2. Chapter 1 Introduction: Themes in the Study of Life

3. Levels of Biological Organization u Biosphere ---to--- molecule

4. Diversity and Unity u Diversity u Taxonomy u 3 Domains Unity Evolution Example: cillia

5. What are Themes? u General principles or ideas that occur over and over. u “Themes” are not a test item, but they are a framework to organize the study of Biology.

6. Unifying Themes in the Study of Life 1. The living world is a hierarchy. Emergent Properties emerge-with each step in life’s hierarchy.

7. 2. The Cell Is the “basic unit” of Life

8. . u Life on Earth uses the nucleic acid and code for Heritable Information. 3. The continuity of life is based on DNA

9. Growth & Development u Organisms increase in size and complexity.

10. u Organisms reproduce their own kind.

11. 4. Structure and function are correlated at all levels of biological organization.

12. . u Structure and Function are related at all levels.

13. u 5. Organisms are “open” systems, they must continually take in energy. u Energy to do work u Sun is ultimate source

14. 6 Regulation Feedback mechanisms: Positive and Negative Organisms maintain their internal environment within tolerable limits.

15. Homeostasis u “homeo” = same “stasis” = state

16. . u Structure and Function are related at all levels.

17. 7. Unity in Diversity u The three Domains of Life The 6 Kingdoms

18. u 8.Evolution—THE CORE THEME-explains unity and diversity.

19. u 9. Scientific Inquiry u Observation-based u Hypothesis-based

20. u 10.Integrating Science & Technology for society. u Marriage of u Understanding natural phenomena u Apply this knowledge for a specific purpose

21. Evolutionary Adaptation u Organisms change over time as they adapt to their environment.

22. u Organisms must adapt, move, or die!

23. 1. Order u Living things are highly organized in structure and function.

24. u Analyzing a biological structure gives us clues about what it does and how it works

25. u Growth - increase in size. Development - increase in complexity. u Life - grows by internal changes. u.u.

26. 4. Energy Utilization u Organisms take in energy and transform it to do work.

27. 5. Response To Environment u Organisms respond to changes or stimuli in their environment.

28. u The speed of the response may be “fast” or “slow”.

29. 6. Homeostasis u “homeo” = same “stasis” = state

30. Science is: u A process. u A way of “knowing”.

31. Science is based on: u Observations u Experiments u Deductive Reasoning

32. Observations: u Are the “keystone” to Science. u If it can’t be “observed”, it can’t be studied by the Scientific Method. u Can be made through your senses or through the use of tools.

33. Scientific Method: u A formal process of inquiry. u Obtains “evidence” through the use of experiments. u Hypothetico-deductive reasoning. u Use deductive logic to test a hypothesis.

35. Scientific Method Steps 1. Identify the problem. 2. What is already known? 3. Formulate a hypothesis. If- (this is what you test)-then (this is your expected result) statement 4. Conduct an experiment.

36. Scientific Method Steps 5. Collect data. 6.Compare data to hypothesis. 7. Conclusions and new hypothesis.

37. Theories vs. Laws u Theory: u A comprehensive explanation of a natural phenonemon suppported by much interrelated research. u Applicable to a particular situation and time.

38. u Laws: True anywhere in the universe, anytime

39. Summary u We will see the “themes” at various times throughout the course. u AP Biology students must be able to design an experiment to test a hypothesis. u Why? This is a national exam test item.

40. Matter u Anything that has mass and occupies space.

41. Element u Matter made up of only one type of atom. u 92 natural elements. u Each element has a symbol.

43. Atoms u Smallest particle of elements.

44. Compound u Elements combined in fixed ratios. u A compound has characteristics beyond those of its combined elements.

