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Ch. 1 - The Science of Biology

Ch. 1 - The Science of Biology. I. HOW DO SCIENTISTS “DO SCIENCE”?. Scientific investigations seek to answer questions using thorough and meticulous skills.

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Ch. 1 - The Science of Biology

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  1. Ch. 1 - The Science of Biology

  2. I. HOW DO SCIENTISTS “DO SCIENCE”? Scientific investigations seek to answer questions using thorough and meticulous skills. ***** Science is so complex that a single step-by-step method may not always be the best way to answer a question, however, all science relies on skills such as asking questions, making observations and inferences, analyzing data and communicating to others. *****

  3. I. HOW DO SCIENTISTS “DO SCIENCE”? A. Ask a question 1. Scientific question – a question based on observations that identifies something you would like to learn more about through experimentation

  4. I. HOW DO SCIENTISTS “DO SCIENCE”? 2. Scientific questions will: a. Be testablethrough experimentation, survey or research b. Be based on observations c. Deal with the natural world d. Be genuine, something we don’t already know the answer to

  5. I. HOW DO SCIENTISTS “DO SCIENCE”? 3. Scientific questions will not: a. Include personal bias and opinion b. Deal with morals and values c. Deal with the supernatural d. Relate to phenomena that cannot be measured 4. Example of a scientific question: When dropped from a height of 5 meters, will buttered toast land butter-side up or butter-side down more often?

  6. TIME FOR A DEMO WITH DOWD! 1. Write: 5 observations about the object your teacher is showing you. Remember: Observations relate to all five senses. 2. Answer: What is the object? 3. Discuss: Talk to a neighbor about what just happened. What is the object that your teacher was showing you? Why did you originally come to the wrong conclusion about what the object was?

  7. I. HOW DO SCIENTISTS “DO SCIENCE”? B. Collect Data: Observations and Inferences 1. Good questions come from careful observations. • Observation – typically using one or more of the 5 senses to take in information from the environment Video: Observe This! 3. Data – any and all information that scientists gather in trying to answer their question

  8. I. HOW DO SCIENTISTS “DO SCIENCE”? a. Two types of data: Quantitative data – expressed as numbers, obtained by counting or measuring. Example of quantitative data: The manatee has one scar on its back.

  9. I. HOW DO SCIENTISTS “DO SCIENCE”? Qualitative data – expressed as descriptions (how something looks) that involve characteristics that can’t be counted. Example of qualitative data: The manatee’s scar appears old.

  10. I. HOW DO SCIENTISTS “DO SCIENCE”? Do now: 1. Make 5 observations about the picture. • Which data is quantitative? Qualitative? • What is going on in this picture?

  11. I. HOW DO SCIENTISTS “DO SCIENCE”? 4. Observations contrastwith an inference. An inference is a logical explanation drawn from available evidence and prior knowledge. a. Example of an inference – Sherry’s toddler is in bed upstairs. She hears a bang and crying. Sherry infers her toddler fell out of bed. b. An inference states probability not certainty. c. Are all inferences correct? No! 5. Let’s review: Observation or Inference?

  12. Observation or Inference? The grass on the school’s front lawn is wet.

  13. Observation or Inference? The fire alarm is going off because we are having a fire drill.

  14. Observation or Inference? The plant is extremely wilted.

  15. Observation or Inference? The car stopped running because it ran out of gas.

  16. Observation or Inference? A student is sitting in the main office.

  17. I. HOW DO SCIENTISTS “DO SCIENCE”? C. Form a hypothesis using observations and collected data. 1. Hypothesis – a clear statement of what you expect the answer to your question to be

  18. I. HOW DO SCIENTISTS “DO SCIENCE”? 2. A hypothesis can be proved wrong, but it can never be proved true beyond ALL doubt. (A hypothesis can often be wrong!) 3. Usually a hypothesis is written as an “If”, “then” statement. 4. Example of a hypothesis: If dropped from a height of 5 meters, then the toast will land buttered side down 75% of the time.

