Ecology

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Ecology

• Chapter 13

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What is Ecology?

• Ecology is the study of the interactions between
  organisms and their environment
• How are organisms related to other organisms?
• How are organisms related to their environment?
• For example, how do plants benefit animals?
• and how do animals benefit plants?

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Levels of Organization

• Pyramid Concept Map
• Directions use pg 397 in the textbook
• Label each box with one of these levels of
  organization organism, population, community,
  ecosystem, biome, and biosphere (chapter 1)
• Define each of the levels
• Give an example or draw what organisms and
  nonliving things would be included in each of the
  levels (some levels will have a wider variety of
  organisms and nonliving things than other levels)

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What level of organization?
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Ecological Methods

• 3 approaches to conducting ecological research
• Observing
• What species live here?
• How many individuals of each species are there?
• Experimenting
• Either set up the experiment in the natural
  environment or in a lab with conditions similar
  to the natural environment
• Ex. Studying how various wavelengths of light
  affect plant growth (set up in the lab although
  plants naturally grow outside)
• Modeling
• Used to study problems or questions that are too
  difficult to study or observe in nature
• For example, make a model of the effects of
  global warming
• Models help scientists make predictions

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Ecological Methods

• Identify the approach that should be used to
  answer the following questions (either observing,
  experimenting, or modeling)
• How does an oil spill affect wildlife?
• How many times a day does a snake eat?
• Is the water in a certain stream safe to drink?

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Sampling Honors Only

• Read pg 401 and answer 1 and 2
• In a forest that measures 5 miles by 5 miles, a
  sample was taken to count the number of silver
  maple trees in the forest. The number of trees
  counted in the grid is shown to the right. The
  grids where the survey was taken were chosen
  randomly. Determine how many silver maple trees
  are in this forest using the random sampling
  technique.   
• p. 420 randomly select 10 quadrats and estimate
  the population size of the bluestems. The study
  plot measures 7 meters on each side, and each
  grid segment measures 1 meter by 1 meter.

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Biotic vs. Abiotic Factors

• Which level of organization includes both living
  and nonliving things?
• Living things biotic factors
• Examples?
• Nonliving things abiotic factors
• Examples?
• Classify as biotic or abiotic insects
  pollinating a plant, fertilizer, sunlight, a
  predator (herbivore), rain, temperature, wind,
  soil
• Both biotic and abiotic factors determine which
  organisms can survive in a particular environment

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Effects of Biotic and Abiotic Factors

• Biodiversity the variety of organisms in an
  ecosystem
• The amount of biodiversity found in an area
  depends on both biotic and abiotic factors
• The moist, warm climate of the rain forest allows
  for a wide variety of organisms to live there
• Keystone species a species that has an
  unusually large effect on its ecosystem
• A change in this single factor can greatly change
  the ecosystem
• The loss of a keystone species causes a ripple
  effect felt across an entire ecosystem

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Notes Quiz

1. What is ecology?
2. List the six levels of ecological organization
   from most broad to most narrow.
3. Define ecosystem.
4. List the three approaches to ecological research.
5. Give one example of a biotic factor and one
   example of an abiotic factor (label which is
   which!)

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Energy Flow

• Do all living things need energy?
• What do organisms need energy for?
• Where does the energy come from?
• Sunlight is the main energy source for life on
  Earth
• Autotrophs (also known as producers)
• Organisms that can capture energy from sunlight
  or chemicals and use that energy to produce food
• Examples plants, some algae, and certain
  bacteria
• Heterotrophs (also known as consumers)
• Organisms that rely on other organisms for their
  energy and food supply
• Examples cows, dogs, humans, earthworms, fungi,
  and some bacteria

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Energy Flow

• Two types of autotrophs
• Photosynthetic autotrophs use solar energy to
  power the process of photosynthesis
• What is the equation for photosynthesis?
• What gas is taken from the air during
  photosynthesis?
• What gas is released into the air during
  photosynthesis?
• Ex. Plants, algae, cyanobacteria
• Chemosynthetic autotrophs use the energy in the
  chemical bonds of inorganic molecules (such as
  hydrogen sulfide) to power chemosynthesis, the
  process of using chemical energy to produce
  carbohydrates
• These autotrophs do not get their energy directly
  from the sun
• Ex. Bacteria that live in very remote places such
  as volcanic vents on the deep ocean floor or hot
  springs (typically live in harsh environments
  where there is little or no sunlight available)

