Interest Grabber Section 1-1 Understanding Fossil Butte In the southwest corner of Wyoming, there is a flat-topped mountain called Fossil Butte. A fossil of a fish was found near the top of Fossil Butte in a rock formation that is about 50 million years old. Fossils of other kinds of fishes, as well as turtles, have been found at Fossil Butte. The land around Fossil Butte is dry, and the Pacific Ocean is more than 1000 km away. How could fossils of sea-dwelling animals have formed at Fossil Butte?
Interest Grabber continued Section 1-1 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?
Section Outline Section 1-1 1 1 What Is Science? A. What Science Is and Is Not B. Thinking Like a Scientist C. Explaining and Interpreting Evidence D. Science as a Way of Knowing E. Science and Human Values
What is and is not Science? Science - is an organized way of using evidence to learn about the natural world. The goal of science is to investigate and understand the natural world, to explain events in the natural world, and to use those explanations to make useful predictions.
Thinking like a Scientist Why won t the car start? Observation - The process of gathering information about events or processes in a careful, orderly way. Data - Information gathered from observations. Quantitative - Expressed as numbers Qualitative - Expressed as characteristics Inference - A logical interpretation based on prior knowledge or experiences.
Observation and Inference Section 1-1 Statement Object A is round and orange. Observation Inference X Object A is a basketball. Object C is round and black and white. Object C is larger than Object B. Object B is smooth. Object B is a table-tennis ball. Each object is used in a different sport. X X X X X X X Object A is a basketball. Object B is a table-tennis ball. Object C is a soccer ball.
Explaining and Interpreting Evidence After the initial observation, scientists must research the evidence they collected by any means necessary. (Computer, Library, Newspaper, Journals, Personal Interview) Next, they propose a Hypothesis. Hypothesis - A proposed scientific explanation for a set of observations. AKA. An Educated Guess A hypothesis can only be useful if it can be tested. A hypothesis could arise from prior knowledge, logical inferences, or an informed, creative imagination.
Scientists often collaborate complex questions in teams
Science is a way of knowing Science is a never ending process. New tools, techniques, and discoveries can lead to new scientific understandings. Look at the picture below What might a scientist do with such a discovery?
Interest Grabber Section 1-2 Mystery Worms A teacher collected some beetles from a rotting log and placed them in a container of dry oatmeal in her classroom. She kept the box covered with a light cloth so that the beetles could not escape. She also asked one of her students to add potato and apple pieces once a week to provide food and moisture for the beetles. After several weeks, the student reported that there were some strange-looking, wormlike organisms in the container.
Interest Grabber continued Section 1-2 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.
Section Outline Section 1-2 1 2 How Scientists Work A. Designing an Experiment 1. Asking a Question 2. Forming a Hypothesis 3. Setting Up a Controlled Experiment 4. Recording and Analyzing Results 5. Drawing a Conclusion B. Publishing and Repeating Investigations 1. Needham s Test of Redi s Findings 2. Spallanzani s Test of Redi s Findings 3. Pasteur s Test of Spontaneous Generation 4. The Impact of Pasteur s Work C. When Experiments Are Not Possible D. How a Theory Develops
How Scientists Work For thousands of years, people have noticed that living things have magically appeared from non-living things. Maggot appear on dead animals or rotting meat. Mice appear on piles of grain. Beatles appear on cow dung. Scholars from that era called this phenomenon Spontaneous Generation.
Designing an Experiment The maggot theory lasted until 1668 when an Italian physician, Francesco Redi, designed an experiment to test his hypothesis. Redi believed that maggots were the larva form of house flies. To test this hypothesis, Redi designed the following experiment.
Section 1-2 Figure 1-8 Redi s Experiment on Spontaneous Generation OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Controlled Variables: jars, type of meat, location, temperature, time Manipulated Variables: gauze covering that keeps flies away from meat Uncovered jars Several days pass Covered jars Responding Variable: whether maggots Maggots appear appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur. No maggots appear
A Controlled Experiment Whenever possible, a hypothesis should be tested by an experiment in which only one variable is changed at a time. All other variables should be kept unchanged, or controlled. This is called a controlled experiment. Manipulated Variable - the variable that is deliberately changed (Gauze). Responding Variable - the variable that is observed (Maggots appear).
Record and Analyze Results Scientist must keep written records of their observations, or data, that occur during their experiment. In the past, most results were written in notebooks or journals. They also could have drawn pictures like the following. Today, records can be kept with computers.
Drawing a Conclusion Scientists use the data from an experiment to evaluate the hypothesis and draw a valid conclusion. Was the hypothesis supported or refuted by the results?
