2. CONCEPTS EXPLORED IN THIS LESSON
1) Introduction to Food Chains
2) Food Chains
3) Humans and Food Chains
4) Food Webs
5) Trophic Levels
6) Ecological Pyramids

3. Keep in mind that the arrow tip always points towards the “eater”.
INTRODUCTION TO FOOD CHAINS
which
organism eats another
Food Chain:
is a sequence of feeding relationships describing ______
___________________.
The ____ is the ______________ for food chains.
Sun
source of energy
eagle
Keep in mind that the arrow tip always points towards the “eater”.
snake
eater
frog
grass-
hopper
grass
food

4. Label and write descriptions on your food chain diagram.
INTRODUCTION TO FOOD CHAINS
Label and write descriptions
on your food chain diagram.
eagle
Since they _______ make their own food,
cannot
they must
eat or “________” other organisms.
consume
snake
frog
They form the _____ of all ________ food chains.
basis
terrestrial
grass-
hopper
They use the energy in
_______ to make their
own food
sunlight
through a process called _____________.
grass
photosynthesis

5. FOOD CHAINS Top carnivore:
any organism that is __________ by any other.
not hunted
It’s at the ___ of its food chain.
top
There are different levels of consumers…..
eagle
quaternary consumer
The ___ consumer in a food chain. It eats ________________.
4th
tertiary consumers
snake
tertiary consumer
The ___ consumer in a food chain. It eats __________________.
3rd
secondary consumers
frog
secondary consumer
The ___ consumer in a food chain. It eats ________________.
2nd
primary consumers
grass-
hopper
primary consumer
The ___ consumer in a food chain. It eats _________.
1st
producers
grass

6. FOOD CHAINS
All organisms eventually die and decompose.
eagle
is the ___________ of living organisms and the _______ of dead organisms.
Detritus:
waste matter
remains
snake
are organisms that ___
_______ and break it down into ________.
Decomposers:
frog
detritus
eat
detritus
grass-
hopper
nutrients
decomposers
grass
are substances
needed for an organism’s
______ and _____.
Nutrients:
The cycle restarts.
nutrients
growth
repair

7. FOOD CHAINS Food chains can occur in _______ ecosystems. aquatic
top carnivore
killer whale
Marine food chains
start with microscopic
aquatic organisms called
_____________
shark
that can perform _____________ to make their own food.
phytoplankton
photosynthesis
larger fish
small fish
zooplankton
phytoplankton

8. chain start without sunlight and photosynthesis?
FOOD CHAINS
Food chains can occur in _______ ecosystems.
aquatic
Though most aquatic food chains start off with photosynthetic phytoplankton that get their energy from the sun, there are exceptions.
In the 1970s, scientists discovered deep sea _________________ in the ocean
hydrothermal vents
which were too deep for _______ to reach.
sunlight
Here they found new types of _______
that could generate energy using the _______ found in the vents.
bacteria
Hydrothermal Vent
sulfides
How could a food
chain start without sunlight and photosynthesis?

9. FOOD CHAINS Food chains can occur in _______ ecosystems. aquatic
Though most aquatic food chains start off with photosynthetic phytoplankton that get their energy from the sun, there are exceptions.
In the 1970s, scientists discovered deep sea _________________ in the ocean
hydrothermal vents
which were too deep for _______ to reach.
sunlight
Chemoautotrophic Bacteria
in Hydrothermal Vents
Here they found new types of _______
that could generate energy using the _______ found in the vents.
bacteria
sulfides
How could a food
chain start without sunlight and photosynthesis?
They didn’t need the ___ for energy.
sun

10. Hydrothermal Vent Organisms
FOOD CHAINS
Food chains can occur in _______ ecosystems.
aquatic
Bacteria in these vents form the basis of vent food chains in the same way as phytoplankton and plants do in other ecosystems.
octopus
secondary
consumer
Hydrothermal Vent Organisms
crab
primary
consumer
chemo-autotrophic bacteria
producer

11. HUMANS AND FOOD CHAINS
Since humans are not hunted for food by any other animal,
and since humans eat almost anything,
(well maybe not this)
this makes us
____________.
top carnivores ?
Where are humans on any food chain?
Count how many of these animals you’ve eaten in your life.

12. What food chains did you participate in when you ate this?
HUMANS AND FOOD CHAINS
Have you ever eaten one of these?
What food chains did you participate in when you ate this?
What is it made of?
wheat
beef
tomato
cheese
onion
lettuce

13. HUMANS AND FOOD CHAINS human human human human human
Humans are mainly _______ consumers because we eat a lot of _____.
primary
cow
When we eat animals, they are usually _________ ,
plants
so this makes us also _________ consumers.
herbivores
secondary
wheat
lettuce
onion
tomato
grass

14. FOOD WEBS No ecosystem is only made up of only one food chain.
Members of one food chain usually also belong to another.
When you put all the _____________ food chains in an ecosystem together, you form a ________.
interconnecting
food web

15. TROPHIC LEVELS Trophic Level:
It is the _______ an organism occupies in a food chain.
position
Each ___ in the chain represents one trophic level.
link
grass
grass-
hopper
frog
snake
eagle
phytoplankton
zooplankton
small fish
larger fish
shark
On land, the first trophic level begins with ______.
plants
In the water, the first trophic level begins with _____________.
phytoplankton

16. TROPHIC LEVELS Trophic Level:
It is the _______ an organism occupies in a food chain.
position
Each ___ in the chain represents one trophic level.
link
grass
grass-
hopper
frog
snake
eagle
phytoplankton
zooplankton
small fish
larger fish
shark
5th trophic level
4th trophic level
3rd trophic level
2nd trophic level
1st trophic level

