Scientific method
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Scientific Method. How Scientists Work. How Scientists Work: Solving the Problems. Much of biology deals with solving problems These problems can be environmental, ecological, health related, etc.

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Scientific Method

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Scientific method

Scientific Method

How Scientists Work


How scientists work solving the problems

How Scientists Work:Solving the Problems

  • Much of biology deals with solving problems

  • These problems can be environmental, ecological, health related, etc.

  • No matter what types of problemsare being studied, scientists use the same problem-solving steps called…

  • The Scientific Method


Scientific method definition

Scientific Method Definition

  • The scientific method is-

    • A logical and systematic approach or process to problem solving. 

    • An organized way of using evidence to learn about the natural world.


Scientific method listing the steps

Scientific MethodListing the Steps

  • Make an Observation

  • Define the Problem

  • Research the Problem

  • State the Hypothesis

  • Experiment to test Hypothesis

  • Collect and Record Data

  • Analyze Data

  • Draw Conclusions

  • Determine Limitations

  • Report Results


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Question

What does the scientist want

to learn more about?

First

Then

Research

Gathering of information

Next

Hypothesis

An “Educated” guess of an

answer to the question

Then

Procedure/

Method

Written and carefully

followed step-by-step

experiment designed to test

the hypothesis

Scientific Method

An Overview

Next

Data

Information collected during

the experiment

And

And

Observations

Written description of what

was noticed during the

experiment

Finally

Conclusion

Was the hypothesis correct

or incorrect?


Scientific method1

Scientific Method

Ask Question

  • Let’s break each of these steps down into their individual components:

Do Background

Research

Think!

Try Again

Construct

Hypothesis

Test with an

Experiment

Analyze Results

Draw Conclusion

Hypothesis is True

Hypothesis is False

or Partially True

Report Results


Experimenting

Experimenting

  • Let’s look at the text book example of the Scientific Method using Redi’s Experiment on Spontaneous Generation

  • He was trying to disprove the idea of SpontaneousGeneration (or actually that flies came frommaggots, which camefrom flies)

Francesco Redi (1668)


Stating the problem

Stating the Problem

  • Example: How do new living things come into being?

  • Spontaneous generation once commonly accepted

  • Redi wanted to show what caused the appearance of maggots (and then flies) on meat


Belief based on prior observations

Belief based on prior observations

  • If leaf lands on water it becomes a fish

  • If bale of hay left in barn it produces mice

  • Muddy soil gives rise to frogs

  • Meat hung out in the market is the source of flies


Belief based on prior observations1

Belief based on prior observations

Redi observed that maggots appeared on meat a few days after flies were on meat

No microscope = no way to see eggs

But Redi believed that maggots came from eggs that were laid by flies


Forming a hypothesis

Forming a Hypothesis

Redi’s Hypothesis:

Flies produce maggots.

  • How could he test this?

    • Through a controlled experiment


Redi s controlled experiment

Jars with meat

Uncovered jars

Covered jars

Redi’s Controlled Experiment

  • Redi used two groups of jars

    • Jars that contained meat and no cover

    • Jars that contained meat and gauze cover


Control and experimental groups

Uncovered jars

Two groups of jars

Covered jars

Control and Experimental Groups

Control group:

  • used as a standard of comparison

  • the group containing the factor (variable) that has been changed

Experimental group:

(manipulated or independent variable)


Variables in an experiment

Variables in an Experiment

  • Variables - Factors that can be changed

  • Controlled Variables - all the variables that remain constant

  • Independent Variable - (also called the Manipulated Variable) - factor in an experiment that a scientist purposely changes

  • Dependent Variable- (also called the Responding Variable) - the outcome or results, factor in an experiment that may change because of the manipulated variable….what a scientist wants to measure or observe


Variables in redi s experiment

Variables in Redi’s Experiment

  • Controlled Variables: jars, type of meat, location, temperature, time

  • Manipulated Variables: gauze covering that keeps flies away from meat


Let s think about this

Two groups of Jars with meat

Uncovered jars

Covered jars

Let’s think about this.…

Uncovered jars

  • Which is the control group?

  • Which is the experimental group?

Covered jars


Scientific method 5745733

Redi’s Experiment on Spontaneous Generation

OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.

HYPOTHESIS: Flies produce maggots.

PROCEDURE

Covered jars

Uncoveredjars

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.


6 collect and record data

6. Collect and Record Data

observations and measurementsmade in an experiment

Data:

Types of Recorded Data

  • Quantitative - observations that involve measurements/numbers; i.e. 3 days, 12 maggots, 4 g, 13 sec, 8 liters

  • Qualitative - observations thatdo not involve numbers, are of a descriptive naturei.e. white maggots covered the meat, leaves were all wilting


Recording the data

Recording the data

Setting up a data table

Graphing data


7 analyze the data

7. Analyze the Data

  • Examine data tables, charts, and graphs

  • Examine experimental notes

  • Look for trends, patterns, and averages

  • What does the data show

  • Put your data into words


8 draw conclusions

8. Draw Conclusions

  • Restate the hypothesis:

    Example: Flies produce maggots.

  • Accept or reject the hypothesis.

  • Support your conclusion with specific, numerical data.

  • What was Redi’s conclusion?

    • Flies lay eggs too small to be seen.

    • Maggots found on rotting meat are produced

      from the eggs laid by flies.

    • Maggots are not appearing due to spontaneous generation!


