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Life Science

Life Science . 8 th Grade Science Content Strand 3. 3.a. Adaptations: traits that help survival & reproduction. Desert- nocturnal, needles on plants, large ears, burrow underground Aquatic- long bodies, fins, gills, webbed feet, leaves that float High altitude (mountains) - low oxygen

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Life Science

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  1. Life Science 8th Grade Science Content Strand 3

  2. 3.a. Adaptations: traits that help survival & reproduction • Desert- nocturnal, needles on plants, large ears, burrow underground • Aquatic- long bodies, fins, gills, webbed feet, leaves that float • High altitude (mountains) - low oxygen • Cold climate- white fur, hibernation, fatty insulation, trees have needles

  3. Adaptations • Name 2 adaptations that we have not mentioned. • How are adaptations formed?

  4. 3.b. Cells • Differences in plant and animal cells: • Plants have: • Cell walls • Large vacuoles • Chloroplasts

  5. 3.b. Cells • Structures: • Nucleus- controls activities, DNA • Cytoplasm- gel-like substance in cells • Cell membrane- controls what enters and exits • Mitochondria- respiration/energy for the cell • Ribosomes- make proteins

  6. 3.b. Cells

  7. Compare and Contrast • Create a list, bubble map, or venn diagram telling the differences between plant and animal cells.

  8. 3.b. Cells • Types of cells: • Nerve- transmit information, found in brain, control senses • Bone- provide shape and support • Blood- carry materials all over body • Muscle- movement • Epithelial- protection, found in skin

  9. 3.b. Cells muscle nueron epithelial bone blood

  10. 3.c. Diseases • Viral- cold, influenza, HIV, chicken pox • Bacterial- tetanus, pneumonia, strep • Fungal- athlete’s foot, ringworm • Protist- malaria • Antibiotics treat bacterial diseases, NOT VIRUSES. • May be spread through direct contact, body fluids, food, water, or animals.

  11. How? • How are antibiotics able to destroy bacteria but not viruses? • What is the name of something has spreads an infectious disease? Name one example.

  12. 3.d. Heredity • Phenotype- physical appearance • Genotype- two alleles(letters) • Pedigree- chart that shows traits in a family • Shaded- expresses trait • Half-shaded- carries but does not express (recessive) • Clear- does not carry or express

  13. Punnette Square • Assume tall (T) is dominant for pea plants and short (t) is recessive. Fill in the Punnette square that would result when a plant with genotype Tt is crossed with another plant with genotype tt.

  14. Pedigree

  15. What do pedigrees show? • How can they be useful to scientist?

  16. 3d. Incomplete dominance- blended traitsRed and white flowers= pink flowers

  17. 3d. Codominance- both are expressedBlack dog+ white dog= black and white dog

  18. 3.e. Food Webs • Population- same species • Community- different species • Niche- an organism’s role • In food webs: • More food= population increases • Fewer prey= fewer predators • Arrows show the flow of energy

  19. What is the level of organization in an ecosystem? • What are the differences between a food web and food chain?

  20. 3.e. Food WebsWhat would happen if the deer were over hunted in this food web?

  21. 3h energy lost as heat • Energy Pyramid • As you go up the pyramid only 10% of energy is passed in the food change because energy is lost in the form of heat by the organism

  22. In the energy pyramid who has the most energy? • Who has the least amount of energy?

  23. 3.f. Selective Breeding • Selective breeding- choosing organisms to mate for best traits • Pros: better traits • Cons: less diversity, more genetic diseases

  24. 3.f. Genetic Engineering • Genetic engineering (gene therapy)- changing genes • Pros: disease-resistant crops, more nutritious foods, faster growing • Cons: may cause genetic defects, decreases diversity

  25. 3.g. Single-celled organisms • Bacteria- digest food, make yogurt, cheese, can be engineered to produce hormones, can break down oil spills • Fungi- • Yeast- makes bread rise, produce alcoholic beverages, ethanol (fuel) • Mold- produce antibiotics, cheese

  26. Nitrogen Cycle • Nitrogen fixing bacteria located in the roots of some plants help convert Nitrogen in the air to nitrites that plants use for fertilizer & animals use from eating plants

  27. 3.h. Respiration • The process through which ALL cells get energy • Take place in mitochondria • Uses oxygen to get energy from food • Releases some heat as wastes • Also called oxidation • C6H12O6 + 6O2-> 6CO2 + 6H2O + energy

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