 Energy Flow in Ecosystems Section One

 Energy Roles  An organisms role is determined by how it obtains energy and how it interacts with other organisms.  What are the three energy roles an organism may have:  Producer  Consumer  Decomposer

 Producers  It is important to remember that energy enters an ecosystems as sunlight  Plants use the light in photosynthesis to turn water and carbon dioxide into food molecules  An organism that can make its own food is a producer

  Producers are the source of all the food in the ecosystem.

 Consumers  An organism that obtains its food by feeding on other organisms is called a consumer  Consumers are classified by what they eat:  Herbivores-only eats plants  Carnivores- only eats animals  Omnivores –eats both plants and animals  What are some examples?

 Carnivore HerbivoreOmnivore Consumer

 Decomposers  Decomposers break down wastes and dead organisms and return the raw materials to the ecosystems.  What are some examples of decomposers?  What would happen if there were none?

 Food chain and food webs  Energy enters most ecosystems as sunlight  The energy is transferred to each organism that eats a producer.  The movement of energy through an ecosystem can be shown in diagrams called food chains and food webs

 Food Chains  A food chain is a series of events in which one organism eats another and obtains energy.  Remember that the first organism in the food chain is always going to be a producer  The second organism feeds on the producer is called 1 st level consumer ‘  The organism that feeds on the 1 st level consumer is called the 2 nd level consumer

 Food chain Producer 1 st level Consumer 2 nd level Consumer

 Food webs  A food web consists of many overlapping food chains  An organism may play more than one role in the ecosystem.  Example:  An omnivore like a mouse is a 1 st level consumer when it eats grass  When the mouse eats a grasshopper it is a second- level consumer

 Food webs  Just as food chains overlap and connect, food webs interconnect as well  All the world’s food webs interconnect in what can be thought of as a global food web.

 Food Webs

 Energy pyramids  When an organisms eats, it obtains energy.  The organism is going to use this energy to carry out its daily functions such as moving growing, and reproducing  Since the animals use energy, it means that only a portion of the energy it obtains will be available to the next organism

 Energy Pyramids  A diagram called an energy pyramid shows the amount of energy that moves from one feeding level to another  The most energy is available at the producer level of the pyramid. As you move up the pyramid, each level has less energy available than the level below.

 Energy Pyramids  In general only about 10% of the energy is passed on to the next higher level.  The organisms at higher higher levels of an energy pyramid do not require less energy than animals on the lower levels.  Since so much energy is lost, it limits the number of consumers an ecosystem can hold.

 Energy pyramids

 Photosynthesis Section Two

  Every living thing needs energy in order to survive.  Cells use energy to:  Carry out their functions  Make proteins  Transport substances in and out of the cell  Most organisms get their energy from the food that they eat. However, plants are different they lack the ability to graze or hunt so they obtain their energy in a different way. Photosynthesis

 They Make It Using……. !! Photosynthesis

 Sources of Energy  The process by which a cell captures energy in sunlight and uses it to make food is called photosynthesis  feandgenetics/photosy nthesis/preview.weml feandgenetics/photosy nthesis/preview.weml

 Sources of Energy  Nearly all living things obtain energy either directly or indirectly from the energy of sunlight captured photosynthesis

 Sources of Energy  Plants manufacture their own food through the process of photosynthesis.  An organism that makes it own food is called an autotroph

 Sources of Energy  An organism that cannot make its own food is called a heterotroph.  Heterotrophs survive by eating other organisms or absorbing them.

 AdenineRibose 3 Phosphate groups Cell Energy: Cells usable source of energy is called ATP ATP stands for adenosine triphosphate

 ADP stands for adenosine diphosphate AdenineRibose2 Phosphate groups

 All energy is stored in the bonds of compounds— breaking the bond releases the energy When the cell has energy available it can store this energy by adding a phosphate group to ADP, producing ATP

 ATP is converted into ADP by breaking the bond between the second and third phosphate groups and releasing energy for cellular processes.

  During photosynthesis plants and some other organisms use energy from the sun and to convert carbon dioxide and water into oxygen and sugars.  Occurs in two stages:  Stage One: Capturing the Sun’s Energy  Stage Two: Using Energy to Make Food The Two Stages of Photosynthesis

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 Stage One: Capturing the Sun’s Energy  The first stage of photosynthesis involves capturing the energy in sunlight.  This energy-capturing process occurs mostly in the leaves.  The chloroplast are green organelles inside plant compounds that absorb light.

  The green color comes from pigments, colored chemical compounds that absorb light.  The main photosynthetic pigment in chloroplast is chlorophyll Stage One: Capturing the Sun’s Energy

  Chlorophyll has a similar function as solar panels. They capture the sun energy, and use the energy to carry out its functions.  Chlorophyll captures light energy and uses it to power the second stage of photosynthesis.