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• Five types of heterotrophs
• Herbivores obtain energy by only eating plants
  (ex. cows, caterpillars, deer)
• Carnivores obtain energy by only eating animals
  (ex. snakes, dogs, owls)
• Omnivores obtain energy by eating both plants and
  animals (ex. humans, bears, crows)
• Detritivores obtain energy by feeding on detritus
  (ex. mites, earthworms, snails, and crabs)
• Detritus is plant and animal remains and other
  dead matter
• Decomposers obtain energy by breaking down
  organic matter (ex. bacteria and fungi)

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Food Chains and Food Webs

• Food chains show the one-way flow of energy in an
  ecosystem
• Energy flows through an ecosystem in one
  direction, from the sun or inorganic compounds to
  autotrophs (producers) and then to various
  heterotrophs (consumers)
• Food webs link all of the food chains in an
  ecosystem together
• Each step in a food chain or food web is called a
  trophic level
• Producers make up the first trophic level
• Consumers make up the second, third, or higher
  trophic levels
• Each consumer depends on the trophic level below
  it for energy

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Example of food chain

• Note the direction of the arrows
• What happens to the energy in a food chain?
• What was the original source of energy in the
  food chain?
• What are the limitations of a food chain?
• What is a
• Primary consumer?
• Secondary consumer?
• Tertiary consumer?
• Quaternary consumer?

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Example of food web

• How is a food web different from a food chain?
• Why are decomposers absolutely essential?
• Which organism, if removed, would impact the food
  web the most?

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Food Web

• Identify the
• Producers
• Primary consumers
• Secondary consumers
• Tertiary consumers
• Herbivores
• Carnivores
• Omnivores
• What is missing from this food web?

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Notes Quiz

1. What is the main energy source for life on earth?
2. Give one example of an autotroph and one example
   of a heterotroph. Be sure to label which is
   which.
3. What is detritus?
4. How do decomposers obtain energy?
5. What is a trophic level?

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Ecological Pyramids

• An ecological pyramid is a diagram that shows the
  relative amounts of energy or matter contained
  within each trophic level in a food chain or food
  web
• Show the decreasing amounts of energy, living
  tissue, or number of organisms at successive
  feeding levels
• Three types of ecological pyramids
• Energy Pyramid
• Biomass Pyramid
• Pyramid of Numbers

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Energy Pyramid

• Shows the amount of energy available at each
  trophic level
• Only part of the energy that is stored in one
  trophic level is passed on to the next trophic
  level
• Organisms use much of the energy that they
  consume for life processes
• Also, some of the energy is released to the
  environment as heat
• Only about 10 percent of the energy available
  within one trophic level is transferred to
  organisms at the next trophic level

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Energy Pyramid

• Try this
• Draw an energy pyramid with five trophic levels.
  If 100 percent of the energy is available at the
  first trophic level, what percentage of the total
  energy is available at the highest trophic level?

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Energy Pyramid

• Suppose that the base of an energy pyramid
  consists of plants that contain 450,000 Calories
  of food energy.
• If all the plants were eaten by mice and insects,
  how much food energy would be available to the
  mice and insects?
• If all the mice and insects were eaten by snakes,
  how much food energy would be available to the
  snakes?
• If all the snakes were eaten by a hawk, how much
  food energy would be available to the hawk?
• How much food energy would the hawk use for its
  body processes and lose as heat?
• How much food energy would be stored in the
  hawks body?

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Biomass Pyramid

• Biomass is the total amount of living tissue
  within a given trophic level
• A Biomass Pyramid shows the amount of living
  organic matter at each trophic level in an
  ecosystem
• Typically the greatest biomass is at the base of
  the pyramid.

