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Shells and Snowflakes

Interest Grabber. Section 1-3. Shells and Snowflakes.

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Shells and Snowflakes

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  1. Interest Grabber Section 1-3 Shells and Snowflakes • How can we distinguish between living and nonliving things, such as a radiolarian (left) and a snowflake (right)? A radiolarian is a tiny living thing that is covered with a glasslike shell and lives in the ocean. A snowflake is a crystal made of frozen water.

  2. Interest Grabber continued Section 1-3 • Work with a partner to answer the following questions. • 1. What are some similarities between the snowflake and the glass shell of the radiolarian? • 2. What are some differences between the snowflake and the glass shell? • 3. Would you classify the shell as a living thing or a nonliving thing? Explain your answer.

  3. Characteristics of Living Things Section 1-3 Characteristic Examples Living things are made up of units called cells. Many microorganisms consist of only a single cell. Animals and trees are multicellular. Living things reproduce. Maple trees reproduce sexually. A hydra can reproduce asexually by budding. Living things are based on a universal genetic code. Flies produce flies. Dogs produce dogs. Seeds from maple trees produce maple trees. Living things grow and develop. Flies begin life as eggs, then become maggots, and then become adult flies. Living things obtain and use materials and energy. Plants obtain their energy from sunlight. Animals obtain their energy from the food they eat. Leaves and stems of plants grow toward light. Living things respond to their environment. Despite changes in the temperature of the environment, a robin maintains a constant body temperature. Living things maintain a stable internal environment. Taken as a group, living things change over time. Plants that live in the desert survive because they have become adapted to the conditions of the desert.

  4. Characteristics of Life 1.Made up of cells 2.Reproduce 3.Based on Genetic Code 4.Grow and Develop 5.Use Energy or materials 6.Respond to the Environment 7.Maintain Internal Balance 8.Evolve.

  5. Make up of Cells. Living things are made up of small self-contained units called cells. Cell- A collection of living matter enclosed by a barrier that separates the cell from its surroundings. They are the smallest units of an organism that can be considered alive.

  6. Reproduction Sexual Reproduction- two cells from different parents unite to produce the first cell of the new organism Asexual Reproduction- new organism has a single parent. A single-celled organism divides in half to form two new organisms.

  7. Genetic Code The Genetic code such as DNA explains how organisms inherit traits.

  8. Growth and Development All living things grow. Bacteria enlarge or get bigger. Some living things go from swimming with gills(tadpoles) to hopping on land(frogs).

  9. Need materials and energy Metabolism- combination of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes.

  10. Response to the Environment Organisms detect and respond to stimuli from their environment. Stimulus- a signal to which an organism responds.

  11. Maintaining Internal balance Homeostasis-process of keeping internal conditions like temperature and water content fairly constant to survive.

  12. Evolution

  13. Figure 1-21 Levels of Organization Section 1-3 Biosphere The part of Earth that contains all ecosystems Biosphere Ecosystem Community and its nonliving surroundings Hawk, snake, bison, prairie dog, grass, stream, rocks, air Community Populations that live together in a defined area Hawk, snake, bison, prairie dog, grass Population Group of organisms of one type that live in the same area Bison herd

  14. Figure 1-21 Levels of Organization continued Section 1-3 Organism Individual living thing Bison Tissues, organs, and organ systems Groups of Cells Nervous system Brain Nervous tissue Smallest functional unit of life Cells Nerve cell Groups of atoms; smallest unit of most chemical compounds Molecules DNA Water

  15. Interest Grabber Section 1-4 Putting Size in Perspective • Here are some measurements: • A young child is just over 1 m in height. The marble in the child’s hand has a diameter of about 0.01 m. A cell in the palm of the child’s hand has a diameter of about 0.0001 m. • How can you put these numbers in perspective? You can use a ratio of the larger object to the smaller one. This requires dividing the larger number by the smaller number. Another way to compare these numbers is to look at the place value of the number 1. Each time the number shifts one place value to the right, it decreases by a factor of 10. Thus, 1 is ten times greater than 0.10, and 10 is one hundred times greater than 0.10.

