Science 2200
Quiz Review
The following review sheet does NOT contain all the material that will be on the
upcoming quiz/test.
You must also understand the notes given, questions assigned, and sections of the
text covered.
If you have missed notes it is your responsibility to make up for the material you
missed.
Unit 1: Ecosystems Introduction
- Ecosystem – a self supporting community of plants, animals and the non-living
environment.
E.g. Tundra, Boreal Forest, Ocean
Sustainable Development
- Once the environment was seen as having unlimited resources.
- We now understand that most resources are limited.
- Our goal now is to use resources without running out.
- Sustainable development – using resources to meet our needs without reducing
the ability of future generations to meet their needs.
- Our resources are limited because the Earth is a closed system.
- Closed system – only energy can enter or leave.
- The Earth is a closed system like a spaceship. How?
1. Only the sun’s energy can enter
2. There are a limited number of resources that must be used wisely.
3. There are non-renewable resources, which will run out.
Biodiversity
- Biodiversity – the different species (kinds) of organisms in an area.
- For an ecosystem to exist there must be many different kinds of organisms so that
food webs will work.
- If you remove one organism from a food web, many more will be affected.
- Some organisms will loose a food source and decrease in numbers, others will
loose a predator and increase in number.
Ecology
- Ecology – the study of ecosystems.
- If you were an ecologist you would study how biotic and abiotic factors influence
each other in an ecosystem.
- Habitat – Where an organism lives.
- Population – group of the same organism in the same area (habitat). E.g. a
school of fish in a pond.
- Community – group of different organisms in the same area (habitat). E.g. a
pond may have different kinds of fish, insects, worms and ducks.
Competition
- Niche – the role of an organism in its habitat. E.g. foxes and black bears live in
basically the same habitat but each survives by having its own niche: eating
different food, coping with winter differently, etc.
- Sometimes organisms eat the same food or want to live in exactly the same area.
- Competition – when organisms compete for the same resources. E.g. Owls and
hawks eat mice. If each animal runs out of other food sources they will compete
for food.
- This could result in some animals not having enough food to survive.
- It could also lead to fights between these animals.
- Often competition results in one organism leaving the area.
Species At Risk p. 12-13
- When there is a change to the biotic or abiotic parts of the ecosystem the
organism become “at risk”
- At risk – organisms that are in danger of dying out.
- Depending on the changes to the ecosystem, some organisms may be in greater
danger of dying out than others.
- There are several terms used to measure how severe this danger is:
1. Vulnerable – in some areas the numbers of this organism are decreasing.
E.g. Atlantic cod.
2. Threatened – if everything stays the same, these organisms will become
endangered. E.g. Peregrine falcon.
3. Extirpated – when an organism no longer lives in an area. E.g. wolf in
Newfoundland.
4. Endangered – an organism that is close to extinction. E.g. Eastern mountain
lion.
5. Extinct – an organism that can be found nowhere. E.g. Labrador duck.
The Causes of Population Decline
1. Loss of habitat E.g. humans may cut down forests to build houses, forcing
birds to move away.
2. Pollution of air and water E.g. humans pollute water and fish die.
3. Natural environmental change E.g. Ponds may dry up and ducks have
nowhere to live.
4. Climate change E.g. global warming forces polar bears to move further
north.
5. Competition for food E.g. Moose were introduced to Newfoundland and
competed with caribou.
Energy Flow p. 22-25
- Everything is made of energy.
- Living things get their energy either from biotic sources (eating food) or abiotic
sources (the sun or volcanoes).
- Trophic level – Feeding level. There are 5 we have to know.
- Primary Producers - Organisms which get energy from inorganic sources e.g.
plants.
- Primary Consumers - Organisms which get energy by eating primary producers
e.g. hare, caribou
- Secondary Consumers - Organisms which get energy by eating primary
consumers e.g. fox, owl.
- Tertiary Consumers – Organisms which get energy by eating secondary
consumers e.g. pine martins.
- Decomposers – Organisms which get energy by eating dead organisms e.g.
fungi.
- As you go up the trophic levels the amount of energy decreases.
- This means there are fewer animals as you go up a food chain.
- Most of the energy an organism takes in is used up: reproducing, lost as waste or
lost as heat.
- Only about 10% of the energy in any trophic level can actually be used by the
next level up.
- Pyramid of Energy – a diagram that shows how much energy is available in
each trophic level.
- Pyramid of Numbers - a diagram that shows how many organisms are in each
trophic level.
- Pyramid of Biomass - a diagram that shows how much dry mass is in each
trophic level.
Questions:
1. Describe an example of sustainable development.
__________________________________________
__________________________________________
__________________________________________
__________________________________________
2. What would you need to develop a sustainable ecosystem on the Moon?
__________________________________________
__________________________________________
__________________________________________
__________________________________________
3. Name and describe three types of ecosystems.
__________________________________________
__________________________________________
__________________________________________
__________________________________________
4. Give an example of organisms which compete and a resource they compete
for.
