Energy Flow Through an Ecosystem

Transcription

1 Energy Flow Through an Ecosystem Photosynthesis Cellular Respiration Food Chains Food Webs What is the process that uses the sun s energy to make simple sugars? Plants in Action Begins with the SUN Photosynthesis Chemical Reaction 6CO 2 + 6H 2 O + sunlight & chlorophyll à C 6 H 12 O 6 + 6O 2 Reactants à Products 1 A chemical reaction where green plants use water & carbon dioxide to store the sun s energy in the form of glucose. Why is photosynthesis important? Makes organic molecules (glucose) out of inorganic materials (carbon dioxide and water). It begins all food chains/webs. Thus all life is supported by this process. It also makes oxygen gas! Photosynthesis A start to ecological food webs! 1

2 Photo-synthesis means "putting together with light" Plants use sunlight to turn water and carbon dioxide into glucose. Glucose is a kind of sugar. Plants use glucose as food for energy and as a building block for growing. Autotrophs make glucose and heterotrophs are consumers of it. How do we know that plants make carbohydrates from just carbon dioxide water and light energy? Experiments! For example Jan Baptisa van Helmont (1648) planted a willow branch weighing 5 pounds into 200 pounds of soil and then after 4 years the tree weighed 169 lbs. and the soil was still nearly 200 lbs. Plant Video Clip Where does photosynthesis occur? 9 This is an elodea leaf x400. Individual cells are clearly visible. The tiny green structures within the cells are chloroplasts. This is where photosynthesis happens. Leaves are green because they contain the pigment: chlorophyll Leaves have a large surface area to absorb as much light as possible Plants Chloroplasts make the oxygen too! 2

3 Why are plants green? Reflected light Transmitted light Why do we see green? Green color from white light reflected NOT absorbed Chlorophyll is located in chloroplast EQUATION FOR PHOTOSYNTHESIS ENERGY 6CO 2 + 6H 2 O + C 6 H 12 O 6 + 6O 2 CARBON DIOXIDE WATER GLUCOSE OXYGEN In plants and simple animals, waste products are removed by diffusion. Plants, for example, excrete O 2, a product of photosynthesis. PHOTOSYNTHESIS What affects photosynthesis? Light intensity: as light increases, rate of photosynthesis increases PHOTOSYNTHESIS What affects photosynthesis? Carbon Dioxide: As CO 2 increases, rate of photosynthesis increases 3

4 PHOTOSYNTHESIS What affects photosynthesis? Temperature: Temperature Low = Rate of photosynthesis low Temperature Increases = Rate of photosynthesis increases If temperature too hot, rate drops Check it! The process that uses the sun s energy to make simple sugars is. A.Cellular respiration B.Glycolysis C.Photosynthesis D.Photolysis Cellular Respiration Cellular Respiration Overview 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 Cells require a constant source of energy for life processes but keep only a small amount of ATP on hand. Cells can regenerate ATP as needed by using the energy stored in foods like glucose. Cellular Respira7on Cellular respira>on is the process by which the energy of glucose is released in the cell to be used for life processes (movement, breathing, blood circula7on, etc ) 4

5 Respira>on occurs in ALL cells and can take place either with or without oxygen present. Aerobic Respira7on: requires oxygen Occurs in the mitochondria of the cell ATP is produced. General formula for aerobic respira>on: C 6 H 12 O 6 + 6O 2 à 6 CO 2 + 6H 2O + 36 ATP Glucose + oxygen à carbon + water + energy dixoide Anaerobic Respira7on: occurs when no oxygen is available to the cell (2 kinds: Alcoholic and Lac>c Acid) Also called fermenta7on Much less ATP produced than in aerobic respira>on Alcoholic fermenta>on occurs in bacteria and yeast Process used in the baking and brewing industry yeast produces CO 2 gas during fermenta>on to make dough rise and give bread its holes glucose à ethyl alcohol + carbon dioxide + 2 ATP Glucose à lac>c acid + carbon dioxide + 2 ATP Lac7c acid fermenta>on occurs in muscle cells Lac>c acid is produced in the muscles during rapid exercise when the body cannot supply enough oxygen to the 7ssues causes burning sensa7on in muscles 5

6 Review Energy: Energy for living things comes from food. Originally, the energy in food comes from the sun. Organisms that use light energy from the sun to produce food autotrophs or producers Examples: plants and some microorganisms Organisms that CANNOT use the sun s energy to make food heterotrophs Ex: animals and most microorganisms Review Diagram Food Chains & Food Webs Organisms that can make glucose during photosynthesis are called PRODUCERS. Producers use most of the energy they make for themselves. Producers use cellular respiration to supply the energy they need to live. 6

7 CELLULAR RESPIRATION is the chemical reaction that releases the energy in glucose. Chemical Reaction 6O 2 + C 6 H 12 O 6 à 6H 2 O + 6CO 2 + energy Reactants à Products The energy that is not used by producers can be passed on to organisms that cannot make their own energy. Organisms that cannot make their own energy are called CONSUMERS. Consumers that eat producers to get energy: Are first order (1 st ) or primary consumers Are herbivores (plant-eaters) Most of the energy the primary consumer gets from the producer is used by the consumer. Some energy in the primary consumer is STORED & not lost to the atmosphere or used by the consumer itself. This energy is available for another consumer (predator). 7

8 A Consumer that Eats Another Consumer for Energy: Is called a secondary consumer. May be a carnivore or a omnivore. May be a predator. May be a scavenger Most of the energy the secondary consumer gets from the primary consumer is used by the secondary consumer. Some of the energy is lost as heat, but some energy is stored and can passed on to another consumer. A consumer that eats a consumer that already ate a consumer: Is called a tertiary consumer May be a carnivore or an omnivore May be a predator May be a scavenger Consumers that eat producers & other consumers Are called omnivores Omnivores eat plants and animals Consumers that hunt & kill other consumers are called predators. The animals that are hunted & killed are called prey. 8

9 Consumers that eat other dead consumers are called scavengers The transfer of energy from the sun to producer to primary consumer then to higher order consumers can be shown in a FOOD CHAIN. Food Chains Show Available Energy More Food Chains Food Webs: Are interconnected food chains They show the feeding relationships in an ecosystem How Many Chains are in this web? 54 9

10 Identify the Producers, Consumers, & Decomposers: Count the Food Chains! 10