Video Transcript
Look at the picture. In this food chain, which organisms
are the producers? (A) Seals, (B) krill, (C) penguins,
or (D) phytoplankton.
This question asks us to identify
the producers in a food chain. So, let’s begin by defining these
terms.
A food chain is a diagram that
shows the one-way flow of energy, in the form of food, from one organism to
another. In most ecosystems, this energy
originates from the Sun. Some organisms, called producers,
can harness light energy from the Sun or chemical energy to make their own food. In contrast, consumers must eat
other organisms. Examples of producers include land
plants and algae. Both of these groups use solar
energy to perform photosynthesis, a process that produces sugars for food.
The first link in any food chain
contains producers. And all the higher links will
contain consumers. The arrows in between the links of
a food chain show that some of the energy contained in an organism is transferred to
the organism that consumes it. The arrows in a food chain always
point in the direction of the energy transfer, for example, from a producer to a
consumer.
Phytoplankton are microscopic,
ocean-dwelling algae. We know they are producers because
they are the first link in this arctic food chain and because algae produce their
own food through photosynthesis.
We now know that the other links in
the food chain, namely, the krill, chinstrap penguin, and seal, are consumers. The krill feed on phytoplankton,
the chinstrap penguin feeds on krill, and the seal feeds on the penguin. Therefore, the correct answer is
(D). In this food chain, the producers
are phytoplankton.