45. Question? u What Elements are necessary For Life? u Life requires about 25 chemical elements.

47. Macroelements u Elements needed in large amounts or quantities. u Examples: C HOPKNS CaFe Mg NaCl

48. ControlMinus Nitrogen

49. Microelements u Elements needed in very small quantities. u Also known as Trace Elements. u Examples: I, Cu, Fl, Zn, Mo, Mn

50. Goiter – minus Iodine

51. Atoms and Molecules u Atomic structure determines the behavior of an element.

52. Atomic Particles u Protons + charge, 1 Dalton mass u Neutrons no charge, 1 Dalton mass u Electrons - charge, essentially no mass

53. Atomic Model

54. u Atomic Number u Atomic Mass

57. Isotopes u Atoms of the same element u with different atomic mass. u caused by changes in the number of neutrons. u Used as “tracers”.

58. Types of Isotopes 1. Radioactive - where the nucleus decays spontaneously, giving off particles and energy. 2. Heavy - has a stable nucleus, but masses more than the standard isotope for the element.

60. Energy & Electrons

61. Energy u The ability to do work.

62. Potential Energy u Is the energy that matter stores u Electrons have potential energy because of their position relative to the nucleus.

64. Electron Energy Levels (shells) u Energy levels around the nucleus of an atom. u 1st level can have 2 electrons and has the lowest potential energy. u Other levels can hold more than 2 electrons and have higher energy levels.

65. Electron Orbitals u The three dimensional space where an electron is found 90% of the time. u Different orbitals have different shapes. u Each orbital can hold only 2 electrons.

66. Electron Orbitals

67. Chemical Behavior Of An Atom u Based on the number and location of electrons in valence shell. u Reactivity arises from the presence of unpaired electrons in valence shell.

68. Valence Electrons u Electrons in the outermost energy level. u Electrons available chemical bonds.

69. Octet Rule u The most stable condition is to have an outer level of 8 electrons. u Exception - 1st level is stable with only 2 electrons. u When stable - no chemical reactions will take place. Ex: Ne, He, (Noble gases)

70. Electrons of the first elements

71. Chemical Bonds-Forming Molecules. u Forces that join atoms together to form molecules. u Usually caused by sharing or transferring valence electrons. u Bond Formation Depends On: u The number of valence electrons that must be gained, lost, or shared to reach the stable condition.

72. Chemical Bond Types u Nonpolar Covalent u Polar Covalent u Ionic u Hydrogen

73. Nonpolar Covalent u When electrons are shared equally between atoms. u Very strong bond. u Important in many molecules found in living things. u Ex: carbon to hydrogen

74. Nonpolar Covalent u Can be single, double, or triple between two atoms. O=O u Each nonpolar covalent bond involves a pair of electrons.

76. Polar Covalent u When electrons are shared unequally between atoms. u Results in “polar” molecules that have charged areas. Ex: Water, H to O bonds

77. Ionic Bonds u Formed when electrons are transferred from one atom to another and ions are formed.

78. Types of Ions u Cations - have lost electrons (p+ > e-) giving them a positive charge. u A n ions - have gained electrons (p+ < e-) giving them a negative charge.

79. Ionic Bonds u Formed when cations and anions attract each other. u Weak chemical bond.

80. Ionic Bonds

82. Types of Bonding Between Molecules or within large molecules u Hydrogen Bonds u Van der Waals

83. Hydrogen Bonds u When a hydrogen atom bonded to one molecule is attracted to the slightly negative area (often N or O) of another molecule. u Very weak individual bond. u Can be a “strong” force if there are many H bonds.

84. Hydrogen Bonds

85. Molecular Shape u Determined by the positions of the atom’s orbitals.

87. Molecular Shape u Crucial in Biology : determines how most molecules of life recognize and respond to one another.

89. Chemical Reactions u The making and breaking of chemical bonds. u Reactions do not destroy matter, they only rearrange it.

90. Chemical Equations u A way to represent what is happening in a chemical reaction. Ex: 2 H 2 + O 2 2 H 2 O

91. Parts of the Equation u Reactants: - the starting materials. u Products: - the ending materials. u Note - all atoms of the reactants must be accounted for in the products. 2 H 2 + O 2 2 H 2 O

93. Chemical Equilibrium u When the conversion of reactants to products is balanced to the reverse reaction. Ex: 3 H 2 + N 2 2 NH 3

94. Summary u We will now put elements together to form molecules and build the next level in the hierarchy.