1. PA Standards:
4.1.7.A – Compare and contrast biomes and their characteristics
4.1.7.B – Explain biogeochemical cycles within an ecosystem
4.1.7.C – Explain the flow of energy within an ecosystem
4.1.7.E – Explain primary and secondary succession in an ecosystem

2. 89. Chapter 2 – Ecosystems & Biomes (Sections 1 – 2)
Organisms take on different “energy roles” during the transfer of energy within an ecosystem:
1) Producer – an organism that absorbs energy from the environment to make its own food
2) Consumer – an organism that eats other organisms as its source of energy
3) Decomposer – an organism that eats dead things, recycling their matter back into the environment

3. 90. Producers They start every food chain
Many use photosynthesis to capture the energy of sunlight to make food (glucose sugar)
These include plants, algae (live in water), and some bacteria
Other producers may capture energy from sources other than the sun

4. 91. Consumers – classified by their place in the food chain:
1) Primary Consumer – the 1st animal in the chain; it eats the producer (plant) so it will be an herbivore (or omnivore)
2) Secondary Consumer – the 2nd animal in the chain; it eats the first animal, making it a carnivore (or omnivore)
3) Tertiary Consumer - 3rd animal may be added

5. 92. Decomposers End every food chain
Allow the matter found in organisms to be recycled after their death
Examples: bacteria, fungi, insects, etc.

6. Identify producers, consumers and decomposers in this online game:

7. Watch the decomposition of a rabbit carcass over 7 days (time-lapse video)

8. 93. “Food Webs” show how one food chain may overlap with others
This occurs when food sources are eaten by more than one consumer

9. Test your knowledge of food chains:
This second interactive presents a series of food chains (from easy to more difficult) to complete:
Now try a “food web”:

10. 94. Energy Pyramids:
These help us see the amount of energy that moves from one feeding level to the next in a food web
The most energy is available starting at the producer level (pyramid bottom)
Only 10% of the energy at one level can be used by the animals at the next
Repeated energy losses moving up the pyramid limit the number of consumer levels possible

11. Here is an Energy Pyramid:
Note the loss of energy as we move upward

12. 95. How to Feed More People:
A larger population of people can be fed if we remove one consumer level from the energy pyramid (the cattle) and eat more plant food ourselves

13. 96. Cycles of Matter:
Every living organism contains these 4 elements in its body: C/H/O/N
That’s carbon, hydrogen, oxygen, and nitrogen
When the organism dies, nature has a way to recycle these elements back into the environment to be used in other organisms

14. The Water Cycle recycles the H2O in the environment
The Water Cycle recycles the H2O in the environment. (Do not copy - your teacher will give you this picture on handout #97)

15. The Carbon-Oxygen Cycle recycles these elements in gas form (this diagram is also on handout #97):

16. The Nitrogen Cycle takes N2 gas from the air and changes it into nitrogen compounds in the soil that plants use (diagram on #97):