This is a good example of a word having different
meanings in different contexts.
Animals giving milk are producers in the way
people usually use the word. The way we
biologists use the word when we are talking about
food webs or food chains is different. Then we
mean living things that do photosynthesis.
Producers have to be plants, or algae, or
one-celled things that do photosynthesis. So a
mother cow produces milk, but she uses the energy
in the food she eats to get that energy. Plants
use the energy of the sun.
to a biologist anything that eats,
moves at some time in its life, and is made of
multiple cells is an animal. Worms, sponges,
jellyfish, bugs, all animals.
Another example is how we use the word “theory” in
science. We mean the best possible explanation for
something, after tons of research and supporting
evidence. In everyday speech, people usually mean
“guess” when they say theory.
Maybe your class can think of other words that
mean different things depending on when and where
people use them.
Thanks for asking,
That's an interesting question. I'm sure
lactating women aren't considered 'producers' in
any sense, because lactating women aren't usually
'considered' at all. [I just heard Gloria Steinem
speak in San Francisco this week, so I'm extra
sensitive to such matters at the moment!]
An online dictionary defines 'producers' as
'people, companies, or countries that...'; but I
see that, of course, producers are also
organisms [and movie makers].
Looking at the definitions of organisms that
are 'producers,' I see that they all make
food out of energy sources that are not food,
such as sunlight [phosynthesis by green plants and
green bacteria] and inorganic chemicals
[chemosynthesis by some bacteria].
So lactating animals aren't producers
because they produce milk, in the same way that
they aren't producers because they 'produce'
That reminds me of guinea pigs, which have been
compared with cows - they both eat grass and can
be eaten for their meat! But not my guinea pigs,
who eat grass but will never be eaten..
'Producer' in ecology is like 'consumer': it
has multiple levels. Plants are primary
producers, meaning that they fix biological energy
that was previously not biological. Anything that
eats plants and builds up a body is a secondary
producer, just as it is a primary consumer. Any
animal is thus a producer at some level, because
all animals' bodies get eaten when they die and
decay if nothing else, but apart from the few
photosynthetic animals or chemosymbiotic animals
that contain algae or bacteria that make their own
food, animals are never primary producers.
This is a fun question. Producers are organisms
that create food, so surely lactating animals
should be included, right? Even though this
seems to make sense, it is actually wrong. You
have to think about where lactating animals get
the material to make their milk. Let’s use cows
for an example. Cows eat grass and their digestive
system breaks down the grass into its most basic
components called macromolecules. The cow’s
body then takes these macromolecules and uses them
to create milk along with everything else in its
Now think about this as opposed to the grass
the cow is eating. The grass is using energy from
the sun to power photosynthesis where carbon
dioxide from the air will be converted to solid
plant mass. While the cow is using organic carbon
(here meaning carbon that came from another
organism), the grass is using inorganic carbon
(carbon not from an organism like carbon dioxide
in the air). Only animals that use inorganic
carbon are considered producers because they
literally produce food from thin air. Thank
you for the question!
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