Plant 1 - Plant 1 1 We believe that the Earth formed 4.5...

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Plant 1 1 ) We believe that the Earth formed 4.5 billion years ago. 2)The first life evolved about 3.8 billion years ago. Only 500 million years passed between the formation of the Earth and the origin of the first life. Three categories of life on Earth: 1) We have a common ancestor 3.8 billion years ago. From this common ancestor we have developed the three great branches. The first one is Bacteria. The second branch came out from the second ancestor and shortly after, branched out again to make two another branch: The Archaea and the Eukarya. Now we will magnify the only branch we will study: Eukarya: The branches on the Eukarya branch: animals, fungi, plants, stramenopiles, slime molds, and the true slime molds. When people first started classifying organisms, they classified them into two groups of either plants or animals. The basis of this classification system goes back to Linnaeus. Animals were organisms which moved, breathed, ate, and which appeared to have a defined lifetime going from juvenile to adult. Plants were organisms that did not move, no apparent eating or breathing, and apparently indefinite lifespan. Fungi exhibited most of the characteristics as plants, they were classified as plants by Linnaeus. Mycologists study fungi. We have found that many of the organisms that were originally classified as the fungi don’t belong there due to differences in genetic material. Three groups that were at one time classified as classical fungi were the slime molds, etc…are now moved on the Eukayra tree. Stramenopiles cause the oak deaths. If you look at the relationship between fungi and animals, we are closely related. We are more related to fungi than we are to plants. About 150,000 – 250,000 species have been discovered, but we believe there are over 1.5 million species. Generalized characteristics of the Fungi: 1) They are non-motile. They don’t move. 2) They are filamentous. One cell connects to another cell to make a filament. Exceptions to this rule is yeast. Yeast Is only a single celled fungus. 3) They absorb their nutrients from living or dead material. They do this by secreting enzymes into their food and digesting the food. Fungi live in their food. 4) Fungi produce structures known as spores. These are unicellular structures capable of giving rise to a new individual. 5) The life cycle of fungi can be both sexual and asexual. When fungi secrete enzymes into the environment, it results in the decomposition of materials. The fungi along with bacteria are the great decomposers in the world. Their activities of decomposition are as essential for life as are the producers. The fungi release CO2 back in the atmosphere and minerals/nutrients back into the soil. They are essential to life. Fungi are also great pests. A fungi living in the forest makes no distinction between a tree ready to decompose and a fence. They can decay almost any conceivable natural substance, and even synthetic substances by their enzymes. The bread industry is based on a yeast: the yeast decomposes the sugars that are
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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 1 - Plant 1 1 We believe that the Earth formed 4.5...

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