Flowchart Section 1-2 Scientific Method Observation Research the Observation Form a Hypothesis Analyze Results Draw a Conclusion Publish Results Set Up a Controlled Experiment
Repeating Investigations Many times after a scientist publishes their work, other scientist will retest their ideas. In the mid 1700 s, an English scientist named John Needham tested Redi s ideas using another organism called animalcules (Discovered by Anton van Leeuwenhoek). Needham believed spontaneous generation could occur under the right conditions. He sealed a bottle containing gravy and heated to kill any living thing. Several days later, he examined the bottle and saw it was filled with activity. He inferred these little animals can only have come from the gravy.
Spallanzani s Test Lazzaro Spallanzani read Redi and Needham s work. He believed Needham didn t heat the gravy enough and decided to do the following experiment.
Figure 1-10 Spallanzani s Experiment Section 1-2 Gravy is boiled. Flask is open. Gravy is teeming with microorganisms. Gravy is boiled. Flask is sealed. Gravy is free of microorganisms.
Pasteur s Test Another scientist named Louis Pasteur wanted to disprove spontaneous generation. He stated that Spallanzani s experiment wasn t valid because living things need air to survive. The sealed bottle of gravy prevented that. Pasteur used a flask that had a curved neck which allowed air in but kept microorganisms out.
Figure 1-11 Pasteur s Experiment Section 1-2 Broth is boiled. Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.
Figure 1-11 Pasteur s Experiment Section 1-2 Broth is boiled. Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.
Figure 1-11 Pasteur s Experiment Section 1-2 Broth is boiled. Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.
Figure 1-11 Pasteur s Experiment Section 1-2 Broth is boiled. Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.
How a Theory Develops As scientists repeat certain experiments, some hypotheses become so well supported that they may become a theory. A theory applies to a well-tested explanation that unifies a broad range of observations.
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.
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.
Interest Grabber List ways how the fire fly and the fire are alike and different. Is It Alive?
What makes something Alive?
Section Outline Section 1-3 1 3 Studying Life A. Characteristics of Living Things 1. Made Up of Cells 2. Reproduction 3. Based on a Genetic Code 4. Growth and Development 5. Need for Materials and Energy 6. Response to the Environment 7. Maintaining Internal Balance 8. Evolution B. Branches of Biology C. Biology in Everyday Life
Characteristics of Living Things 1. Made Up of Cells All Living things are made up of small, self-containing units called Cells. Cells are the smallest unit of an organism that can be considered alive. Living things made up of only one cell are called Unicellular Organisms. Living things that are made up of more than one cell are called Multicellular Organisms.
2. Reproduction All organisms produce new organisms through reproduction. There are two types: 1. Sexual Reproduction - Involves the joining of two cells from two parents. 2. Asexual Reproduction - Involves only one parent - Dividing in two - Budding Hydra
3. Based on a Genetic Code Offspring resemble their parents. In asexual reproduction, the offspring will have identical traits as the parent. In sexual reproduction, the offspring will have a combination of traits from the two parents. Biologists know the directions of inheritance are carried by a molecule called DNA (Deoxyribonucleic Acid).
4. Growth and Development Single-celled, such as bacteria, grow simply by increasing in size. Multicellular organisms go through a process of development. One fertilized egg cell divides over over again until a mature organism is formed. As these cells divide, they change shape and structure to form cells such as liver, brain, or muscle cells. This is called differentiation.
5. Need for Materials and Energy Organisms use energy and a constant supply of materials to grow, develop, and reproduce. The combination of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes is called metabolism. All organisms get their materials from their environment, but the way they obtain it varies. Plants, some bacteria, and algae obtain their energy directly from the sun. They convert light into a form of energy that is stored in certain molecules (Photosynthesis). All other organisms rely on this stored energy by eating plants or animals that have eaten the plants.
6. Responding to the Environment Organisms detect and respond to stimuli from their environment. A stimulus is a signal to which an organism responds. Examples of external stimuli: Enough water and proper temperatures, a seed germinates. Roots grow down due to gravity. Leaves and stems grow toward light. Examples of internal stimuli: Low levels of blood sugar causes a feeling of hunger.
7. Maintaining Internal Balance Most living things maintain constant internal levels even though the external environment is changing. This is called Homeostasis. The internal temperature of an organism remains constant. If the temperature drops below a critical temperature, the body cause the muscles to shiver. This shivering increases the body temperature to the correct level. If the temperature gets to high, your body begins to sweat. The evaporation of the sweat removes excess heat from the skin.
8. Evolution Although there are many changes in an organisms life, the traits they get from their parents remain the same. As a group,any given organism can change over time. Changes from a generation to the next might not seem significant, but these changes over several hundred generations can be dramatic. Changes in groups of organisms are essential for survival in a world that is always changing. This is called Evolution.
