Basic descriptions of food chains and food webs. Energy flow in ecological communities is emphasized (I hope)

1. Food chains
Moving matter and energy through a community

2. Food chains start with producers
Producers absorb
energy from the
environment (sun)
and convert it to
chemical energy
Leaf - cc licensed flickr photo by epSos.de: http://flickr.com/photos/epsos/3384297473/

3. Producers are eaten by herbivores
Herbivores are also
known as primary
consumers.
Consumers eat
other organisms to
get energy.
Saddleback caterpillar - cc licensed flickr photo by cotinis: http://flickr.com/photos/pcoin/2282362342/

4. Herbivores are eaten by carnivores
Carnivores get
energy by eating
other animals.
Consumers that eat
herbivores are
secondary consumers
Orange eyed green tree frog - cc licensed flickr photo by rainforest_harley: http://flickr.com/photos/rainforest_harley/232636845/

5. Carnivores can be eaten by other carnivores
Carnivores that eat other
carnivores are called
higher order carnivores.
A tertiary consumer eats
secondary consumers.
Common garter snake 1 - cc licensed flickr photo by C.A. Mullhaupt: http://flickr.com/photos/mullhaupt/2268466823/

6. 4th degree consumers
4th degree consumers eat
tertiary consumers.
Great horned owl - cc licensed flickr photo by .imelda: http://flickr.com/photos/imelda/1315548794/

7. Trophic level

8. Trophic level
Organisms can be classified by food source (herbivore,
carnivore, omnivore.

9. Trophic level
Producers
Organisms can be classified by food source (herbivore,
carnivore, omnivore.

10. Trophic level
Producers Primary consumers
(herbivores)
Organisms can be classified by food source (herbivore,
carnivore, omnivore.

11. Trophic level
Producers Primary consumers Secondary consumers
(herbivores) (carnivores)
Organisms can be classified by food source (herbivore,
carnivore, omnivore.

12. Trophic level
Producers Primary consumers Secondary consumers Tertiary consumers
(herbivores) (carnivores) (carnivores)
Organisms can be classified by food source (herbivore,
carnivore, omnivore.

13. Trophic level
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
Organisms can be classified by food source (herbivore,
carnivore, omnivore.

14. Trophic level
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
Organisms can be classified by food source (herbivore,
carnivore, omnivore.
Organisms can also be classified by trophic level
(position within a food chain):

15. Trophic level
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
Organisms can be classified by food source (herbivore,
carnivore, omnivore.
Organisms can also be classified by trophic level
(position within a food chain):
Producers are trophic level 1

16. Trophic level
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
Organisms can be classified by food source (herbivore,
carnivore, omnivore.
Organisms can also be classified by trophic level
(position within a food chain):
Producers are trophic level 1
Herbivores are trophic level 2

17. Trophic level
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
Organisms can be classified by food source (herbivore,
carnivore, omnivore.
Organisms can also be classified by trophic level
(position within a food chain):
Producers are trophic level 1
Herbivores are trophic level 2
Secondary consumers are trophic level 3

18. Trophic level
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
Organisms can be classified by food source (herbivore,
carnivore, omnivore.
Organisms can also be classified by trophic level
(position within a food chain):
Producers are trophic level 1
Herbivores are trophic level 2
Secondary consumers are trophic level 3
etc.

19. Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)

20. Something’s missing
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)

21. Something’s missing
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
Cellulose decomposers slide 1 - cc licensed flickr photo by INeedCoffee / CoffeeHero: http://flickr.com/photos/digitalcolony/3317136736/

22. Something’s missing
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
Cellulose decomposers slide 1 - cc licensed flickr photo by INeedCoffee / CoffeeHero: http://flickr.com/photos/digitalcolony/3317136736/
Decomposers break down the bodies of producers and
consumers. This is necessary for the recycling of matter in
an ecosystem.

23. Energy flows through a food chain
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)

24. Energy flows through a food chain
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
The 10% rule:
At each step in the food chain, about 10%
gets passed along to the next step.

