what primiture form of plants were the predominant life form on earth for millions of years?
140554
ferns   ferns   ferns..
361629
millions of years ago.....\n a meteor hit the earth causing the dust, dirt, sand, and other particles to fly into the air and stay. at this time the particles caused a darkness which blocked the sun whit prevnted the plants to grow & the herbivores died.... when the herbavores died the carnivores died because herbavors were thier main source of food.
360993
when plants and animals died millions of years ago, they decayed into a variety of substances. they got buried in the earth, and over time, heat and pressure reaaranged the molecules. both plants and fossil fuels are made primarily of carbon and hydrogen.
827501
Plants are believed to have evolved from green algae, as they are both photosynthetic possessing the same pigments for photosynthesis.  Fungi are actually quite dissimilar from plants as they are not photosynthetic, some are parasites and all are chemotrophic.  They also use chitin in their cell walls as opposed to cellulose.  Fungi also store energy in the form of glycogen not starch, as plants do.
815771
Well plants are organisms that don't breathe in oxygen. They breathe in carbon dioxide.
987220
Plants are a major group of living things including familiar organisms such as trees, flowers, herbs, and ferns. About 350,000 species of plants have been estimated to exist. As of 2004, some 287,655 species had been identified, of which 258,650 are flowering.
1128758
"The oldest indications for the existence of real land plants have been found in cores from boreholes in Oman. They contained fours of mutually connected spores (tetrads) enveloped by remains of the spore sac in which they had been formed. Research on the spore walls point to a relationship with the liverworts. The fossils have been found in the Middle Ordovician and are about 475 million years old."\n\nSee the link below for 2 pages of info on the development of this.
183731
This doesn't really belong in Earth Sciences.  Biology or Botany are more specific categories for questions about living matter.  However, I'm in a good mood because it's Friday.  Check the link.
242921
I don't think that there is a word for this either. But in botany study of leaves is probably carried out more often by paleobotanists than by regular botanists. This is because leaf fossils are very common fossils. See the link for a news story about a leading fossil leaf botanist.\n\nOf course, leaves can be studies by other branches of botany, like plant physiology.
628242
Plants.\n\nThey breathe in CO2 and breathe out Oxygen
469202
The Oldest plant in the world is the Algae is the oldest plant in the world! It's 3.2 billion years old, it was the first plant to grow by means of photosynthesis.
976958
Palisade mesophyll is the top layer of mesophyll, and it has the most exposure to the sun. It differs from the structure of spongy mesophyll in that it is tightly packed and arranged almost geometrically. This is to optimize the collection of light, and maximize the surface area that is exposed to light. There is also a tiny gap between each cell to allow water through (by capillary action) as well as CO2. Palisade cells also have the most chloroplast. Sun-loving plants tend to have a thicker palisade layer.\n\nIn comparison, spongy mesophyll is arranged loosely, to allow air in between the cells. It is lower down in the leaf, and does not receive as much sunlight, so it also has fewer chloroplasts.
840716
Pre-Cambrian life was mostly soft-bodied -- there were very few if any creatures with bones, skeletons, or hard shells, so there were very few fossils left.\n\nBesides, it was a long, long time ago -- and geological activity on the earth (volcanic action, subduction of continental plates, erosion, etc.) have wiped out a lof of what was the surface of the earth then. :)
1176345
the earth is about 4.5 billion years old
80189
The short answer is that no one knows, exactly.  That said, there are some things we do know.  Life originated on the Earth, shortly after the Earth itself formed.  Most agree that the presence of liquid water was an important factor for the creation of life.\n\nThe prevailing theory is that life spontaneously originated, from complex chains of amino acids which were common in tidal pools, over a very long period of time, during the first 500 million years of the Earth's existence. \n\nMore complex life evolved as a result of 'natural selection' again over a very long period of time (2 billion years or so).  The process continues to this day, with large numbers of organisms competing for limited resources within a very stable (some say self-regulating) environment.\n\nSome people claim that life is a consequence of the fundamental mathematical properties of the universe, and inevitable where the right conditions exist.\n\nMany people argue over the definition of 'life.'  For example, one could say that 'fire' shares many of the same qualities of 'life,' in that it grows, reproduces, breathes, eats, and eventually dies. Most would agree however that 'fire' is not 'alive.'  By the same argument, 'viruses' have been hotly debated as to whether or not they constitute life.
154496
Earth is the third planet from the Sun. It is the largest of the solar system's terrestrial planets, and the only planetary body that modern science confirms as harboring life. Scientific evidence indicates that the planet formed around 4.57 billion (4.57×109) years ago, and shortly thereafter (4.533 billion years ago) acquired its single natural satellite, the Moon.
993258
The Earth was formed around 4.57 billion (4.57×109)[1] years ago