Food Chains

1
Food Chains Energy Flow
2
Food Chains vs. Food Webs

• Food chains show the path of food from a producer
  to the final consumer
• Food webs consist of interconnected food chains

3
Food Chain
4
Food Web
5
Trophic Levels

• Primary consumers (herbivores) feed directly on
  producers
• Secondary consumers (carnivores) feed on primary
  consumers
• Tertiary consumers feed on carnivores

6
Aquatic Ecosystems
7
Terrestrial Ecosystems
8
Food Chains

• Which are more numerous in an ecosystem
  producers or consumers?
• Producers are always more numerous than
  consumers, why?

9
Energy Loss

• Of the energy that an organism consumes, only a
  small fraction (ecological efficiency of about
  10) is transferred to the next trophic level

10
Where does that energy go?

• Most of the energy is lost as heat

Thats hot.
Drop it like its HOOOTT
11
(No Transcript)
12
(No Transcript)
13
Rules of Energy Pyramids

• Not everything in the lower levels gets eaten
• Not everything that is eaten is digested
• Energy is always being lost as heat

14
House Analogy

• Just like how much of the energy used to heat a
  house is wasted, much of the energy used by
  organisms is wasted

15
Efficiency Example

• Cars are only about 25 efficient
• Only 25 of the total energy in gasoline is used
  to make cars move
• What happens to the other 75???

16
Energy Efficiency

• Why is it more energy efficient to eat grains
  directly, rather than the meat of grain-eating
  animals?

15 lbs. of feed
1 lb. of beef
17
Energy Efficiency

• Why is it more energy efficient to eat grains
  directly, rather than the meat of grain-eating
  animals?

6 lbs. of feed
1 lb. of pork
18
Energy Efficiency

• Why is it more energy efficient to eat grains
  directly, rather than the meat of grain-eating
  animals?

5 lbs. of feed
1 lb. of chicken
19
Energy Efficiency

• Why is it more energy efficient to eat grains
  directly, rather than the meat of grain-eating
  animals?

2 lbs. of feed
1 lb. of fish
20
Summary Question

• Why do food chains rarely have more than 4 or 5
  trophic levels?

21
Primary Productivity

• Gross primary productivity (GPP) the rate at
  which an ecosystem's producers convert solar
  energy into chemical energy as biomass
• Net primary productivity (NPP) the rate at which
  energy for use by consumers is stored in new
  biomass
• NPP GPP rate producers use biomass

22
Net Primary Productivity
23
Net Primary Productivity
24
The Food Chain RAP

• From the SUN ENERGY flows
• Captured by plants this energy goes
• CHLOROPHYLL and WATER plus CO2
• Used in PHOTOSYNTHESIS to manufacture food
• Plants get energy right from the sun
• Making sugar for their food, a food chain has
  begun
• Plants are PRODUCERS, the first link in the chain
• Animals eat these plants for energy is obtained

25
The Food Chain RAP

• Some cant make food these are CONSUMERS
• They search for edibles this is no rumor
• An animal like a mouse is the second shackle
• Itll eat only plants but animals it wont tackle

26
The Food Chain RAP

• REFRAIN
• OH OH OH PLEASE DONT EAT ME!
• OH OH OH PLEASE JUST LET ME BE
• OH OH OH ILL BE REAL GOOD
• OH OH OH JUST DONT MAKE ME FOOD

27
The Food Chain RAP

• Our mouse will nibble, on a plant as a treat
• Mice dont make food, only plants do this feat
• Now this second link involves such a critter
• Whose diet is plant material for lunch and dinner
• The next animal could include a snake
• Snakes are PREDATORS that sit and lie and wait
• Theyll sit and stare with a watchful eye
• Until a mouse comes passing by

28
The Food Chain RAP

• REFRAIN
• OH OH OH PLEASE DONT EAT ME!
• OH OH OH PLEASE JUST LET ME BE
• OH OH OH ILL BE REAL GOOD
• OH OH OH JUST DONT MAKE ME FOOD

29
The Food Chain RAP

• Now you gotta be quick you cant be lazy
• or this food chain will drive you crazy
• You gotta be speedy you gotta be faster
• to move too slow would be disaster
• The snake had to act to stay alive
• And thats a fact it aint no jive
• The snake will find food, and to its own dismay
• Soon it too will become the PREY

30
The Food Chain RAP

• So the snake just feasted on the mouse
• The snake better be careful he better look out
• Up in the air up in the sky
• A hungry hawk is soaring by

31
The Food Chain RAP

• REFRAIN
• OH OH OH PLEASE DONT EAT ME!
• OH OH OH PLEASE JUST LET ME BE
• OH OH OH ILL BE REAL GOOD
• OH OH OH JUST DONT MAKE ME FOOD

32
The Food Chain RAP

• On the snake the hawk will swoop
• After it eats the hawk will poop
• Who will clean up all this mess?
• Here come the DECOMPOSERS at their best
• If youre a hawk youll eat a snake
• A snake eats a mouse to stay in shape
• A mouse eats some seeds and some grain
• Put it together you have a FOOD CHAIN

33
The Food Chain RAP

• REFRAIN
• OH OH OH PLEASE DONT EAT ME!
• OH OH OH PLEASE JUST LET ME BE
• OH OH OH ILL BE REAL GOOD
• OH OH OH JUST DONT MAKE ME FOOD