Chapter 1 Introduction to Biology

1. Chapter 1Introduction to Biology LESSON 1: UNIFYING PRINCIPLES OF BIOLOGY

2. Lesson Objectives • State the four unifying principles of biology as defined by the College Board. • Briefly explain how biological life on Earth evolves. • Explain the purposes of free energy processes and homeostasis in biological organisms. • Describe the theories and dogma of biological information. • Describe how living things interact and the levels of structural, biological, and ecological organization in biological systems.

3. The “Big Ideas” • Evolution…evolution drives the diversity and unity of life • Free Energy…biological systems utilize free energy and molecular building blocks to grow, to reproduce, and to maintain dynamic homeostasis • Information…living systems store, retrieve, transmit, and respond to information essential to life processes • Systems…biological systems interact, and these systems and their interactions possess complex properties http://youtu.be/ibhnP5suqK8(9:09)

4. Evolution Evolution…evolution drives the diversity and unity of life What is diversity? • Diversity • Do all species on Earth live in the same type of habitat • Do we all reproduce alike • Do we are physically resemble one another • Do we all have the exact same resource needs Evolution drives the diversity of life which insures survival through variations that develop through genetic mutations that are transferred between or within populations of species by means of non-random mating, and immigration and emigration of individuals within and from populations.

5. Evolution…continued What is the unity of life? • What do we mean by ‘unity of life’? • universal usage of DNA to store genetic information • the ribosome technique of protein synthesis • proteins serve as enzymes and catalysts • the same 20 amino acids are always used • a universal genetic code • DNA triplets coding for same amino acid • the use of proteins and lipids to make membranes • the use of the ATP-ADP cycle for chemical energy

6. Free Energy Free Energy…biological systems utilize free energy and molecular building blocks to grow, to reproduce, and to maintain dynamic homeostasis

7. Homeostasis

8. Information • Information…living systems store, retrieve, transmit, and respond to information essential to life processes

9. Systems • Systems…biological systems interact, and these systems and their interactions possess complex properties • Describe how living things interact and the levels of structural, biological, and ecological organization in biological systems.

10. Lesson Summary • Four underlying principles form the basis of biology. They are evolution, free energy, information, and systems. • The great diversity of life on Earth today is the result of 4 billion years of evolution. During that time, living things evolved from simple, single-celled organisms to complex, multicellular life forms. • Biological systems utilize free energy & molecular building blocks to grow, to reproduce and to maintain dynamic homeostasis. • Living systems store, retrieve, transmit & respond to information essential to life processes. • Many living things interact with one another in some way. The interactions are often necessary for their survival.

11. LESSON 2: DISCOVERY OF CELLS AND MICROSCOPESLesson Objectives State the cell theory, and list the discoveries that led to it. Be able to identify the parts of a compound light microscope. Explain the differences between a SEM (Scanning Electron Microscope) and a TEM (Transmission Electron Microscope).

12. Abiogenesis or Biogenesis? • Recipe for Bees • Kill a bull during the first thaw of winter • Build a shed. • Place the dead bull on branches and herbs inside the shed. • Wait for summer. The decaying body of the bull will produce bees.

13. Aristotle…300 B.C. (2300 years ago) • Living things follow a set of natural rules different from nonliving things • Special “vital forces” (magical forces in the air) brought living things into being from nonliving things • A hypothesis known as : spontaneous generation also called abiogenesis

14. About 350 years ago Challenges began to arise to the beliefs of Aristotle • How did they challenge these ideas • Through experiments and observations to answer the questions about life….. • Do living things come from nonliving things?????

15. OBSERVATIONS…Discovery of Cells • Cell: smallest unit that can carry out the processes of life; including transport of materials, obtaining and using energy, waste disposal, replication, and responding to their environment. • If you look at living organisms under a microscope you will see they are made up of cells; which are the basic unit of all living things

16. Anton von Leeuwenhoekmid 1600s • Dutch businessman credited for creating 1st microscope; • Magnification 200X • Opened up new world • Changed ideas about disease & sterilization for the next 200 years!! ANIMALCULES

17. Robert Hookelate 1600s (1663) English physicist; used one of 1st light microscopes. Coined the term “cell” after observing cork cells

18. EXPERIMENTS…Francesco RediItalian Physician • 1668 • Studied maggots • Did not believe they came from decaying meat • Set up an experiment

19. Redi’s Experiment

20. Success??? • Redi thought so, but… • No air could get into the experimental jars • There was no “vital force” • People still believed in spontaneous generation or abiogenesis • Back to the drawing board…

21. Redi’s Second Experiment Control Group Experimental Group

22. Conclusion • Maggots do not come from dead meat. • Hypothesis has been supported! • Does this disprove abiogenesis? • Only for flies!

23. The Debate Continued…. • Was Redi right, Aristotle’s ideas had survived for a millennia, how could they be WRONG!!!! • Let’s follow the history of the scientific investigation and further observations that finally solved the riddle…

24. John Needham (British Biologist & Roman Catholic priest • Mid-1700’s • Believed in abiogenesis for microscopic organisms • Needham’s Experiment • Broth in flask boiled to sterilize it… • Killing microorganisms, then sealed • Microorganisms found growing in flask!!!!