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Pyramid of Numbers

• Shows the number of individual organisms at each
  trophic level

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Notes Quiz

1. What are the three types of ecological pyramids?

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Food Web Project

1. Construct a food web using the pictures of the
   organisms and the information about what each
   eats.
2. Tips Dont glue anything down until you have it
   all laid out! Be sure to draw the arrows in the
   correct direction!
3. Pick one food chain within the food web that has
   at least four trophic levels. Draw that chain
   separately (dont draw organisms, just write
   names) and label each of the organisms using the
   following terms autotroph, heterotroph, primary
   consumer, secondary consumer, tertiary consumer,
   quaternary consumer, producer, herbivore,
   carnivore, omnivore (Hint many of the organisms
   in the food chain will have more than one
   description or label)
4. For that particular food chain, draw an energy
   pyramid. Label the base of your energy pyramid
   as having 10,000 J. Label each subsequent
   trophic level with the appropriate amount of
   energy available.

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Matter vs. Energy

• What is matter?
• What is energy?
• Everything on earth is either matter or energy
• Constant input of energy from the sun
• Earths biosphere is a closed system. Nothing
  leaves or enters except energy from the sun,
  the ultimate source of all energy on Earth.
• No new matter is created atoms are not created,
  just simply rearranged matter is continually
  recycled
• Biological systems do not use up matter they
  transform it
• Ex. photosynthesis
• The same carbon atoms that make up your body may
  once have been part of a tree, or gases spewed by
  a volcano, or even part of a dinosaur!

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The Hydrologic (water) cycle

• The hydrologic cycle is the circular pathway of
  water on Earth from the atmosphere, to the
  surface, below ground, and back.
• 1. Water evaporates.
• 2. Water condenses to form clouds.
• 3. Water precipitates in the form of rain, sleet,
  or snow.
• 4. Water hits the ground and runs off into either
  the ocean or another body of water.
• 5. Water hits the ground and seeps into the
  groundwater.
• 6. Groundwater is taken up by the roots of
  plants.
• 7. Water evaporates from the stomata of leaves
  during transpiration (returns the water to the
  atmosphere).
• 8. Water is also returned to the atmosphere
  during cellular respiration (we breathe out
  carbon dioxide and water)

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The Hydrologic Cycle
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Nutrient (biogeochemical) Cycles

• Organisms need more than energy and water to
  survive!
• The food organisms eat contains energy, but it
  also contains important chemicals that sustain
  the organism
• What are nutrients?
• All the chemical substances that an organism
  requires to live
• Like water, nutrients are passed between
  organisms and the environment through
  biogeochemical cycles
• Nutrients are matter and matter is constantly
  recycled within the biosphere
• Two important nutrient cycles include the carbon
  cycle and the nitrogen cycle

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The Carbon Cycle
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Carbon Cycle

• 1. Carbon dioxide in the atmosphere is taken up
  by plants during photosynthesis. Plants use the
  carbon dioxide to make glucose.
• 2. Animals consume the plants and the glucose
  (carbon-containing compound) is passed on to the
  animals through the food chain.
• 3. Plants release carbon dioxide back into the
  atmosphere during cellular respiration.
• 4. Animals release carbon dioxide back into the
  atmosphere during cellular respiration.
• 5. Carbon dioxide is released into the atmosphere
  when fossil fuels are burned (combustion).
• 6. Animals and plants die and are decomposed.
  Carbon dioxide is released into the atmosphere
  during the process of decomposition.
• 7. Fossil fuels are formed when dead animal and
  plant materials are compressed for millions of
  years and turns into coal.

