Survey of Biology Biol & 100 Chapter 1

1. Survey of BiologyBiol& 100Chapter 1

2. Science and the Scientific Method • Biology is simply stated, the study of life. • Science is a process, one way of knowing the natural world • Scientific Method, process of science, leads to • Scientific Knowledge, the pattern of observations and explanations for these observations • While the scientific method is largely unchanged, scientific knowledge continues to grow as new tools and insights develop.

3. Scientific Method

4. In a correlation, two variables show a clear relationship (positive or negative). # of bars # of churches In reality, both variables respond to a third variable which is the actual cause. # of churches # of bars Population size Correlation vs. Cause & Effect While correlations are fertile areas to generate hypotheses, they are insufficient to support a cause-and-effect relationship Ideally, we would perform an experiment in which we manipulate one variable to see if this leads to a change in the other.

5. Hypothesis • Hypothesis is a statement that can be tested. • It often takes form of “if-then” statements • “If we increase the amount of carbon dioxide, CO2 , in the atmosphere, then plant growth will increase. • A testable hypothesis must make specific predictions that can be verified (or not) by an experiment or further observations • The hypothesis may be quantitative (Numerical) or qualitative (Verbal) • Quantitative – Plant growth will double with a 25% increase in carbon dioxide. • Qualitative – Plant growth will increase if CO2 increases.

6. Designing an Experiment • In our experiment, we, the scientists will deliberately manipulate the level of carbon dioxide. This will be our independent variable. • To prevent other factors from interfering, such as light and water, we will have these as the control variables • The dependent variable is the variable we will measure as a response to our experiment, in this case, plant growth.

7. Accept or Reject Hypothesis • If the results we obtained did not align with the predictions of our hypothesis, we would reject it. • If the experiment appeared to be flawed, it should be repeated. • The hypothesis may be tentatively accepted if the results are consistent with our predictions from the hypothesis. • We can not prove that a hypothesis is the true explanation. However, we can have confidence in a hypothesis if it survives repeated tests, especially repeated tests.

8. Scientific Method

9. Scientific Theories vs. Scientific Law • A scientific law is a description of patterns in nature that happen over and over in the same way • Law of Gravity, Boyle’s Law • A theory is a widely accepted, plausible explanation in science that explains why something happens • Einstein’s Theory of Relativity, Atomic Theory • The Geocentric Theory was replaced by a Heliocentric Theory, because it is more consistent with observations.

10. Inductive and Deductive Reasoning • Deductive Reasoning – process of using general principles to predict specific facts in a situation. • Say there is a lion behind one of two doors. One door is open, and another one is closed. Which door would the lion be behind? • Inductive Reasoning – process of using general principles by careful examination of specific cases. • Once again, there are two doors, and behind the one on the left, you hear a growling noise. Which door would the lion be behind?

11. Properties of Life • All living beings possess the following five characteristics: • Metabolic Process – the ability to uptake and process nutrients, as well as eliminate the waste. • Generative Processes – the ability to reproduce and grow • Responsive Properties • Control Process • Unique Structural Organization

12. Properties of Life • Responsive Process – ability to respond to changes in their surroundings. • Irritability – recognize a stimulus and react to it. • Individual adaption – adapt to a stimulus by changing • Evolution – where certain characteristics change within a population due to a slow change in genetic make-up • Control Process – mechanisms that ensure an organism will carry out all metabolic activities • Homeostasis regulates constant internal environment • Enzymes are proteins that control the rate at which certain chemical reactions occur

13. Levels of Organization for Living Things Least to Most Complex Atoms Molecules Cell Tissue Organ Organ System Organism Population Community Ecosystem Biosphere

14. Level of Organization for Living Things (Least to Most Complex) • Cell – Smallest unit that displays the characteristics of life • Some organisms, WBC, nerve cell • Tissue – Group of cell that displays the characteristics of life • Perform a certain function like heart cells

15. Level of Organization for Living Things (Least to Most Complex) continued • Organ – group of tissues that work together to perform a particular function • Ex. Heart, Lungs • Organ System – group of organs that work together to perform a particular function • Nervous System contains brain, nerves and brain system • Organism – An independent living unit