Protist6 - terrestrial plants. The life cycle of green...

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Protista Green Algae Green algae can be either unicellular or multicellular. They live mostly in fresh water, but some can live on land in moist soils. A few green algae are found in marine environments. These organisms often live symbiotically with aquatic and marine animals. They are of particular interest because the group from which land plants evolved, the charophyta, are green algae. The green algae are often classified in the Kingdom Plantae, based on two characteristics shared with higher plants: 1) green algae use chlorophyll a and b in photosynthesis; 2) the chloroplasts of green algae are enclosed in a double membrane. This second characteristic indicates that the chloroplasts evolved from endosymbiosis of a prokaryote, as is the case with higher plants. Also, analysis of genetic material indicates a high degree of relatedness between green algae and
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Unformatted text preview: terrestrial plants. The life cycle of green algae is shown below. Figure %: Life cycle of the Green Algae Haploid spores give rise to a multicellular haploid leaf-like structure called a thallus. The thallus produces gametes. Green algae are isogamus, meaning they have only one type of gamete, rather than having separate male and female gametes. When two gametes meet, fertilization takes place and a diploid zygote is formed. The zygote then germinates, undergoes meiosis and forms haploid spores. The diploid phase of the life cycle is brief and unicellular. There are a few exceptions this general life cycle, such as the Ulva (sea lettuce), which has a multicellular diploid phase similar to that found in brown algae....
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This note was uploaded on 01/27/2012 for the course BIOLOGY BSC1005 taught by Professor Rodriguez during the Winter '09 term at Broward College.

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