Biology & Science

1. Biology & Science

2. Biology • Defined: the study of life • Organism: anything that can carry on the processes of life • Species: organisms that can create fertile offspring • Over 2 million known species • More diverse along equator • Oldest life (bacteria) = 3.5 billion years old

3. Is Fire Alive? • Made of cells 2) Reproduces 3) Grows and Develops 4) Has organization 5) Requires energy 6) Responds to environment no yes yes no yes yes

4. Are Cars Alive? yes • Made of cells 2) Reproduces 3) Grows and Develops 4) Has organization 5) Requires energy 6) Responds to environment no no yes yes yes

5. Life Characteristics • All life (from bacteria to humans) has a few common characteristics 1) Based from cells • Cell = most basic unit of life • All cells capable of carrying on life processes • Some cells specialized for specific duties • Ex: Red blood cells carry O2

6. Life Characteristics 2) Requires energy • Energy = ability to do work or cause change • Energy controls metabolism (ability to break down materials) • Most life energy obtained from the sun • Autotrophs: create energy from the sun (ex: plants & algae) • Heterotrophs: consumer others for energy (ex: fungi & animals)

7. Life Characteristics !*%!?%&# 3) Responds to environment • Stimulus = environmental factors • ex: Sound, light, touch

8. Life Characteristics • 4) Reproduces and develops • Genetic material (DNA/RNA) passed to next generation • Asexual reproduction: offspring produced from a single parent • Offspring genetically identical to parent • Sexual reproduction: offspring is a genetic mixture of two parents • More diversity

9. What is science? • Science is a way of thinking, questioning, and gathering evidence. • Scientific method

10. Scientific Method • Defined: Series of steps to collect information or solve problems 1) Observation 2) Hypothesis 3) Experimentation 4) Data Analysis 5) Conclusion

11. Observation and Hypothesis • 1st step: Make an observation • Example: Why is there little ground vegetation in this forest? • 2nd step: Create a hypothesis • If…then statement • Example: If there are tall trees blocking sunlight, then few plants will grow near the ground.

12. 3rd step: Design an Experiment • Experiments test the independent variable • Independent variable: factor altered • Two parts to an experiment • Control group: comparison group • Ex: patch of forest with the large trees • 2) Experimental group: contains the independent variable • Ex: patch of land w/o canopy trees • Data collected is called the dependent variable • Ex: growth height of the plants

13. Here is a well designed setup

14. 8cm rain/month • 8cm rain/month • 6 hours sun/day • 6 hours sun/day Control Group Experimental Group • Grazing animals • 60⁰ temp • 60⁰ temp • Grazing animals • Large canopy trees • Patch of open land The experimental plants grew 1 meter taller. What most likely caused this change?

15. Here is a poorly designed setup

16. 8cm rain/month • 8cm rain/month • 6 hours sun/day Control Group Experimental Group • 4 hours sun/day • Grazing animals • 60⁰ temp • 80⁰ temp • Grazing animals • Large canopy trees • Patch of open land The experimental plants grew 1 meter taller. What most likely caused this change? • Unknown! Too many changed variables!

17. 4th Step: Data Analysis • Collect data to either support/reject your hypothesis • Ex: Plants on the ground grew almost 1m taller w/o the canopy trees • No hypothesis is proven after 1 experiment

18. 5th Step: Conclusion • Your findings could be shared and repeated by others • Theory develops over time • Theory = long standing hypothesis • Theories and hypotheses change based on new information

19. Farmer Bob wants to test his new fertilizer to help his crops grow better. He sections off two large areas of his field. In section A, he waters his crops as usual but adds no fertilizer. In section B, he waters his crops as usual and also adds his experimental fertilizer. After 1 growing season, he records the growth of the crops. Name the control group _________________________________________________ Name the experimental group ____________________________________________ Name the independent variable __________________________________________ Name the dependent variable ____________________________________________ Section A Section B Substance added to the crops Growth of the crops

20. The United States military wants to see if soldiers with only 4 hours of sleep can operate at the same level as those who normally get 7 hours of sleep. One hundred solders are allowed to only sleep for 4 hours a night and another hundred are allowed to sleep for 7 hours a night. During the day, the soldiers are tested for marksmanship on the firing range. Name the control group _________________________________________________ Name the experimental group ____________________________________________ Name the independent variable __________________________________________ Name the dependent variable ____________________________________________ Soldiers with 7 hours sleep Soldiers with 4 hours sleep Amount of sleep given Score on the firing range

21. Example • Smithers thinks that a special juice will increase the productivity of workers. • He creates two groups of 50 workers each and assigns each group the same task (in this case, they're supposed to staple a set of papers). • Group A is given the special juice to drink while they work. • Group B is not given the special juice. • After an hour, Smithers counts how many stacks of papers each group has made. • Group A made 1,587 stacks • Group B made 2,113 stacks. • Identify the: • Control Group • 2. Independent Variable • 3. Dependent Variable • 4. What should Smithers' conclusion be? Group B If special juice is given. # of stapled stacks of paper Special juice does NOT increase productivity

22. A teacher wants to know if her new teaching method is more successful than traditional teaching methods. She compares test scores of her period 2 class (received the traditional teaching method) verses her period 4 class (received new teaching method). Each class has a random mix of honors students. Name the control group _________________________________________________ Name the experimental group ____________________________________________ Name the independent variable __________________________________________ Name the dependent variable ____________________________________________ Period 2 students Period 4 students Teaching method Test scores

23. A high school soccer team on average scores 2.2 goals per game by practicing 4 days a week. The coach wants to see if practicing 5 days a week will help the team score more goals. The coach has the team practice 5 days per week and compares the goals scored per game. Name the control group _________________________________________________ Name the experimental group ____________________________________________ Name the independent variable __________________________________________ Name the dependent variable ____________________________________________ Practicing 4 days per week Practicing 5 days per week Length of practice Goals scored per game

24. The city of Los Angeles wants to know if there is a connection between physical fitness and air pollution. Fifty volunteers from the mayor’s office agree to be tested. First, they are asked to ride a stationary bike for 1 hour in a pollution-free air chamber. A week later, the 50 volunteers return and are again asked to ride a stationary bike for 1 hour in a chamber filled with air pollutants common to Los Angeles. Their heart rates are monitored throughout the 1 hour bike rides. Name the control group _________________________________________________ Name the experimental group ____________________________________________ Name the independent variable __________________________________________ Name the dependent variable ____________________________________________ Volunteers who breathed common polluted air Volunteers who breathed clean air Quality of air breathed Heart rates