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

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