How Did Amazing Tiny Structures Called Plastids Help Make Plants and People Possible?

Evolution is rarely straightforward and the selection for symbiotic plastids is a big part of the reason why plants and you exist.

Rich Sobel
15 min readDec 4, 2020


This image was taken from the Wikipedia article about plastids and was photographed by Kristian Peters

What do you really know about how evolution produced creatures like the giant California Redwoods, or whales, elephants and humans?

What if I told you it all came about in no small part due to some tiny microscopic structures that are found inside one particular kind of cell?

And that these tiny structures are organelles called plastids.

All right, I can already hear you saying, why would I ever want to know about plastids?!

Simple. Without plastids, you probably wouldn’t be here to read this today.

Seriously. They’re. That. Important!

In this article, we’ll delve into how they came to be, where they’re found, what they do, how they evolved, how they are maintained and reproduced in cells, how they get passed to new cells and anything else about them we need to know!

So, let’s learn a bit about plastids and in particular, the ones found in red algae and see the critical role they played in the development of life on this planet.

What are plastids?

I know that you have heard of chloroplasts. These are the plastids in plants that convert sunlight and basic chemicals to nutrients and energy by the process we know as photosynthesis.

So you DO have some notion of what plastids are, at least one kind!

But that’s only one of several different kinds of plastids found in many different forms of life on our planet.

As I said, plastids are tiny organelles found in most plants and algae. You can also find them in ferns, mosses, sea slugs and some parasitic worms.

Derivation- The term plastid was derived from the Greek, πλαστός; plastós: formed, molded – plural plastids)

Plastids are where photosynthesis and many other biochemical pathways take place in these organisms. Plastids contain a small genome, but most of…



Rich Sobel

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