Introduction to Biology

1. Introduction to Biology

2. What is biology? • Biology - the science of life • Bio- = life -logy = the study of • There is a lot of living stuff… • Too many for one person to be an expert in everything • Biology is broken down into many branches so scientists can specialize

3. Branches of Biology Botany – the study of plants Zoology – the study of animals Anatomy – the study of structuresof living things Physiology – the study of the functions of living things Taxonomy – the study of classification of living things Cytology – the study of cells

4. Characteristics of Living Things • How do you determine if something is living? • Is a crystal garden alive? • Is a wooden table living? • Characteristics of Life Video • There are seven (7) criteria that must be met for something to be classified as ‘living’

5. Properties of Life • Cellular Organization • All living things must have at least one cell • Cell – a highly organized, tiny structure that can perform all life processes • We will study cells more in depth later…

6. Properties of Life • Homeostasis • Homeostasis– maintaining a constant internal state in a changing environment • What happens when you go for a run? • What do cold-blooded animals do to keep their body temperature stable? • A stable internal environment is important in order to function properly

7. Properties of Life • Metabolism • Metabolism – the sum of all chemical processes that occur in an organism • Chemical processes are used in order to obtain energy • Almost all energy used by living things comes from sunlight • What do I mean by this?? Obviously humans don’t use photosynthesis…

8. Properties of Life • Responsiveness • Responding to the outside environment • Examples: 1. Plants bending toward light 2. Turning towards a loud, sudden noise 3. Putting on a hat in winter

9. Properties of Life • Reproduction • Reproduction –producing offspring • Essential…because nothing lives forever (except vampires)

10. Properties of Life • Heredity • Heredity – the passing of genetic information from parent to offspring • Why children tend to look like their parents • Inherited traits change over generations (evolution) • More on this later

11. Properties of Life • Growth • Everything grows, even single-celled organisms • Galapagos tortoise: one of the longest lived species in the animal kingdom • Harriet – about 170 years old

12. Solving Real-World Problems • Biologists are working to solve today’s problems, such as: • Preserving our environment • Improving the food supply • Understanding the human genome • Fighting disease

13. Solving Real-World Problems • Preserving our environment • Expert: conservation biologists • Exploring ways to achieve a balance between people’s growing need for land and the need to preserve the environment

14. Solving Real-World Problems • Improving the food supply • Expert: genetic engineer • Genetic engineering of crop plants has made some plants resistant to herbicides • Or poisonous to insect pests • Or even more nutritious!

15. Solving Real-World Problems • Understanding the human genome • Expert: geneticist • Genome: the complete genetic material contained in an individual • Only government program to be finished before the deadline and under budget!!!

16. Solving Real-World Problems • Fighting disease • Expert: virologist, doctors, lots of people • AIDS – fatal disease caused by HIV • HIV = human immunodeficiency virus • A virus that attacks and destroys the human immune system • New vaccines are being tested • Attack 2 or more parts of the HIV virus at the same time • One part may mutate • Unlikely that both parts will mutate in the same virus particle • There is finally hope of a successful vaccine to control the outbreak of AIDS • 2yo 'cured' of HIV • Another one

17. Scientific Method Collecting Observations Asking Questions Hypothesizing and Making Predictions Confirming Predictions Drawing conclusions

18. Scientific Method • Observation – the act of noting or perceiving objects or events using the senses • All scientists have a certain way of investigating the world • Scientific investigations begin with observations • Observations cause scientists to ask questions about their observations

19. Scientific Method • Scientific investigations tend to have common stages • These stages are called the Scientific Method • There is more than one way to conduct an investigation

20. Scientific Investigations • Hypothesis • An explanation that might be true • A statement that can be tested by additional observations or experimentation • Prediction • The expected outcome of a test • This assumes that the hypothesis is correct

21. Scientific Investigations • Experiment • A planned procedure to test a hypothesis • Control group • A group in an experiment that receives no experimental treatment • Necessary for comparing the results of the experiment

22. Scientific Investigations • Independent Variable • The factor that is changed in an experiment • Dependent Variable • The variable that is measured in an experiment • The outcome of the dependent variable depends on what is done to the independent variable

23. Scientific Investigations • Drawing Conclusions • Once data are collected and analyzed a conclusion is made • Either the data supports the hypothesis or it does not • There is often more than one possible reason for a result • All of the factors that may affect an outcome must be considered

