Food chains, food webs and food pyramids.
Ecology is the study of the interactions of organisms with other organisms and with their
____________environment.
Food chains and food webs are often used to show these
producing
interactions.
detritivores
Plants are known as producers because they use _________ and
phytoplankton
inorganic materials to produce organic compounds. This occurs
chemical
through the process of photosynthesis, where light energy is
consumers
converted into _____________ energy. Animals that fed upon
primary
plants are called _____________consumers while animals that eat
energy
other animals are known as secondary or tertiary____________.
zooplankton
Scavengers feed on dead organisms. Decomposers and
food web
___________break down non-living organic matter into materials
herbivore
that are then available to enter the food chain as nutrients.
consumers
A food chain shows how each living organism gets its food. A
sunlight
__________ ___consists of many food chains which are interrelated trophic
and divided into separate feeding groups or __________levels. The
physical
trophic level of an organism is usually its position in the energy flow predator
pyramid of an ecosystem. The food pyramid helps us to visualise the
fact that in an ecological system there need to be many _______________organisms at the
bottom level of the pyramid in order to sustain fewer organisms at the top level. Energy is
transferred from one trophic level to the next trophic level in a food chain and food web.
When one organism consumes another, about 5 – 10% of the chemical energy is
transferred to the ____________ . 90% of energy is lost as heat energy to the environment.
A food chain shows how each living organism gets its food. A simple food chain starts with a
producer. The producer is eaten by a primary consumer (_____________) which is eaten by
a secondary consumer (carnivore). A tertiary consumer eats the secondary consumer. Most
food chains have no more than four or five links so that the animals at the end of the chain
can get sufficient____________.
_________________are small microscopic producers found on the top layer of the ocean
(where there is light) __________________are organisms that feed on phytoplankton.
Some zooplankton are herbivores and others are carnivorous, feeding on smaller
organisms.
The sun is the ultimate source of energy for a food chain.
The producers act as “translators” for this energy. Without them the ________________on
earth could not use this energy.
Use the organisms in the table below to construct a marine food web. Put the producers at
the bottom and arrange the consumers in their different trophic levels from primary
consumer to fifth order consumer.
Organisms in a Marine Food Web
Organisms
Trophic Prey/food
Predators/grazers
level
Phytoplankton
Photosynthesis
Krill and herbivorous zooplankton
Herbivorous
phytoplankton
fish
zooplankton
Carnivorous
krill
Fish, blue whales and birds.
zooplankton
Krill
phytoplankton
Fish, blue whales, birds, penguins,
leopard seal, other seals and baleen
whale.
Squid
Krill, fish and herbivorous Fish, penguin, elephant seal, sperm
zooplankton
whale, and small toothed whale.
Fish
Krill and squid
Penguin, leopard seal and elephant
seal
Other birds
Krill and fish
Leopard seal
Other seals
Krill and carnivorous
Small toothed whale
zooplankton
Elephant seal
Fish and squid
Small toothed whale
Leopard seal
Krill, fish, other birds and small toothed whale
penguins
Penguin
krill, fish and squid
Leopard seal and small toothed
whale
Baleen whale
krill
Small toothed whale
Small toothed
Other seal, leopard seal,
None
whale
elephant seal and baleen
whale
Sperm whale.
Squid
None
1. Fill in the “trophic level” column. Is it possible to be in more than one trophic level in a
food web?
2. Which is the top predator in this community?
3. Where would humans fit in?
4. What might happen if krill was removed from the food web?
5. What might happen if the small-toothed whale was removed from the food web?