Biology Standard SB4 (b)

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Biology Standard SB4 (b) Powered By Docstoc
					The flow of matter and energy through ecosystems
The flow of energy
 In a food chain, energy is passed from one link to another. When a
  herbivore eats, only a fraction of the energy (that it gets from the plant
  food) becomes new body mass; the rest of the energy is lost as waste or
  used up by the herbivore to carry out its life processes (e.g., movement,
  digestion, reproduction). Therefore, when the herbivore is eaten by a
  carnivore, it passes only a small amount of total energy (that it has
  received) to the carnivore. Of the energy transferred from the herbivore
  to the carnivore, some energy will be "wasted" or "used up" by the
  carnivore. The carnivore then has to eat many herbivores to get enough
  energy to grow.
  Because of the large amount of energy that is lost at each link, the
  amount of energy that is transferred gets lesser and lesser ...
  The further along the food chain you go, the less food (and hence
  energy) remains available.
 The energy pyramid
                                  Carnivores are the fewest in
       Carnivores are contained   numbers in a healthy
       on the top level.          ecosystem. The carnivore has
                                  to eat a lot to get enough
                                  energy to live.
                                               The primary consumers are
Your primary consumers                         herbivores they eat the plant
are in level two.                              life. A percentage of the
                                               energy is used by the
                                               herbivores the rest becomes
                                               waste.
Level one houses
the producers.                                            In a healthy
Producers get                                             ecosystem this is
their energy from                                         the largest
the sun.                                                  group.
Photosynthesis
Photosynthesis - The cycle of
plants and how they make
energy! The sun(light energy),
water, minerals and carbon
dioxide are all absorbed by the
plant. The plant then uses
them to make glucose/sugar,
which is the energy/food for
the plant. Oxygen is also
produced by the plant in this
cycle, which is then let off into
the air! Have you noticed how
clean and pure the air feels
when there are plants around?
They are filling the air with
oxygen!
The Water Cycle
 The Water Cycle (also known as the hydrologic cycle) is the journey
  water takes as it circulates from the land to the sky and back again.
  The Sun's heat provides energy to evaporate water from the Earth's
  surface (oceans, lakes, etc.). Plants also lose water to the air (this is
  called transpiration). The water vapor eventually condenses, forming
  tiny droplets in clouds. When the clouds meet cool air over land,
  precipitation (rain, sleet, or snow) is triggered, and water returns to the
  land (or sea). Some of the precipitation soaks into the ground. Some of
  the underground water is trapped between rock or clay layers; this is
  called groundwater. But most of the water flows downhill as runoff
  (above ground or underground), eventually returning to the seas as
  slightly salty water.
This is how the water cycle works
The Nitrogen Cycle
  Nitrogen is a component of many organic molecules. It forms an essential
  part of amino acids (which make up proteins) and DNA. Nitrogen is essential
  for all living cells.
 What is the nitrogen cycle?
     Nitrogen is the major component of earth's atmosphere. It enters the food
  chain by means of nitrogen-fixing bacteria and algae in the soil. This nitrogen
  which has been 'fixed' is now available for plants to absorb. These types of
  bacteria form a symbiotic relationship with legumes--these types of plants are
  very useful because the nitrogen fixation enriches the soil and acts as a 'natural'
  fertilizer. The nitrogen-fixing bacteria form nitrates out of the atmospheric
  nitrogen which can be taken up and dissolved in soil water by the roots of
  plants. Then, the nitrates are incorporated by the plants to form proteins,
  which can then be spread through the food chain. When organisms excrete
  wastes, nitrogen is released into the environment. Also, whenever an organism
  dies, decomposers break down the corpse into nitrogen in the form of
  ammonia. This nitrogen can then be used again by nitrifying bacteria to fix
  nitrogen for the plants.
The Nitrogen cycle in the soil
The Carbon Cycle
 Carbon moves from the atmosphere to plants.
  In the atmosphere, carbon is attached to oxygen in a gas called carbon dioxide
  (CO2). With the help of the Sun, through the process of photosynthesis, carbon
  dioxide is pulled from the air to make plant food from carbon.
 Carbon moves from plants to animals.
  Through food chains, the carbon that is in plants moves to the animals that eat
  them. Animals that eat other animals get the carbon from their food too.
 Carbon moves from plants and animals to the ground.
  When plants and animals die, their bodies, wood and leaves decay bringing the
  carbon into the ground. Some becomes buried miles underground and will
  become fossil fuels in millions and millions of years.
 Carbon moves from living things to the atmosphere.
  Each time you exhale, you are releasing carbon dioxide gas (CO2) into the
  atmosphere. Animals and plants get rid of carbon dioxide gas through a process
  called respiration
The carbon cycle
Phosphates in the web of things
 Phosphate is mainly present in bones in animals, but is
 incorporated in most tissues of plants and animals -
 and through digestion gets absorbed and incorporated
 in a person's body and is dynamically present, being
 released and excreted through urine and feces. Thus
 excreted phosphate returns to the environment where
 it is available for uptake into plants and into the food
 web.
Phosphates are everywhere
The process as a whole
 The plants produce energy from the sun. The energy from the sun is partly
 stored within the plant, which is eaten by the herbivores. Some of the
 energy taken from the plants is stored and the rest is waste which falls back
 to the soil and becomes nutrients that feeds the soil. The carnivores and
 omnivores then eat and some of that energy is used and the rest is waste.
 The decomposers turn the waste into a fuel source that keeps a healthy
 ecosystem.

				
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Lingjuan Ma Lingjuan Ma
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