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Chapter 1 The Science of Biology. 1-1 What is Science? Objectives:  State the goals of science  Describe the steps used in the scientific method.

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Presentation on theme: "Chapter 1 The Science of Biology. 1-1 What is Science? Objectives:  State the goals of science  Describe the steps used in the scientific method."— Presentation transcript:

1 Chapter 1 The Science of Biology

2 1-1 What is Science? Objectives:  State the goals of science  Describe the steps used in the scientific method

3 Goal of science The world around us can only be explained by that which we can observe  To investigate and understand nature  To explain events in nature  Use those explanations to make useful predictions

4 Science Can Change Ideas  Science- organized way of using evidence to learn about the natural world  It’s a process!  Term can also refer to the body of knowledge scientists have built up after years using this process  Some ideas or “facts” will change in time

5 Scientific Methodology  Involves observing, asking questions, making inferences and forming hypotheses, conducting controlled experiments

6 Scientific Method Make Observations Form a Hypothesis Set Up a Controlled Experiment Record Results Analyze Results Draw a Conclusion Publish Results

7 Scientific Method  Observation - the act of noticing or describing events or processes in a careful, orderly way  gather information using one or more of the senses

8 Scientific Method  Inference- logical interpretation based on prior knowledge and experience  Inferences can inform hypotheses

9 Observations vs. Inferences StatementObservation Inference Object A is round and orange. 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 X

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11 Scientific Method  Hypothesis - a scientific explanation for a set of observations that can be tested in ways that support or reject it

12 Formulating a Hypothesis 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. 1. Formulate a hypothesis that might explain the presence of the “worms” in the container. 2. How could you test your hypothesis?

13 Scientific Method  In order to have a controlled experiment, only one variable can be changed at a time  All other conditions should be kept unchanged or controlled  Independent (manipulated) variable- variable that is deliberately changed  Dependent (responding) variable- variable that is observed and changes in response to the independent variable

14 Scientific Method A controlled experiment typically consists of a  Control group - the group that is exposed to the same conditions as the experimental group except for one independent variable  Experimental group - is exposed to the independent (manipulated) variable

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16 Scientific Method  A scientist would likely set up several sets of control and experimental groups with hopes their observations are reproduced or replicated

17 Scientific Method  Two types of data - records of experimental observations or gathered information  Qualitative- descriptive; involves characteristics that cannot be easily measured or counted  Quantitative - involves numbers like when measuring or counting objects  A variety of tools can be used to collect data  Most are computer-controlled

18 Scientific Method  Care must be taken to avoid error in data collection  Data analysis and sample size should be chosen carefully  Instruments for measurement and data collection have limited accuracy  A small sample size produces less accurate results than a large sample size

19 Scientific Method Examining the data allows you to draw a conclusion: Option 1: Data supports the hypothesis  never proves it Option 2: Data refutes the hypothesis  proves it wrong Option 3: Revise hypothesis and test again

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21 When Experiments are Not Possible  Examples:  Observing animals  Prohibited by ethical considerations  Scientists attempt to maintain controlled experiments  Study large groups of subjects  Identify as many relevant variables as possible

22 1.2 Science in Context  Objectives:  Explain how scientific attitudes generate new ideas  Describe the importance of peer review  Explain what a scientific theory is  Explain the relationship between science and society

23 The Process of Science Scientific Methodology Communi -cating Results Science and Society

24 Exploration and Discovery Scientific Ideas come from 1. Scientific attitudes 2. Practical problems 3. Technology

25 Exploration and Discovery 1. Scientific attitudes help generate new ideas  Curiosity  Skepticism - question existing ideas and refuse to accept explanation without evidence  Open-mindedness - willing to accept other ideas that don’t agree with their hypothesis  Creativity

26 Exploration and Discovery  Practical problems  E.g. Reducing human impact on the environment

27 Exploration and Discovery  Role of Technology  Advances in technology enable scientists to pose new questions and gather data in new ways

28 The Process of Science Scientific Methodology Communi -cating Results Science and Society

29 Communicating Results  Communication and sharing ideas is vital to modern science  Peer review - a process where scientific findings are reviewed by anonymous, independent experts  Work that is accepted is published in a scientific journal allowing other researchers to access that information and to test and evaluate it  Peer-reviewed doesn’t guarantee article is “correct”, but ensures work meets certain criteria

30 Scientific Theories  Theory - well-tested explanation that unifies a wide range of observations  Happens when a hypothesis is so well supported by the scientific community  Or inspired by evidence from related hypotheses  Allows scientists to make accurate predictions about new situations

31 Scientific Theories  No theory is considered absolute truth  Although some theories are considered the dominant theory because the majority of scientists share that view  May be revised or replaced by a more useful explanation

32 The Process of Science Scientific Methodology Communi -cating Results Science and Society

33  Science alone cannot answer the questions that affect our society  Issues must involve society in which we live, our economy, laws and moral principles  We must understand its context in society and its limitations

34 Science and Society Pure science does not include ethical or moral viewpoints  Biologists try to explain what life is, how life operates, how it changed over time  They cannot answer why life exists or what the meaning of life is  Science can tell us how technology can be applied  But moral and ethical viewpoints may limit its use

35 Science and Society  The way science is applied in society can be affected by bias  It is a personal viewpoint, not a scientific one  Scientific data can be misinterpreted or misapplied by scientists who want to prove a particular point

36 Science and Society  Understanding science can help ensure it is applied in ways that benefit humanity  It will help you make complex decisions that involve cultural customs, values, and ethical standards  Will help you realize we can predict the consequences of our actions and take and active role in directing our future and that of our planet

37 1-3 Studying Life Objectives:  List the characteristics of living things  Identify the central themes of biology  Explain how life can be studied at different levels  Discuss the importance of a universal system of measurement