25. Energy flows through a food chain
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
The 10% rule:
At each step in the food chain, about 10%
gets passed along to the next step.

26. Energy flows through a food chain
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
The 10% rule:
At each step in the food chain, about 10%
gets passed along to the next step.

27. Energy flows through a food chain
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
The 10% rule:
At each step in the food chain, about 10%
gets passed along to the next step.

28. Energy flows through a food chain
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
The 10% rule:
At each step in the food chain, about 10%
gets passed along to the next step.

29. Where does the other 90% of the energy go?
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)

30. Where does the other 90% of the energy go?
Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
Used by organism
Lost to environment as heat.
Passed along to decomposers.

31. Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)

32. Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
Food Chain Big ideas

33. Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
Food Chain Big ideas
All energy in a food chain is absorbed by producers

34. Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
Food Chain Big ideas
All energy in a food chain is absorbed by producers
Matter is recycled by decomposers

35. Producers Primary consumers Secondary consumers Tertiary consumers 4th degree consumers
(herbivores) (carnivores) (carnivores) (carnivores)
Food Chain Big ideas
All energy in a food chain is absorbed by producers
Matter is recycled by decomposers
Energy flows through a food chain; 10% is passed
along at each step

36. Food Webs
Mapping out predator-prey relationships

37. Food chains represent flow of energy in a
community but over-simplify the predator-prey
relationships. Most organisms have multiple prey
species and multiple predators (they eat many
different things and get eaten by many different
things).

38. A food web shows multiple food chains within
a community.
cc licensed flickr photo by cicadas: http://flickr.com/photos/cicada/2569385115/

39. Some (parts of) food webs consist of food chains that
begin with plants. These are called grazing webs
cc licensed flickr photo by cicadas: http://flickr.com/photos/cicada/2569385115/

40. Some (parts of) food webs consist of food chains that
begin with plants. These are called grazing webs
cc licensed flickr photo by cicadas: http://flickr.com/photos/cicada/2569385115/

41. Some (parts of) food webs consist of food chains that
begin with dead organic matter. These are called detrital
webs
cc licensed flickr photo by cicadas: http://flickr.com/photos/cicada/2569385115/

42. Some (parts of) food webs consist of food chains that
begin with dead organic matter. These are called detrital
webs
cc licensed flickr photo by cicadas: http://flickr.com/photos/cicada/2569385115/

43. There is often overlap between the grazing and detrital food webs.
Which populations here are part of both webs? Which are only in the
grazing web? Which are only in the detrital web?
cc licensed flickr photo by cicadas: http://flickr.com/photos/cicada/2569385115/

44. Food Web stability
In some food webs, the populations in the
web can survive if one species is removed.
Other populations can fill in as prey or
predator species. A food web with more
populations in it and/or more links
between populations is less likely to
collapse due to the removal of one species.
(A community collapses when all/most of
the populations in the community suffer
sudden, dramatic population decrease.)
In some communities, there are species
that, if removed, can lead to collapse of the
entire community. These are called
keystone species.
cc licensed flickr photo by Martin LaBar (going on hiatus):
http://flickr.com/photos/martinlabar/3376987854/

45. Pyramid of Numbers
Visually represents # of
organisms at each trophic
level in a community

46. Pyramid of Numbers
Visually represents # of
organisms at each trophic
level in a community

47. Pyramid of Numbers
Visually represents # of
organisms at each trophic
level in a community
Which trophic level
has the greatest
number? Why?

48. Pyramid of biomass
Visually represents the
total mass of all
organisms at each
trophic level

49. Pyramid of biomass
Visually represents the
total mass of all
organisms at each
trophic level
Why is a pyramid
of biomass a better
representation?

50. Pyramid of biomass is a better
representation because:
If one of the trophic levels
consists of a few large
organisms, it does not
represent the amount of food
energy stored at that level. The
pyramid of biomass shows the
number of food molecules
stored at the trophic levels.