24. Constructing a Theory • Theory • A set of related hypotheses that have been tested and confirmed many times by many scientists • A theory unites and explains a broad range of observations • Theory is used by the general public to mean a guess or lack of certainty

25. Constructing a Theory In Science, a theory is a well-supported scientific explanation that makes useful predictions

26. Matter and Substances Section 3.1

27. The Nature of Matter • Atom – smallest unit of matter that cannot be broken down by chemical means • Consists of: • Electrons • Protons • Neutrons

28. Nature of Matter • Elements • Element – pure substance made of only one kind of atom • Elements differ in the number of protons their atoms contain

29. Nature of Matter • Chemical Bonding • Atoms can join with other atoms to form stable substances • The force that joins atoms is called a chemical bond • Compound • substance made of the joined atoms of two or more different elements

30. Nature of Matter • Covalent Bonds • Form when two or more atoms share electrons to form a molecule • Molecule – groups of atoms held together by covalent bonds • Ex) water

31. Nature of Matter • Covalent bonds (cont) • The arrangement of their electrons determines how atoms bond together • An atom becomes stable when its outer electron level is full • Not full: an atom will react with other atoms that can provide electrons to fill its outer shell

32. Nature of Matter • Hydrogen bonds • In a water molecule, the shared electrons are attracted more strongly by the oxygen nucleus than by the hydrogen nuclei • Molecules with unequal distribution of electrical charge are called polar molecules • Ex) two water molecules

33. Nature of Matter • Ionic Bonds • Ion - when an atom or molecule has gained or lost one or more electrons • Ions have an electrical charge because they contain an unequal number of electrons and protons • Ions of opposite charge may interact to form an ionic bond

35. Water and Solutions Section 3.2

36. Water in Living Things • Many organisms release excess heat through water evaporation • This ability to control temperature enables cells to maintain a constant internal temperature when the external temperature changes • HOMEOSTASIS!!

37. Water in Living Things • Cohesion • An attraction between substances of the same kind • Because of this, water and other liquids form thin films and drops • Because water has hydrogen bonds, the attraction between water molecules causes a condition known as surface tension

38. Water in Living Things • Adhesion • Attraction between different substances • Adhesion powers a process called capillary action • Water molecules move upward through a narrow tube • Ex) stem of a plant

39. Water in Living Things • Solution • Mixture in which one or more substances are evenly distributed in another substance

40. Polarity • The polarity of water enable many substances to dissolve in water • When ionic compounds are dissolved in water, the ions become surrounded by polar water molecules • Result: a mixture of water molecules and ions • Nonpolar molecules do not dissolve in water well

41. Water and Solutions • Acids and Bases • Compounds that form hydrogen ions when dissolved in water are called acids • When an acid is added to water, the concentration of hydrogen ions in the solution is increased above that of pure water

42. Water and Solutions • Compounds that reduce the concentration of hydrogen ions in a solution are called bases • Many bases form hydroxide ions when dissolved in water

43. Water and Solutions The pH scale measures the concentration of hydrogen ions in a solution

44. Carbon Compounds Section 3.3

45. Building Blocks of Cells • Biomolecules – parts of a cell that are made up of large, complex molecules • Basic unit: carbon • Can form bonds with as many as four other atoms • Four types: • Carbohydrates • Lipids • Proteins • Nucleic Acids

46. Carbon Compounds • Carbohydrates • Molecules made of sugars • made of carbon, hydrogen and oxygen atoms • In the proportion of 1:2:1 • Carbohydrates are a key source of energy • Found in most foods (especially fruits, vegetables, and grains)

47. Carbohydrates • Common sugar: glucose • A monosaccharide = single sugar • Two sugars can be linked to make a disaccharide • = simple carbohydrate • Many sugars can be linked to make a polysaccharide • = complex carbohydrate

48. Carbohydrates Chitin – found in shells of insects Cellulose – found in the cell walls of plants Carbs are also used as an ‘identifier’ on the surface of cells

49. Lipids Fats, steroids, waxes Long chains of carbon and hydrogen atoms Main function: storing energy

50. Proteins • Building blocks are amino acids • Chains of amino acids folded into different shapes • Different shapes = different function • Structure • Support • Movement • Transportation