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Invitation to Biology

Invitation to Biology. Chapter 1. 1.1 Life’s Levels of Organization. Nature has levels of organization Unique properties emerge at successively higher levels . Organization Within An Organism. Atoms are organized into molecules

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Invitation to Biology

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  1. Invitation to Biology Chapter 1

  2. 1.1 Life’s Levels of Organization • Nature has levels of organization • Unique properties emerge at successively higher levels

  3. Organization Within An Organism • Atoms are organized into molecules • In multicelled species, cells are organized into tissues, organs, and organ systems • All organisms consist of one or more cells • Emergent properties: Life emerges at the cellular level

  4. Organization of Groups of Organisms • Population • All individuals of one species in a specific area • Community • All populations in a specific area • Ecosystem • A community interacting with its environment

  5. Organization of Life on Earth • Biosphere • All regions of Earth that hold life • Land, water, and atmosphere

  6. Levels of Organization

  7. Levels of Organization

  8. molecule cell tissue organ organ system atom Fig. 1.3a, p. 4

  9. multicelled organism population community ecosystem biosphere Fig. 1.3b, p. 4

  10. KEY CONCEPTS:LEVELS OF ORGANIZATION • We study the world of life at different levels of organization, from atoms and molecules to the biosphere • “Life” emerges at the level of cells

  11. 1.2 Overview of Life’s Unity • Organisms require energy and materials to sustain their organization and activities • Nutrients are required for growth and survival • Producers make their own food • Consumers eat other organisms

  12. Ecosystem: Energy Flow and Material Cycling

  13. Energy input, from sun Producers Nutrient cycling Consumers energy output (mainly metabolic heat) Fig. 1.4, p. 6

  14. Overview of Life’s Unity • Organisms sense change • Receptors respond to stimulation • Responses keep internal conditions within ranges that cells can tolerate (homeostasis)

  15. Response to Stimulus

  16. Overview of Life’s Unity • Organisms grow and reproduce • Based on information encoded in DNA • Inheritance transmits DNA from parents to offspring through reproduction mechanisms • Development transforms first cell into an adult

  17. Instructions Assemble Materials

  18. Development

  19. Fig. 1.7a, p. 7

  20. Fig. 1.7b, p. 7

  21. Fig. 1.7c, p. 7

  22. Fig. 1.7d, p. 7

  23. Fig. 1.7e, p. 7

  24. KEY CONCEPTS:LIFE’S UNDERLYING UNITY • All organisms are alike in key respects: • Consist of one or more cells • Live through inputs of energy and raw materials • Sense and respond to changes in their external and internal environments • Cells contain DNA (molecule that offspring inherit from parents; encodes information necessary for growth, survival, and reproduction)

  25. Animation: Life's levels of organization CLICK HERE TO PLAY

  26. Animation: One-way energy flow and materials cycling CLICK HERE TO PLAY

  27. Animation: Building blocks of life CLICK HERE TO PLAY

  28. Animation: Insect development CLICK HERE TO PLAY

  29. 1.3 So Much Unity, So Many Species • The world of life, past and present, shows great diversity • Classification systems organize species in ever more inclusive groups

  30. Genus and Species • Species: One kind of organism • Each species has a two-part name • First part: Genus name • Combined with the second part, it designates one particular species

  31. Domains • Current classification groups all species into three domains • Bacteria (single-celled prokaryotes) • Archaea (single-celled prokaryotes) • Eukarya (protists, plants, fungi, and animals)

  32. Bacteria and Archaea Bacteria Archaea

  33. Eukarya

  34. Eukarya

  35. Eukarya

  36. Eukarya

  37. Life’s Three Domains

  38. KEY CONCEPTS:LIFE’S DIVERSITY • The world of life shows great diversity • Many millions of kinds of organisms (species) have appeared and disappeared over time • Each species is unique in at least one trait—in some aspect of its body form or behavior

  39. Animation: Three domains CLICK HERE TO PLAY

  40. Animation: Life's diversity CLICK HERE TO PLAY

  41. 1.4 An Evolutionary View of Diversity • Life’s diversity arises from mutations • Changes in molecules of DNA which offspring inherit from their parents • In natural populations, mutations introduce variation in heritable traits among individuals

  42. Variation in Heritable Traits • Some trait forms are more adaptive than others • Bearers are more likely to survive and reproduce • Over generations, adaptive forms of traits tend to become more common in a population • Less adaptive forms of the same traits become less common or are lost

  43. Evolution • Populations evolve • Traits that help characterize a population (and a species) can change over generations • Evolution • Change which occurs in a line of descent

  44. Selection • Natural selection • In natural populations • Differential survival and reproduction among individuals that vary in one or more heritable traits • Artificial selection • Breeding of captive populations • Traits selected are not necessarily adaptive

  45. Artificial and Natural Selection

  46. 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

  47. 1.5 Critical Thinking and Science • Critical thinking is a self-directed act of judging the quality of information as one learns • Science is a way of looking at the natural world • Helps minimize bias in judgments • Focuses on testable ideas about observable aspects of nature

  48. Evidence-Based Thinking

  49. 1.6 How Science Works • Researchers generally • Observe something in nature • Form hypotheses (testable assumptions) about it • Make predictions about what might occur if the hypothesis is not wrong • Test their predictions by observations, experiments, or both

  50. Experiments • Tests used to support or falsify a prediction • Variable characteristic is measured and changed • In the control group, variables do not change

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