1. The Biosphere

2. What is Ecology?
• Ecology- the study of
relationships between
organisms and their
environment.

3. Levels of Ecological
Organization
• Biosphere- the entire planet: land air, water,
atmosphere
• Biome- a group of ecosystems that have the same
climate & dominant communities.
• Ecosystem- a collection of LIVING organisms AND
the ENVIRONMENT of a particular area.
• Community- all organisms that live w/in an
ecosystem.
• Population- all members of the same species in an
area
• Species- organisms that can interbreed reproduce
fertile offspring

4. Diversity
• The measure of the number of
living things in an ecosystem.

5. What Determines
Diversity?
• 1)Size of ecosystem.
• 2) Latitude of ecosystem.
– a) more sunlight promotes
growth
– b) longer growing season=more
producers
– c) more producers = more
consumers

6. Ways to Study Ecology?
1) Observation
2)Experimenting
3)Modeling

7. Energy in Ecosystems
• Producers- take energy
from surroundings &
store it in complex
molecules.
– Photosynthetic- plants,
(some) bacteria, algae
– Chemosynthesis-
bacteria, algae
– AKA autotrophs
– *Sunlight- main source
of energy; source of
– life.

8. • Consumers- consume/eat other organism
– Animals, most protists, bacteria and
fungi
– AKA heterotrophs

9. 3 Types of Consumers
• 1) Herbivores
• 2) Carnivores
• 3) Omnivores
• 4) Detritivores-
organisms that
feed on dead
material. Mites,
earthworms, snails,
crabs, etc.

10. Food Chain

11. Who Eats Who?
• Food Chain-
– Straight line sequence depicts
simple feeding relationships and
illustrates the path of energy
transfer.

12. Food Web

13. Who Eats Who…
• Food web-
– Shows complex relationship of ecosystem
through overlapping food chains.
– Network of feeding relationships
• Keystone species-
– Most important species in a food web
– Cannot be easily replaced
– Affects every other species

14. Energy Flow in an
Ecosystem
• Energy flows through
an ecosystem from
the sun to producers,
to consumers. Each
step in the series of
organisms eating
other organisms is
called a trophic level
(eating level)

15. Trophic Levels
• Group of organisms whose energy source
is the same number of steps from the
sun.
• Autotrophs- plants & other organisms
that make their own food. (1st trophic
level)
• Herbivores- animals that eat plants (2nd
trophic level)
• Omnivores-eats both plants & animals
• Heterotrophs- cannot make own food
feed on other organisms waste (above

17. How many trophic levels are
possible?
• Few ecosystems have more than
4 or 5 trophic levels because
energy diminishes at each level.
• Energy pyramids- represent the
energy present at each level of
the food web.