle. We do this by adding nitrogen
into the soil with fertilizer as well as
other activities that put more nitrous
oxide gas into the atmosphere. This adds
in more nitrogen than is needed by
normal cycle and upsets the cycle's
balance.
• Video