Bio Lab Wksht & HW Questions 28

Bio Lab Wksht & HW Questions 28 - Draw your...

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23 b. Phylum Phaeophyta (brown algae): Brown algae are common in temperate marine waters. Anatomically, they are differentiated into a blade (flat leaflike photosynthetic region), a stipe (stemlike support) and a holdfast (rootlike anchor). Consult the diagram of the Laminaria life cycle diagram Fig. 28.21, p. 562 of your text. You will notice that superficially, they resemble plants. The similarities are analogous because the body plan evolved independently in the brown algae and plant lineages. Examine the preserved material on display, and draw and label the blade, stipe and holdfast. Laminaria exhibits a sporic life cycle. Sporangia, located on the surface of the blade, produce zoospores by meiosis. Examine the prepared slide of a cross-section through the blade under the 40X objective. Can you locate the sporangia on the slide?
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Unformatted text preview: Draw your observations. C-4. Kingdom Rhodophyta (red algae): The red algae are a group of predominantly marine organisms that lack flagellated stages in their life cycle. They possess chlorophyll a as well as various other accessory pigments. The red algae you are looking at today exhibits sporic meiosis, a life cycle where both haploid and diploid generations are multicellular (refer back to Fig. 1). Polysiphonia is a widespread marine alga with a branching, filamentous thallus (body). The filaments are often thicker than one cell. Examine preserved material available on demonstration and make a sketch in the space to the right. Note the relatively simple thallus. (Note: the specimen is colourless because pigments were removed during the preservation process.)...
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