Name _________________________________________________________________ Period ________

Unit 13 Notes: EcologyFood Chains and Levels of Organization in Ecology

_____________ factors- all living organisms inhabiting the Earth_____________ factors- nonliving parts of the environment (i.e. temperature, soil, light, moisture, rocks)Levels of Organization in Ecology• Organism → Species → Population → Community → Ecosystem → Biome → Biosphere• Species - Group of organisms so similar to one another that they can breed and produce

______________________ offspring. • Population - Groups of individuals that belong to

the same ____________________ and live in the same area.

• Communities - Assemblages of different _____________________ that live together in a defined area.

• Ecosystem - Collection of all _____________ and nonliving things in a determined place.

• Biome - Group of ecosystems that have the same ____________________ and similar dominant communities.

• Biosphere – Part of the planet in whichall life exists, including land, water, and air Which two levels are not shown? (All ecosystems combined).

Eat and Be Eaten1. Decomposer – break down dead organic matter __________________________

• Includes: bacteria and fungus 2. Detritivore - _____________ on plant and animal remains

• Includes:1. maggots2. dung beetles

3. earth worms4. sow bugs (rolly

polly)Food Chain vs. Food Web

1. Food Chains follow just ____________ path as animals find food.2. Food Webs follows _______ possible energy paths

***Both food chains and food webs show the ______________of energy in an ecosystem.

1. List all of the producers. ______________________________________________________

2. List the primary consumers. ______________________________________________________

3. List the higher level consumers. _____________________________________________________

4. What is the top consumer? _____

5. What begins the flow of energy in the picture? ______________

Trophic Levels• Trophic Levels - corresponds to the different ________________ or ________________ in the food chain.

– Represents the feeding ________________________ in a food chain such as primary producers, herbivore, primary carnivore, etc.

Food Chains Always Begin With _________________________ And End With ____________________.

Matter vs. Energy• Matter – Has _____________, takes up __________________, is usually a “thing”• Energy – Not like matter, does ___________ have mass,

_______________________take up space, energy moves matter– Forms of energy: light, heat, sound, motion,

and ___________________________

How Much Energy is Passed On?• Only 10% is passed on to the next trophic

____________________• The other 90% is lost/given off as

________________

Food Chains: Matter and Energy• As you go along a food chain, the matter

and energy ________________________. • This can be represented in a

________________________.

Pyramids• Pyramids are ___________________ at the bottom…more matter and energy are at the bottom of the

pyramid!

• Ecological Pyramid - Diagram that shows the ____________________ amounts of energy or matter contained within each trophic level in a food chain or food web.

Two Types of Ecological Pyramids

1. Pyramid of Biomass – Represents the biomassat each ____________________ level

Biomass – Total amount of living________________ within a trophic level

Usually expressed in grams per unit area.

As you go along a food chain, the amount of ___________________ decreases!

2. Pyramid of Numbers – Represents the _______________________ of organisms at each trophic level

As you go further down a food chain, thenumbers of organisms ____________________because there is less energy available!

Exception - If you have a large producersuch as a tree), the pyramid of numbersmay look _____________________ in shape.

Read the information and then use the diagrams below to answer the questions that follow.When producers convert the sun’s energy into food energy, they use some of it for daily functions, store some, and use some to build new plant tissue. When a herbivore, such as a cow, eats the plant, does the cow get 100% of the plant’s energy? Will one plant, such as alfalfa, support one cow? Of course not! Much of the plant is of no use to the cow. A single cow may need millions of plants in order to survive. The small amount of usable energy in each plant is then used to support the cow’s daily activities. A very small fraction of the energy is stored, or used to make “more cow”. As you can see, the amount of energy available to any member of a food web decreases as you go higher and higher into the chains of the web. The same is true for numbers and mass of organisms. This concept is often shown as a pyramid of energy, mass, or numbers. Use the chart below to answer the questions that follow.

ORGANISM NUMBERS MASS AVAILABLE ENERGYYoung human 1 50 kg .06%

cow 4 1,000 kg 7.00%Alfalfa plant 20 million 8,000 kg 100%

1. Fill in the pyramids so that the three organisms are placed in their correct levels, then answer the questions that follow.

a. What is the source of energy for all of the ecological pyramids above? ______________________b. In general, what kind of organism makes up the base of any ecological pyramid?

_________________________c. How is the energy loss from one trophic level to the next reflected in the pyramid of numbers

above? _________________________________________________________________________________________________d. Suppose an ecosystem has a greater number of individual herbivores than individual producers.

