Chapter 1 the science of biology
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Chapter 1: The Science of Biology. Key Concept: What is the goal of science?. Standards: I&E: 1a-1g. 1-1: What Is Science?. 1-1. The goal of science is to: investigate and understand the natural world. explain events in the natural world.

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Chapter 1: The Science of Biology

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Chapter 1: The Science of Biology

Key Concept:

What is the goal of science?

Standards: I&E: 1a-1g


1-1: What Is Science?

1-1


  • The goal of science is to:

    • investigate and understand the natural world.

    • explain events in the natural world.

    • use those explanations to make useful predictions.

1-1


1-2 How Scientists Work


Scientists follow logical steps to: (1) generate new ideas, (2) answer questions, and (3) draw conclusions.

These steps are called the Scientific Method.

1-2


Scientific Method steps:

1. Observe, ask questions.

2. Formulate a hypothesis.

3. Design a controlled experiment.

4. Make careful observations.

5. Analyze and draw conclusions.

1-2


  • Thinking Like a Scientist

    • Scientific thinking begins with observation.

    • Observation is the process of gathering information about events or processes in a careful, orderly way.

This leads to curiosity about something.

1-2


Curiosity

HYPOTHESIS

A possible explanation for an event or set of observations.

- It is a prediction about the outcome of an experiment.

1-2


An "educated guess"

1-2


A hypothesis may be ruled out or confirmed.

  • A hypothesis must be testable.

  • They are tested by performing a controlled experiment.

1-2


Examples of hypotheses:

  • Seeds need light to grow.

  • Hyenas are closely related to dogs.

(hyenas are more closely related to cats)


Hypotheses are often stated in “if - then” statements.

  • If hyenas are related to dogs, then genetic testing should show this.

  • If my dog likes brand “A” of dog food, then he will eat more of it.

1-2


What is a controlled experiment?

  • Two identical experiments:

  • Variables: factors which change or can affect things.

  • Control: setup where no change is made.

1-2


Redi’s Experiment

1

2

Experiments must be repeatable!

1-2


EXPERIMENT

Next step is to record and analyze results:

Data

1-2


  • Next step: Forming a Conclusion

    • Scientists use the data from an experiment to evaluate a hypothesis and draw a valid conclusion.

    • Redi’s results supported the hypothesis that maggots were produced by flies, not spontaneous generation.


The conclusion may, or may not support the hypothesis.

If not, hypothesis can be changed.

1-2


All experiments have variables.Variable= factor that can change in an experiment.

1-2


Examples of variables:

  • Temperature

  • Length of time

  • Type of dog food

Most scientific experiments are designed to consider only 1 variable.


Other variables must be controlled. The control variable stays the same, while the manipulated variable changes.

1-2


Example: We want to determine what makes the best bread.


Possible Manipulated Variables:(you would pick 1)

  • Amount of sugar

  • Presence of salt

  • Oven temperature

  • Baking time


What can be controlled:

  • Amount of water

  • Amount of yeast

  • Oven temperature

  • Baking time


With sugar

No sugar

(1 variable only!)

Another

example


A hypothesis that is supported by many experiments done over a period of time is called a Theory.

Theories are not facts, but probable explanations.

1-2


Examples of theories

  • Theory of evolution

  • Theory of plate tectonics

  • The cell theory

Theories are changeable and expandable, and most importantly, theories are FALSIFIABLE.

1-2


Observation

Curiosity

Experiment

Hypothesis

Experiment

Experiment

Theory

Experiment

(If all exp’ts support hypothesis)

1-2


1–2

  • In an experiment, the variable that is deliberately changed is called the

    • control.

    • manipulated variable.

    • responding variable.

    • constant control


1–2

  • The mistaken belief that living organisms can arise from nonliving matter is called

    • biogenesis.

    • Pasteur's theory.

    • spontaneous generation.

    • Spallanzani’s hypothesis.


1–2

  • Which of the following was the manipulated variable in Redi’s experiment?

    • the kind of meat used

    • the temperature the jars were kept at

    • the gauze covering on some jars

    • the kind of fly that visited the jars


1–2

  • A well-tested explanation that unifies a broad range of observations is a

    • hypothesis.

    • variable.

    • control.

    • theory.


1–2

  • A scientific explanation does not become a theory until

    • a majority of scientists agree with it.

    • it has been supported by evidence from numerous investigations and observations.

    • it is first proposed as an explanation.

    • it is published in a textbook.


Scientific Law

  • A theory attempts to explain everything about something, including its cause.

