1. Chapter 3
The Biosphere

2. 3-1 What is Ecology?
Ecology – study of the interactions between organisms and their environment

3. Levels of Organization (smallest to largest)
Species (Individual)
Population
Communities
Ecosystem
Biome
Biosphere (entire planet)

4. Levels of Organization
Biosphere
Biome
Ecosystem
Community
The study of ecology ranges from the study of an individual organism to populations, communities, ecosystems, biomes—and, finally, to the entire biosphere. The information that ecologists gain at each level contributes to our understanding of natural systems.
Population
Individual

5. Ecological Methods
Scientists conduct research for ecology in three ways:
Observing
Experimenting
Modeling

6. 3-2 Energy Flow
Energy flow is extremely important in determining a system’s capacity to sustain life.

7. Producers Sunlight is the main source of energy for living things.
Some organisms can also use inorganic chemical compounds for energy.
Autotrophs/Producers – organisms that use energy from the sun or chemicals to produce its own food. (PLANTS)

8. Photosynthesis – autotrophs that use solar energy to make carbohydrates.
Chemosynthesis – autotrophs that use chemical energy to make carbohydrates.

9. Consumers
Heterotrophs/Consumers – organisms that get their energy from the foods they eat.
Herbivores – eat plants
Carnivores – eat animals
Omnivores – eat plants and animals
Detritivores – feed on dead matter
Decomposers – break down organic matter

10. CARNIVORES
HERBIVORES
DECOMPOSERS
OMNIVORES
DETRITIVORES

11. Feeding Relationships
Energy flows through an ecosystem from the sun or chemical compounds, to autotrophs, and then to heterotrophs.

12. Trophic Levels – each step in a food chain or food web.
Food Chain – a series of steps in an ecosystem where organisms transfer energy by eating and being eaten (see figure 3-7)
Food Web – complex interactions of feeding relationships among various organisms in an ecosystem.
Trophic Levels – each step in a food chain or food web.
Producers = 1st level
Consumers = 2nd, 3rd, or higher levels

13. Feeding Relationships
In some marine food chains, the producers are microscopic algae and the top carnivore is four steps removed from the producer.
Small Fish
Zooplankton
Squid
Food chains show the one-way flow of energy in an ecosystem. In this marine food chain, energy is passed from the producers (algae) to four different groups of consumers.
Shark
Algae

15. Ecological Pyramids
A diagram that shows the relative amounts of energy or matter at each trophic level.
3 Pyramids
Energy
Biomass
Pyramid of numbers

16. Energy Pyramid – shows the amount of energy passed from one level to the next.
Only about 10% of the energy in one level is available to organisms in the next level.
0.1% Third-level consumers
1% Second-level consumers
10% First-level consumers
Ecological pyramids show the decreasing amounts of energy, living tissue, or number of organisms at successive feeding levels. The pyramid is divided into sections that represent each trophic level. Because each trophic level harvests only about one tenth of the energy from the level below, it can support only about one tenth the amount of living tissue.
100% Producers

17. Biomass – total amount of living tissue within a trophic level.
Biomass Pyramid – shows the amount of food available for each trophic level.
Biomass – total amount of living tissue within a trophic level.
50 grams of human tissue
500 grams of chicken
5000 grams of grain
Ecological pyramids show the decreasing amounts of energy, living tissue, or number of organisms at successive feeding levels. The pyramid is divided into sections that represent each trophic level. Because each trophic level harvests only about one tenth of the energy from the level below, it can support only about one tenth the amount of living tissue.

18. Pyramid of Numbers – the number of organisms at each trophic level.
Ecological pyramids show the decreasing amounts of energy, living tissue, or number of organisms at successive feeding levels. The pyramid is divided into sections that represent each trophic level. Because each trophic level harvests only about one tenth of the energy from the level below, it can support only about one tenth the amount of living tissue.