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The Carbon Cycle

• Aspects of the carbon cycle include
• Processes that take in CO2 from the atmosphere
• Photosynthesis plants take in carbon dioxide
  and use the carbon to build carbohydrates
• Those carbohydrates are passed along food webs to
  other organisms
• Formation of fossil fuels (coal and petroleum
  carbon) occurs when the remains of dead organisms
  are buried and the pressure of the overlying
  earth converts the remains into coal and
  petroleum
• Gasoline provides the energy needed to run a car.
  Where did this energy come from?
• Processes that release CO2 into the atmosphere
• Respiration
• Decomposition of plants and animals
• Volcanoes
• Mining, burning fossil fuels, and the cutting and
  burning of forests

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The Carbon Cycle Hon Only

• Carbon cycling that occurs within the oceans
• Photosynthesis and respiration of aquatic
  organisms
• The ocean and the atmosphere exchange CO2 CO2
  dissolves into the ocean and CO2 may also return
  to the atmosphere once dissolved in the ocean
  water
• The carbohydrates created by the photosynthetic
  aquatic organisms are passed along food webs to
  other organisms in the aquatic environment
• Calcium carbonate, a compound that contains
  carbon, accumulates in the ocean
• Marine organisms convert carbon into calcium
  carbonate, a compound that is used to build
  marine organisms bones and shells
• Calcium carbonate can also build up in ocean
  sediment (ocean rock)
• Over time, these marine organisms will decompose
  and the calcium carbonate will be broken down
  into carbon dioxide (and then the carbon cycle in
  the ocean continues!!)
• This carbon dioxide will may eventually return to
  the atmosphere via volcanic activity

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The Carbon Cycle

• What will happen if vast (large) areas of forests
  are cleared?

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The Nitrogen Cycle
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Nitrogen Cycle

• 1. Nitrogen fixation occurs when atmospheric
  nitrogen is converted to ammonia by
  nitrogen-fixing bacteria that live on the roots
  of legumes.
• 2. The process of assimilation is when ammonia,
  nitrates, or nitrites are absorbed by plants.
• 3. Nitrogen is passed from plants to animals as
  animals consume these producers (passed along the
  food chain).
• 4. Animals die and as their bodies decompose,
  decomposers break down the nitrogen-containing
  compounds that are in the decaying body into
  ammonia.
• 5. Ammonia is converted to nitrates and nitrites
  by nitrifying bacteria in a process known as
  nitrification.
• 6. In denitrification nitrates and nitrites are
  converted to atmospheric nitrogen by denitrifying
  bacteria.

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The Nitrogen Cycle

• All organisms require nitrogen to make amino
  acids (remember, amino acids are used to build
  proteins)
• Both producers and consumers use nitrogen to
  build their own proteins
• Where is nitrogen found?
• 78 percent of the atmosphere is made up of
  nitrogen gas
• Ammonia, nitrite ions, and nitrate ions are found
  in the waste produced by many organisms as well
  as in dead and decaying matter
• Urea and urine are nitrogen-based compounds that
  are generally referred to as pee
• Nitrate is a major component of plant fertilizers
  (man-made)
• Also, nitrogen gas in the atmosphere may be
  converted to nitrates and nitrites by the energy
  released in lightning

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The Nitrogen Cycle
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The Nitrogen Cycle
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Notes Quiz

1. What occurs during transpiration?
2. What is another name for the water cycle?
3. Anything that has mass and takes up space is
   _______ ______ is the ability to do work.
4. What is combustion?
5. Carbon dioxide is released into the atmosphere
   during the process of _______ and taken from the
   atmosphere during the process of __________.
6. What carbon-based compound is made during
   photosynthesis?
7. How are fossil fuels formed?
8. Organisms use nitrogen to build their own
   ________.
9. During the process of _________, bacteria convert
   ammonia to nitrates and nitrites.
10. During the process of _________, bacteria convert
    nitrates and nitrites to atmospheric nitrogen.
11. During the process of _________, bacteria convert
    atmospheric nitrogen to ammonia.
12. During the process of _________, plants absorb
    ammonia, nitrates, and/or nitrites.

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Chapter 13 Vocabulary
Food chain Herbivore Carnivore Omnivore Detritivor
e Decomposer Trophic level Food web Hydrologic
cycle Biogeochemical cycle Nitrogen
fixation Biomass Energy pyramid

• Ecology
• Community
• Ecosystem
• Biome
• Biotic
• Abiotic
• Biodiversity
• Keystone species
• Producer
• Autotroph
• Heterotroph
• Consumer
• Chemosynthesis