Biology: The Study of Life Chapter 1 Biology: The Study of Life

Science -an organized way of using evidence to learn about the natural world -the body of knowledge that scientists have built up What is the goal of science? To investigate and understand the natural world, to explain events in the natural world and to use those explanations to make useful predictions **Scientists propose explanations that can be tested by examining evidence Why does it rain?

Evidence Based on Observation -gathering information about events or processes; -involves the five senses Data -the information gleaned from your observations -Qualitative vs. quantitative data

qualitative data? Quantitative? Which of your observations can be considered qualitative data? Quantitative?

Sense Observation Inference See Wet pavement -rained -s/o washed their car Hear A bird singing -mark a territory -attract a mate Smell Touch Sticky tabletop -s/o spilled syrup Taste

-interpretation based upon prior knowledge or experience INFERENCE -interpretation based upon prior knowledge or experience ex: Since I cannot test all of the bacteria & sequence all of them, then…. HYPOTHESIS -a proposed scientific explanation for a set of observations or an answer to a scientific question -experiment -gather more data

The way it was : Aha!!! Meat --- maggots Grain --- mice Dung --- beetles Aha!!! Spontaneous generation- life arising from nonliving matter 1668-Franscesco Redi said…

3. Controlled Experiment 4. Record and Analyze Results Scientific Method- problem-solving for scientific questions 1. State the problem 2. Hypothesis 3. Controlled Experiment 4. Record and Analyze Results 5. Draw conclusions

-Manipulated/Independent Variable -Responding/Dependent Variable 3. Controlled Experiment Whenever possible, a hypothesis should be tested an experiment in which only one variable is changed at a time. All other variables should be kept unchanged or controlled Why? -Manipulated/Independent Variable -Responding/Dependent Variable -

Spontaneous generation of maggots did not occur! Redi’s observation: Maggots appeared on meat a few days after flies were present Redi’s hypothesis: Flies laid eggs to small for people to see and produced maggots Conclusion: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur!

Quick quiz: What was Redi’s hypothesis? What were the controlled variables (give 2) What was the manipulated variable? What was the question of the responding variable? Why did he design an experiment testing only one variable?

He observed He hypothesized He experimented He recorded He concluded

Pasteur’s experiment disproved spontaneous generation

Jar of pasta sauce Once it is opened, the jar must be kept in the refrigerator to keep the contents from spoiling. Q: What can you infer from Pasteur’s work about why an opened jar must be kept in a refrigerator? Q: Describe a controlled experiment to test the hypothesis that you propose based upon your answer to the first question?

Theory Theoretical? “That’s just in theory” A well-tested explanation that unifies a broad ranges of observations A well –supported hypothesis Not absolute truth!!

8 Characteristics of Life Cells a. Unicellular b. Multicellular Reproduction a. asexual reproduction b. sexual reproduction 3. Genetic Code 4. Growth & Development 5. Obtain and use Energy a. metabolism b.photosynthesis 6. Respond to the environment a. stimulus 7. Homeostasis 8.Evolution http://www.youtube.com/watch?v=uM_CgOgJGG0

1. Cells-the smallest and basic unit of life Unicellular vs. multicellular

2. Reproduction asexual vs. sexual

3. Genetic Code -our directions for inheritance (DNA)

4. Growth & Development Growth Changing shape & structure Development Cells look diferent/diferent functions Differentiation Getting larger

5. Obtain & Use Energy Metabolism-the total of all chemical reactions

6. Response to the environment stimulus…..response

maintain constant internal conditions 7. Homeostasis- maintain constant internal conditions

8. Evolution The tree is rooted in the ancestral tetrapoda (amphibia).

Levels of Organization: Biosphere Ecosystem Community Population Organism Groups of Cells Organ Systems Organs Tissues Cells Molecules Atoms

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