Author: Nijmy Alan Cadet Date Created: 11/18/03 Reason: Science 1001c:evolution class Profesor: Mr. lasalle

This site contians information on the four major classifications of  plants wich are the angiosperms, bryophytes, gymnosperm, and vascular plants.

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Because these clasifications contian many plant species we will only focus on the lilly's for the angiosperms, the moss for the bryphytes, the conifer for the gymnosperms, and ferns for the vascular plants.

Quick History of Plants

---All Plants share a common Ancestor, Scientists have concluded that Plants evolved from a Multicellular Terrestrial Green Algae that lived more than 430 million yeas ago. No organism lived on land until about 430 million years ago when a layer of Ozone formed. The ozone protected organisms from the sun's Ultraviolet Radiation. The conclusion that Plants evolved from Green Algae is supported by many Structural and Biochemical similarities between Plants and Green Algae. ---BRYOPHYTES are the Most Primitive type of Plants and All Bryophytes are Nonvascular Seedless Plants, therefore they produce spores. ---Vascular Plants contain specialized conducting tissue (xylem and phloem) that transport water and dissolved substances from one part of the plant to another.  Vascular plants can grow larger and live in more environments than nonvascular plants.  The strong stems of vascular plants allow the plants to grow tall, enabling them to rise above other plants and receive more sunlight than shorter plants do. ---Conifers are Woody Plants, and most have Needle or Scale-like Leaves. The Conifers are the most common Gymnosperms, and include pine, cedar, redwood, fir, spruce, juniper, cypress, and bald cypress trees. A Conifer usually bears Both Male and Female Cones.  The Small Male Cones typically grow in clusters.  The Male cones release clouds of Pollen, and then the cones fall from the branches. ---Angiosperms first appeared in the fossil record about 135 million years ago. By about 90 million years ago, Angiosperms begun to outnumber Gymnosperms. Angiosperms also gain an advantage by using Animal Pollination rather than the less efficient Wind Pollination.  Wind pollination is also used by some Angiosperms, such as grasses and many Deciduous Trees.