1. zChapter 1: Exploring Life

2. Unifying Themes in Biology zEvolution~ biology’s core theme; differential reproductive success (sex!) zEmergent Properties~ hierarchy of life zThe Cell~ all organism’s basic structure zHeritable Information~ DNA zStructure & Function~ form and function zEnvironmental Interaction~ organisms are open systems zRegulation~ feedback mechanisms zUnity & Diversity~ universal genetic code zScientific Inquiry~ observation; testing; repeatability zScience, Technology & Society~ functions of our world

3. Hierarchy of Organization zMolecule zOrganelle zCells zTissues zOrgan zOrganism

4. Feedback Regulation: Negative zAccumulation of an end product of a process slows that process zExample: sugar breakdown generates ATP; excess ATP inhibits an enzyme near the beginning of the pathway

5. Feedback Regulation: Positive zAn end product speeds up its production zExample: blood clotting in response to injury

6. The Process of Science zThe Scientific Method zDeductive reasoning z“If….then” Logic zHypothesis vs. Theory

7. Properties of Living things

8. Early Views of life zVitalism : The insistence that there is some big, mysterious extra ingredient in all living things z Led to idea of spontaneous generation z Flies came from dead animals z Mice came from Hay

9. z Idea was challenged by scientist Francesco Redi in 1698. z Designed an experiment where 3 jars contained meat. The Redi Experiment

10. Setup 1 z One Jar contained meat and had an open top which would allow the passage of flies. y (maggots would appear on the meat)

11. Setup 2 z The second jar was covered with an airtight lid not allowing the passage of flies.  (no maggots would appear on the meat)

12. Setup 3 z The third was covered by a screen allowing passage of eggs, but not flies.  (few maggots would appear on meat)

13. Conclusion z Since the third setup would theoretically allow the passage of “ethers”, but no maggots appeared, it was implied that flies were the source of the maggots. y Led to the theory of Biogenesis x All life comes from preexisting life

14. PROPERTIES of LIFE z Be made of Cells. z The Cell is the basic unit of life y Is self contained and possesses a barrier (membrane) which separates itself from the environment. z Two types of organisms. y Unicellular - One celled organism (Uni=1) y Multicellular - Many cells (Multi=”many”)

15. PROPERTIES of LIFE z Living Things must Reproduce. z Must be able to create more of it’s own kind z Two types of reproduction: y Sexual - Two parent organisms combine genetic material to produce the offspring. y Asexual - When a single organism can divide or “bud” to create it’s offspring without another of it’s species.

16. PROPERTIES of LIFE z Living things must Have DNA. z (Universal Genetic Code?)

17. PROPERTIES of LIFE z Living things must Grow & Develop. z Growth refers to two processes. y Increase in the number of cells. y Increase in the size of cells. z Development refers to changes in the organism which occur through it’s life- span. y Includes cell differentiation. y Includes organ development y Includes aging & death.

18. PROPERTIES of LIFE z Living things obtain & use energy. z Energy is used by all living things for growth, development & reproduction. y Life processes which result in “building” the organism ia known as Anabolism. y Life process where energy is extracted by “breaking-down” substances is called Catabolism.

19. PROPERTIES of LIFE z Living things must Respond (or react) to their environment in some way. z Something which causes an organism to react is known as a Stimulus (stimuli). z The ability of an organism to react is called Irritability. z Most responses are geared for maintaining Homeostasis. y Homeostasis is a process where an organism maintains a stable internal environment so life can continue. y Some examples include temperature, pH, and water content of the cell.