chapter 1 biology: the study of life
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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, - PowerPoint PPT PresentationTRANSCRIPT
Chapter 1Biology: 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
Observation-gathering information about events or processes; -involves the five senses
Data-the information gleaned from your observations
-Qualitative vs. quantitative data
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
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 :
Meat --- maggotsGrain --- miceDung --- beetles
Aha!!! Spontaneous generation-
life arising from nonliving matter
1668-Franscesco Redi said…
Scientific Method- problem-solving for scientific questions
1. State the problem2. Hypothesis3. Controlled Experiment4. Record and Analyze Results5. Draw conclusions
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
-
Redi’s observation: Maggots appeared on meat a few days after flies were presentRedi’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:
1) What was Redi’s hypothesis?2) What were the controlled variables (give 2)3) What was the manipulated variable?4) What was the question of the responding
variable?5) Why did he design an experiment testing only
one variable?
He observed
He hypothesized
He experimented
Herecorded
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 Life1. Cells
a. Unicellularb. Multicellular
2. Reproductiona. asexual reproductionb. sexual reproduction
3. Genetic Code4. Growth & Development5. Obtain and use Energy
a. metabolismb.photosynthesis
6. Respond to the environmenta. stimulus
7. Homeostasis8.Evolution
http://www.youtube.com/watch?v=uM_CgOgJGG0
1. Cells-the smallest and basic unit of lifeUnicellular vs. multicellular
2. Reproductionasexual vs. sexual
3. Genetic Code-our directions for inheritance (DNA)
4. Growth & Development
Growth Changing shape & structureDevelopment Cells look diferent/diferent functionsDifferentiation Getting larger
5. Obtain & Use EnergyMetabolism-the total of all chemical reactions
6. Response to the environmentstimulus…..response
7. Homeostasis-maintain constant internal conditions
8. Evolution
The tree is rooted in the ancestral tetrapoda (amphibia).
Levels of Organization:
BiosphereEcosystemCommunityPopulationOrganismGroups of Cells
Organ SystemsOrgansTissues
CellsMoleculesAtoms
Science,Technology and Society