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CHAPTER 1 – THE SCIENCE OF LIFE

Section 1-1: The World of Biology Section 1-2: Themes in Biology Section 1-3: The Study of Biology Section 1-4: Tools + Techniques. CHAPTER 1 – THE SCIENCE OF LIFE. Biology + You Biology The study of life

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CHAPTER 1 – THE SCIENCE OF LIFE

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  1. Section 1-1: The World of Biology Section 1-2: Themes in Biology Section 1-3: The Study of Biology Section 1-4: Tools + Techniques CHAPTER 1 – THE SCIENCE OF LIFE

  2. Biology + You • Biology • The study of life • Offers an organized and scientific framework for posing + answering questions about the natural world Section 1-1: the world of biology

  3. Biologists study questions about: • How living things work • How they interact with their environment • How they change over time • Studies many different kinds of living things • Examples: bacteria to elephants Section 1-1: the world of biology

  4. By studying biology you can make important decisions on issues that impact you and society • Biologists actively work to solve real-world issues + problems • Examples: • Improving foodsupply • Curing diseases • Preserving our environment Section 1-1: the world of biology

  5. Characteristics of Life • Living things share 7 characteristics of life Section 1-1: the world of biology

  6. (1) Organization + Cells • Organization • The high degree of order within an organism’s internal + external parts and in its interactions with the living world • Ex: Rock vs. Owl? • All living things, whether made up of 1 cell or many cells have some degree of organization Section 1-1: the world of biology

  7. Organization + Cells • Cell • The smallest unit that can perform all life’s processes • Unicellular • Organisms made up of only 1 cell • Ex: bacteria • Multicellular • Organisms made up of multiple cells • Ex: humans or trees Section 1-1: the world of biology

  8. Organization + Cells • Reverse Biological Hierarchy • Organ systems • Group of organs • Organs • Group of tissues • Tissues • Group of cells • Cells • Organelles • Tiny cell structures that carry out functions necessary for the cell to stay alive • Biological molecules • Chemical compounds used in structures + other cellular functions • Atoms • Simplest particle of an element that retains all the properties of a certain element Section 1-1: the world of biology

  9. (2) Response to Stimuli • Stimulus • A physical or chemical change in the internal or external environment • Example: • Brightness of light • Organisms must be able to respond + react to changes in the environment to stay alive Section 1-1: the world of biology

  10. (3) Homeostasis • A mechanism to maintain stableconditions • Example: • Water content in a cell • Homeostasis • The maintenance of a stable level of internal conditions even though the environmental conditions are constantly changing • Organisms have regulatory systems that maintain internal conditions such as: • Temperature • Water content • Uptake of nutrients by the cell Section 1-1: the world of biology

  11. (4) Metabolism • Living organisms use ENERGY to power all the processes such as repair, movement, + growth • Metabolism • Sum of all the chemical reactions that take in and transform energy and materials from the environment • Example: • PHOTOSYNTHESIS (plants) • Obtaining FOODENERGY (animals) Section 1-1: the world of biology

  12. (5) Growth + Development • All living things grow and increase in size • Nonliving things, such as crystals or icicles, grow by accumulating more of the same material they are made of • Growth of living things result from division + enlargement of cells Section 1-1: the world of biology

  13. Growth + Development • Cell Division • The formation of 2 new cells from an existing cell • Unicellular • Division, enlargement • Multicellular • Division, enlargement, development • Development • The process by which an organism becomes a mature adult • Involves cell division + cell differentiation (specialization) • As a result of development, an adult organism is composed of many cells specialized for different functions Section 1-1: the world of biology

  14. (6) Reproduction • Reproduction • Process of producing new organisms • Not essential to the survival of an individualorganism • Essential for the continuation of a species • During reproduction, organisms transmit hereditary information to their offspring • Known as deoxyribonucleicacid (DNA) • Gene • Short segment of DNA that contains the instructions for a single trait Section 1-1: the world of biology

  15. Reproduction • Sexual • Hereditary info. combines from two parents • sperm + egg • Offspring similar to parents, not identical • Example: Frogs • Asexual • Hereditary info. Not combined; only one parent reproduces • Offspring identical to parent • Example: Bacteria Section 1-1: the world of biology

  16. (7) Change through Time • Although individual organisms experience many changes during their lifetime, their basic genetic characteristics do not change • However, populations of living organisms evolve or change through time • The ability of populations of organisms to change over time is important for survival in a changing world • This also explains the diversity of life-forms Section 1-1: the world of biology

  17. All definitions Meaning of Biology (purpose, how it affects your lives, etc…) 7 Characteristics of Life (meanings + examples) Section 1-1: WHAT TO KNOW…

  18. (1) Diversity + Unity of Life • Diversity • Variety of life • Biologists have identified more than 1.5 million species on Earth Section 1-2: themes in biology

  19. Unity • Features that all living things have in common: • The genetic code • Rules that govern how cells used the hereditary information in DNA • Presence of organelles that carry out all cellular activities Section 1-2: themes in biology

  20. “Tree of Life Model” • Places organisms that have more similar sets of genes on closer branches, or lineages, of the tree • They place more distantly related organisms on more distant branches • Scientists think that all living things have descended with modification from a single common ancestor • Thus all of life is connected • How do Biologists group life? Section 1-2: themes in biology

  21. “Tree of life” model

  22. Section 1-2: themes in biology • Domains • 3 major subdivisions • Bacteria • Archaea • Eukarya • Kingdoms • 6 major categories • Eubacteria • Archaebacteria • Fungi • Protista • Plantae • Animalia

