The study of life

1. The study of life Warm-up: What does it mean to be alive? What is the definition of life?

2. Which of these are considered living?

3. What are some characteristics of life?

4. Characteristics of life Response to the environment adaptation order reproduction Energy processing regulation Growth and development

5. Some definitions of life from various sources • Life is the property or quality that distinguishes living organisms from dead organisms and inanimate matter, manifested in functions such as metabolism, growth, reproduction, and response to stimuli or adaptation to the environment originating from within the organism. American Heritage Dictionary Life is a characteristic that distinguishes objects that have Signaling and self-sustaining processes from those that do not, either because such functions have ceased (death), or else because they lack such functions and are classified as inanimate. Wikipedia Life is a distinctive characteristic of a living organism from a dead organism or a nonliving thing as specifically distinguished by the capacity to grow, metabolize, respond (to stimuli), adapt, and reproduce. Biology Online

6. Biologists explore life from the microscopic to the global scale

7. 1 The biosphere Figure 1.3 • From the biosphere to organisms

8. 9Organelles 1 µm Cell 8Cells Atoms 10Molecules 10 µm 7Tissues 50 µm 6Organs and organ systems Figure 1.3 • From cells to molecules

9. Table 1.1 • Eleven themes that unify biology

10. LET’S TALK ABOUT THIS CLASS

11. What is your definition of life?

12. SCIENTIFIC INQUIRY • Biology blends two main processes of scientific inquiry: • Discovery science • Hypothesis-based science At the heart of science is inquiry

13. Biology blends two main processes of scientific inquiry: • Discovery science • Describes natural structures and processes as accurately as possible through careful observation and analysis of data • Hypothesis-based science, inquiry that asks specific questions • Usually involves the proposing and testing of hypothetical explanations, or hypotheses A possible explanation that can be tested and falsified. It is an explanation on trial. WHAT IS A HYPOTHESIS?

14. Observations Questions Hypothesis # 1:Dead batteries Hypothesis # 2:Burnt-out bulb Prediction: Replacing bulb will fix problem Prediction: Replacing batteries will fix problem Test prediction Test prediction Figure 1.25 Test does not falsify hypothesis Test falsifies hypothesis We all use hypotheses in solving everyday problems

15. Scarlet king snake Key Range of scarlet king snake Range of eastern color snake NorthCarolina SouthCarolina Eastern coral snake Scarlet king snake Figure 1.27 A Case Study in Scientific Inquiry: Investigating Mimicry in Snake Populations • In this case study • Mimicry in king snakes is examined • The hypothesis predicts that predators in non–coral snake areas will attack king snakes more frequently than will predators that live where coral snakes are present

16. To test this mimicry hypothesis • Researchers made hundreds of artificial snakes, an experimental group resembling king snakes and a control group of plain brown snakes (a) Artificial king snake (b) Brown artificial snake that has been attacked

17. Key Key % of attacks on artificial king snakes % of attacks on brown artificial snakes Field site with artificial snakes 17% In areas where coral snakeswere absent, most attackswere on artificial king snakes 83% X X X NorthCarolina X X X X X SouthCarolina X X X X X 16% X 84% In areas where coral snakes were present, most attacks were onartificial brown snakes Figure 1.29 • After a given period of time • The researchers collected data that fit a key prediction