Ecosystem Interactions & Energy Flow Notes

Essential Questions:

1. How do animals obtain energy to grow?

2. How are energy and matter transferred between organisms and their environment?

BACKGROUND INFORMATION:

• Energy is essential for metabolism {All of the chemical processes that build up or break down materials in an organism’s body}

• The law of conversation of energy states that energy cannot be created or destroyed. Form of energy may change, but not the amount of energy.

• Cells are living systems that have inputs and outputs of both matter and energy

• Plant and animal cells have specialized organelles that carry out specific functions within the cell

• Carbon-based molecules, such as carbohydrates and proteins, make up the basic structural and functional units of all organisms.

• Organisms interact with one another in nature and form specific relationships with other individuals of the same or different species.

LESSON - Flow of Energy & Matter in Ecosystems

1. An ecosystem is a complex web of interconnected biotic and abiotic components.

2. Changing one component may affect many others (destabilize the ecosystem)

3. Everyone in the ecosystem relies on the environment for survival

4. A food chain is a sequence that links by their feeding relationships.

5. There are different types of consumers

6. Carnivores - only eat animals

7. Omnivores - eat both plants and animals

8. Detritivores - organisms that eat detritus[a] or dead organic matter

9. Decomposers - organisms that break down organic matter into simpler compounds

10. Important to economic stability as they return vital nutrients to the environment

11. Trophic levels are the levels of nourishment in a food chain.

12. The first trophic level is occupied by producers, the second level is occupied by primary [b]consumers (usually herbivores), the third & fourth trophic levels contain secondary [c]and tertiary consumers[d], and so on…

13. Energy flows up the food chain from the bottom trophic level to the top.

14. Food chains are limited because energy is lost as heat to the environment at each trophic level[e]

15. A food web models the complex network of feeding relationships between trophic levels within an environment.

16. Represents the flow of energy within and beyond an ecosystem

17. The stability of the food web depends on the presence of producers (base of the food web)

18. Shows how different food chains within an ecosystem are related and gives a better idea of how energy and matter are transferred between organisms and trophic levels within the ecosystem

RECAP:

• Most ecosystems get their energy from sunlight and where the producers use that sunlight to make food (using photosynthesis)

• Herbivores eat the producers but burn some energy in the process (from cell processes such as cellular respiration)

• Carnivores eat herbivores, where some of the energy is converted into heat, leaving the energy unavailable for us by the carnivore.

• Higher levels in the food chain receive less overall energy than the levels below them

COMMENTS BELOW:

[a]detritus, in ecology, matter composed of leaves and other plant parts, animal remains, waste products, and other organic debris that falls onto the soil or into bodies of water from surrounding terrestrial communities.

[b]Primary consumers make up the second trophic level. They are also called herbivores. They eat primary producers—plants or algae—and nothing else. For example, a grasshopper living in the Everglades is a primary consumer.

[c]The organisms that eat the primary consumers are meat eaters (carnivores) and are called the secondary consumers. The secondary consumers tend to be larger and fewer in number.

[d]Tertiary consumers are those that eats the secondary consumers (large predators). For example, owls that eat snakes.

[e]Full EXPLAINATION - Food chains are limited in length because energy is lost as heat to the environment at each trophic level. Organisms use the remaining energy to carry out life functions such as cellular respiration and growth. In this way, less and less energy is available for the next organism in the chain. Eventually, there is not enough energy to support another trophic level.