Download 4.2 Food Chains and webs

Sponge: Set up Cornell Notes on pg. 37
Topic: 4.2 Food Chains and Webs
Essential Question: Draw three food
chains, each with at least 3 linkages (4
organisms)-words only
BIOZONE: P. 168-171,174
Text: P. 752-753
4.2 Food Chains and webs
EQ: Draw three food chains, each with at least
3 linkages- words only
Key Vocabulary:
Food Chains
Food Webs
Trophic Levels:
Primary/Secondary/Tertiary/
Quaternary Consumer
Get out homework for signature
(Monday’s and Tuesday’s)
P. 36
Trophic Level Pyramid
In class: Construct a food web
Build-Your-Own Food Web
Understanding
• Most ecosystems rely on a supply of energy from
sunlight
The Importance of Sunlight
• All life you see around you on Earth’s surface relies either
directly or indirectly on sunlight
Understanding
• Light energy is converted to chemical energy in carbon
compounds by photosynthesis
The role of photosynthesis
Remember photosynthesis:
• Takes simple inorganic CO₂ and convert it into energy-rich
sugar C₆H₁₂O₆
• Light energy from sun is being converted into chemical energy
(food)
The role of photosynthesis
• Chemical energy refers to the fact that organic compounds
such as carbs, proteins, and lipids are rich in energy
– Can be measured by calories or kilocalories
– One way to release the chemical energy from organic compounds is
to digest the food
Understanding
• Chemical energy in carbon compounds flows through
food chains by means of feeding
Food Chains
• By feeding on producers, consumers can utilize the chemical
energy to grow and stay healthy
Food Chains
• A food chain is a model that shows a sequence of feeding relationships
and energy flow between species
• A food chain follows the connection between one producer and a single
chain of consumers within an ecosystem.
GRAMA GRASS
DESERT COTTONTAIL
*The direction of the arrow shows the direction of energy flow
HARRIS’S HAWK
Trophic levels refer to an organism’s position in a food chain.
T5= Quaternary Consumer
T4= Tertiary Consumer
Draw on top
of P. 36include
examples
T3= Secondary Consumers
T2= Primary Consumers
T1= Primary Producers
……C a r n i v o r e s…….
• Classify organisms by their feeding relationships with the other organisms in
the same ecosystem
herbivores
plants
Understanding
• Most species occupy different trophic levels in multiple
food chains
Organisms can fit into more than one tropic level!
• Ex: A common seal is in T3 when it feeds on Grey Mullet
• But will be in T4 when it feeds on lobster
T4
T3
T3
T2
T1
T2
T1
Understanding
• A food web shows all the possible food chains in a
community
• A food web emphasizes complicated feeding relationships and energy
flow in an ecosystem.
• An interconnecting series of food chains.
• Since organisms usually eat more than one type of food, a simple food chain does
not tell the whole story
ENERGY
Arctic Marine Food Web
Food Webs
• https://www.youtube.com/watch?v=MGODmyXkkPU
3m7s
Understanding
• Energy losses between trophic levels restrict the length
of food chains and the biomass of higher trophic levels
Energy Levels in Trophic levels
• The number of levels is limited by how much energy enters the
ecosystem
– Energy is lost at each level
• So the # of organisms in the chain as well as the quantity of light available at
the beginning will determine how long the chain is
Determining an organism’s tropic level
In order to determine the tropic level of each organism start with the
producer.
• Remember: some organisms occupy more than one trophic level or
take their food from multiple trophic levels
Algae mosquito larva dragonfly larva fish raccoon
Algae (T1) mosquito larva (T2) dragonfly larva (T3) fish (T4)raccoon (T5)
In Class Practice: Construct a Food Web
Middle of p.
36
Just use
words and
arrows
• Algae (plant) is eaten by the mayfly larva
• Leaf debris is eaten by the caddis fly larva and the
blackfly larva
• The mayfly larva, caddis fly larva, and the blackfly
larva are eaten by juvenile trout (fish)
• The juvenile trout is eaten by the kingfisher (bird)
• The mayfly larva is also eaten by the sculpin (fish) and
the stonefly larva, all of which are eaten by adult
trout
Please include labels to indicate the tropic level of
each organism (T 1-5)
T3/
On the bottom p. 36: Construct a food web containing up to
10 organisms
• All trophic levels must be labeled (T1/T2 etc.)
• Remember: some organisms occupy more than one trophic level or take their food from
multiple trophic levels
• Must have pictures