Chapter 1 Invitation to Biology

1. Hsueh-Fen Juan 阮雪芬 Sep. 11, 2012 Chapter 1Invitation to Biology

2. 1.1 Life’s Levels of Organization • We understand life by thinking about nature at different levels of organization • Nature’s organization begins at the level of atoms, and extends through the biosphere • The quality of life emerges at the level of the cell

3. Making Sense of the World • Nature is everything in the universe except what humans have manufactured

4. A Pattern in Life’s Organization • Atoms • Fundamental building blocks of all substances • Molecules • Consisting of two or more atoms • Cell • The smallest unit of life • Organism • An individual consisting of one or more cells

5. A Pattern in Life’s Organization • Population • Individuals of the same species in the same area • Community • Populations of all species in the same area • Ecosystem • A community and its environment • Biosphere • All regions of the Earth where organisms live

6. Levels of Organization in Nature

7. Levels of Organization in Nature

8. Emergent Properties • Each level of organization in nature has emergent properties – a characteristic of a system that does not appear in any of its component parts

9. 1.1 Key Concepts:Levels of Organization • We study the world of life at different levels of organization, which extend from atoms and molecules to the biosphere • The quality of “life” emerges at the level of cells

10. 1.2 Overview of Life’s Unity • All living things have similar characteristics • Continual inputs of energy and the cycling of materials maintain life’s complex organization • Organisms sense and respond to change • DNA inherited from parents is the basis of growth and reproduction in all organisms

11. Energy and Life’s Organization • Energy • The capacity to do work • Nutrients • Atoms or molecules essential in growth and survival that an organism cannot make for itself

12. Producers and Consumers • Producers • Acquire energy and raw materials from the environment • Make their own food (photosynthesis) • Consumers • Cannot make their own food • Get energy by eating producers and other organisms

13. Organisms Sense and Respond to Change • Organisms sense andrespond to change both inside and outside the body by way of receptors • Receptor • A molecule or cellular structure that responds to a specific form of stimulation

14. Homeostasis • Homeostasis • Organisms use receptors to help keep conditions in their internal environment within ranges that their cells can tolerate

15. Organisms Grow and Reproduce • Organisms grow, develop, and reproduce using information in their DNA, a nucleic acid inheritedfrom parents • Information encoded in DNA is the source of an individual’s distinct features (traits)

16. Same Materials, Many Products • 20 amino acids are the building blocks used to build a great variety of proteins

17. 1.2 Key Concepts:Life’s Underlying Unity • All organisms consist of one or more cells, which stay alive through ongoing inputs of energy and raw materials • All sense and respond to change; all inherited DNA, a type of molecule that encodes information necessary for growth, development, and reproduction

18. 1.3 Overview of Life’s Diversity • Of an estimated 100 billion kinds of organisms that have ever lived on Earth, as many as 100 million are with us today

19. Scientific Naming • Each type of organism is given a two-part name that includes genus and species names • Genus • A group of species that share unique features • Species • Individuals that share one or more heritable traits and can interbreed (if sexually reproducing)

20. Classification Systems • Classification systems group species by their shared, heritable traits • All organisms are classified into three domains • Bacteria, archaea, and eukaryotes • Eukaryotes include plants, animals, protistsandfungi

21. Comparison of Life’s Three Domains

22. 1.3 Key Concepts:Life’s Diversity • Many millions of kinds of organisms, or species, have appeared and disappeared over time • Each kind is unique in some aspects of its body form or behavior

23. One-Way Flow of Energy and Cycling of Materials through an Ecosystem

24. 1.4 An Evolutionary View of Diversity • A theory of evolution by natural selection is an explanation of life’s diversity

25. Variation and Mutation • Information encoded in DNA is the basis of traits an organism shares with others of its species • Mutations are the original source of variation in traits

26. Adaptation • Some forms of traits are more adaptive than others, so their bearers are more likely to survive and reproduce • Over generations, adaptive traits tend to become more common in a population; less adaptive forms of traits become less common or are lost

27. Evolution and Natural Selection • Evolution is change in a line of descent • Traits that characterize a species can change over generations in evolving populations • Natural selectionis an evolutionary process • Differential survival and reproduction among individuals that vary in the details of their shared, heritable traits

28. 1.4 Key Concepts:Explaining Unity in Diversity • Theories of evolution, especially a theory of evolution by natural selection, help explain why life shows both unity and diversity • Evolutionary theories guide research in all fields of biology

29. 1.5 Critical Thinking and Science • Critical thinking is judging the quality of information • Science is limited to that which is observed • Helps minimize bias in judgments by focusing on testable ideas about observable aspects of nature

30. A Guide to Critical Thinking

31. 1.6 How Science Works • Scientists make and test potentially falsifiable predictions about how the natural world works

32. Observations, Hypotheses, and Tests • Researchers make observations, form hypotheses (testable assumptions), and make predictions about what might occur if the hypothesis is correct

33. A Scientific Approach

34. Research in Laboratory and Field

35. Systems Biology 牛頓2003年11月2003年11月 Prof. Kitano