Plant Evolution

[897tgigvib]

http://en.wikipedia.org/wiki/Plant_Evolution

The past few years, especially since 1996, have really been great for understanding how plants evolved. I thought I'd post this Wikipedia article in the plant identification group. It is a good one and will be further improved as research continues.

For example, Ordovician microfossils are still being worked on and discovered because so many of the Orogeny events of that period have folded over, and a few are being found that have folded over and sandwiched with Silurian and then broken.

Which reminds me, the chronological geological periods articles have also greatly improved.

The understandings of these things helps our understandings of climate, including climate change.

One example, is for how it affects where grapes will grow.

 

[digitS']

Grapes??!

You know, there is a rather narrow idea about the evolution of human culture into civilization. Civilization may be defined by specialized labor that developed out of a village farming culture. Non-farmers gathered in cities (civis, Latin relating to citizens [city people] from civitas, a community of citizens).

These communities gathered together initially for the making and imbibing of wine. So, a discussion of where grapes will grow necessary evolves into a discussion of civilization.

Steve

 

[hoodat]

Plants often evolve to fill very narrow niches that are sparsely inhabited by competitive plants.

 

[897tgigvib]

Yes, that is one adaptation mechanism, competition avoidance.

 

[Chickie'sMomaInNH]

plants also evolved to survive, and by that, they learned to be toxic or to create tons of seeds that could hitch hike on or in the local animal life.

 

[hoodat]

There are many survival mechanisms used by plants. Here in the Southern California chaparral we have quite a few plants with seeds that don't sprout until they have been in a brush fire. That gives them a head start on the grass that might otherwise smother the seedlings.

 

[897tgigvib]

Early on in the evolution of plants, over 400 million years ago, as plants began to colonize land, they had to evolve basic things such as water transport, and ways to avoid dessication.

 

[897tgigvib]

Before plants could colonize land, something had to become plants! From Wikipedia: I will not edit this article, but I might create a simpler one. They want those for wikimedia commons, but I want it for the standard!

Procaryote cells have no nucleus or chromosomes, and they are much smaller than plant or animal cells. They are the bacteria and relatives of bacteria, and are very abundant and diverse in the world.

Emergence of eukaryotes[edit]
Main article: Hypotheses for the origin of eukaryotes


Modern taxonomy classifies life into three domains. The time of the origin of these domains is uncertain. The Bacteria domain probably first split off from the other forms of life, but this supposition is controversial. Soon after this, by 2 Ga,[89] they split into the Archaea and the Eukarya. Eukaryotic cells (Eukarya) are larger and more complex than prokaryotic cells (Bacteria and Archaea), and the origin of that complexity is only now becoming known. (Starting around 1996).

Around this time, the first proto-mitochondrion was formed. A bacterial cell related to todays Rickettsia,[90] which had evolved to metabolize oxygen, entered a larger prokaryotic cell, which lacked that capability. Perhaps the large cell attempted to digest the smaller one but failed (possibly due to the evolution of prey defenses). The smaller cell may have tried to parasitize the larger one. In any case, the smaller cell survived inside the larger cell. Using oxygen, it metabolized the larger cells waste products and derived more energy. Part of this excess energy was returned to the host. The smaller cell replicated inside the larger one. Soon, a stable symbiosis developed between the large cell and the smaller cells inside it. Over time, the host cell acquired some of the genes of the smaller cells, and the two kinds became dependent on each other: the larger cell could not survive without the energy produced by the smaller ones, and these in turn could not survive without the raw materials provided by the larger cell. The whole cell is now considered a single organism, and the smaller cells are classified as organelles called mitochondria.[91]

A similar event occurred with photosynthetic cyanobacteria[92] entering large heterotrophic cells and becoming chloroplasts.[85]:6061[93]:536539 Probably as a result of these changes, a line of cells capable of photosynthesis split off from the other eukaryotes more than 1 billion years ago. There were probably several such inclusion events. Besides the well-established endosymbiotic theory of the cellular origin of mitochondria and chloroplasts, there are theories that cells led to peroxisomes, spirochetes led to cilia and flagella, and that perhaps a DNA virus led to the cell nucleus,[94],[95] though none of them are widely accepted.[96]

=====

This article does not address directly where the Chromosomes come from! The reason for that is very good. It can't yet be proven that they came from a similar endosymbiotic event that postulates a spirochete invaded the cell which had mitochondria in it. Proof of this may be found in the structure of the chromosome compared with the structure of the spirochete bacteria. Some as yet unknown small structure in common such as a Ribozymic activity produces. ...

in the future, technology such as microscopic 3d printing may help solve the problem.

 

[hoodat]

I was surprised to learn that grass is one of the newest plant families. Trees, flowers and woody perrenials were here long before grass evolved.

 

[897tgigvib]

Grasses and the Orchids have a relationship that is hard to understand with the Monocots being so late to evolve. I kind of think that there will be a fossil grass found someday that is like, 90 million years older, some very rare form.

What is even more difficult is the transition from Gymnosperms to Dicots.