Plant origins

[Ezkerraldean]

Where did land plants originate from? Are there any fossils or genetic links that link land plants to earlier marine plants or protists? From what i gather, modern marine plants are all derived from terrestrial ones, and that seaweeds etc. are in fact protists.

Plant evolution is a bit hazy to me (probably just because they seem more boring than animals!)

[Jet Black]

Where did land plants originate from?


the ground... ho ho

commence serious replies -->

[Codec]

I think Cooksonia is the first example of a vascular plant. However there are quite a few seaweeds and so on that survive half in/half out of the water, so its probably not such a great leap as for animals.

[Berthold]

Lynn Margulis wrote in her book "Symbiotic Planet" that mycorrhiza (http://en.wikipedia.org/wiki/Mycorrhiza) is a very old feature of terrestrial plants (the article I linked to mentions it , too).

[Ezkerraldean]

stonewarts, eh? curiously plant-like freshwater green algae. looks like it was green algae. i think i've answered my own question! must look more into this kind of thing.

[nygreenguy]

Where did land plants originate from? Are there any fossils or genetic links that link land plants to earlier marine plants or protists? From what i gather, modern marine plants are all derived from terrestrial ones, and that seaweeds etc. are in fact protists.

Plant evolution is a bit hazy to me (probably just because they seem more boring than animals!)



Land plants are most closely related to green algae, specifically Order Charales. So, land plants descendants most likely resembled Chara. Heres how they are similar:
-Photosynthetic pigments
-Food reserve
-Cell wall composition (cellulose, hemi-cellulose, pectin)
-Plasmodesmata
-Details of cell division
-3D plant body (nodes,internodes, branches)
-Apical growth
- Oogamy
- Biflagellated sperm
- Heteromorphic life cycle

And yes, there is a lot of molecular data linking Charales and Plants, and land plants evolved from protists, not marine plants.

And while mosses are the "simplest" plants, they are not ancestors of modern plants. The oldest moss fossil is a liverwort (Pallavicinites devonicus) which is 370 myo and the oldest vascular plant is Cooksonia, from 410 myo. So, bryophytes are polyphyleticwith vascular plants.

The first plants were literally stems with sporangia!

so, we have fossil and molecular evidence showing land plants came from green-algae.

Plant evolution is REALLY exciting. (way more than animal)

[nygreenguy]

I think Cooksonia is the first example of a vascular plant. However there are quite a few seaweeds and so on that survive half in/half out of the water, so its probably not such a great leap as for animals.


But they are not plants!

Lynn Margulis wrote in her book "Symbiotic Planet" that mycorrhiza (http://en.wikipedia.org/wiki/Mycorrhiza) is a very old feature of terrestrial plants (the article I linked to mentions it , too).


Well, this would first require roots/rhizomes which many first plants didnt have.