Plant 4 - Plant 4 Angiosperms predominates because 1)They...

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Plant 4 Angiosperms predominates because 1)They developed extra protection around the seed (the fruit). 2) They began to use insects/animals to disperse the pollen. Facilitated transport allows the angiosperms to invest less energy in pollen grains. Higher plants=gymnosperms and angiosperms; once the plant puts down its roots, it is there for the rest of its life. Plants have had to develop mechanisms that detect subtle changes in their environment, and responding or adapting to these changes. The fertilization: 2 cells of interest include the egg and the polar nuclei in an angiosperm embryo. With double fertilization. One of the nuclei unites to form the 3N Nucleus, and the other nucleus forms with the egg to form the 2N embryo. Now to talk about the products of the 3N fusion, and the embryo. As the embryo continues to develop and we look at developing seeds, we find that the embryo have taken one of two different pathways. One pathway: we are looking at the seed at the end of the embryo formation. There are two prominent bumps . Second pathway: we are looking at the seed at the end of embryo formation and there is one prominent bump. Angiosperms are divided into two groups based on the structure of the seed. The Eudicots, and the Monocots. This refers to that in some mature seeds, there are two bumps (called cotyledons, or seed leaves) which is a Eudicot. An angiosperm with one seed leaf are known as Monocots. They have one seed leaf present in the seed. Lets look at a typical Eudicot embryo axis: There are two cotyledons on the axis. These are the ones you see in the seed. The region of the axis which is above the cotyledons is known as the epicotyls. The region below the cotyledons are the hypocotyls. At either end of the axis (the top or bottom end of the axis) are zones of high cell division activity. A lot of mitosis goes on in these zones. A zone of high cell division
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This note was uploaded on 02/04/2010 for the course BIO 1B taught by Professor Carlson,mischel,power during the Spring '07 term at Berkeley.

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Plant 4 - Plant 4 Angiosperms predominates because 1)They...

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