This type of “trophy” has to do with the way an organism gets carbon and energy. My teacher didn’t do a good job of explaining this, so it took me FOREVER to get the hang of it, but maybe this will help you decipher the code.

Where does the energy come from?

If it comes from light, then it’s a photo-something-troph. Otherwise, it’s a chemo-something-troph. It’s that simple because, as far as scientists know, organisms on earth only get energy from light or by converting the energy that’s stored in CHEMical compounds (thus the chemo- prefix).

In most cases, an organism is either one or the other photo- or chemo-. In rare cases, however, you’ll encounter an organism that’s both. We call these “mixotrophs.”

Where does the carbon come from?

In order to grow, earthlings need organic “building blocks” in order to make things like skin or muscle or ANY other part of the body (this goes for organisms that don’t have skin or muscle as well). There are two ways to get these carbon compounds: make it yourself or eat something that makes it.

If you’re an organism that makes the carbon compounds yourself, then you’re a something-AUTO-troph. If you eat something-auto-trophs, then you’re a something-HETERO-troph.

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SO…

From what you’ve read, what does it mean to be a CHEMOAUTOTROPH? (don’t read any more until you think you know)

If you said that it means the organism in question consumes its organic carbon compounds instead of making those compounds itself AND it gets its energy from converting chemical energy rather than light… THEN YOU’RE CORRECT!!!

Here’s an easy way to remember:

• If it uses light for energy, then the term “photo” should be in the name. If not, then it shouldn’t.
• If it makes its own organic carbon compounds, then the term “auto” should be in the name. Otherwise, no.

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I hope this helps!

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Best of Luck,

Grey