This document defines key concepts in ecology, including biotic and abiotic factors, producers and consumers, food chains and webs, and ecological relationships. It explains that ecology is the study of interactions between organisms and their environment. Biotic factors are living things, abiotic are non-living. Producers use sunlight to make their own food while consumers rely on other organisms for resources and energy. Food chains show simple energy transfer, while webs account for multiple feeding interactions. Ecological pyramids illustrate biomass and numbers decreasing at each trophic level.

1. Ecology
The study of the interactions
between organisms and their
environment.

2. Biotic Factors
All of the living organisms that
inhabit an environment.

3. Abiotic Factors
All of the nonliving parts of the
environment.

4. List the biotic “things” that
inhabit this environment.
List the abiotic “things” that
inhabit this environment.

5. List the biotic “things” that
inhabit this environment.
List the abiotic “things” that
inhabit this environment.

6. List the biotic “things” that
inhabit this environment.
List the abiotic “things” that
inhabit this environment.

7. List the biotic “things” that
inhabit this environment.
List the abiotic “things” that
inhabit this environment.

8. An organism- ex. deer

9. A population- more than one deer
that live in the same place at the
same time.

10. A community- more than one
population that live in the same
place at the same time.

11. An ecosystem- a community along
with the abiotic factors that
influence the community.

12. •Biosphere – the area of the
Earth where all life exists.

13. the place where an organism lives.
Habitat

14. Niche
the role a species plays in a community-feeding
relationships, space, etc. It tells how a species
uses and affects its environment.

16. Ways Organisms Interact
• Autotrophs-organisms that use energy
from the sun or energy stored in chemical
compounds to manufacture their own
food.
• Also known as Producers- all other organisms in
the community depend on the producers. Ex.
Plants, algae

17. Ways Organisms Interact
• Heterotrophs-organisms that depend on
other organisms for their source of food
and energy.
• Also known as Consumers.

18. Herbivores- eat only producers.

19. Carnivores- kill and feed on other
animals

20. Omnivores – eat either plants or
animals

21. Scavengers-feed on dead organisms
that they did not kill

22. Scavengers-feed on dead organisms
that they did not kill

23. Decomposers - break down and absorb
the nutrients into basic molecules so that
the nutrients can be recycled back into
the ecosystem. Ex. many of the bacteria,
some protozoans, and most fungi.

24. Relationships
• Symbiosis - a
relationship where
there is a close and
permanent
relationship between
organisms of
different species.

25. Commensalism – a relationship where one
species is benefited and the other is neither
harmed nor benefited.

26. Commensalism – a relationship where one
species is benefited and the other is neither
harmed nor benefited.

27. Commensalism – a relationship where one
species is benefited and the other is neither
harmed nor benefited.

28. mutualism – a relationship where both
species benefit.

29. mutualism – a relationship where both
species benefit.

30. parasitism – a relationship where one
organism is harmed (but usually not killed)
and the other organism is benefited.

31. parasitism – a relationship where one
organism is harmed (but usually not killed)
and the other organism is benefited.

32. parasitism – a relationship where one
organism is harmed (but usually not killed)
and the other organism is benefited.

33. Competitors
* Competition – ecological interaction
between two or more species that use the
same limited resource such as food, light,
and water. No two organisms can occupy
exactly the same niche without one of the
organisms becoming extinct.

34. Predator-prey relationships
• Predator – an organism that kills and feeds on
that organism
• Prey – the organism that is killed

36. Energy Relationships

37. Food Chains
• Shows the simple relationship of what organism
consumes what organism. This relationship very
seldom exists in nature since it represents only
one way that energy can be transferred in an
ecosystem.
• 2 Rules for food chain or food web.
– 1. Always start with a producer organism.
– 2. The arrows always go in the direction of energy
flow.
• Food chains can consist of no more than two to five
links.

38. Food Chains
• *10% rule in food chains – As energy is
transferred from one trophic level to the
next, 90% of the energy is lost as heat to
the environment and only 10% is
transferred as tissue in the next trophic level
for the next trophic level to use. This is a
rough rule of thumb to show what happens
to energy in a food chain.

39. Simple food chain
Grass → Grasshopper → Shrew → Rat Snake
Organism
*10% Rule 10,000C 1,000C 100C 10C
Grass Grasshopper Shrew Rat Snake
Trophic Level 1st
2nd
3rd
4th
Also known as aProducer
Also known as anAutotroph
Producer
1st
Consumer 2nd
Consumer 3rd
Consumer
Heterotroph Heterotroph Heterotroph
Herbivore 1st
Carnivore 2nd
Carnivore
*only 10 C of the original 10,000 C in the grass is left in the food chain
for the rat snake. If food chains are any more than five links long, there is not enough
energy left for organisms at higher levels. It also explains why one sees so few top carnivores in
the environment. There are not very many hawks in the environment because they are at the top
of the food chain.

40. Food Webs
Tries to explain all of the feeding
relationships at each trophic level in a
community. A food web is more realistic
than a food chain since most organisms
feed on more than one organism.

42. Ecological Pyramids
• Shows relationships in food chains and food webs.
– The bottom - represents the producers,
– 2nd
level- the herbivores
– 3rd
level- the 1st carnivore
– 4th
level- top carnivore.
*The shape of the pyramid indicates that it is largest on the bottom
and gets smaller toward the top.
• pyramid of energy – shows energy relationships between trophic levels in
the form of calories
• pyramid of numbers – shows number relationships between numbers of
organisms at different trophic levels
• pyramid of biomass – shows the living mass at each trophic level in a food
web or food chain.

46. Biomes
Bring colors, markers, or colored
pencils tomorrow!!