Activity 1: Energy Flow in Ecosystems
While scratching your heads, dive into your knowledge centre, your brain. Within our Temperate Rainforest biome, there are many ecosystems. There are forests, lakes, ponds, logs, and many more. Focus in one one particular ecosystem, one area. Create a list of biotic organisms that exist within that system.
Now...once you have completed that, which organism is at the top of the food chain? Who is likely to be eaten first?
Now...once you have completed that, which organism is at the top of the food chain? Who is likely to be eaten first?
Your predictions should be recorded in your individual Google document, Sustaining Earth's Ecosystems – Energy Flow in Ecosystems.
Once you have finished your brainstorming you should move on to Time to Research portion of this activity. While you are reading the notes below and watching the videos, you should be making notes in your individual Google Document, Sustaining Earth's Ecosystems – Personal Notes, if you prefer you can record your "personal notes" on paper.
Once you have finished your brainstorming you should move on to Time to Research portion of this activity. While you are reading the notes below and watching the videos, you should be making notes in your individual Google Document, Sustaining Earth's Ecosystems – Personal Notes, if you prefer you can record your "personal notes" on paper.
Time to Research (Read, Watch, and Take Notes)
How Energy Flows in Ecosystems
Biomass is the total mass of all living things in a given area.
- Biomass can also refer to the mass of a particular type of matter, such as organic materials used to produce biofuels.
- Biomass is generally measured in g/m2 or kg/m2 .
- Obtaining food from the ecosystem
- Contributing energy to the ecosystem
- Plants are called producers because they produce carbohydrates from carbon dioxide, water, and the Sun’s energy.
- Consumers get their energy by feeding on producers or other consumers.
- Decomposition is the breakdown of wastes and dead organisms by organisms called decomposers through the process of biodegradation.
Energy Flow and Energy Loss in Ecosystems
Food Chains & Food Webs
Scientists use different methods to represent energy moving through ecosystems.
Food chains show the flow of energy in an ecosystem. Each step in a food chain is a trophic level
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Terrestrial Food Chain
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Consumers
There are four classifications of consumers in the food chain.
Detrivores – consumers that obtain energy and nutrients from dead organisms and waste matter
Carnivores – secondary or tertiary consumers
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Herbivores – primary consumers
Omnivores – consumers that eat both plants and animals
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Most organisms are part of many food chains.
- Food webs represent interconnected food chains.
- Food webs are models of the feeding relationships in an ecosystem.
- Arrows in a food web represent the flow of energy and nutrients.
- Following the arrows leads to the top carnivore(s).
Aquatic Food Web
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Terrestrial Food Web
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Food Pyramids
Food pyramids show the changes in available energy from one trophic level to another in a food chain.
- Energy enters at the first trophic level (producers), where there is a large amount of biomass and therefore much energy.
- It takes large quantities of organisms in one trophic level to meet the energy needs of the next trophic level.
- Each level loses large amounts of the energy it gathers through basic processes of living.
- 80 – 90 percent of energy taken in by consumers is used in chemical reactions in the body and is lost as thermal energy.
- There is very little energy left over for growth or increase in biomass.
- Each level loses large amounts of the energy it gathers through basic processes of living.
Food pyramids are also known as ecological pyramids.
- Ecological pyramids may show biomass, population, or energy numbers.
- The amount of life an ecosystem can contain is based on the bottom level of the ecological pyramid, where producers capture energy from the Sun.
- Each level in the energy pyramid = a loss of 90 percent of total energy available.
- Lower trophic levels have much larger populations than upper levels.
- This shows the importance of maintaining large, biodiverse populations at the lowest levels of the food pyramid.
- Lower trophic levels have much larger populations than upper levels.
Videos
- Food Chains for Kids: Food Webs, the Circle of Life, and the Flow of Energy - FreeSchool - by FreeSchool
- Understanding Ecosystems for Kids: Producers, Consumers, Decomposers - FreeSchool - by Free School
- Exploring Ecosystems: Costal Food Webs | California Academy of Science - by California Academy of Science
- Bill Nye the Science Guy on the Food Web (Full Clip) - by Bill Nye
Check-In - To Be Completed Before Moving On
Let's have a check in. Take the time to answer the following questions; record your answers in Sustaining Earth's Ecosystem - Energy Flow in Ecosystems. (You should be able to answer the following questions without having to refer to your notes).
Lastly take the list you created at the beginning of this lesson and place those biotic organisms into a food chain or food web. If you are creating a food web, this may be done on a separate piece of paper and handed in separately if you wish.
- Why are plants called producers?
- What role do decomposers have in the ecosystem?
- Explain the difference between a food chain, a food web, and a food pyramid.
- What is the purpose of the food pyramid?
- Create a food chain for an ecosystem that may exists in other biomes (not our Temperate Rainforest).
- Once you have completed this food chain, share it on the Padlet Wall above. Make sure to include which biome and ecosystem it is from.
Lastly take the list you created at the beginning of this lesson and place those biotic organisms into a food chain or food web. If you are creating a food web, this may be done on a separate piece of paper and handed in separately if you wish.