When did life seperate in to the plant and animal kingdoms ?

Factual Questions
1

These we know for sure…

  1. we know the first ‘life’ emerged in the oceans
  2. we know all life originated from common single-celled life forms
  3. at some pont of time, these sea-dwellers crossed the shore and slowly adapted to life on land.

question is… when did plant and animal lifes became seperate?

were there plants already on land when these life-forms came to land? definetly the complex animal life-forms that crossed shore did not evolve later in to plants . i am guessing they were already on land…

so then, when did plants cross? how long before animals? and how exactly did they mange the mighty migration-to-land (being plants and all)

did plants even start in the oceans as animals did? i am pretty sure they did…

do we have a name for the life-form that was the common ancestor to both ‘plants’ and ‘animals’ ?

2

I don’t think we have a good handle on the answer to that. I’m looking at Richard Dawkin’s “The Ancestor’s Tale” right now, and although he doesn’ state it and the graph he gives ends at 500M years ago (plants and animals split before then), it looks like about 1.2 - 1.3 billion years ago. But keep in mind that biologists now list more than 2 kingdoms, so this split was a splilt for plants and “some other organism”, not just what we’d call animals. For instance, the branch that led to fungi are still on the same branch that led to animals at that point.

It was a long after this that the land was colonized by either plants, animals or anyting else.

3

Tricky question, largely because at this stage, everything was single-celled, so all-in-all, pretty similar. Not to mention things get pretty fuzzy in the fossil record when looking back that far. Nevertheless, we know that within the early protists, there evolved the protozoan lineage (which would eventually lead to fungi and animals) and the algae (which would lead to plants).

It should be kept in mind, however, that plants and animals do not share a direct common ancestor (the most recent comon ancestor fo the two groups would have been the earliest eukaryotes, at around 850 million years ago. True plants probably arose ~570 million years ago, while complex animals arose ~575 million years ago; seemingly around the same time, but the branches had diverged widely in the roughly 280 million years since the lineages separated.

The first unambiguous land plant fossils are dated to around 415 million years or so ago. It is thought that the first terrestrial animals (arthropods) ventured onto land at about the same time (some trace fossils indicate that arthropods may have even beaten vascular plants to land, having ventured onto terra firma during the the late Ordivician).
did plants even start in the oceans as animals did? i am pretty sure they did…

As noted above, the most recent common ancestor of both plans and animals would have been the first eukaryote. But, those first eukaryotes also gave rise to a host of other groups, including the fungi, amoebozoans, anterokonts, chromists, etc. (need I point out that the old “five kingdom” paradigm is outdated?).

4

It depends on what exactly you mean by “plant” and “animal.” There are much more fundamental divisions between life forms than that between multicellular plants and animals, and the former “Kingdom” system is no longer adequate for classification.

There is a much more fundamental distinction between what are called “procaryotes,” including bacteria-like forms, which have a very simple cell form, and “eucaryotes,” including protozoa, algae, other unicellular forms, plus multicellular plants and animals, which have much more complex cells.

But it has been found that there is an even more fundamental genetic distinction within procaryotes, between a group called “Archaea” and other bacteria. Because of this, modern classifications recoginize three “Domains,” a level higher than Kingdom, Archaea, Bacteria, and Eucaryota.

Within bacteria, there are photosynthetic forms, the cyanobacteria, formerly called “blue-green algae.” In some sense these are “plants,” in that they manufacture their own food from sunlight, but they are not closely related to multicellular plants or other kinds of algae.

Even within the Eucaryota, the “kingdom” system doesn’t work very well. It has been a practice over the past few decades to recognize four kingdoms within the Eucaryota, the Protista for one-celled forms, plus the multicellular Plantae, Animalia, and Fungi (which are neither plants nor animals). However, the Protista themselves are quite diverse, and include some forms which are more closely related to plants, some to animals, and some to fungi. A real classification would probably have to recognize probably twenty different “kingdom-level” groups within the Eucaryota alone.

There were probably types of archaea and bacteria, including cyanobacteria, that were capable of living on land at very early periods. Likewise, simple algae may have colonized the land early in their history. The earliest fossils of multicellular land plants are from Silurian, 425 million years ago. It is possible that multicellular animals may have colonized even earlier than this, to feed on terrestrial algae or fungi.

5

However, they are probably related to parts of plants. The chloroplasts in true plant cells, like the mitochondria in most eukaryotic cells, are decended from independant prokaryotic organisms which merged into the cells at some point, and the prokaryotes which most closely resemble the chloroplasts would, if I remember correctly, be the blue-green algae.