1. Matter and Energy in the Ecosystem
Roles of Living Things
Ecosystem Structure
Energy in the Ecosystem
Cycles of Matter

2. Roles of Living Things Movement within an ecosystem includes:
The flow of energy
The cycling of matter
Recap: 1 necessity of all living things is ENERGY

3. Roles of Living Things
Organisms in most ecosystems obtain energy in 3 basic ways, as:
Producers – plants, protists, bacteria
Consumers – all animals, fungi, protists, bacteria
Decomposers – bacteria and fungi

4. Producers (Autotrophs)
Organisms that make their own food from inorganic molecules and energy.
Almost all producers capture energy from the sun and use it to make food through photosynthesis.
Nearly all the energy entering the biosphere comes from the sun through photosynthesis.
Plants – terrestrial ecosystems
Photosynthetic protists and bacteria – aquatic ecosystems

5. Consumers (Heterotrophs)
Organisms that cannot make their own food and obtain energy by eating other organisms.
4 Basic Types of Consumers:
Herbivores (primary consumers) – eat only plants
Carnivores – eat herbivores (secondary consumer), or eat other carnivores (tertiary consumer)
Omnivores – eat both consumers and producers (can be primary, secondary, or tertiary).
Scavengers – feed on bodies of dead organisms (can be primary, secondary, or tertiary).

6. Can you think of some examples for each type of consumer at each trophic level?
4 Basic Types of Consumers:
Herbivores (primary consumers) – eat only plants
Carnivores – eat herbivores (secondary consumer), or eat other carnivores (tertiary consumer)
Omnivores – eat both consumers and producers (can be primary, secondary, or tertiary).
Scavengers – feed on bodies of dead organisms (can be primary, secondary, or tertiary).

7. Decomposers
Consume the bodies of dead organisms and other organic wastes.
From fallen leaves of a tree to the bodies of herbivores and carnivores and even animal waste.
They complete the cycle of matter in an ecosystem, recycling the nutrients from organism back into the environment.

8. Trophic Levels
Different levels or layers in the structure of feeding relationships in an ecosystem.
Omnivores, scavengers, and decomposers feed at ALL trophic levels above the first.
Most ecosystems have three, four, or five trophic levels.
Each level depends on the one below it.

11. Food Chains and Food Webs
– a series of different organisms that transfer food between the trophic levels of an ecosystem.
– a network of food chains representing the feeding relationships among the organisms in an ecosystem

12. Diversity and Stability
Figure 4.6 in your textbook, page 58, shows what happens to an ecosystem when a consumer (Baleen whales) is removed.
Figure 4.7, page 59, compares different sized ecosystems, one with fewer species and one with more species.
- Which food web represents a more stable ecosystem?

13. Biological Magnification
The increasing concentration of a pollutant in organisms at high trophic levels in a food web.
Example – mercury, DDT pesticide
This shows how pollutants taken in by a few organisms affects the whole food web.

14. Energy in the Ecosystem
Ecological pyramid – a diagram that shows the relative amounts of energy in different trophic levels in an ecosystem.
Biomass – the total amount of organic matter present in a trophic level. (potential food for the next trophic level)
- Only part of the energy from one trophic level gets passed to the next. (See TB pg 61, Figure 4.8)