__________________________________________
__________________________________________
__________________________________________
__________________________________________
5. What is the difference in habitat and niche?
__________________________________________
__________________________________________
__________________________________________
__________________________________________
6. What is the difference in community and population?
__________________________________________
__________________________________________
__________________________________________
__________________________________________
7. In your own words describe the classification system for species at risk.
__________________________________________
__________________________________________
__________________________________________
__________________________________________
8. How can human activity lead to biodiversity loss?
__________________________________________
__________________________________________
__________________________________________
__________________________________________
Human Impact on Energy Flow
- Humans once took only what they needed from the environment and this had
little impact on the energy in an ecosystem.
- Populations grew because of better medicines and jobs available in cities.
- Cities use a lot of energy in a very small space and areas around cities have to be
used for farmland.
- This damages local ecosystems.
Energy Flow and Predators
- Humans also affect ecosystems and energy flow by directly killing animals. E.g
The wolf was extirpated in Newfoundland by humans.
- Removing predators upsets food chains and food webs.
- The prey increase in number.
- What the prey eat will then decrease in number.
- This will cause the prey to begin to starve.
- In some parts of Newfoundland there is a serious problem because there are no
wolves.
- In Terra Nova national park the large numbers of moose and hare may lead to
them destroying the park.
- Predators also help maintain biodiversity in ecosystems.
- Predators keep the numbers of their prey low.
- This prevents prey from competing too much with each other and other species.
- If competition is too high, some species will be become extirpated.
- Others will eat too much of the food in the area and begin to starve.
Global Warming
- Billions of years ago the Earth had much more carbon dioxide in its atmosphere.
- Human activity during the last 100 years has increased the amount of carbon
dioxide in the atmosphere.
- Carbon dioxide in the atmosphere traps heat from the sun causing global
warming.
- Global warming results increased temperatures and more energetic weather
systems, i.e. more hurricanes.
Cycling of Matter p. 26-29
- Energy flows through an ecosystem. Atoms and chemical compounds do not
flow, they cycle.
- Atoms and chemical compounds remain constant in an ecosystem.
- Instead of flowing, they change their form. E.g. water.
- Water goes from being a liquid in ponds or the ocean to water vapour (a gas)
when the liquid evaporates to liquid rain or solid ice.
The Carbon cycle
- The process of carbon going from a solid to a gas form and back again is the
carbon cycle.
- All life is based on carbon.
- The solids include organic (biotic) molecules such as glucose (sugar). The gas is
carbon dioxide.
- Two biological reactions cycle carbon between these forms:
1. Photosynthesis – the process where plants use light energy to make sugar. This
process takes carbon from a gas and puts it into a solid.
2. Cellular respiration – the process where plants and animals use sugar to make
energy. This process takes carbon from a solid and puts it into a gas.
The Nitrogen Cycle
- All living things need nitrogen to make proteins.
- Nitrogen can go from a gas (78% of the air) to a solid.
- Bacteria in the soil can take nitrogen gas and make solid nitrogen.
- Plants take solid nitrogen and use it.
- Animals get solid nitrogen by eating plants or other animals.
- Some of the bacteria that make solid nitrogen live inside plants.
- The bacteria get food and a safe place to live.
- The plants get nitrogen they can use form the bacteria.
Succession p. 48-49
- Succession – the process that turns one ecosystem into another.
- Climax community – the community of biotic factors that exist after succession
occurs.
- Many factors influence the speed of succession. These can be put into two
categories:
1. Gradual change – occurs over decades or centuries. E.g Glaciers melt, ponds
dry up, forests are buried in snow.
2. Sudden change – starts in hours to years. E.g. Meteorite impact, volcanic
eruption, human activity.
Human Impact on Succession p.32-33
- A major problem occurs when farms are fertilized.
- If too much fertilizer is used the soil becomes acidic.
- If the soil becomes too acidic, nothing can grow.
- Also when a farm is fertilized and the fertilizer enters the soil, then it enters
ponds or rivers.
- When in the ponds it causes algae to grow. (Algae bloom)
- When the algae dies bacteria decompose it.
- Those bacteria us up a lot of oxygen and animals and plants in the pond die.
- Organic Farm – a farm that does not use pesticides nor fertilizer.
Questions
1. What problems were caused by the removal of wolves from Newfoundland.
2. What biological reactions are involved in the carbon cycle? How are they
like opposites?
3. Label a diagram of the carbon cycle.
4. Why is nitrogen important to living things?
5. Label a diagram of the nitrogen cycle.
6. What is a climax community? List two types of climax communities in
Newfoundland.
7. How can fertilizing farms affect ecosystems?
8. List two advantages and disadvantages of organic farms?
9. How did humans affect the ecosystems around Newfoundland 200 years
ago? How do we effect ecosystems in Newfoundland today?