  • A scientific law describes something that is always true. It does not explain why, only that it does.

2-1


Examples of Scientific Laws:

  • Law of gravity: any 2 objects attract each other. (doesn’t say anything about why)

  • In biology, Law of Dominance: a dominant trait will show itself when a dominant and recessive trait are mixed.

2-1


Let’s experiment!

Pill bug, sow bug, roly polies

Phylum Crustacea – related to crabs, shrimp

We want to observe their behavior and see what environment they prefer.

Manipulated variable = ?

Control variables = ?


For example:

Manipulated variable

= moisture

Hypothesis: If pill bugs prefer moist environments, then they will move to the side of a choice chamber which has more moisture.


  • Wink Dinkersen8/20/09Per. 3

  • Title: Investigation of Roly Poly Behavior

  • Hypothesis: If roly polies prefer ______ environments, they will move toward the _____ side of a choice chamber.

  • Objective: To investigate . . .

  • Materials:

  • Choice chamber

  • 10 roly polies

  • paper circles

  • Stopwatch

  • Data table

  • Anything else

  • Procedure:

  • Make a choice chamber with 2 petri dishes

  • Line dishes with filter paper

  • Add 20 drops of water to one side

  • Count out 10 roly polies

  • Place 5 in each side of the choice chamber

  • Data table:

  • Graph on separate pg.

  • Conclusion:


Possible manipulated variables:

(Each lab group picks one)

  • Moisture (dry vs. moist)

  • Light (light vs. dark)

  • Temperature

  • Color

  • Vinegar vs. water

  • Other?


Develop a hypothesis:

  • If pill bugs prefer _____________ then they will move to the ______________ side of the choice chamber.

Dark

Dark


Design an experiment:

  • State the objective of your experiment.

    Objective: to determine _____________________________.


Design an experiment:

  • List all the materials you will use.

    • Choice chamber

    • 10 roly polies

    • Paper towel

    • Timer

    • Data sheet

    • Whatever you need for your manipulated variable


Light vs. Dark:Aluminum foil to cover one side.

Moist vs. Dry:Moist paper towel, dry paper towel.

Warm vs. Cold:Ice pack for one side, book for other.

Color:Colored paper for each side.

Vinegar vs. Water:drops of vinegar for one side, drops of water for other.


Write your procedure in detail so that someone else could follow it:

1. Gather choice chamber (CC) and other materials to run expt.

2. cut out paper disk to fit in each side of CC.

3. Count out 10 roly polies.

4. Place 5 roly polies in each side of CC.

5. . . .

10. We will keep __?__, __?__, __?__,

the same.

Also tell me what the control variables are!


Lastly:

  • Make a data sheet

  • Assign roles (timer, recorder, etc.)

  • Do your experiment!


Table 1. The number of roly polies in each side over time.


Measurements:

  • Count how many bugs in each side every 60 seconds for 15 minutes.

Do NOT harm or tease the creatures!


On paper (1 paper turned in per lab group):

  • Name, date, title of experiment

  • Hypothesis

  • Objective

  • List of materials

  • Outline of procedure

  • Data table

  • Area for graph of data

  • Conclusion


  • Name:Per. 3

  • Title: Investigation of Roly Poly Behavior

  • Hypothesis: If roly polies prefer moist environments, they will move toward the wet side of a choice chamber.

  • Objective: To investigate . . .

  • Materials:

  • Choice chamber

  • 10 roly polies

  • Stopwatch

  • Data table

  • Anything else you think you’ll need

  • Procedure:

  • Make a choice chamber with 2 petri dishes

  • Line dishes with filter paper

  • Add 20 drops of water to one side

  • Count out 10 roly polies

  • Place 5 in each side of the choice chamber

  • Data table:

  • Graph on separate pg.

  • Conclusion:


Conclusion

Data from this lab showed that roly polies preferred the ____________ environment over the ___________ environment. I accept/reject my hypothesis that __________________________.


  • Rubric (50 pts)

  • Hypothesis: (5)

  • Objective: (5)

  • Materials: (5)

  • Procedure: (10)

  • Data table: (10)

  • Graph on separate pg. (10)

  • Conclusion: (5)


  • Honors:

  • Introduction

    • 1.Intro

    • 2.Hypothesis

    • 3.Objective

  • Procedures (brief)

  • Results, including graph and data table.

  • Conclusion

20 points each = 80 points total


Teacher notes

  • Limit trt #s to 5 or so. Tell alpha groups to agree on 1 trt so they can work together as group.

  • Don’t try electricity –waste of time.

  • Watch glitter


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