How did the plants develop on earth?

[Siyatanush]

Can any forum member make it simple to make me understand how did so many varieties of plants develop on the earth? 

[Strange]

This is a huge question. The short answer is evolution (https://en.wikipedia.org/wiki/Evolutionary_history_of_plants).

The full answer is several years study at university and probably some postgraduate research. 

To provide an answer in between those extremes, probably requires something a bit more specific. Like: how did plants gan the ability to photosynthesise; or when did they colonise land or ...

(I found a page that seemed to have a good summary of the timeline of plant evolution, but then I noticed it said things like "how things evolve is not understood" and "millions of years ago, supposedly" and "it is illegal to talk about god in the UK", so I decided it probably wasn't a reliable source!)

p.s. Have requested this is moved to a more appropriate section of the forum

Edited December 15, 2018 by Strange
p.s.

[Phi for All]

!

Moderator Note

Moved to Evolution, Morphology, and Exobiology. 

 

[Itoero]

10 hours ago, Siyatanush said:

Can any forum member make it simple to make me understand how did so many varieties of plants develop on the earth? 

This huge variation is imo due to plant reproduction. Many plant species create a very big number of seeds(or whatever plants use to reproduce) In general, seeds are dispersed trough wind/gravity, water and/or animals.(The water lily for example  makes fruit that floats in the water for a while and then drops down to the bottom to take root on the floor of the pond.) This dispersing and the often huge number of seeds causes (all the time) many new plants to be created often in area's with a (slightly) different climate...which causes plants to adapt. This is imo a main reason for the huge variation of plants. I hope I explained this well.

There are about 320 thousand species of plants, that's a big diversity  https://en.wikipedia.org/wiki/Plant

[Siyatanush]

That is a huge diversity. I never thought number would be so big.

[StringJunky]

Whatever properties a plant has that can assist in its reproductive success, in any given environment, will proliferate those properties. So, you've got random changes occurring at the DNA level, via mutation, which just might happen to be beneficial to the plant''s reproductive success in the environment they grow up in. You've got lots of different possible substrate environments, competition, climates and micro-climates they need to adapt to, so that facilitates a wide variety of plants existing.

Edited December 16, 2018 by StringJunky

[Siyatanush]

By the way, which was the first plant that grew? How many years did that happen? Can we give information on which plant developed when? 

[StringJunky]

31 minutes ago, Siyatanush said:

By the way, which was the first plant that grew? How many years did that happen? Can we give information on which plant developed when? 

https://en.wikipedia.org/wiki/Evolutionary_history_of_plants

[Strange]

40 minutes ago, Siyatanush said:

By the way, which was the first plant that grew? How many years did that happen? Can we give information on which plant developed when? 

The first land plants were liverworts and mosses

https://en.m.wikipedia.org/wiki/Timeline_of_plant_evolution

[MarkE]

55 minutes ago, Siyatanush said:

By the way, which was the first plant that grew? How many years did that happen? Can we give information on which plant developed when? 

First the non-vascular bryophytes (mosses, liverworts, hornworts) during the Ordovician period (which started around 490 million years ago) that evolved from green algae. Mosses lack true leaves, true roots and vascular tissue. It therefore can’t conduct sugar or water through the plant, only diffusion and osmosis.

Then came the vascular seedless plants (ferns, horsetails, clubmosses) during the Devonian period (which started around 420 million years ago). A fern is vascular, but still contains spores, just like moss, and thus a swimming flagellated sperm cells. The oldest-known vascular plants have been identified in deposits from the Devonian. One of the richest sources of information is the Rhynie chert, a sedimentary rock deposit found in Rhynie, Scotland. A rich diversity of fungi (that often live together with plants, or algae such as lichens) is also known from the Rhynie chert.

(By the way, when the haploid spore germinates it generates a multicellular gametophyte by mitosis. Male gametophyte = anther (tip of stamen), female gametophyte = ovary. Both produces gametes. The sporophyte stage (growing phase, the non sexual part) is barely noticeable in these lower plants, or ‘spore plants’. In seedless vascular plants the diploid sporophyte became the dominant phase of the lifecycle.)

