The rocky shore is loaded with piles and piles of seaweed, slimy plants that grow in the sea. They’re very different from land plants. For one thing, they don’t have any roots. Some of them can cling to rocks with “holdfasts,” but those aren’t roots. A seaweed can just float wherever it wants to, and its nutrients are all around it in the ocean itself. They don’t need tough and woody stems because the water supports them and keeps them buoyant. Many of them have little balloon-like sacs that fill with gas to further support them.
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| Slimy and rubbery seaweed, the source of all life. |
Seaweeds are so alien as compared to land plants, and yet
the sea is where the action first really began for the land plants. Sea plants were the first to begin using
photosynthesis, in which the chloroplasts capture the sun’s energy and store
it. The eerie part is that these
chloroplasts (you know them by their bright green chlorophyll color) were once separate bacteria that were taken in by an early sea cell. The cell gave a bacterium a safe and
nurturing place to live, and the bacterium in turn gave the cell sugars and the
sun’s stored energy. Eventually,
chloroplasts became part of sea plants, but they still have their own DNA. They can’t be made by the plant themselves
but must be inherited from each chloroplast daughter cell during cell division.
It is chloroplasts, these ancient cyanobacteria, that have
made it possible to transfer the sun’s energy to all living creatures on the
planet. That’s right. We owe our lives, it seems, to chloroplasts,
which are also known as “autotrophs.” An
autotroph produces food (fats, proteins, carbohydrates) from its surroundings,
i.e., the sun or different chemical reactions, but it doesn’t need any living
source of energy to do this. It sort
of creates something from nothing. It
takes inorganic material or electromagnetic energy and turns it into something
that can sustain life.
I don’t mean to sound too bookwormish here, but the idea
fascinates me. Chloroplast is of Greek
origin: chloros meaning green, and
plastes meaning “the one who forms.” Can
you get anymore esoteric than that? And
that’s the legacy that seaweed gave to our land plants. The land plants feed us and the animals, and
the animals in turn also feed us. None
of it would be possible without the chloroplast, without that one seaweed cell
that swallowed up a chloroplast and made a relationship with it, allowing it to
safely flourish.
Bacteria are the true creators and destroyers on this
planet. They form everything, and then
they break it down and reform it again.
It’s rather humbling to know that you’re just part of a gigantic
bacterial cycle. People will come and
go, but the cycle remains. Who gets the
last laugh?
