Educational worksheet on ecological pyramids, including questions about food chains, energy transfer, and a diagram to label trophic levels.

Here are the answers and explanations for the questions on the Ecological Pyramids Worksheet.

1. Give one example of a food chain that exists in nature.
* Answer: Grass $\rightarrow$ Mouse $\rightarrow$ Snake $\rightarrow$ Hawk
* Explanation: A food chain shows who eats whom. It always starts with a producer (like grass) that gets energy from the sun. Then a primary consumer (mouse) eats the grass, a secondary consumer (snake) eats the mouse, and a tertiary consumer (hawk) eats the snake.

2. In an ecological pyramid, what happens to energy, biomass, and # of species as you move up? Why?
* Answer: They all decrease.
* Why: Energy is lost as heat at every step. Because there is less energy available at the top, the ecosystem can support fewer animals (biomass and numbers drop). If you go up the pyramid, you have less "fuel" to keep organisms alive.

3. What is biomass?
* Answer: Biomass is the total mass (weight) of living or recently living things in a specific area. Usually, we measure it as the weight of the dry organic matter.

4. In an ecosystem, can there be more carnivores than herbivores? Explain why or why not.
* Answer: No.
* Explanation: Herbivores (plant-eaters) provide the food energy for carnivores (meat-eaters). Because energy is lost when moving up levels (the 10% rule), you need a huge amount of plants to support some herbivores, and a huge number of herbivores to support just a few carnivores. If there were more carnivores than herbivores, the carnivores would eat all the prey and then starve.

5. What is the 10% rule? What is its significance? Why is energy lost?
* The Rule: Only about 10% of the energy from one level is passed on to the next level.
* Significance: This limits how many trophic levels an ecosystem can have (usually only 4 or 5) because the energy eventually runs out.
* Why lost: Energy is used by the organism for life processes (moving, breathing, staying warm) and is released as heat. Some parts of the organism (like bones or fur) aren't eaten or digested, so that energy isn't passed on either.

6. Brainstorm to create a list of 2 human activities that interfere with ecosystems, food chains, and food webs.
* Answer:
1. Pollution: Burning fossil fuels or dumping waste changes the environment and can kill producers or consumers.
2. Deforestation/Overhunting: Cutting down trees removes homes and food sources; killing too many animals breaks the links in the food web.

7. Label the ecological pyramid.
*(Based on the diagram provided)*
* Bottom Level (Producers): Grass, Autotrophs. (These make their own food).
* Second Level (Primary Consumers): Grasshopper, Heterotrophs. (These eat producers).
* Third Level (Secondary Consumers): Chicken. (These eat primary consumers).
* Top Level (Tertiary Consumers): Hawk. (These eat secondary consumers).
* General Labels:
* Consumers: Includes Grasshopper, Chicken, and Hawk.
* Heterotrophs: Includes all animals (Grasshopper, Chicken, Hawk) because they must eat others for energy.

8. Discuss what trophic level humans can occupy... and explain what happens to contaminants... (what is this called?).
* Trophic Level: Humans are omnivores, so we can be Primary Consumers (if we eat plants), Secondary Consumers (if we eat cows/chickens), or Tertiary Consumers (if we eat fish that ate other fish).
* Contaminants: As you move up the pyramid, pollutants like mercury become more concentrated. This is because a predator eats many prey animals, accumulating all the toxins stored in their bodies.
* Name: This process is called Biomagnification.

9. Look at the food web on the first page of the article. Who does the Maned Geese depend on for survival?
* Answer: Sedge.
* *(Note: Based on the answer key provided in red text).*