1. The Science of Biology Chapter 1

2. 1.1 The Diversity of Life Archaea Bacteria ProtistaFungiPlantaeAnimalia Taxonomists classify organisms into 6 Kingdoms Prokaryotic Kingdoms: (2) 1.Archaea Includes bacteria (prokaryotes) that thrive in extreme environments 2.Bacteria Includes common bacteria (prokaryotes) Eukaryotic Kingdoms: (4) 3.Protista Includes eukaryotic organisms that are not a fungus, plant, or animals. 4.Fungi Eukaryotic organisms that digest food by absorption 5.Plantae Eukaryotic, photosynthetic organisms 6.Animalia Eukaryotic, non-photosynthetic consumers. KINGDOMS

3. 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 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)

4. 1.3 The Organization of Life Living organisms function and interact with each other at many levels These levels are organized in a hierarchy of increasing complexity Cellular Level Organismal Level Populational Level

6. 1.3 The Organization of Life Each higher level contains novel properties not present at the simpler level of organization These properties are termed emergent properties They are a consequence of the structural organization that is the hallmark of life They characterize many aspects of the living world

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 It is also how a computer works

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

12. Inductive Vs Deductive Reasoning

13. 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 2. Hypothesis Guess regarding the observation If more than one guess, alternative hypotheses are formed 3. Prediction Expected consequences based on the correct hypothesis 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

14. 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

15. 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

16. 1.9 Four Theories Unify Biology 1. The Cell Theory 2. The Gene Theory 3. The Theory of Heredity 4. The Theory of Evolution

17. The Cell Theory: Organization of Life Robert Hooke, 1665 Discovered cells Anton van Leeuwenhoek, 1670s Discovered single-celled life Components of the Cell Theory 1.All living organisms are composed of cells 2.Cells are the basic units of life 3.All cells come from other cells

18. The Gene Theory: Molecular Basis of Inheritance The information that determines what an organism is like is encoded in its genes Genes are located along DNA molecules The entire set of DNA instructions that specifies a cell is termed its genome

19. The Theory of Heredity: Unity of Life This theory was first advanced by Gregor Mendel in 1865 It basically states that genes of an organism are inherited as discrete units Later, other biologists proposed the chromosomal theory of inheritance Genes are physically located on chromosomes

20. The Theory of Evolution: Diversity of Life Introduced by Charles Darwin (1859) The diversity of the living world is attributed to natural selection An essential component of this theory is that evolution involves “descent by modification”

22. Darwin…..

23. Biologists divide all living organisms into three great groups, termed domains 1.Bacteria 2.Archaea 3.Eukarya