1. Chapter 3 – The Biosphere

2. 3.1 Ecologists study environments at different levels of organization.
Ecology is the study of the interactions among living things, and between living things and their surroundings.

3. Ecosystem
Community
Population
Organism

4. Biotic and Abiotic Factors
Biotic factors are any living part of an environment.
plants
animals
fungi
bacteria

5. Abiotic factors are any nonliving part of the environment.
Sunlight
Temperature
Precipitation
Humidity
Wind

6. Biotic and Abiotic Factors Together
Physical factors can be strongly influenced by the activities of organisms.
Also, a change in physical factors can strongly affect the survival of the living organisms.

7. 3.2 Energy in Ecosystems
Living organisms need energy for growth, reproduction, and their metabolic processes.
Producers provide all of the available energy in an ecosystem
Primary Productivity
Producers are also called autotrophs because they make their own food.
Most producers uses sunlight as an energy source.

9. Heterotrophs acquire energy from other organisms.
Also called consumers

10. Consumers are not all alike.
Herbivores eat plants.
Carnivores eat other animals.
Omnivores eat both plants and animals.
Detritivores eat dead organic matter (detritus).
Decomposers break down organic matter into simpler compounds.
decomposer
carnivore

11. 3.3 Energy Flow in Ecosystems
A food chain links species by their feeding relationships.
A food chain follows the connection between one producer and a single chain of consumers within an ecosystem.
The ultimate source of energy for all producers and consumers is the sun.

12. Trophic Levels First Level – Producers
Determine the available energy in the ecosystem
Second Level – First Level Consumers
AKA – primary consumers
Herbivores
Third Level – Second Level Consumers
AKA – secondary consumers
Omnivores and carnivores

13. Fourth Level
Third level consumers (carnivores that eat other carnivores)
AKA - top carnivores or tertiary consumers
Decomposers – obtain energy from dead and decaying matter at all trophic levels.
produce detritus
Ex: bacteria and fungi
decomposer

14. Energy Flow
An energy pyramid shows the distribution of energy among trophic levels.
Only 10 percent of the energy at each tier is transferred from one trophic level to the next.
90 percent of the energy is lost into the atmosphere as heat.
energy transferred
energy
lost
0.1% 1%
10%
100%

15. Food Webs A food web shows a complex network of feeding relationships.
An organism may have multiple feeding relationships in an ecosystem.
A food web emphasizes complicated feeding relationships and energy flow in an ecosystem.

17. Pyramid of Biomass
tertiary
consumers
secondary
primary
producers
75 g/m2
150g/m2
675g/m2
2000g/m2
Biomass is usually measured in grams of organic matter per unit area.
Why does the amount of biomass decrease moving up the trophic levels?

18. 3.4 Cycles of Matter
Elements essential for life cycle through ecosystems.
A biogeochemical cycle is the movement of a particular chemical through the living and non- living parts of an ecosystem.
Matter is recycled within and between ecosystems.
Biogeochemical Cycles

19. Water Cycle

20. Carbon Cycle

21. Nitrogen Cycle