1. Principles of Ecology
7-1

2. The Study of Ecology
A look at how individual organisms interact with each other and with their environment

3. Living and Nonliving
The nonliving parts of the environment are called the abiotic factors
air currents, temperature, moisture, light, soil
often determine which species survive in a particular environment
The living organisms that inhabit an environment are called biotic factors

4. Abiotic factor to skin…

5. Levels of Organization
Ecologists have organized the living world into levels
the organism by itself (its species)
populations – group of organisms
communities – interacting populations
ecosystems – interacting populations + the abiotic factors
Biomes - group of ecosystems (same climate, etc.)
biosphere – part of Earth that can support life

7. Modern Ecological Research
Observing (->)
What species live here?
Experimenting
Test your hypothesis
Modeling
Helps make predictions on eco- data
Ex. “At this rate, the bald eagle will be extinct by the year 2020”

8. Example
Temperatures too low or too high affect the survival of the flies
What is the optimal temperature for their survival?

9. Organisms Autotrophs - (Producers)
Produce their own food from sun: Photosynthesis
water + carbon dioxide + light energy 
Sugar + Oxygen
Light energy
H2O + CO2 === C6H12O6 + O2
Plants, algae, certain bacteria

10. Autotrophs

11. Heterotrophs - Consumers
herbivores (eat only plants)
Cows, deer
carnivores (eat only meat)
Snakes, owls
omnivores (eat both plants and meat)
Humans, bears
scavengers eat dead matter
Vultures, crabs
decomposers (break down organic matter)
Earthworms, bacteria

12. Herbivore

13. Carnivore

14. Omnivore

15. Scavengers

16. Decomposers

17. Energy Flow Flows through an ecosystem in one direction
SUN  Autotrophs  Heterotrophs
Energy Flow is represented by
-Food chains
-Food webs

18. Food Chain
Nutrients and energy move from autotrophs to heterotrophs and eventually to decomposers.
Relatively rare because species can be eaten by more than one thing.

19. Food Web -Shows the complex feeding relationships between organisms
-Food webs are more realistic than food chains
-Each organism represents a feeding step, or trophic level

20. TROPHIC LEVELS
-Producer
-Primary
consumer
-Secondary
-Tertiary
-Decomposer

21. Trophic levels
Each trophic level depends on the one before it for energy.

22. Higher trophic levels are layers on top of one another
Only 10% of energy / matter is transferred between levels
Can illustrate:
Energy
Numbers
Biomass (total weight of living matter)

23. The 10% rule… AMOUNT OF ENERGY FROM ONE TROPHIC LEVEL TO THE NEXT…
PRODUCER PRIMARY SECONDARY
CONSUMER CONSUMER

24. Survival Relationships
Most species survive because of relationships with other species
Symbiosis – close, permanent relationship between organisms of different species
commensalism
mutualism
parasitism

25. commensalism

26. mutualism

27. parasitism Filarial worms (causes
Elephantitis). Spread by mosquitos passing the worm larvae into bloodstream

28. Predator / Prey Relationship
Predators seek out and eat other organisms
Prey are the animals that are eaten – the unlucky ones!

30. Organisms Habitat – place where an organism lives
shared – creates competition
Niche – strategies and adaptations used by an organism to get food, shelter, and to reproduce
advantageous to occupy a different niche than others in same habitat

31. Elephant vs. Lion
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Squirrel and Mongoose vs Cobra
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