  In the second stage, the cell uses the captured energy to produce sugars.  The cell needs two materials to make this work:  Water  Carbon dioxide  Water enters the plant through the roots and the carbon dioxide enters the plant through small openings on the underside of the leaves called stomata Stage Two: Using Energy to Make Food

  Inside the chloroplasts, the water and carbon dioxide undergo a series of complex chemical reactions.  The reactions are powered by the energy captured in the first phase.

  Stage Two produces two products:  Sugar  Oxygen  Recall that the sugar is a type of carbohydrate and the cells use energy in the sugar to carry out important cell function. Stage Two: Using Energy to Make Food

  The other product of photosynthesis is oxygen, which exits the leaf through the stomata.  Almost all oxygen in the Earth’s atmosphere was produced through the process of photosynthesis

  The events of photosynthesis can by summed up by the following equation: The Photosynthesis Equation

  How photosynthesis is used: 1.Plants use some of the sugar for food. 2.The plant breaks down the sugar molecule to release the energy they contain. 3.The energy is then used to carry out the cells functions. 4.Used in the cell wall as cellulose 5.Stored for later use The Photosynthesis Equation

  When you eat food from plant, such as potatoes or carrots, you are eating the plant’s stored energy. The Photosynthesis Equation

 Respiration Section Three

 1.Before your body can provide your body with energy, it must pass through your digestive system. 2.In your digestive system your food is broken into small molecules. 3.Molecules go from your digestive system through the bloodstream to your body cells. 4.Inside the cells, the energy in the molecules is released How Food Gets to Your Cells

  Cellular Respiration is the process by which cells obtain energy from glucose.  During cellular respiration, cells break down simple food molecules such as sugar and release the energy they contain.  Cells of all living things carry out cellular respiration continuously. What is Cellular Respiration?

  There are two types of cellular respiration:  Aerobic –requires oxygen  Anaerobic – does not require oxygen  andgenetics/cellularrespiration/preview.weml andgenetics/cellularrespiration/preview.weml Types of Cellular Respiration

  During photosynthesis, plants capture and the energy from sunlight and “save” it in the form of carbohydrates, including sugars and starches.  When cells need energy they “withdraw” it by breaking down the carbohydrates in the process of cellular respiration. Storing and Releasing Energy

  Like photosynthesis, respiration is a two-stage process.  Stage one also known as glycolosis, takes place in the cytoplasm of the organism’s cells The Two Stages of Cellular Respiration-Aerobic

  There, molecules of glucose are broken down into smaller molecules.  In this stage oxygen is not involved and only a small amount of energy is released The Two Stages of Cellular Respiration-Aerobic

  Stage Two also known as oxidization, takes place in the mitochondria.  Small food particles are broken down more  The chemical reactions require oxygen, and they release a lot of energy.  This is way they call the mitochondria the “power house” of the cell The Two Stages of Cellular Respiration-Aerobic

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  Products of respiration:  Energy is release in both glycolysis(stage 1) and oxidation (stage 2).  Carbon dioxide  Water  These products are going to be diffused through the cell membrane The Two Stages of Cellular Respiration-Aerobic

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  Although respiration occurs in a series of complex steps, the overall process can be summarized in the following equation: The Respiration Equation

  How organisms get the raw materials for respiration:  Plants undergo photosynthesis to make their own sugar  Animals get their sugar from consuming food  The oxygen used in respiration comes from the air or the water surrounding the organism The Respiration Equation

 Photosynthesis vs. Respiration Photosynthesis  Chemical formula is opposite respiration  Turn carbon dioxide and water into sugar and oxygen Respiration  Chemical formula is opposite photosynthesis  Turn sugar and oxygen into carbon dioxide and water

 Photosynthesis vs. Respiration  Photosynthesis and respiration keep the levels of oxygen and carbon dioxide fairly consistent in Earth’s atmosphere.

  Some cells are able to obtain energy from food without using oxygen ----anaerobic respiration  Organisms who do this:  Single celled organisms who live in places that contain no oxygen  Mud  Deep ocean Fermentation

  Organisms who obtain their energy through fermentation, an energy-releasing process that does not require oxygen.  The amount of energy released during fermentation, however, is much lower than the amount released during respiration. Fermentation

  Two Examples of Fermentation:  Alcoholic fermentation  Lactic acid fermentation Types of Fermentation

  One type of fermentation occurs when yeast and some other singled-celled organisms break down sugars.  This is sometimes called alcoholic fermentation because this is one product that is produced.  The products of alcoholic fermentation are carbon dioxide and a small amount of energy. Alcoholic Fermentation

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  CO2 in bread caused by yeast causes it to rise.  CO2 is the source of bubbles in beer

  Lactic Acid Fermentation occurs when your cells use up oxygen faster than it can be replaced. Because your cells lack oxygen, fermentation occurs. Lactic Acid Fermentation

  The fermentation supplied your cells with energy  One product of this type of fermentation is an acid called lactic acid.  When lactic acid builds up you feel pain in your muscles Lactic Acid Fermentation