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PHOTOSYNTHESIS AND CELLULAR RESPIRATION
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Energy Flow Through the Ecosystem
ENERGY FLOW THROUGH THE ECOSYSTEM
All living things need energy to power the processes of life. For example, it takes energy to grow. It also takes energy to produce offspring. In fact, it takes energy just to stay alive.
Producers for the base of all food chains (or food pyramids or food webs). Energy flows ONE WAY in the ecosystem. Diagrams of energy flow Food Chains – a series of steps in which organisms transfer energy by eating and being eaten. Energy flows through an ecosystem in a one-way stream, from primary producers to primary consumers to secondary consumers to tertiary consumers.
Food chains, food pyramids and food webs are pictorial representations of how energy moves through the ecosystem. Each level of these representations is called a "trophic level".
Food Webs = network of feeding interactions. o Food chains are found within food webs
Example of a Food Web
- At each level of a food chain (or pyramid or web), a lot of energy
- (~ 90%) is lost from the ecosystem.
- Since energy cannot be created or destroyed, the energy is not gone, but it is lost from the system, because it is no longer in a form that is biologically useful.
- Only about ten percent of the energy passes to the next level.
- Where does that energy go?
- Some energy goes into animal wastes.
- Energy also goes into growing things that another consumer can't eat, like fur.
- It's because so much energy is lost that most food chains have just a few levels. There’s not enough energy left for higher levels.
Food Pyramids - a series of steps depicted as a pyramid in which organisms transfer energy by eating and being eaten. You can see the loss of energy at each trophic step in the pyramid since the area of the trophic steps gets smaller as you get away from the producers at the bottom. Pyramid diagrams show the relative amount of energy available at each trophic level.
FOOD PYRAMID
Created by ScientistCindy
This is an food pyramid or energy pyramid. It shows the flow of energy through the ecosystem and shows how energy is lost at each trophic level. The more levels in an energy pyramid between producer and a given consumer, the smaller percentage of the original energy is available.
Producers – Make their own energy (food)
Consumers – Must consume other organisms to gain energy
Producers are autotrophic and make their own food via photosynthesis.
The consumers that eat producers are called primary consumers.
Primary consumers are vegetarians (herbivores) or omnivores.
The consumers that eat primary consumers are secondary consumers.
Secondary, tertiary and quaternary consumers are meat-eaters (carnivores) or omnivores.
The consumers that eat secondary consumers are tertiary consumers.
...Remember that energy can’t be created or destroyed. It can only change form. So, let's follow the energy through the food chain and see what happens to it!
Energy decreases as it moves up trophic levels because energy is lost as metabolic heat (and as energy the consumer needs to live, breath, grow and carry out all its biological functions) when the organisms from one trophic level are consumed by organisms from the next level. (90 % of the energy is lost at each trophic level). Trophic Level = each step in a food chain or food pyramid or food web.
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Energy From the Sun
Photosynthesis uses light energy to convert carbon dioxide and water into oxygen and sugar (glucose). Photosynthesis takes CO2 from the air and adds O2 to the air.
- Ecosystems get their energy from the Sun.
- Most use energy in the ecosystem comes from the sun (a little comes from chemotrophs).
- Only producers can use sunlight to make usable energy.
- Producers convert the sunlight into glucose.
- For example: Plants create chemical energy from abiotic factors that include solar energy.
- The food energy created by producers is passed through the food chain.
- In this way, energy flows from one living thing to another.
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Chemosynthesis - Energy from inorganic molecules In the process called chemosynthesis, bacteria harness chemical energy from inorganic molecules (such as hydrogen sulfide) to produce carbohydrates. Chemosynthesizers often live in extreme environments = deep ocean vents, hot springs, etc. |
[ REACTANTS ] [ PRODUCTS ]
Light energy comes in packets called PHOTONS.
Photosynthesis when photons are absorbed by the photosensitive pigment, chlorophyll.
CHLOROPHYLL exists inside of specialized structures called CHLOROPLASTS which are in the leaves of plants.
Chlorophyll reflects green light and gives plants their green color.
Photosynthesis when photons are absorbed by the photosensitive pigment, chlorophyll.
CHLOROPHYLL exists inside of specialized structures called CHLOROPLASTS which are in the leaves of plants.
Chlorophyll reflects green light and gives plants their green color.
Chloroplasts most likely evolved as a result of a larger prokaryotic cell engulfing a photosynthesizing bacteria. This is the endosymbiotic theory. Some of the evidence that supports this theory is...
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Vocabulary
VOCABULARY
- Autotroph: (auto = by itself; trophikos = to feed) – a self feeder. Does not need to eat other organisms for food.
- Carnivore: kills and eats other animals (vore=eater; carne = meat) meat-eaters
- Omnivore (omni = all; vore = eater) = eats both plants and animals
- Herbivore (Herb= plant vore = eater) = eats only plants
- Chemosynthesis: when an organism can harness chemical energy from inorganic molecules (such as hydrogen sulfide) to produce glucose
- Consumer: Organisms that rely on other organisms for energy and nutrients.
- Food chain: a series of steps in which organisms transfer energy by eating and being eaten.
- Food web: a network of feeding interactions. Food web: The complex eating relationships among species within an ecosystem. In a diagram of a food web organisms are connected to the organisms they consume by arrows representing the direction of energy transfer.
- Heterotroph: consumers - must acquire energy from other organisms, typically by ingesting them.
- Photosynthesis: uses light energy to convert carbon dioxide and water into oxygen and energy-rich carbohydrates
- Primary producer: (autotrophs) – are the first producers of energy-rich compounds that are later used by other organisms.
- Scavenger: consume the carcasses of other animals that are already dead.
- Secondary Consumer: An organism that eats primary producers. (example: A grasshopper eats a leaf.)
- Trophic level: Each step in a food chain or a food web
- Glucose – a simple carbohydrate with the chemical formula C6H12O6 that is the nearly universal food for life
- Heterotroph/ Consumer - organism that consumes other organisms for food
- Photosynthesis process of using the energy in sunlight to make food (glucose)
CELLULAR RESPIRATION
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- - ATP is an energy-carrying molecule that cells use to power their metabolic processes
- Producer organism that makes its own food
- - Cellular Respiration - process in which cells break down glucose and make ATP for energy
Cellular respiration has 3 parts.
1) Glycolysis
2) The Kreb's Cycle / The Citric Acid Cycle
3) The Electron Transport Chain / Oxidative Phosphorylation
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1) Glycolysis
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2) The Kreb's Cycle / The Citric Acid Cycle
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Plants undergo both photosynthesis and cellular respiration
Plants take in CO2 during photosynthesis and make glucose. The glucose is then used by the plants or organisms that consume the plants for the process of cellular respiration to make ATP. Photosynthesis releases oxygen into the atmosphere Cellular respiration produces carbon dioxide ( CO2 ) which is released back into the atmosphere.
Notice that the reactants of cellular respiration are the products of the photosynthesis and the reactants of photosynthesis are the products of the cellular respiration. Cellular respiration is basically photosynthesis in reverse.
The main point of cellular respiration is to create ATP which is used as a source of energy within the cell.