Gymnosperms (from cycads to ginkgos to conifers), dominated the landscape in the early Triassic (about 250 million years ago) and middle Jurassic. Angiosperms (flowering plants) surpassed gymnosperms by the middle of the Cretaceous (about 100 million years ago. The same genes that are responsible for flower development in Amborella (ancient, basal angiosperm) are the same genes that are responsible for the male cones of the gymnosperms, so it seems that the flower developed from the male cone).

- - -

What I don't quite understand myself is how "Fungi probably colonized the land during the Cambrian, over 500 million years ago, (Taylor & Osborn, 1996". That would mean before the Ordovician period, and thus before plants came onto land. But how could they have survived without their counterpart symbiont to deliver them glucose? Maybe you (or somebody else) can help me with this question? Thanks.

Edited December 16, 2018 by MarkE

[Strange]

9 minutes ago, MarkE said:

What I don't quite understand myself is how "Fungi probably colonized the land during the Cambrian, over 500 million years ago, (Taylor & Osborn, 1996". That would mean before plants came onto land. But how could they have survived without their counterpart symbiont to deliver them glucose? Maybe you (or somebody else) can help me with this question? Thanks.

Where is that quotation from?

But it looks like algae colonised land along with fungi during the Cambrian:

Quote

Land plants evolved from a group of green algae, perhaps as early as 850 mya,^[8]...  Co-operative interactions with fungi may have helped early plants adapt to the stresses of the terrestrial realm.^[13]

https://en.wikipedia.org/wiki/Evolutionary_history_of_plants#Colonization_of_land

[MarkE]

20 minutes ago, Strange said:

Where is that quotation from?

But it looks like algae colonised land along with fungi during the Cambrian:

https://en.wikipedia.org/wiki/Evolutionary_history_of_plants#Colonization_of_land

From the same link in that description I've provided.

So green algae were the first to colonise land, and fungi along with them as symbionts? I've always interpreted this development of algae colonising the land synonymous to evolving from algae first into moss (which is why lichens show morphological similarities with mosses), but I guess there was a period that green algae could survive on land without having to evolve into moss first?

Edited December 16, 2018 by MarkE

[StringJunky]

1 hour ago, MarkE said:

From the same link in that description I've provided.

So green algae were the first to colonise land, and fungi along with them as symbionts? I've always interpreted this development of algae colonising the land synonymous to evolving from algae first into moss (which is why lichens show morphological similarities with mosses), but I guess there was a period that green algae could survive on land without having to evolve into moss first?

It seems algae are adapted to many environments.

Quote

David Nelson and colleagues analyzed green microalgae from different locations around the United Arab Emirates and found that one microalga, known as Chloroidium, is one of the most dominant algae in this area. This included samples from beaches, mangroves, desert oases, buildings and public fresh water sources. Chloroidium has a unique set of genes and proteins and grew particularly well in freshwater and saltwater. Rather than just harnessing sunlight, the microalgae were able to consume over 40 different varieties of carbon sources to produce energy. The microalgae also accumulated oily molecules with a similar composition to palm oil, which may help this species to survive in desert regions.

https://medium.com/roots-and-shoots/how-do-algae-survive-in-the-desert-5bb14ae25199

 

[Strange]

1 hour ago, MarkE said:

but I guess there was a period that green algae could survive on land without having to evolve into moss first?

They still do:

(Took me a long time to identify this stuff in my garden)

[MarkE]

So when it's said that fungi colonised the land before plants, it's meant that they were able to do this as symbionts of green algae?

Edited December 16, 2018 by MarkE

[Strange]

7 minutes ago, MarkE said:

So when it's said that fungi colonised the land before plants, it's meant that they were able to do this as symbionts of green algae?

If not symbionts, feeding on them, at least.

[Strange]

Possibly interesting: "Ten new plants discovered this year: Plants have been on the planet for hundreds of millions of years – but we’re still discovering new ones."

https://www.bbc.com/news/science_and_environment

[qidran]

It starts with ocean plants, which are algae. Then the plants came onto dry land about 450 million years ago! Through evolution, they have adapted to dry land and became the plants that we’re familiar with right now. Experts said that those plants must had evolved from seaweeds in the ocean.