How would this affect the shape of the ecosystem’s pyramid of numbers? _________________________________________________________________________________________________

e. In the pyramid of energy, why do different trophic levels have different amounts of energy available? _________________________________________________________________________________________________

f. Which trophic level contains the most available energy? _______ g. If trophic level 1 contains 10,000 kcal of energy, how much will transfer to level 3? _______________

Notes: InteractionsSymbiotic Relationships

Mutualism Commensalism Parasitism PredationDefine (Fill in each blank with “benefit, harmed, or killed”

Relationionship that _____________ both species.

When one species ________________ from the relationship and the other is neither benefited nor _________________.

One organism ______________s and the other (the host) is ____________________.

One organism benefits and the other is ____________________.

Scenario Example (Describe one)

Carrying Capacity and PredatorsCarrying Capacity

• _____________________ of species that can be _______________________________ by an ecosystem. • Population Growth is Represented by one of two graphs:

– Exponential - individuals in a population reproduce at a constant rate (Ideally happens IF there are unlimited resources) = (J-curve)

– Logistic – The growth of a population slows or stops as resources become less available (S-curve) ***This is what our Population is represented with***

Factors that Affect Population Size1. Number of _______________2. Number of _______________3. Number of individuals that enter or leave a population

– __________________ = movement of individuals INTO an area (growth)– __________________ = movement of individuals OUT of an area (shrink)

Limiting factor - any biotic or abiotic factor that restricts the existence of organisms in a specific environment.

Limiting factors:a. Density independent: factors that affect all members of the population ___________ if population is dense or not.

Natural disasters: floods, earthquakes, wildfires, tornadoes, mudslides, pollution, habitat destruction

b. Density dependent: factors that affect ________________ populations EX: competition, predation, crowding and stress, parasitism, and disease

Competition• Competition – A ____________________ between organisms for the same ________________________; The

fitness of one of the organisms is __________________________ by the presence of another.– Limited supply of at least one ________________________ used by both organisms is required

• Example : Animals compete for food, mating, or ______________________ and plants can compete for water, food, minerals, ___________________________.

Predators• Organism that ___________________ and _______________ other organisms.

– Can be _________________________ or omnivores• The Importance of Predators

– We need them to control the ______________________________ – They also get rid of weak, crippled, stupid, stunted, and diseased organisms (survival of the

fittest)

Part 5: Organism Interactions Directions: Use the word bank to match the definition or description to the statement. Words may be used more than once.

Symbiosis Resource Prey Niche Competition Biotic factors Abiotic factors Predator

_____________________ 1. Living organisms within an ecosystem

_____________________ 2. Physical (nonliving) factors that shape an ecosystem

_____________________ 3. An organism’s role (what it eats and where it reproduces) in an ecosystem

_____________________ 4. Results when organisms of the same or different species attempt to use a resource (food, water, shelter, etc.)

_____________________ 5. Anything that is necessity for life: food, water, nesting site, sunlight; etc.

_____________________ 6. Organism that is captured or eaten

_____________________ 7. Organisms that kills and eats the other organism

_____________________ 8. Organism that is killed and eaten by another organism

_____________________ 9 Any relationship in which two species live closely together

_____________________ 10. A wolf captures a deer. The wolf is the:

_____________________ 11. A lion captures a zebra. The zebra is the:

_____________________ 12. An owl is active and hunts at night; it builds its nest in trees

13. If two organisms occupy the same niche in the same habitat at the same time, what must be true about the organisms?

14. Owls and hawks often live in the same areas and hunt the same foods. Why can they survive together in the same habitat?

Ecological SuccessionEcosystems are constantly changing in response to natural and human disturbances. Succession is a series of predictable ______________ that occurs in a community over ____________.

Causes:1. _________________________________________ land 2. Climate ___________________________________ 3. Introduce nonnative species 4. ______________________________________________________________

Natural, gradual changes in the types of species that live in an area; can be primary or secondary1. Primary succession

a. Begins in a place ___________________________________________(Ie. )b. Starts with the arrival of living things such as ______________ that don’t need soil to survivec. Lichens add organic matter and break down rock into soild. Then simple plants like ________________ & ___________________ start to grow in new soil

e. Simple plants start to die, soil thickens allowing flowering plants to begin to grow then small shrubs and trees, then ______________ and small animals can survive.

2. Secondary Successiona. Begins in a place ____________________________________ and once was home of living

organismsb. Occurs faster and has different pioneer species than primary succession. (ie. )

Climax CommunityA ______________ group of plants and animals that are the end result of succession.

