1. Chapter 1 Exploring Life and Science

2. What characteristics are shared by living organisms? 1.Organized from the atom to the biosphere 2.Maintain a relatively constant internal environment (homeostasis) 3.Respond to internal and external stimuli 4.Use materials and energy from the environment 5.Reproduce offspring 6.Growth and development 7.Evolutionary history through which organisms change over time

3. How are living things organized? From Simple to Complex Atoms: –are the smallest chemical units Molecules: –are a group of atoms working together Organelles: –are a group of molecules working together Cells: –are a group of organelles working together Tissues: –are a group of similar cells working together

4. How are living things organized? From Simple to Complex Organs: –are a group of different tissues working together Organ systems: –are a group of organs working together Organism: –is an individual

5. How are living things organized? From Simple to Complex Population: –Organisms of the same species in a particular area Community: –Interaction populations in a particular area Ecosystem: –A community plus the physical environment Biosphere: –Regions of the Earth’s crust, waters, and atmosphere inhabited by living things

7. Reproducing and Growth & Development DNA: –Hereditary information directs: Structure of the Cell Cell Metabolism –Genes Allow cells and organisms to make more of themselves Direct development so that the organism resembles the parents Growth and Development: –Growth: increase in size and number of cells –Development: All changes that occur from birth to death Repair after an injury

8. Homeostasis Homeostasis: –All body systems working together to maintain a stable internal environment Systems respond to external and internal changes to function within a normal range –e.g. body temperature, fluid balance Failure to function within a normal range results in disease

9. Maintaining Normal Limits Receptor: –receives the stimulus Control center: –processes the signal and sends instructions Effector: –carries out instructions

10. Maintaining Normal Limits Figure 1–3

11. Figure 1–4 Negative Feedback The response of the effector negates the stimulus

12. Positive Feedback The response of the effector reinforces the stimulus Figure 1–5

13. Homeostasis Requires coordinated efforts of multiple organ systems. Any adjustment made by one physiological system has direct and indirect effects on a variety of other systems. Therefore, the use of homeostasis integrates the human body to allow for the support of life.

14. Evolution and Adaptation Evolution: –Process by which a species changes through time –New variations arise allowing species to capture more resources  them to survive –Each successive generation include this variation representing an adaptation to the environment

16. How are living organisms classified? Three Domains: –Eukarya, Archaea, and Bacteria Eukarya Kingdoms: –Vertebrate Animalia –Invertebrate Plantae, Fungi, and Protista Archaea Kingdom: –Archaea Bacteria Kingdom: –Eubacteria

17. How do we classify humans? HumanHouse Cat DomainEukarya KingdomAnimalia PhylumChordata ClassMammalia OrderPrimatesCarnivora FamilyHominidaeFelidae GenusHomoFelis Speciessapiensdomesticus

18. What distinguishes humans? 1.Cultural heritage or patterns of our behavior passed from one generation to the next 2.Well-developed brains 3.Upright stance 4.Language Skills 5.Varied Tool Use 6.Modification of our environment for our own purpose which may threaten the biosphere

19. What do we know about Science? 1.Science is a way of knowing about the natural world 2.Science and scientists should be objective 3.Scientific conclusions may change or be modified as our understanding and technology increases 4.Science is studied using the scientific method

20. Science as a Process Scientific Theory: –Tells us about the order and the patterns in the world –Examples: Cell, Homeostasis, Genes, Evolution Principle: –Theories that are accepted as valid by an overwhelming number of scientists

21. The Steps of the Scientific Method

22. The Scientific Method in Action 1.Observations: -Many patients had a particular bacterium near their ulcers 2.Hypothesis: -Heliobacter pylori is the cause of gastritis and ulcers 3.Experimental/observations: -1 st : H. pylori was isolated and grown from ulcer patients -2 nd : Humans swallowing a H. pylori solution resulted in inflammation in their stomachs 4.Conclusion: -H. pylori was the cause of most ulcers and can be cured by antibiotics

23. A Controlled Study Variables: –Experimental variable is the variable that is purposely changed or manipulated –All other variables need to remain constant Groups: –Test group is a group of subjects that are exposed to the experimental variable –Control group is a group for comparison that is not exposed to the experimental variable

25. Reading about scientific information Scientific journals are considered the best source of information but can be difficult for the lay person to understand Often the lay person reads secondary sources and must be wary of information taken out of context Be careful of information on the Internet by using reliable sources such as URLs with.edu,.gov and.org

26. What should you look for when you read about science? Beware of anecdotal data Understand methodology and results Does the data justify the conclusions inferred by the scientists? Be able to read a graph Have some understanding of statistics –Standard Error (example 5 ± 1) –Statistical Significance (P< 0.5) Possibility that the results are due to some other factor other than the experimental variable

27. Does science have social responsibilities? Science is a way of acquiring knowledge about the natural world through a systematic process separating it from ethics, religion and aesthetics Technology is the application of scientific knowledge to human interests -Biotechnology (genetically modified crops) -Gene technology (cloning of humans or gene therapy to modify inheritance) -Use of stem cells from embryos