  19. I. HOW DO SCIENTISTS “DO SCIENCE”? D. Test the hypothesis by conducting an experiment. 1. Experimenting – the process of testing a hypothesis by gathering more data in controlled conditions

  20. I. HOW DO SCIENTISTS “DO SCIENCE”? 2. What is a “controlled experiment”? a. Controlled Experiment – tests only one variable (factor) at a time because one variable is changed and all others remain the same 3. A controlled experiment compares a control group to an experimental group. C No Light Water  D No Light No Water 

  21. I. HOW DO SCIENTISTS “DO SCIENCE”? 4. Variables: a. Independent Variable – the factor that you change/manipulate in the experimental group b. Dependent Variable – the factor that is observed and changes in response to the manipulated variable c. Controlled Variable – the factors that remain the same and are not manipulated

  22. TIME FOR A DEMO WITH DOWD! PROBLEM-Will adding blue food coloring to clear water turn the water blue? HYPOTHESIS-

  23. I. HOW DO SCIENTISTS “DO SCIENCE”? 5. Let’s review: Identify the variables in the experimental scenario below. Mrs. Oleykowski wanted to determine if there was a correlation between eating a nutritionally balanced breakfast and success on tests. One group of students was given a healthy breakfast and another group ate their regular breakfast before a test. They found that 7 out of 10 students who ate the healthy breakfast scored 80% or better on tests while 5 out of 10 students who ate their regular breakfast scored 80% or better on tests. a. What is the independent variable? ________________________________ b. What is the dependent variable? __________________________________ c. What are the controlled variables? ________________________________ d. Who is the control group? _______________________________________ e. Who is the experimental group? __________________________________

  24. I. HOW DO SCIENTISTS “DO SCIENCE”? E. Analyze results 1. Analysis – interpreting and analyzing the results of the experiment 2. Tables and graphs are usually used to organize the data

  25. I. HOW DO SCIENTISTS “DO SCIENCE”? 3. Ask and conclude: Do the results support the hypothesis? a. If the answer is yes repeat experiments or observations to verifyresults b. If the answer is no check for errors; formulate a new hypothesis F. Communicate results 1. Communicate results through written or oral reports.

  26. I. HOW DO SCIENTISTS “DO SCIENCE”? G. Important scientists and their experiments: 1. For centuries, people accepted the existing explanation for the sudden appearance of organisms that somehow “life” arose from nonliving matter. Example: Maggots came from meat; mice came from hay 2. Spontaneous Generation – the idea that living things come from nonliving things

  27. I. HOW DO SCIENTISTS “DO SCIENCE”? 3. In 1668, Francesco Redi, an Italian physician, proposed a different hypothesis for the appearance of maggots. a. Observation: Flies land on meat that is left uncovered. Later, maggots appear on the meat. b. Hypothesis: Flies produce maggots. c. Procedure:

  28. I. HOW DO SCIENTISTS “DO SCIENCE”? Independent Variable: Gauze covering the jar that keeps flies away from the meat. Dependent Variable: Whether maggots appear Experimental Group: Covered Jars Control Group: Uncovered jars d. Conclusion: Maggots form only when flies come in contact with meat, therefore, spontaneous generation did not occur.

  29. I. HOW DO SCIENTISTS “DO SCIENCE”? 4. In 1864, Louis Pasteur, a French scientist, studied spontaneous generation and the presence of air. a. Hypothesis: Microorganisms come from other microorganisms. b. Procedure:

  30. I. HOW DO SCIENTISTS “DO SCIENCE”? H. Theory 1. As evidence from multiple scientific investigations build up, a hypothesis may come so well supported that scientists consider it a theory. 2. Theory – a well tested statement of what is thought to be true a. A theory is supported by a lot of evidence. 3. Examples of theories: Germ Theory, Big Bang Theory, Theory of Evolution

  31. II. STUDYING LIFE A. Biology 1. Biology – the study of life and living things a. Organism – any living thing b. Examples of organisms: c. Approximately how many species of organisms are believed to live on earth? Guess: ________ Actual: 40 million How many have been identified and studied? 2 million