_ Grasses in ____________________ or ___________________in deserts.

The Carbon Cycle

Why is Carbon important?• All _________________ things are made of carbon!!!

––

Carbon Does Not Stay Still – It Is On the Move!1. In the atmosphere, carbon is attached to some oxygen in a gas called ______________

______________________.2. Plants use carbon dioxide and sunlight to make their own food and grow. The

carbon becomes part of the plant. 3. Animals consume plants. The carbon becomes part of the ______________________.4. Plants that die and are buried may turn into fossil fuels made of carbon like _______________ and oil

over millions of years. 5. When humans _______________ fossil fuels, most of the carbon quickly enters the atmosphere as

________________________________.

Photosynthesis Using light energy, plants combine carbon dioxide (CO2) from the atmosphere and water (H20) to

form ____________________ and ________________________ in the process of photosynthesis. sunlight

Carbon Dioxide + Water → Sugar + Oxygen What is Sugar (Glucose) Used For?

1. Source of _________________________2. Building _______________________ for other compounds

such as proteins, oils, and starches.

Respiration In respiration, the compounds containing carbon are ________________________________, and carbon

dioxide is ______________________________. Plants, _________________________, and microorganisms all carry out respiration!

Is the Carbon Cycle Balanced?• The Carbon-Oxygen cycle is _____________ of balance.• There is more carbon dioxide being _________________________ into the atmosphere than is being

_________________________.

Combustion• Most of the carbon dioxide is produced during the process of ________________________ called

combustion.• When compounds containing carbon (wood, coal, or oil) are burned, the carbon is chemically

combined with oxygen, and _________________________________is released.• The use of carbon dioxide by plants during photosynthesis is a much ____________________ process. • As a result of the imbalance between these two processes, the level of carbon dioxide in the

atmosphere is ______________________.

Decomposers• When organisms die, decomposers break down the _____________________ compounds in

their bodies, and carbon dioxide is _______________________ to the atmosphere.• During decomposition (decay), other chemicals are also ____________________ to the soil or released

into the air. One of these chemicals is ____________________.

1. What kinds of things release carbon into the air?

2. What form is the carbon in when releases into the air? _________

3. How does the decomposition of animal remains release carbon into the environment?

4. What kinds of organisms use carbon from the atmosphere?

5. What do these organisms use it for?

The Nitrogen CycleNitrogen

• Plants and animals need nitrogen to make ______________________.• How Do PLANTS Get Nitrogen ?

– Special _________________________, in the soil and water, must change or “fix” nitrogen gas (N2) into nitrogen ________________________ (NO3

-) or ammonium ions (NH4+) that plants can

_________________. – These bacteria are called nitrogen-fixers.

• Most nitrogen-fixing bacteria live in little houses, or _________________, on the __________________ of plants called legumes.

• Legumes - Members of a large family of plants that include _______________, beans, alfafa, and ___________________.

• Nitrogen Fixers have a ____________________________ relationship with the plants• The plants provide food and cover for the bacteria, and the bacteria convert

nitrogen gas into ______________________ for the plant.• How Do ANIMALS Get Nitrogen ?

– Animals get nitrogen from plants or from other plant-eating animals, in the _________________ of protein.

– Animals must ____________ protein to get nitrogen! We can’t _____________________ in nitrogen!

How is Nitrogen Recycled? Nitrogen is recycled by special ______________________ that break down the nitrogen compounds

(proteins) in _________________ plants and animals, and in animal wastes. If plants do ________ use the nitrogen compounds as fertilizer, special forms of bacteria may

____________________ it. These bacteria convert the unused fertilizer into nitrogen ___________ and release it into the atmosphere.

Lightning and the Nitrogen Cycle• Lightning plays a __________________ role in the nitrogen cycle.• Lightning _________________________ nitrogen and oxygen in the atmosphere.

– The “fixed” nitrogen, (which is dissolved in the _______________) enters the _________________. • The burning of ___________________________________ is another source of nitrogen.

– Combustion causes nitrogen and oxygen to _________________________ creating nitrogen oxides (NOx).

1. From where do plants get nitrogen? ______________________

2. From where do animals get nitrogen? _____________________

3. How can nitrogen get into the soil from a living animal? ______________________________________________

4. When plants and animals die, how does the nitrogen from their tissues get into the soil? ______________________________________________

5. Bacteria living in the soil convert some nitrogen into a usable form for plants. This process is called _______________.