Bio Lab Wksht & HW Questions 45

Bio Lab Wksht & HW Questions 45 - Mnium or...

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40 How do the sperm cells produced in the antheridium reach the egg cells in the archegonial heads? Examine fresh or dried demonstration material of a moss and distinguish between the sporophyte and the gametophyte. The sporophyte results from mitotic divisions of the fertilized egg in the archegonium. It is dependent upon the gametophyte for some of its nutrients. Examine sporophytes under the dissecting microscope and look for all of the structures described below. Sometimes a calyptra , which represents the remnants of the archegonium, may still be present. Beneath the calyptra the operculum should be visible. In some of the sporophytes, the operculum has fallen off of the capsule (also called the sporangium ). This allows for examination of peristome teeth underneath. What is the function of the peristome? Relate this material to prepared slides of
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Unformatted text preview: Mnium or Polytrichum sporophyte sections and sketch a typical moss capsule below. Indicate which structures are haploid and which are diploid. Observe demonstration material available for the other two phyla of seedless nonvascular plants. Hornworts (Phylum Anthocerophyta) are very small. A typical hornwort is available on demonstration. Can you distinguish between the sporophyte and the gametophyte? Conversely, liverworts (Phylum Hepatophyta) are much larger and more common. Use a hand lens to examine the surface of the living Marchantia, a typical liverwort. Note the presence of pores on the surface. What is their function? Make sketches of both organisms in the space below. Are you looking at gametophytes or sporophytes? Are they haploid or diploid? Hornwort L i v e r w o r t...
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