Ecology Test Review Key Levels of Organization in the Biosphere

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Ecology Test Review Key
What is Ecology? (pg. 63)
Ecology is the study of interactions between organisms and their environments, focusing on energy
transfer. It is a science of relationships.
All living factors are called biotic factors.
(pg. 90) Ex. Plants, animals, etc.
All nonliving factors are called abiotic factors.
(pg. 90 ) Ex. Climate, soil, rocks, water, etc.
Levels of Organization in the Biosphere (pgs. 21, 63-64, 90-91)
Species → Population → Community → Ecosystem → Biome → Biosphere
1. Species - Group of organisms so similar to one another that they can breed and produce fertile
offspring.
2. Population - Groups of individuals that belong to the same species and live in the same area.
3. Communities - Assemblages of different populations that live together in a defined area.
4. Ecosystems – Collection of all the organisms that live in a particular place, together with their nonliving,
or physical, environment.

Habitat- (pg. 90) the place in which an organism lives out its life (address)
5. Biome -- Group of ecosystems that have the same climate and similar dominant communities.
6. Biosphere -- Contains the combined portions of the planet in which all of life exists, including land,
water, and air, or atmosphere.
PRACTICE: Use the terms above in the levels of organization section from above to fill in the following:
What term is used to refer to each of the following?
Habitat
1. Lake Houston (location)
Species
Ecosystem
Population
2. Mississippi river and all of the forms of
life that are sustained by it
3. A flock of ducks
Population
Biome
4. The Sahara desert
Biosphere
5. All livable areas on Earth
Community
6. The deer, ducks, shore birds, fish and
rabbits living in and around Lake
Houston
Community
Ecosystem
ENERGY FLOW THROUGH AN ECOSYSTEM
The flow of energy through an ecosystem begins with thesun, and is passed on through various organisms:
sun  producers  consumers  decomposers


Producers – autrophic organisms that are able to make their own food from inorganic substances.
Examples: (pg. 67) plants, algae, bacteria
Consumers – heterotrophic organisms that get energy by eating producers or other consumers.
Examples: (pg. 68) animals, decomposers
Types of Consumers: (pg. 69)
1. Herbivores–
eatsonly plants
Ex. Deer, cow,
rabbit, insects
2. Carnivores–
Eatsonly meat
Ex. hawk, lion,
sharks,
3. OmnivoresEatsboth plants and animals
Ex.humans
Level of Consumers:
Use the three types of consumers from above to fill in the following blanks:
Primary consumer Secondary consumer Tertiary consumer 4th …..
herbivores
carnivores
(omnivores can be a 1st, 2nd or higher level consumer)

Decomposers – obtain energy from dead and decaying organisms. (pg. 69)
Examples: bacteria, fungus, sow bugs, earthworms
FEEDING RELATIONSHIPS (pg. 69-70)
Each step in a food chain or web is called a trophic level, or a feeding relationship between organisms.
FOOD CHAIN one way flow of energy
Illustrates only one feeding relationship
FOOD WEB many possible feeding relationships
within an ecosystem.
(Label each trophic level below)
5th
2nd
Tertiary consumers
4th
Arrows
show the
flow of
energy
and
matter.
Quaternary consumers
3rd
2nd
1st
Secondary consumers
Primary consumers
Producers
ECOLOGICAL PYRAMIDS (pg. 72-73)
Ecological pyramids diagram that shows the relative
1. What would happen to this food web is the plants
were removed?All organisms would die…no energy
2. Which organism is most vulnerable to changes in
populations? Plants
3. What happens to the owl population if the foxes we
killed off by humans? increase because there is more
food for them.
amounts of energy or matter contained within each trophic
level in a food chain or food web.in a food chain or web.
Pyramid of Energy
A pyramid of energy is used to illustrate the amount of
usable energy at each trophic level.
• Only 10% is passed on to the next trophic level
• The other 90% is lost/given off as heat.
Pyramid of Numbers
As you go further down a food chain, the
numbers of organisms decrease because there
is less energy available!
*Compare the pyramid of energy to the pyramid of numbers. Why
must there be so many more individuals at lower trophic levels?
Because there is less energy available.
3rd
consumers
Secondary
consumers
Ecological Pyramids: (pg. 72-73)
1.
2.
3.
4.
5.
6.
Level 3
Level 2
Level 1
Symbiotic Relationships
Which trophic level contains autotrophic organisms? Level 1
Which trophic level contains herbivores? Level 2
Which trophic level contains carnivores? Level 3
Which trophic level contains the most available energy? Level 1
Which trophic level contains the least available energy? Level 3
How much energy is transferred to the next trophic level? 10%
3 Types of Symbiosis:
1.
Parasitism: one organism (parasite) benefits and the other is harmed (host).
EX: ticks feed on the blood of other animals.
2. Commensalism: One organism benefits and the other organism is neitherharmed or helped.EX: barnacles on a
whale or birds building nests in trees.
3. Mutualism Both organisms benefit from the relationship.
EX: pollination of flowers
Predator-Prey Relationships
 Predation: interaction in which one organism captures and feeds on another organism.
 Predator: organism that does the killing and eating.
Prey: Organism that iseaten (food).
NUTRIENT CYCLES:
WHAT HAPPENS TO THE NUTRIENTS WHEN ORGANISMS DIE?
 Energy cannot be recycled or used again.
 However, nutrients/elements in an ecosystem can be recycled.
The Carbon Cycle Pg. 77
Decomposers
Directions: Use the diagrams above, and the diagrams and text to answer the following:
1. (pg. 77) Name and discuss the process that removes carbon dioxide from the atmosphere? Plants
and other producers remove carbon (CO2)from the air through Photosynthesis.
2. Name and discuss the processes in which carbon dioxide is returned to the atmosphere?Carbon
(CO2)is put back into the air through the burning of fossil fuels (combustion), by plants and
animals through cellular respiration and by decomposers through cellular respiration.
The Nitrogen Cycle Pg. 78
by bacteria
and/or
lightning
Nitrogen Facts
Air is 78% nitrogen
Nitrogen is one of the
elements found in plant
fertilizers
Protein contains nitrogen
Directions: Use the diagrams above, diagram on pg. 78, and text to answer the following:
1. (pg. 78) Bacteria living in the roots of the plant help the plant by taking Nitrogen from the
atmosphere and “fixing” it so the plant can use it. These bacteria live in nodules called legumes.
2. Bacteria living in the soil help plants by taking Nitrogen from the atmosphere and “fixing” it so the
plant can use it as fertilizer.
3. What process transforms nitrogen into usable forms that plants can use? Nitrogen fixation
4. Where do animals ultimately get their proteins from? From the plants or from the animals that
eat the plants.
5. (pg. 78, fig. 3-14) How has farming affected the nitrogen cycle?Farmers can use chemical
fertilizers adding Nitrogen to the soil, or they can rotate crops, planting legumes to add
nitrogen to the soil.