25. LazzaroSpallanzani (Italian Scholar) • 1768 • Did not believe in spontaneous generation • Read about Needham’s work • Samples had not been heated enough • Broth in two flasks boiled to sterilize… • Sealed one immediately after boiling • Left other open • Bacteria found growing only • in open flask

26. More Observations1839… • Schleiden and Schwann made an important discovery about living things Beliefs are about to change…..

27. Matthias Schleiden1839 “All plants are made of cells.” German botanist

28. Theodor Schwann1839 “All animals are made of cells” Further concluded all plants and animals are made of cells German scientist

29. More Observations1839… • BUT….Schleidenand Schwann did not understand where cells came from. Was the belief of the time dating back to the time of Aristotle (300 B.C.) right? Did cells come from nonliving matter (Abiogenesis).

30. Rudolf virchow1855 “Where a cell exists, there must have been A preexisting cell…” German physician Still one more experiment before true understanding…

31. Does Abiogenesis happen? • A contest was devised by the French Academy of Sciences with a cash award for the person who could disprove abiogenesis.

32. Louis PasteurFrench Scientist • Mid- 1800s • Knew he needed to let air in, but not dust • Was inspired by…

33. Swan Necked Flask • Pour broth into flask • Heat neck & shape • Boil broth • Wait!

34. Pasteur’s Experiment

35. Conclusion--1859 • Since no microorganisms could get into the broth (they were trapped in the curve of the swan neck), none grew. • Pasteur broke the neck off a year later, allowed it to be exposed to air & microorganisms began to quickly grow.

36. Biogenesis • Living things do NOT come from non-living things. Spontaneous generation does NOT occur, even with very small organisms. • Living things only come from other living things!

37. Cell Theorywidely accepted explanation of the relationship between cells and living things • All organisms are made up of one or more cells. • All the life functions of an organism occur within cells. • All cells come from preexisting cells.

38. Let’s Step Back and Talk About Microscopes • Magnifying glasses had been in use since the 1300s • Magnification power of early microscopes was limited by glass quality used in the lenses and the amount of light reflected off the object. • Today we are not limited by light and mirrors when viewing specimen…

39. Scanning Electron Microscope • Runs a pencil-like beam of electrons back and forth across the surface of a specimen

40. Creating 3-D Images

41. Shines a beam of electrons through a thin specimen. Transmission Electron Microscope

42. Creating detailed flat one dimensional imageshttp://www.kqed.org/quest/television/the-worlds-most-powerful-microscope

43. Unfortunately, in class we only have compound light microscopesParts of the microscope review…

44. Lesson Summary • Discoveries about cells using the microscope and experimental observations led to the development of the cell theory. This theory states: • All organisms are made of one or more cells • All the life functions of organisms occur within cells • All cells come from already existing cells. • Electron microscopes can produce highly magnified one dimensional and 3-D image of specimens.

45. LESSON 3: THE NATURE OF SCIENCELesson Objectives Identify the goal of science. Describe how scientists study the natural world; using the scientific method. Explain how and why scientists do experiments. Describe types of scientific investigations. Explain what a scientific theory is.

46. The Goal of Science • Scienceis a distinctive way of gaining knowledge about the natural world that starts with a question and then tries to answer the question with evidence and logic. • The goal of science is to understand the natural world. To achieve this goal, scientists make certain assumptions. They assume that: • Nature can be understood through systematic study. • Scientific ideas are open to revision. • Sound scientific ideas withstand the test of time. • Science cannot provide answers to all questions.

47. Nature Can Be Understood • Though scientific laws. Scientific laws are statements that describe what always happens under certain conditions in nature. • LAW OF GRAVITY

48. Scientific Ideas Can Change • Knowledge is a process • New observations are made • Ideas are retested • Testing leads to challenges and possible revisions of ideas • Thus scientists gradually build an increasingly accurate and detailed understanding of the natural world.

49. Scientific Knowledge Can Withstand the Test of Time • Scientific knowledge that have been tested repeatedly and found to be true are considered scientific theory. • By true we mean they are supported by a great deal of scientific evidence. • Scientific theories are distinguished from philosophical theories in that each of their theorems are statements about observable data, whereas a philosophical theory includes theorems which are ideas or principles. • Biological Scientific Laws and Theories you should know: • Theory of Evolution by Natural Selection • Cell Theory • Law of Biogenesis • Laws of Thermodynamics

50. Science Cannot Answer All Questions • Scientific knowledge is based on evidence and logic, derived from questioning and the testing of things observed. • An observation is anything that is detected either through human senses or with instruments and measuring devices that extend human senses. • Things that cannot be observed or measured by current means—such as supernatural beings or events—are outside the bounds of science. • Consider these two questions about life on Earth: • Did life on Earth evolve over time? • Was life on Earth created through another method? The first question can be answered by science on the basis of scientific evidence and logic. The second question could be a matter of belief. Therefore, it is outside the realm of science.