9 determine limitations

9. Determine Limitations

  • Scientists look for possible flaws in their research

  • They look for faulty (inaccurate) data

  • They look for experimental error or bias's

  • They decide on the validity of their results

  • They make suggestions for improvement or raise new questions


10 publish results

10. Publish Results

  • Communication is an essential part of science

  • Scientists report their results in journals, on the internet, or at conferences

  • This allows their experiments to be evaluated and repeated

  • Scientists can build on previous work of other scientists

Redi’s experiment

on insects generation


Scientific method 5745733

  • What is the difference

  • between

  • Hypothesis

  • Theory

  • Law


Introduction to biology

Introduction to Biology


The scope of biology

THE SCOPE OF BIOLOGY

  • Biology is the scientific study of life

  • Interactions between different kinds of organisms affect the lives of all


Life s levels of organization define the scope of biology

Life’s levels of organization define the scope of biology

  • A structural hierarchy of life, from molecules to ecosystems, defines the scope of biology

  • An ecosystem consists of:

    • Biotic factors

      • all organisms living in a particular area

    • Abiotic factors

      • all nonliving physical components of the environment that affect the organisms (soil, water)


Scientific method 5745733

  • Ecosystems include:

    • all the organisms in an area, which make up a community

    • interbreeding organisms of the same species, a population

  • At the top of life’s hierarchy is the ecosystem


Scientific method 5745733

  • organ systems

  • organs

  • tissues

  • cells

  • molecules

  • Organisms are made up of:


Scientists use two main approaches to learn about nature

THE PROCESS OF SCIENCE

Scientists use two main approaches to learn about nature

  • In discovery science, scientists describe some aspect of the world and use inductive reasoning to draw general conclusions

    • Example: birds migrate

      South each year during

      colder months

      because it is warmer.


Scientific method 5745733

  • They propose a hypothesis

  • They make deductions leading to predictions

  • They then test the hypothesis by seeing if the predictions come true

  • In hypothesis-driven science, scientists use the “scientific method”


With the scientific method we pose and test hypotheses

With the scientific method, we pose and test hypotheses

  • The main steps of the scientific method


Experimental design

Experiments designed to test hypotheses must be controlled experiments

Experimental Design

  • Control groups must be tested along with experimental groups for the meaning of the results to be clear

    • Independent variable

    • Dependent variable


The diversity of life can be arranged into three domains

EVOLUTION, UNITY, AND DIVERSITY

The diversity of life can be arranged into three domains

  • Grouping organisms by fundamental features helps make the vast diversity of life manageable for study

  • Scientists classify organisms into a hierarchy of broader and broader groups


Scientific method 5745733

  • Domain Bacteria - Domain Eukarya

  • Most classification schemes group organisms into three domains:

  • Domain Archaea


Unity in diversity all forms of life have common features

Unity in diversity: All forms of life have common features

  • All organisms share a set of common features, signs of unity in life’s vast diversity

    • All are made of cells

    • All have DNA as their genetic blueprint

  • These orchids show the variety possible within one species


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  • Each species has its own nucleotide sequence

  • DNA is made of chemical units called nucleotides


Scientific method 5745733

Characteristics of Living Things:

  • The genetic information in DNA underlies all of the features that distinguish life from non-life

  • Order and regulation (homeostasis)

  • Growth and development

  • Use of energy from the environment

  • Response to environmental stimuli

  • Ability to reproduce

  • Evolutionary change


Evolution explains the unity and diversity of life

Evolution explains the unity and diversity of life

  • Charles Darwin is a central figure in biology

  • He synthesized the theory of evolution by natural selection

    • A theory in science is a comprehensive idea with broad explanatory power

  • Evolution is the core theme of biology


Scientific method 5745733

  • The theory of natural selection explains the main mechanism whereby all species of organisms change, or evolve


Scientific method 5745733

  • Evolution happens when populations of organisms with inherited variations are exposed to environmental factors that favor the success of some individuals over others

  • Natural selection is the editing mechanism

  • Evolution is based on adaptations


Connection biology is connected to our lives in many ways

BIOLOGY AND EVERYDAY LIFE

Connection: Biology is connected to our lives in many ways

  • Biology is connected to a great number of important issues

    • Environmental problems and solutions

    • Genetic engineering

    • Medicine


Scientific method 5745733

  • Evaluating everyday reports in the press about a large range of subjects requires critical thinking and some familiarity with many areas of biology

  • Many technological advances stem from the scientific study of life


Your turn

Your turn….

  • WAIT for Ms. Allard tell you to turn on your clicker and log in.

  • NO talking. You can use your notes but do not use each other!

  • You will NOT be able to change your answer so be sure you have read and understand the question(s) before you hit SEND!

  • Do NOT log off until Ms. Allard tells you to do so!


Scientific method 5745733

iRespond Question

Multiple Choice

F

The ability to move and use oxygen are 2 characteristics of all living things.

A.) true

B.) false

C.)

D.)

E.)


Scientific method 5745733

iRespond Question

Multiple Choice

F

Biology can be related to our every day lives.

A.) true

B.) false

C.)

D.)

E.)


Scientific method 5745733

iRespond Question

Multiple Choice

F

The core theme of biology is

A.) a hierarchy

B.) the scientific method

C.) DNA

D.) evolution

E.)


Scientific method 5745733

iRespond Question

Multiple Choice

F

The prefix "a" means

A.) with

B.) without

C.) single or solitary

D.) one

E.)


Scientific method 5745733

iRespond Question

Multiple Choice

F

The prefix "bio" means

A.) self

B.) story

C.) life

D.) study of

E.)


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