  23. (2) Interdependence of Organisms • Ecology • Branch of biology that studies organisms interacting with each other and the environment • Studies show that organisms depend on each other as well as on minerals, nutrients, water, gases, heat, etc… Section 1-2: themes in biology

  24. (3) Evolution of Life • Individual organisms change during their lifetime, but their genetic characteristics do not change • Evolution • Process by which the inherited characteristics within populations change over generations • “Descent with modification” Section 1-2: themes in biology

  25. Evolution of Life • As a theme it helps us understand how the various branches of the “treeoflife” came into existence and have changed over time • It also explains how organisms alive today are related to those that lived in the past • It also helps us understand the mechanisms that underlie the way organisms look and behave Section 1-2: themes in biology

  26. NaturalSelection • Theory of Natural Selection • Organisms that have certain favorable traits are better able to survive and reproduce successfully than organisms that lack these traits • Adaptations • Traits that improve an individuals ability to survive and reproduce • Ex. Rabbits + their envt • The survival and reproductive success of organisms with favorable traits cause a change in populations of organisms over generations • This descent with modification is an important factor in explaining the diversity of organisms we see on Earth today Section 1-2: themes in biology

  27. All definitions Themes of Biology (be able to explain each) Examples for topics Section 1-2: what to know…

  28. Science is a systematic method that involves forming and testing hypotheses Science relies on evidence, not beliefs, for drawing conclusions Section 1-3: the study of biology

  29. Science as a process • Science is categorized by an organized approach called the scientificmethod • Based on two important principles: • Events in the natural world have natural causes • Example: Thundering + Lightning • Uniformity • The idea that the fundamental laws of nature operate in the same way at all places and at all times • Example: the law of gravity Section 1-3: the study of biology

  30. Steps to the scientific method: Section 1-3: the study of biology

  31. (1) Observation: • The act of perceiving a natural occurrence that causes someone to pose a question • (2) Form a hypothesis: • A proposed explanation for the way a particular aspect of the natural world functions • (3) Make a prediction: • A statement that forecasts what would happen in a test situation if the hypothesis were true Section 1-3: the study of biology

  32. (4) Experiment: • Used to test the hypothesis + predictions • Controlledexperiment • Compares an experimental group + a control group • Control group– normal standard • Experimental group – has one difference from control group • Independent variable – manipulated variable • Dependent variable – responding variable (affected by IV) Section 1-3: the study of biology

  33. (5) Collecting data, analyzing data, + drawing conclusions • Quantitative data • Data measured in numbers • The goal of analyzing data is to determine whether the data are reliable, and whether they support or fail to support the predictions or hypothesis • May use statistics to determine relationships between variables • An experiment can only disprove, not prove, a hypothesis Section 1-3: the study of biology

  34. Inference • A conclusion made on the basis of facts and previous knowledge rather than on direct observation • Ex. If you see smoke…. • Build models to represent or describe things • Theory • When a set of related hypotheses are confirmed to be true many times, and it can explain a great amount of data • Examples: • Cell Theory • Theory of Evolution Section 1-3: the study of biology

  35. (6) Communicate data • Collaboration with other scientists is important to public knowledge • Publish findings in scientific journals • Present them at scientific meetings Section 1-3: the study of biology

  36. All definitions Steps of Scientific Method (be able to explain each) Examples for topics Section 1-3: what to know…

  37. Microscopes as Tools • Tools • Objects used to improve the performance of a task • Microscopes • Tools that extend human vision by making enlarged images of objects • Used to study organisms, cells, cell parts, and molecules Section 1-4: Tools + Techniques

  38. Light Microscope (compound) • Shines light through a specimen and has two lenses to magnify an image Section 1-4: Tools + Techniques

  39. 4 major parts of CLM: • Eyepiece • AKA - ocular lens • Magnifies image 10x • Objective Lens • Enlarges image of the specimen • Found on revolving nosepiece • May have up to 4 different powered lenses • Stage • Platform that supports a slide holding the specimen • Light Source • Provides light for viewing the image • Lamp or mirror Section 1-4: Tools + Techniques

  40. Magnification + Resolution • Magnification • The increase of an object’s apparent size • PowerofMagnification • Degree of enlargement • Ocular lens x Objective lens • Example: 10 x 25 = 250x • *CLM – highest mag = 2,000x • Resolution • The power to show details clearly in an image Section 1-4: Tools + Techniques

  41. Electron microscopes • Uses a beam of electrons to produce an enlarged image of an object • Used to examine cells in more detail or to view cell parts or viruses • More powerful in magnification + resolution than LM • Images are always in black & white • Specimen is placed in a vacuum • Cannot view living specimens Section 1-4: Tools + Techniques

  42. Section 1-4: Tools + Techniques

  43. Section 1-4: Tools + Techniques • SEM • Showers electrons over surface of specimen • Produces a 3-D image • 100,000x • TEM • Transmits electrons through specimen • Can see internal features of specimen • 200,000x

  44. Units of Measure • Metric System • Common measurement system scientists use • Decimal system based on powers of 10 • Known as the SI system • Base units • Fundamentals units used to describe measurements • Know prefixes – Table 1-2, p. 23 Section 1-4: Tools + Techniques

  45. Section 1-4: Tools + Techniques

  46. Derived units • Produced by mathematical relationships between two base units or derived units • Common examples: • Area (m2) • Volume (m3) Section 1-4: Tools + Techniques

  47. Safety • Hazards can be chemical, physical, radiological, or biological • “Common- sense” habits • Example: • Splashing chemicals into eyes • Know safety symbols – p. 24 Section 1-4: Tools + Techniques

  48. All definitions • Parts of Microscope (+ functions) • Differences between CLM + EM • SI System • Base units (know TABLE) • Safety Symbols Section 1-4: what to know…

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