Plant evolution?

Question

I consider myself a mild skeptic of a lot of what evolution describes when dealing with Earth's animal kingdom but I've never really seen or heard hardly anything on plants and such and how they came into being? Could someone give me a quick overview of how evolution states seeds, cells, and plants came to be? Wouldn't they (Being plantlife and such) have evolved first before animal life and thus be the true orgins of everything?

Answer 1

I have a book right here in front of me called, "The Evolution of Plants," by Willis and McElwain.  I bought it for myself as a reference and for fun reading (I'm weird like that)....  

The book is 378 pages, so not really something easy to distill into a short answer, but I can give some bits and pieces.  The earth is about 4.2 billion years old.  Prokaryotes (unicellular organisms without a nucleus) were abundant around 3.5 billion years ago, as can be see in fossil stromatolite beds.   Eukaryotes (cells with nuclei) appear in fossils starting from about 2.7 billion years ago.  The first algae appear around that time (algae are protists, not plants).  Nonvascular plants make it to land by about 450 million years ago, and then vascular plants appear by about 400 million years ago. The appearance of plants creates a lot of interesting, prominent effects in the geologic record (first soils, co2 depletion and rise of oxygen in the atmosphere).  

Many events in plant evolution had huge impacts on animal evolution.  Examples are the appearance of flowering plants, which then diversified and took over many/most biomes around the time of the dinosaur extinction; the appearance of C4 vegetation, which only happened about 10 million years ago and had huge effects on herbivores (tons of herbivores went extinct in many areas, and those that survived had to completely change their teeth anatomy).  Grasses only appeared about 55 million years ago, so if you see a movie with a brontosaurus eating grass...  you know they didn't do their homework.

Answer 2

Animals diverged into their own kingdom before they became terrestrial so have no connection with the emerging  plant kingdom. Evidence for marine animals begins with fossils dating back 600 million years ago (mya) in the early Paleozoic. The majority of animal fossils come later with the Cambrian period (~525 mya) because the organisms had hard body parts that fossilized better than soft tissue. Nearly 30 groups from this period survive  including arthropods, echinoderms (sea urchins and starfish), mollusks (snails, clams), and chordates (the group we belong to). Organisms that photosynthesized were still algae.

http://www.palaeos.com/Paleozoic/Cambria...

http://www.devoniantimes.org/opportunity...

The plant kingdom arose from the algal organisms that made the transition to land. As plants are defined today the Bryophytes (liverworts, hornworts, and true mosses), with no specialized water conducting cells, are the eldest true terrestrial species dating back to the Silurian period 425 mya. Plants occupied the land before the animals emerged  but after animals evolved in the sea.

Land was slowly occupied by plants as they developed methods of retaining then moving water internally as they competed for space and exposure to light.

Tetrapods did evolve from lobe-fin fish like Acanthostega.

http://www.devoniantimes.org/index.html

http://www.devoniantimes.org/Order/old-o...

Plant evolution

http://universe-review.ca/R10-23-plants....

http://www.mansfield.ohio-state.edu/~sab...

http://www.palaeos.com/Plants/default.ht...

http://sci.waikato.ac.nz/evolution/plant...

Timelinehttp://en.wikipedia.org/wiki/Timeline_of...

Moss genome tells of origin of land plants

http://www.berkeley.edu/news/media/relea...

Our shared plant/animal common ancestor was a simple eukaryotic organism in the early Protista Kingdom. If you are really interested the endosymbiotic theory covers the rise of the eukarya.

The endosymbiotic theory is based on the idea of cellular communication driving evolution. The archaebacterial and eubacterial cells merged to become the first nucleated cell but this continued to occur and the many organelles such as mitochondria and chloroplast provide evidence that this process was repeated.

http://www.springerlink.com/content/926u...

http://users.rcn.com/jkimball.ma.ultrane...

http://www.biology.iupui.edu/biocourses/...

http://www.morris.umn.edu/~goochv/CellBi...

Answer 3

Plants split pretty early from animals but they are still multicellular eukaryotes.  The earliest land plants probably evolved from green algae.  The algae incorporated blue green bacteria to photosynthesis sugar.  They were able to start colonizing the land about 700 million years ago.  There was then sufficient ozone to protect them from excessive UV radiation.  By 400 million years ago, they had evolved conductive tissue that allowed them to grow larger.  They still needed water on the ground to supply their eggs and sperm the ability to swim to each other.  They had also developed spores to transport themselves across the land.  Eventually seeds evolved in pine trees or gymnosperms. Seeds are essentially spores that added a bit of nutrition to aid embryonic plant.  They were wind pollinated and protected a large seed that had nutrients that gave it a boost and enabled gymnosperms to colonize most of the land.  Then other plants sometimes were aided by insects and developed much better fertilization and often grew fruits to have animals transport the seeds.  Those were the angiosperms.

Answer 4

They did evolve before animals - But they certainly weren't the first cells.

There are many theories about plant cells. One of the foremost is the thought that the chloroplasts within plant cells were once from another organism and were absorbed by prehistoric cells, with which they lived in a symbiotic relationship.

Anyways, as to "the true origins of everything"... I'm afraid you likely don't know enough to understand the full answer. Suffice it to say, plant and animal cells have organells which help them function. There are also cells which have no organelles and are very primitive. It is from these cells with no organelles, called prokaryotes, that more complex life came from.