  16. Interest Grabber continued Section 1-4 • 1. How does the height of the child compare to the diameter of the marble? • 2. How does the marble diameter compare to the diameter of the cell? • 3. How does the height of the child compare to the diameter of the cell?

  17. Section Outline Section 1-4 • 1–4 Tools and Procedures A. A Common Measurement System B. Analyzing Biological Data C. Microscopes 1. Light Microscopes 2. Electron Microscopes D. Laboratory Techniques 1. Cell Cultures 2. Cell Fractionation E. Working Safely in Biology

  18. Making a Graph From A Data Table Section 1-4 Water Released and Absorbed by Tree Absorbed by Roots (g/h) Released by Leaves (g/h) 20 Water released by leaves Time 15 8 AM 1 2 10 Relative Rates (g/h) 10 AM 5 1 12 12 PM 4 5 2 PM 6 17 Water absorbed by roots 4 PM 9 16 0 6 PM 14 10 8 AM 10 AM 12 PM 2 PM 4 PM 6 PM 8 PM 8 PM 10 3 Time

  19. Videos Video Contents • Click a hyperlink to choose a video. • It’s Alive!, Part 1 • It’s Alive!, Part 2

  20. Video 1 Video 1 It’s Alive!, Part 1 • Click the image to play the video segment.

  21. Video 2 Video 2 It’s Alive!, Part 2 Click the image to play the video segment.

  22. Go Online Internet • The latest discoveries in humanity’s effects on the world • Links from the authors on science and ethics • Interactive test • Articles on the nature of science • For links on experimenting, go to www.SciLinks.org and enter the Web Code as follows: cbn-1012. • For links on microscopes, go to www.SciLinks.org and enter the Web Code as follows: cbn-1014.

  23. Interest Grabber Answers Section 1 Answers • 1. Working with a partner, think of several questions that a scientist might ask in order to understand why there are fish fossils in the desert of Wyoming. Write these questions on a sheet of paper. • 2. Discuss your questions with your partner, and suggest a possible answer to each question. • 3. How could a scientist go about finding an answer to each of the questions? What other kinds of fossils have been found here? Is there evidence that a lake or inland sea existed in Wyoming at the time the fish lived here? Students may not be able to suggest answers for all of their questions. Students may know that most fish fossils formed in layers of mud and sand, which is evidence that the area was once under water. Scientists would have to dig to look for more fossils and catalog what is found in the same layers with the fish. Geologists would have to map the fossil deposit and look for evidence of a lake shore or inland sea.

  24. Interest Grabber Answers Students may say that the “worms” are immature beetles, or that there might have been worm eggs or worms in the oatmeal. If students thought that the worms were immature beetles, they may suggest isolating some of the worms to see if they develop into beetles. If students thought that there were eggs in the oatmeal, they may suggest taking a fresh sample of the oatmeal to see if worms hatch in it. Student answers should indicate that the control remains unchanged and is a standard of comparison. Variables are the factors that are subject to change. Section 2 Answers • 1. Formulate a hypothesis that might explain the presence of the “worms” in the container. • 2. How could you test your hypothesis? • 3. Identify the variables in your proposed experiment. Identify the control in your proposed experiment.

  25. Interest Grabber Answers Section 3 Answers • Work with a partner to answer the following questions. • 1. What are some similarities between the snowflake and the glass shell of the radiolarian? • 2. What are some differences between the snowflake and the glass shell? • 3. Would you classify the shell as a living thing or a nonliving thing? Explain your answer. Both are tiny; both look crystalline. Possible answer: The snowflake was not formed by a living thing, but the glass shell was. Students will likely say that the shell is nonliving, although it once surrounded the living thing that formed it.

  26. Interest Grabber Answers Section 4 Answers The child’s height is 100 times the diameter of the marble. The diameter of the marble is 100 times the diameter of the cell. The height of the child is 10,000 times the diameter of the cell. • 1. How does the height of the child compare to the diameter of the marble? • 2. How does the marble diameter compare to the diameter of the cell? • 3. How does the height of the child compare to the diameter of the cell?

  27. End of Custom Shows • This slide is intentionally blank.

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