5. Living things contain genetic information in the form of DNA and RNA Universal genetic code 6. Living things pass on heritable information to their

Transcription

1 Biology BIOLOGY 102 Lecture 1: Introduction to Biology Scientific study of life From Greek Bios life Logia study of 1. All living things are made of one or more cells 2. Living things carry out metabolism All chemical reactions required to sustain life Includes respiration, digestion, building things, breaking them down 3. Living things maintain homeostasis Internal balance that keeps things constant 4. Living things grow and reproduce themselves Living things come from other living things 1

2 5. Living things contain genetic information in the form of DNA and RNA Universal genetic code 6. Living things pass on heritable information to their offspring 7. Living things detect and respond to their surroundings Light, sound, touch, chemicals, heat, etc 8. Living things adapt in the short term Adjust to new conditions 9. Living things evolve in the long term Genetic distribution in a population will change over many generations based on natural selection 10. Living things are highly organized Complexity Some of these topics are covered in BI 102 2

3 10. Living things are highly organized Complexity So Is A Virus Alive? Passes on heritable information Detects and responds to surroundings Adapts Evolves BUT Some of these topics are covered in BI 102 So Is A Virus Alive? Is not made of cells Does not carry out metabolism Does not maintain homeostasis Does not grow Cannot reproduce itself Contains RNA or DNA, not both Biomolecules Molecules that make up living things All living things are made of the same 4 types of biomolecules Carbohydrates Lipids Proteins Nucleic acids NOPE Many questions How Do We Do Biology? Many careers All the same approach Organized method of problem solving Always follows the same steps You do this every day without realizing it 3

4 Example: Your car won t start How would you use the scientific method to find out why? Step 1: Make an observation Notice the problem or phenomenon, and state it clearly What is the observation in our scenario? Step 2: Ask a question Gather information about the observation, and phrase it as a question The most obvious question in our scenario is Why won t the car start? Step 3: Formulate a hypothesis Proposed explanation or answer to the question What would be some hypotheses here? Step 4: Make a prediction Decide which hypothesis is most likely Assume that the hypothesis is true, and predict what will happen when you test it Example: The car battery is probably dead; if I jump it, the car will start Step 5: Test the hypothesis by experiment Manipulate only one variable Goal is to support or refute the hypothesis Multiple experiments are required Results must be repeatable 4

5 IMPORTANT!! Key to designing a good experiment No matter the outcome, you will have new, useful information What is a good experiment here? A bad one? Step 6: Draw a conclusion about the validity of the hypothesis Do the results support the hypothesis? Example: We jump the car and it starts Our hypothesis is supported What if it doesn t start? Now what? or Revise the hypothesis and repeat Example: Maybe it s out of gas Scientists repeat this process many times Gradually accumulate knowledge to understand some part of nature 1. Observation 2. Question Revise and repeat 3. Hypothesis 4. Prediction 5. Experiment 6. Conclusion at Work Classic experiment by Francisco Redi ( ) 1697) Known that maggots appear on spoiled Thought to be proof of spontaneous generation at Work 1. Observation Flies swarm around ; maggots appear on 2. Question Where do the maggots come from? 3. Hypothesis Maggots come from flies 4. Prediction Keeping flies away from will prevent the maggots from appearing 5

6 at Work 5. Experiment Obtain two identical jars and two pieces of Place in each jar at Work 6. Conclusion Maggots do not generate spontaneously But does this really prove that the maggots come from flies? 7. Revise and repeat Leave the jar uncovered Seal the jar Control situation Maggots appear on No maggots appear Experimental situation at Work 5. Experiment Obtain two identical jars and two pieces of at Work 6. Conclusion Maggots come from flies Place in each jar Leave the jar uncovered Place gauze on the jar Control situation Maggots appear on Maggots appear on gauze, not on Experimental situation Hypothesis More Science Terms Educated guess based on prior observations Theory A generalization based on many observations and experiments Scientific theory A well-tested, verified set of hypotheses that fit together and have yet to be disproved Law An observation with no known exceptions Scientific theories Cell theory Germ theory More Science Terms Theory of evolution Atomic theory Laws Gravity Conservation of mass 6