# Chapter 2:The Science of Biology

### Chapter 2:The Science of Biology

Applied Biology

Mrs. Musselman

2.1 Science as Inquiry & Observation

Biology – The study of Life

 Science as Inquiry

– People are constantly asking questions about what they observe in nature and investigating to find answers.

(Example: Why do plants grow toward light?)

2.1 Science as Inquiry & Observation

 Observationsmade using our 5 senses and tools such as microscopes, telescopes, etc.

 Datarecorded observations

 Qualitative Data – descriptions, sketches, photos

 Quantitative Data – numerical measurements

### Metrics!!!!

Use this conversion chart to complete the practice worksheet. (Hint: move the decimal point)

### Measuring and Graphing!!!!

Unit – amount used to measure something

Mass – amount of “stuff”/matter in something

Volume – amount of space something takes up

Meter – basic unit of length or distance

(tool = meter stick or ruler)

### Measuring and Graphing (cont.)

Liter – basic unit of liquid volume

(tool = graduated cylinder or beaker)

Gram – basic unit of mass

(tool = scale)

Degrees Celcius – basic unit for measuring the temperature (amount of heat) in something

### Measuring & Graphing (cont.)

Construct a bar graph using the class shoe size information collected.

DATA

X axis =

Shoe Size # Students

Y axis =

8

9

6 or lower

7

10

11 or higher

### Warm-Up

 What tool(s) are used to measure:

– Liquid Volume?

Mass?

Length?

– Temperature?

### Inferences in Science

 Inference – logical conclusion based on observations and prior knowledge

DEMO?

### Warm - Up

 Come up with an example of and

INFERENCE .

YOU MAY NOT USE the examples we did in class (doorbell or gold credit card).

 You will be asked to share your example with the class so maybe you want to write it down.

### Doorbell = An Everyday Inference

You hear the doorbell ring….What do you think?

Inference: Someone is at the door

(prior knowledge tells you that whenever the doorbell has rang in the past, someone was there)

### 2.2 Hypothesis-Based Science

 Science RARELY follows the exact steps of the scientific method!!!

 The hypothesis is important!!!

 People use Hypothesis-Based Science every day to solve problems

Example: Flashlight doesn’t work = dead batteries?

Band aids

The Stuff of Genius - Velcro - YouTube

### Review: Put the “steps” of the scientific method in “order”

____ question

____ test/Experiment

____ hypothesis

____ observation

____ prediction

### Hypothesis

Hypothesis – suggested answer to a welldefined scientific question

 Often based on past experiences & prior

Knowledge

 Only useful if it can be tested

### Experimentation

 Variable – condition that can change within an experiment

Independent Variable – It’s what your testing the effects of (ex. Humidity, tem.)

Dependent Variable – Data being collected (depends on independent)

– Constant – factor that stays the same for all experimental groups in experiment

 Controlled Experiment – tests the effects of only a single indep. variable at a time.

Control Group vs. Experimental Group

 Control group – does NOT have the variable being tested

– The standard for comparison

 Experimental group – has the variable being tested

 Controlled Experiment Video

### Sample Experiment

You hypothesize that sunlight is beneficial to plant growth because you noticed that your houseplants seem to grow well in the window.

You get two groups of plants (3 in each group). One group is placed under a grow light and the other is placed inside a dark cabinet for 1 week. You water both groups of plants 3 ml of water every day and both groups are kept at 23 degrees Celsius all week.

At the end of the week you measure the height of the plants in each group to arrive at a conclusion.

### Sample Experiment

Identify the:

Observations (for hypothesis) =

Independent variable =

Dependent variable =

Experimental group =

Control group =

Constants =

Bob Experiment #1 from yesterday and be ready to answer the ?’s below!!!

1.What is the difference between the independent variable and the dependent variable in an experiment?

2.How many indep. Variables does a good controlled experiment test at a time?

3. Write the steps of the hypothesis-based

“scientific method” in order.

### 2.3 Understanding Science

Scientific Evidence

 Consists of many observations & experiments that have been repeated many times and all yielded similar results .

What makes a Hypothesis Scientific?

 Must be TESTABLE & FALSIFIABLE

 Falsifiable Hypothesis – can be proven wrong by an experiment if it is incorrect

 Must stand up to repeated experimental tests

(including new technology tests)

– Example: Fungi not related to plants (as once thought)

### Scientific Theories

 Theory – a well-tested explanation that makes sense of a great variety of scientific evidence

– Example: Cell Theory and Evolution

### Models

Model –representation

Not always exact replicas…but help simplify and explain

### Communication in Science

 Science is intensely social!

 Researchers share and publish data

 Driven by cooperation & competition