38 Characteristics of Living Things 1. Made up of Basic Units called Cells 2. Based on a Universal Genetic Code 3. Obtain and Use Materials and Energy 4. Grow and Develop 5. Reproduce 6. Respond to their Environment 7. Maintain a Stable Internal Environment 8. Change Over Time  ALL of these characteristics must be present for something to be considered living

39 Made up of Basic Units called Cells  Organisms are composed of one or more cells Unicellular (one cell) Paramecium caudatum Multicellular (many cells) Ginkgo biloba

40 Based on a Universal Genetic Code  Organisms store the complex information they need to live, grow, and reproduce in a genetic code known as DNA  DNA is copied and passed from parent to offspring  Life’s genetic code, with a few minor variations, is nearly identical in every organism on Earth

41 Obtain and Use Materials and Energy  Organisms take in materials and energy to grow, develop, and reproduce  Chemical reactions used by an organism to build up or break down materials is referred to as metabolism  Ex: photosynthesis and cellular respiration

42 Grow and Develop  Growth refers to the increase in an organism’s size  Achieved when cells divide  Development refers to the changes in that organism that occur over its life  As an organism develops, its cells can differentiate to look different and carry out different functions

43 Reproduce Organisms produce new similar offspring  Sexual reproduction- genetic information from two parents unites to produce the first cell of the new organism Sexual reproduction-  Used by most plants and animals, protists, fungi, and bacteria  Bacteria use a simple type of SR  Asexual reproduction- a single organism produces an offspring identical to itself  Bacteria, fungi, protists, some plants

44 Respond to their Environment  Organisms detect a stimulus (stimuli plural) which causes a response  Stimulus - signal to which organism responds  Response- reaction to stimulus

45 Maintain a Stable Internal Environment  Homeostasis is the process by which organisms maintain a relatively stable internal environment even when external conditions change drastically  Ex: regulation of body temperature, glucose, water and salts

46 Change Over Time  Taken as a group, living things evolve  A shared history is evidenced by the fossil record and similar physiology and biochemistry (proteins and DNA)

47 CharacteristicExamples 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. 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, dogs, and maple trees contain similar hereditary information in the form of DNA. 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.

48 Copyright Pearson Prentice Hall Big Ideas in Biology Cellular Basis of Life  Organisms are composed of one or more cells, which are the smallest units that can be considered fully alive.

49 Copyright Pearson Prentice Hall Big Ideas in Biology Information and Heredity  Genetic code is common, with minor variations, to every organism on Earth.  That information, carried in DNA, is copied and passed from parents to offspring.

50 Copyright Pearson Prentice Hall Big Ideas in Biology Matter and Energy  Matter serves as nutrients to build body structure and energy to fuel the processes of life.

51 Big Ideas in Biology Growth, Development, and Reproduction  All living things reproduce and the offspring is most often smaller than the mature form. New organisms undergo growth and development where they become larger and generalized cells become specialized to carry out different functions.

52 Copyright Pearson Prentice Hall Big Ideas in Biology Homeostasis  An organism’s ability to maintain a relatively stable internal environment.

53 Copyright Pearson Prentice Hall Big Ideas in Biology Evolution  In biology, evolution, or the change in living things through time, explains inherited similarities as well as the diversity of life.

54 Copyright Pearson Prentice Hall Big Ideas in Biology Structure and Function  Structures evolve in ways that make particular functions possible, allowing organisms to adapt to a wide range of environments.

55 Copyright Pearson Prentice Hall Big Ideas in Biology Unity and Diversity of Life  All living things are fundamentally alike at the molecular level, even though life takes an almost unbelievable variety of forms.

56 Copyright Pearson Prentice Hall Big Ideas in Biology Interdependence in Nature  All forms of life on Earth are connected together into a biosphere, which literally means “living planet.”

57 Copyright Pearson Prentice Hall Big Ideas in Biology Science as a Way of Knowing  Science is not just a list of “facts.”  The job of science is to use observations, questions, and experiments to explain the natural world.

58 Big Ideas in Biology Big IdeaBook Chapter(s) Related fields of biology or careers Cellular Basis of Life1.3, 7, 9microbiologist Information and heredity11Researching genetics Matter and Energy2, 8, 9Zoology, physicians Growth, Development and Reproduction 10, 11, 24Medical, OB/GYN, zoologi Homeostasis1.3, 7.4, 30.1 medical Evolution16 and 17Biogeography, paleontologists Structure and Function7.2, 17.2, 23… Zoologist, medical Unity and Diversity of Life11, 16, 18Genetics, evolution, taxonomy Interdependence in Nature1.3 and 3Conservationist, field biologist Science as a Way of Knowing1, 16, 19, and 6 research

59 What measurement system do most scientists use? Most scientists use the metric system when collecting data and performing experiments. SI: A Common Measurement System

60 Copyright Pearson Prentice Hall A Common Measurement System Because the metric system is based on multiples of 10, it is easy to use.

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62 Redi’s Experiment, designed to refute Spontaneous Generation - the idea that life could arise from nonliving matter 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 jarsCovered jars Several days pass Maggots appearNo maggots appear Responding Variable: whether maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

63 Repeating Redi  Key assumption in science- experimental results can be reproduced because nature acts in a consistent manner  Redi’s work followed by  Needham -used an experiment with “animalcules” to attack Redi’s work  Spallanzani - improved upon Needham’s experiment  Pasteur -allowed broth to come into contact with the air

64 Spallanzani’s Experiment Gravy is boiled.Flask is open. Gravy is boiled. Flask is sealed. Gravy is free of microorganisms.

65 Pasteur’s Experiment Broth is boiled.Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms. Showed that all living things come from other living things


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