1. Chapter 1
The Science of Biology

2. 1-1 What is Science? Goal of science Observations vs. inferences
What is a hypothesis?

3. Goal of science To investigate and understand nature
To explain events in nature
Use those explanations to make useful predictions
Science- organized way of using evidence to learn about the natural world
It’s a process!
Term can also refer to the body of knowledge scientists have built up after years using this process

4. Observations vs. Inferences
Observation- gather information using one or more of the senses
Information gathered is called evidence or data
Two types of observations
Qualitative- involves characteristics that cannot be easily measured or counted
Quantitative- involves numbers like when measuring or counting objects

5. Observations vs. Inferences
Inference-logical interpretation based on prior knowledge and experience

6. Observations vs. Inferences
Statement Observation Inference
Object A is round and orange. X
Object A is a basketball.
Object C is round and black and white.
Object C is larger than Object B.
Object B is smooth.
Object B is a table-tennis ball.
Each object is used in a different sport.

7. Explaining the Evidence
A hypothesis is a possible explanation for a set of observations or an answer to a scientific question
Must be testable!

8. Formulating a Hypothesis
Mystery Worms
A teacher collected some beetles from a rotting log and placed them in a container of dry oatmeal in her classroom. She kept the box covered with a light cloth so that the beetles could not escape. She also asked one of her students to add potato and apple pieces once a week to provide food and moisture for the beetles. After several weeks, the student reported that there were some strange-looking, wormlike organisms in the container.
1. Formulate a hypothesis that might explain the presence of the “worms” in the container.
2. How could you test your hypothesis?

9. 1-2 How Scientists Work Designing an Experiment
Publishing and Repeating Investigations
When Experiments are Not Possible
How a Theory Develops

10. Designing an Experiment
State the Problem
Analyze Results
Form a Hypothesis
Draw a Conclusion
Set Up a Controlled Experiment
Publish Results
Record Results

11. Controlled Experiment
Only one variable must be changed at a time
All other variables should be kept unchanged or controlled
Manipulated (independent) variable- variable that is deliberately changed
Responding (dependent) variable- variable that is observed and changes in response to the manipulated variable

12. Redi’s Experiment, designed to refute Spontaneous Generation- the idea that life could arise from nonliving matter
OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.
HYPOTHESIS: Flies produce maggots.
PROCEDURE
Uncovered jars
Covered jars
Controlled Variables:
jars, type of meat,
location, temperature,
time
Several
days pass
Manipulated Variables:
gauze covering that
keeps flies away from
meat
Responding Variable:
whether maggots
appear
Maggots appear
No maggots appear
CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

13. Recording and Analyzing Results
Lab reports
Scientific drawings
Online storage

14. Drawing a Conclusion After testing your hypothesis…
Option 1: Data supports it
“data supports the hypothesis”
Never proves it
Option 2: Data proves it wrong
“hypothesis is refuted”
Rewrite and test again

15. Repeating Redi
Key assumption in science- experimental results can be reproduced because nature acts in a consistent manner
Redi’s work followed by
Needham-used an experiment with “animalcules” to attack Redi’s work
Spallanzani- improved upon Needham’s experiment
Pasteur-allowed broth to come into contact with the air

16. Spallanzani’s Experiment
Gravy is boiled.
Flask is
open.
Flask is
sealed.
Gravy is free of
microorganisms.
Gravy is boiled.

17. Pasteur’s Experiment
Broth is boiled.
Broth is free of
microorganisms
for a year.
Curved neck
is removed.
Broth is
teeming with microorganisms.
Showed that all living things come from other living things

18. When Experiments are Not Possible
Examples:
Observing animals
Prohibited by ethical considerations
Attempting to maintain a controlled experiment
Study large groups of subjects
ID as many relevant variables as possible

19. Developing a Theory
Theory- well-tested explanation that unifies a wide range of observations
Happens when a hypothesis is so well supported by the scientific community
No theory is considered absolute truth
May be revised or replaced by a more useful explanation

20. 1-3 Studying Life Characteristics of living things Branches of biology
Biology in everyday life

21. Characteristics of Living Things
1. Made Up of Cells
2. Reproduce
3. Based on a Genetic Code
4. Grow and Develop
5. Need Materials and Energy
6. Respond to the Environment
7. Maintain Internal Balance
8. Evolve

22. Characteristic Examples
Living things are made up of units called cells.
Many microorganisms consist of only a single cell. Animals and trees are multicellular.
Living things reproduce.
Maple trees reproduce sexually. A hydra can reproduce asexually by budding.
Living things are based on a universal genetic code.
Flies produce flies. Dogs produce dogs. Seeds from maple trees produce maple trees.
Living things grow and develop.
Flies begin life as eggs, then become maggots, and then become adult flies.
Living things obtain and use materials and energy.
Plants obtain their energy from sunlight. Animals obtain their energy from the food they eat.
Living things respond to their environment.
Leaves and stems of plants grow toward light.
Living things maintain a stable internal environment.
Despite changes in the temperature of the environment, a robin maintains a constant body temperature.
Taken as a group, living things change over time.
Plants that live in the desert survive because they have become adapted to the conditions of the desert.