  32. II. STUDYING LIFE 2. You are an astronaut exploring a strange new planet. You discover a previously unidentified object. You are attempting to determine if it is a living organism. Below, list some of the characteristics you would look for to classify it as “living”. _____________________________________________ _____________________________________________ _____________________________________________

  33. II. STUDYING LIFE B. Characteristics of Life 1. Made Up of Cells a. A cell is the basic unit of life b. Cell – a collection of living matter enclosed by a membrane

  34. II. STUDYING LIFE c. Unicellular or single-celled organisms – made of one cell • Example of unicellular organisms: bacteria

  35. II. STUDYING LIFE d. Multicellular organisms – made of more than one cell • Example of multicellular organisms: plants and animals e. All organisms began their life as a single cell, but as they matured they develop not only many cells, but many typesof cells. • How do cells become different from each other? Differentiation

  36. II. STUDYING LIFE 2. Based on a Genetic Code a. All living things contain DNA inside each of their cells. b. DNA is vital to the successful reproduction of the cell because the DNA tells the cell its role and location within the organism. c. In multicellular organisms, the DNA of every body cell, even different kinds of cells, is identical.

  37. II. STUDYING LIFE 3. Reproduction a. All living things produce new organisms through reproduction. b. Reproduction is essential for a species to continue to survive and pass on their genetic information to the next generation.

  38. II. STUDYING LIFE c. Two kinds of reproduction: Asexual Reproduction – one cell divides in half to form two new cells; contains an identical copy of DNA • Organisms who reproduce asexually: bacteria Reproduction of Hydra

  39. II. STUDYING LIFE Sexual Reproduction – cells from two different parents unite to produce the first cell of a new organism • Organisms who reproduce sexually: dogs, cats, bacteria, orchid, plants, humans

  40. II. STUDYING LIFE 4. Maintain Internal Balance a. Homeostasis – ability to maintain stable internal conditions even with changes in an environment b. Example of homeostasis: When you get too hot, your biological thermostat turns on your “air conditioning” by causing you to sweat. Sweating helps to remove excess heat from your skin.

  41. II. STUDYING LIFE 5. Require Nutrition (Energy) a. Organisms use their energy for: growth, reproduction of new cells, maintaining homeostasis b. Metabolism – the total of all the chemical processes taking place in an organism

  42. II. STUDYING LIFE c. Two ways to obtain energy: Heterotroph – an organism who consumes their food; consumer • Examples of a heterotroph: dogs, cat, wolf, humans Autotroph – an organism who makes their own food; producer • Examples of an autotroph: plants

  43. II. STUDYING LIFE 6. Growth and Development a. All living things grow, due to cell division and enlargement. b. As organisms grow, do the number of their cells increase or does the cell’s size increase? 2-week-old puppy 2-year-old puppy puppy 

  44. II. STUDYING LIFE 7. Respond to the Environment a. All living things interact with other living and non-living parts of their environment. b. Ecologyisa branch of biology that studies these interactions. c. Let’s review: Describe all the interactions that a _________________ would have on a daily basis with it’s environment. __________________________________________ __________________________________________ __________________________________________

  45. II. STUDYING LIFE 8. Evolution a. Evolution – theory that over time, populations of organisms may change due to many adaptations passed from one generation to the next b. Adaptation - any inherited trait that allows an organism an advantage to be bettersuited in its environment

  46. II. STUDYING LIFE c. Theory of Evolution by Natural Selection – organisms that have adaptations are better able to survive and reproduce than organisms without these traits. Therefore, this can change what the population looks like!

  47. II. STUDYING LIFE C. Branches of Biology 1. Biology is such a vast topic that scientists approach their studies from a variety of perspectives. Some scientists focus on studying a specific field of science. For examples, zoologists study animals and botanists study plants. On the other hand, some scientists focus on studying living systems at different levels of organization. Do now: Use page 21 in textbook to complete Levels of Organization Table

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