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1 The Living World Chapter 1: The Science of Biology Specific Learning Outcomes: 1.1 List the major properties of life. 1.2 Explain how science is distinguished from other ways of seeking understanding of life. 1.3 Explain the significance of major unifying themes of modern biology. 1.4 Explain the limitations of science. 1.5 Identify how the steps in the scientific process were used to determine the effects of CFCs on the earth s ozone layer.

2 1.1 The Diversity of Life Biology is the study of living things Living things can be divided into six kingdoms Fig. 1.1 Archaea Bacteria Protista Fungi Plantae Animalia

3 1.2 Properties of Life Biology is the study of life But what does it mean to be alive? Living organisms and many non-living things share three properties Complexity Movement Response to stimulation

4 1.2 Properties of Life All living organisms share five basic properties 1. Cellular Organization All living organisms are composed of at least one cell 2. Metabolism All living organisms use energy 3. Homeostasis All living organisms maintain stable internal conditions

5 1.2 Properties of Life All living organisms share five basic properties 4. Growth and reproduction All living organisms grow and reproduce 5. Heredity All living organisms possess a genetic system that is based on DNA Deoxyribonucleic acid

6 1.4 Biological Themes The living world is organized by major themes Indeed, five general themes unify and explain biology as a science Refer to Table 1.1 Evolution, cooperation, flow of energy structure determines function, and homeostasis

7 1.4 Biological Themes 1. Evolution The genetic change in a species over time It is a result of a process termed natural selection Variation may also be caused by artificial selection 2. The Flow of Energy All living organisms require energy The sun is the source of energy for ecosystems Plants capture energy via photosynthesis They then act as an energy source for other organisms

8 1.4 Biological Themes 3. Cooperation Cooperation between organisms is critical for evolution Symbiosis occurs when two organisms of different species live in direct contact 4. Structure Determines Function Biological structures are well suited to their function This is true at every level of organization

9 1.4 Biological Themes 5. Homeostasis All living organisms act to maintain a relatively stable internal environment Maintaining homeostasis requires a lot of signaling back-and-forth between cells

10 1.5 How Scientists Think Deductive Reasoning Using accepted general principles as a guide to explain specific observations It is the reasoning of Mathematics Philosophy Politics Ethics

11 1.5 How Scientists Think Inductive Reasoning Discovering general principles through examination of specific cases It is used by scientists to develop hypotheses about how the world works

12 Fig. 1.5

13 1.6 Science in Action: A Case Study In 1985, a scientist discovered low levels of ozone in the upper Antarctic atmosphere The culprit was later revealed to be chlorofluorocarbons (CFCs) Coolants in air conditions; propellants in aerosols CFCs condense into tiny ice crystals Warmed by the sun, they attack and destroy ozone

14 Fig. 1.6 How CFCs attack and destroy ozone

15 1.6 Science in Action: A Case Study The ozone layer protects us from the sun s ultraviolet (UV) rays 1% drop in ozone 6% increase in skin cancers Its depletion is a serious world problem So governments have rushed to correct the situation There is now a worldwide reduction in CFC production The ozone layer will recover by mid-21 st century

16 1.7 Stages of a Scientific Investigation The scientific process can be divided into six stages 1. Observation Careful observation of a process or phenomenon Question asked 2. Hypothesis A probable answer regarding the observation If more than one answer, alternative hypotheses are formed 3. Prediction Expected consequences based on the correct hypothesis

17 1.7 Stages of a Scientific Investigation The scientific process can be divided into six stages 4. Testing The hypothesis is tested through an experiment 5. Controls A factor that influences a process is called a variable In a control experiment, all variables are held constant 6. Conclusion Based on the results of the experiment, a hypothesis is either accepted or rejected

18 Observation Question Conclusion Hypothesis Prediction Experiment

19 Fig. 1.7 Observation The scientific method Question Hypothesis 1 Hypothesis 2 Hypothesis 3 Hypothesis 4 Hypothesis 5 Experiment Reject hypotheses 1 and 4 Potential hypotheses Hypothesis 5 Hypothesis 3 Hypothesis 2 Experiment Reject hypotheses 2 and 3 Remaining possible hypotheses Hypothesis 5 Last remaining possible hypothesis Predictions Experiment 1 Experiment 2 Experiment 3 Experiment 4 Predictions confirmed

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21 1.8 Theory and Certainty A theory is a set of hypotheses that have been tested many times and not rejected It indicates a higher degree of certainty However, there is no absolute truth in science So the acceptance of a theory is provisional

22 1.8 Theory and Certainty Note: To scientists, a theory represents that of which they are most certain To the general public, a theory represents lack of knowledge or a guess

23 1.8 Theory and Certainty The limitations of science It is limited to organisms and processes that can be observed and measured Supernatural and religious phenomena are beyond the scope of science There are also practical limits Science cannot be relied upon to solve all problems

24 The Living World Chapter 1: The Science of Biology Specific Learning Outcomes: 1.1 List the major properties of life. 1.2 Explain how science is distinguished from other ways of seeking understanding of life. 1.3 Explain the significance of major unifying themes of modern biology. 1.4 Explain the limitations of science. 1.5 Identify how the steps in the scientific process were used to determine the effects of CFCs on the earth s ozone layer.