17. TROPHIC LEVELS
As organisms eat one another, ______ is transferred up the food chain.
energy
eagle
0.1 kcal
However, as energy is moved from one trophic level to the next, only ___ % of the energy makes it to the next level.
- 0.9 kcal 10
snake
1 kcal
- 9 kcal
This 10 % is used to build _______
biomass
frog
10 kcal
as well as to fuel ______________.
bodily functions
- 90 kcal
This means that ___% of the energy is lost, 90
grass-
hopper
100 kcal
mostly in the form of _______
detritus
heat
- 900 kcal
and as ____ from metabolic processes.
grass
1000 kcal

18. ECOLOGICAL PYRAMIDS Ecological Pyramids:
These are diagrams that represent each
trophic level according to its ______ , _______ or _________.
energy
biomass
population
Total energy
present in
tertiary
consumers.
1) Pyramid of Energy:
This pyramid indicates the amount of ______ that is present in each trophic level.
energy
Total energy
present in
secondary consumers.
The amount of energy always _________ as you move up trophic levels.
Total energy present in primary consumers.
decreases
Total energy present in producers.

19. ECOLOGICAL PYRAMIDS Ecological Pyramids:
These are diagrams that represent each
trophic level according to its ______ , _______ or _________.
energy
biomass
population
1) Pyramid of Energy:
This pyramid indicates the amount of ______ that is present in each trophic level.
energy
The amount of energy always _________ as you move up trophic levels.
decreases

20. ECOLOGICAL PYRAMIDS Ecological Pyramids:
These are diagrams that represent each
trophic level according to its ______ , _______ or _________.
energy
biomass
population
2) Pyramid of Biomass:
Total biomass
present in
tertiary
consumers.
This pyramid indicates the amount of _______ that is present in each trophic level, in a given area.
biomass
Total biomass
present in
secondary consumers.
Biomass is the amount of
_________ (without water) within organisms.
dry matter
Total biomass present in primary consumers.
On land, the amount of biomass _________ as you move up trophic levels.
decreases
Total biomass present in producers.

21. ECOLOGICAL PYRAMIDS Ecological Pyramids:
These are diagrams that represent each
trophic level according to its ______ , _______ or _________.
energy
biomass
population
2) Pyramid of Biomass:
This pyramid indicates the amount of _______ that is present in each trophic level, in a given area.
biomass
Biomass is the amount of
_________ (without water) within organisms.
dry matter
On land, the amount of biomass _________ as you move up trophic levels.
decreases

22. ECOLOGICAL PYRAMIDS Ecological Pyramids:
These are diagrams that represent each
trophic level according to its ______ , _______ or _________.
energy
biomass
population
2) Pyramid of Biomass:
Total biomass present in
tertiary consumers.
In the water, the amount of biomass ________ as you move up trophic levels,
increases
Total biomass present in
secondary consumers.
creating an
_______ pyramid.
inverted
This is only possible because the reproductive rate of the organisms ________ as you go down trophic levels.
Total biomass present in primary consumers.
increases
Total biomass present in phytoplankton.

23. ECOLOGICAL PYRAMIDS Ecological Pyramids:
These are diagrams that represent each
trophic level according to its ______ , _______ or _________.
energy
biomass
population
2) Pyramid of Biomass:
In the water, the amount of biomass ________ as you move up trophic levels,
increases
creating an
_______ pyramid.
inverted
This is only possible because the reproductive rate of the organisms ________ as you go down trophic levels.
increases

24. Total population of primary consumers. Total population of producers.
ECOLOGICAL PYRAMIDS
Ecological Pyramids:
These are diagrams that represent each
trophic level according to its ______ , _______ or _________.
energy
biomass
population
3) Pyramid of Numbers:
Total population
of tertiary
consumers.
This pyramid indicates the _________ of individuals
at each trophic level.
population
Total population of
secondary consumers.
The typical pyramid of numbers _________ as you move up trophic levels.
decreases
Total population of primary consumers.
This occurs when many _____ and _________ producers feed a ______ number of consumers.
small
numerous
smaller
Total population of producers.

25. ECOLOGICAL PYRAMIDS Ecological Pyramids:
These are diagrams that represent each
trophic level according to its ______ , _______ or _________.
energy
biomass
population
3) Pyramid of Numbers:
This pyramid indicates the _________ of individuals
at each trophic level.
population
The typical pyramid of numbers _________ as you move up trophic levels.
decreases
This occurs when many _____ and _________ producers feed a ______ number of consumers.
small
numerous
smaller

26. Total population of primary consumers.
ECOLOGICAL PYRAMIDS
Ecological Pyramids:
These are diagrams that represent each
trophic level according to its ______ , _______ or _________.
energy
biomass
population
3) Pyramid of Numbers:
Total population
of tertiary
consumers.
However, when the producers are ____ ,
and are _____ in number than the primary consumers,
large
fewer
Total population of
secondary consumers.
the pyramid looks like this.
Total population of primary consumers.
Give an example of the kind of producers that would result in this type of pyramid.
Total population
of producers.

27. ECOLOGICAL PYRAMIDS Ecological Pyramids:
These are diagrams that represent each
trophic level according to its ______ , _______ or _________.
energy
biomass
population
3) Pyramid of Numbers:
However, when the producers are ____ ,
and are _____ in number than the primary consumers,
large
fewer
the pyramid looks like this.
Give an example of the kind of producers that would result in this type of pyramid.

28. The End!

29. Created by Anh-Thi Tang – Tangstar Science
Copyright © August 2014 Anh-Thi Tang (a.k.a. Tangstar Science)
All rights reserved by author.
This document is for personal classroom use only.
This entire document, or any parts within, may not be electronically distributed or posted to any website including teacher or classroom blogs or websites.