Characteristics of Living Things Section 1-3 Characteristic Living things are made up of units called cells. Living things reproduce. Living things are based on a universal genetic code. Living things grow and develop. Living things obtain and use materials and energy. Living things respond to their environment. Living things maintain a stable internal environment. Taken as a group, living things change over time. Examples Many microorganisms consist of only a single cell. Animals and trees are multicellular. Maple trees reproduce sexually. A hydra can reproduce asexually by budding. Flies produce flies. Dogs produce dogs. Seeds from maple trees produce maple trees. Flies begin life as eggs, then become maggots, and then become adult flies. Plants obtain their energy from sunlight. Animals obtain their energy from the food they eat. Leaves and stems of plants grow toward light. Despite changes in the temperature of the environment, a robin maintains a constant body temperature. Plants that live in the desert survive because they have become adapted to the conditions of the desert.
B. Branches of Biology With all the different organisms found on this planet, it is almost impossible for one person to study this huge range of diversity. Examples: Zoologists study animals Botanists study plants Paleontologists study ancient life Scientist break down the levels of life to make it easier to study. They are:
Figure 1-21 Levels of Organization Section 1-3 Biosphere Ecosystem The part of Earth that contains all ecosystems Community and its nonliving surroundings Biosphere Community Populations that live together in a defined area Hawk, snake, bison, prairie dog, grass, stream, rocks, air Population Group of organisms of one type that live in the same area Hawk, snake, bison, prairie dog, grass Bison herd
Figure 1-21 Levels of Organization continued Section 1-3 Organism Individual living thing Bison Groups of Cells Tissues, organs, and organ systems Nervous tissue Brain Nervous system Cells Smallest functional unit of life Nerve cell Molecules Groups of atoms; smallest unit of most chemical compounds Water DNA
C. Biology in Everyday Life Biology touches your life EVERY day. It help you understand and appreciate other forms of life. Provides information about the foods you need. Describes the conditions of good health and behaviors and diseases that can harm you. Identifies environmental factors that might threaten you, such as the disposal of wastes from human activities.
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.
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?
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
A Common Measurement System International System of Measurement - a measuring system based on units of tens. Also called the metric system. Prefixes: Kilo- Hecta- Deka- Base Deci- Centi- Milli- 1000 100 10 1 1/10 1/100 1/1000 Km Hm Dam m Dm Cm Mm
Types of Measurement Length - the distance from one point to another. SI unit: Meter Mass - the amount of matter something has. SI unit: Kilogram Volume - the amount of space something takes up. Si unit: Cubic Meter or Milliliter Temperature - the amount of heat something has. SI unit: Celcius Time - the period between two events. SI unit: Second
Types of Microscopes 1. Compound Light Microscope - Allows light to pass through a specimen and uses two lenses to form an image. 2. Transmission Electron Microscope - (TEM) Sends a beam of electrons through a thin specimen. 3. Scanning Electron Microscope - (SEM) Scan a narrow beam of electrons back and forth across the surface of the specimen.
A Common Measurement System Kilo- Hecta- Deka- Base Deci- Centi- Milli- 1000 100 10 1 1/10 1/100 1/1000 Km Hm Dam m Dm Cm Mm
Making a Graph From A Data Table Section 1-4 Water Released and Absorbed by Tree Time 8 AM 10 AM 12 PM 2 PM 4 PM 6 PM 8 PM Absorbed by Roots (g/h) 1 1 4 6 9 14 10 Released by Leaves (g/h) 2 5 12 17 16 10 3 Relative Rates (g/h) 20 15 10 5 0 Water released by leaves Water absorbed by roots 8 AM 10 AM 12 PM 2 PM 4 PM 6 PM 8 PM Time
Videos Click a hyperlink to choose a video. It s Alive!, Part 1 It s Alive!, Part 2
Video 1 It s Alive!, Part 1 Click the image to play the video segment.
Video 2 It s Alive!, Part 2 Click the image to play the video segment.
Go Online 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.
Interest Grabber 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. 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? 2. Discuss your questions with your partner, and suggest a possible answer to each question. 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. 3. How could a scientist go about finding an answer to each of the questions? 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.
Interest Grabber Answers 1. Formulate a hypothesis that might explain the presence of the worms in the container. Students may say that the worms are immature beetles, or that there might have been worm eggs or worms in the oatmeal. 2. How could you test your hypothesis? 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. 3. Identify the variables in your proposed experiment. Identify the control in your proposed experiment. Student answers should indicate that the control remains unchanged and is a standard of comparison. Variables are the factors that are subject to change.
Interest Grabber 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? Both are tiny; both look crystalline. 2. What are some differences between the snowflake and the glass shell? Possible answer: The snowflake was not formed by a living thing, but the glass shell was. 3. Would you classify the shell as a living thing or a nonliving thing? Explain your answer. Students will likely say that the shell is nonliving, although it once surrounded the living thing that formed it.
Interest Grabber Answers 1. How does the height of the child compare to the diameter of the marble? The child s height is 100 times the diameter of the marble. 2. How does the marble diameter compare to the diameter of the cell? The diameter of the marble is 100 times the diameter of the cell. 3. How does the height of the child compare to the diameter of the cell? The height of the child is 10,000 times the diameter of the cell.
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