THE WORLD OF PLANTS
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THE WORLD OF PLANTS
A vast world which covers microscopic beings and huge trees 100 metres tall weighing more than 100 tons. Chlorophyll: responsible for photosynthesis. The first plants to appear in the seas were unicellular algae: their evolution and appearance upon dry land. Mosses, ferns, conifers and flowering plants. Characteristics and reproductive devices of each of the above. Summary.
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INTRODUCTION
The Plant kingdom is that enormous silent world ranking from microscopical beings to huge giants of trees measuring more than 100 meters high and weighing more than 2,000 tons.
Chorophyll.
Plants and sunlight.
THE FIRST PLANTS
Seas are very stable media and it was there that the very first organisms appeared.
The first plants were no more than single-celled algae.
Since life first appeared upon earth, it has spent approximately 75% of its time confined within the seas and solid-land was similar to a desert without life.
CROSSING TO LAND
In order to live on land, plants first needed to develop a series of devices whereby they could transport food all over their bodies and also transport their sex cells.
They also needed a support. They developed roots, stems and leaves.
Moss is one of the most primitive plants.
Ferns. Their reproduction process whereby they undergo sexual and asexual cycles.
SEEDS
Spermatophytes. Conifers.
Sequoia trees.
Flowers constitute the reproductive organs of superior plants.
Fertilisations of flowers. Insects.
Magnolia trees. Orchids.
Other plants depend upon wind for pollination. Wheat, barley.
Plants with flower are the most varied and developed plants which exist.
SUMMARY |
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