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Welcome to Lab Day Identifying Microscope Slides Lab Activity • In the Classroom you will learn about 8 different slide specimens. • In the lab, you will go from station to station to view different specimens under the microscope. • Your Job: Draw and label from prepared slides. Some Specimens Amoeba Human Skin Hyaline Cartilage Yeast Cells Hydra Pollen Grains Spirogyra vegetative Typical bacteria Amoeba • The amoeba is a tiny, one-celled organism. • Amoebas live in fresh water, in salt water, in wet soil, and in animals. • Amoebas eat algae, bacteria, and plant cells. Amoeba • Amoebas move by changing the shape of their body, forming pseudopods (temporary foot-like structures). • The word pseudopod means “false foot.” Human Skin • Skin is your protective layer. • It keeps germs and water out. • Skin keeps your body fluids and salts in. • Your skin contains glands which manufacture sweat. Human Skin • Skin is alive. • It has many sheets of layers of flat, stacked cells in which you’ll find nerves, blood vessels, hair follicles, glands, and sensory receptors. Skin Factoids • As an adult, you may have more than 20 square feet of skin. • You are likely to shed some 40 pounds of skin in a lifetime. Skin Fact • Right now there are over a million dust mites; microscopic critters invisible to the naked eye, on your mattress and pillow, chomping on the dead skin cells that fell off you last night. Cartilage • Cartilage is usually found in close association with bone. • It is a type of connective tissue. • Cartilage is tough, semi-transparent, elastic and flexible. Cartilage Functions • Reduces friction at joints. • Cartilage joins bones firmly together. • Acts as a shock absorber. • Provides sturdiness without impeding movement. Yeast Cells Yeast Cells • Yeast are eukaryotic microorganisms classified in the kingdom Fungi. • By fermentation, the yeast species converts carbohydrates to carbon dioxide and alcohols. Yeast Cells • Yeasts are unicellular, although some species with yeast forms may become multicellular through the formation of strings of connected budding cells known as pseudohyphae. Hydra • Hydra is a genus of small, simple, freshwater animals that possess radial symmetry. • Hydra are predatory animals. Hydra • Biologists are especially interested in Hydra due to their regenerative ability; and that they appear not to age or to die of old age. Hydra • Hydra mainly feed on small aquatic invertebrates such as Daphnia and Cyclops. • When feeding, Hydra extend their body to maximum length and then slowly extend their tentacles. Mixed Pollen • The pollen grain is the structure used to transport the male gamete (DNA) to the female part of a flower. • Pollen grains are microscopic. Pollen Grains • Just a pinch of pollen powder contains thousands and thousands of grains. • The outer wall of pollen is composed of a substance called sporopollenin which is very tough. Pollen Grains • Most species of pollen have some level of allergenicity but some are particularly notorious for inducing symptoms of hay fever. Pollen Grains • Grass pollen affects about 95% of all hay fever sufferers and birch tree pollen affects about 20%. • One of the most allergenic species on an international level is the wind pollinated ragweed. Spirogyra Vegetative • Spirogyra is a green algae. • It can be found all over the world in fresh water habitats such as ponds, lakes, and slow flowing streams. It can even survive in Antarctica! Spirogyra • The whole filament is covered by a thin, sticky layer of mucilage (think of it as glue) which causes many filaments to stick together forming a huge spirogyra mass. Spirogyra • Oxygen released during photosynthesis becomes trapped in the huge filamentous mass which causes it to float. Typical Bacteria • Bacteria grow in a wide variety of habitats and conditions. • When most people think of bacteria, they think of diseasecausing organisms. Bacteria • Streptococcus bacteria, shown in this picture, is growing in a culture. • It was isolated from a man with strep throat. • Disease-causing bacteria are known as pathogenic bacteria. Bacteria • While pathogenic bacteria are notorious for such diseases as cholera, tuberculosis, and others, such disease-causing species are a comparatively tiny fraction of the bacteria as a whole. Lab Safety • Wild play and practical jokes are forbidden during labs. • Keep lab and work space neat and clear. • Report any unsafe activities. • Stay on task. • No running or excessive voices. Violators will lose lab privileges! Microscope Care • Handle Gently • Do not turn light switch off and on. • Do not adjust magnifying lenses, they are already set. • Focus slowly and in small increments. • Call teacher or aide if you need help. Go Lets Lab To