Ecology - PowerPoint 7

							 Ecology
Chapter 13
             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?
   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)
What level of organization?
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
               Ecological Methods
•    Identify the approach that
     should be used to answer
     the following questions
     (either observing,
     experimenting, or
     modeling):
    1. How does an oil spill affect
       wildlife?
    2. How many times a day does
       a snake eat?
    3. Is the water in a certain
       stream safe to drink?
         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.
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
   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
                 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!)
                   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
                        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)
• 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)
   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
             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
             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?
Food Web
    Identify the:
    1. Producers –
    2. Primary consumers –
    3. Secondary consumers –
    4. Tertiary consumers –
    5. Herbivores –
    6. Carnivores –
    7. Omnivores –
    8. What is missing from this food
       web?
              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?
         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
             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
              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?
               Energy Pyramid
•    Suppose that the base of an energy pyramid
     consists of plants that contain 450,000 Calories
     of food energy.
    1. If all the plants were eaten by mice and insects, how
       much food energy would be available to the mice and
       insects?
    2. If all the mice and insects were eaten by snakes, how
       much food energy would be available to the snakes?
    3. If all the snakes were eaten by a hawk, how much
       food energy would be available to the hawk?
    4. How much food energy would the hawk use for its
       body processes and lose as heat?
    5. How much food energy would be stored in the hawk’s
       body?
            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.
       Pyramid of Numbers
• Shows the number of individual organisms
  at each trophic level
              Notes Quiz
1. What are the three types of ecological
   pyramids?
2.
3.
4.
5.
               Food Web Project
1.   Construct a food web using the pictures of the organisms and
     the information about what each eats.
2.   Tips: Don’t 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 (don’t 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.
                Matter vs. Energy
• What is matter?
• What is energy?
• Everything on earth is either matter or energy
• Constant input of energy from the sun
• Earth’s 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!
      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)
The Hydrologic Cycle
  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
The Carbon Cycle
                    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.
                  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
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
           The Carbon Cycle




• What will happen if vast (large) areas of forests
  are cleared?
The Nitrogen Cycle
                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.
             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
The Nitrogen Cycle
The Nitrogen Cycle
                           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.
        Chapter 13 Vocabulary
Ecology            Food chain
Community          Herbivore
Ecosystem          Carnivore
Biome              Omnivore
Biotic             Detritivore
Abiotic            Decomposer
Biodiversity       Trophic level
Keystone species   Food web
Producer           Hydrologic cycle
Autotroph          Biogeochemical cycle
Heterotroph        Nitrogen fixation
Consumer           Biomass
Chemosynthesis     Energy pyramid