BIOL 101 Lecture 2 Methods & Beliefs

in Science

The nature of science• Science:

– A systematic process for learning about the world and testing our understanding of it

– The accumulated body of knowledge that results from a dynamic process of observation, testing, and discovery

• Science is essential:– To sort fact from fiction – Develop solutions to the problems we face

Six Criteria of Science

• Consistent• Observable• Natural• Predictable• Testable• Tentative

Steven Dickhaus (1989)

PseudoscienceAppears scientific, but….

• Uses scientific sounding jargon• Appears to conduct research• Usually more rhetoric than data: questions• Fails to follow scientific methods• Often faults “established scientific

community” or claims a conspiracy against revealing “the truth.” What are we hiding?

PseudosciencePseudoscience is not necessarily fraud; just bad science.

• Extraordinary claims• Claims usually lack substance• Practices bias confirmation• Often pushes particular agenda• Ignores contrary data• Value of data often exaggerated

Twenty-five percent of parents believe vaccines could cause developmental problems

Fact or Fiction?

Vaccines cause autism

Jenny McCarthy

Shark Cartilage Cures Cancer

Global Warming

Fact or Fiction?

Discovery or observational science.

Hypothesis-driven or experimental science.

Two Primary Approaches to Science

Scientists test ideas

Hypothesis-Driven Studies

Discovery/Observational Studies

Some Scientific Questions Can’t Be Answered By Experimentation

One current view of hominid evolution.

Discovery or observational science is still science; falsifiable hypotheses based on natural phenomenon are proposed to best account for observations.

Discovery/Observational Studies

A way of investigating the world in order to form general rules about why things happen.

Science is a way of knowing based on experimental or observational evidence and its interpretation.

Science is a discipline largely defined by its primary method – the scientific method.

Pure Science- pursuit of knowledge

Applied Science- search for practical uses of scientific knowledge

tetradoxin

Pain relief in terminal cancer patients

Science is empirical. It relies on observation and experience.

The phenomenon studied must be measurable.

Phenomenon that cannot be measured:Is this painting beautiful?Does God exist?

It must be consistent with known natural laws and well-established, well-documented existing theories.

It must be derived objectively from independently confirmable observations.

All scientific knowledge must be regarded as tentative.

Characteristics of Scientific Explanations

Hypothesis:Overfishing Antarctic Krill has an effect on the Antarctic food web.

Hypothesis:The fibropapilloma virus causes tumors in green sea turtles.

Hypothesis:Cigarette smoking causes lung cancer.

Hypothesis:Infants who are breast fed are smarter than infants who are given formula.

Hypothesis:Exercise makes people happy.

Scientific statements must be testable and reproducible (i.e., valid & reliable).

What Kind of People Are Scientists?

Reality:Scientists can be egocentric, emotional nutcakes at least as well as anyone.

The Textbook CaseScientists are dispassionate and always reasoned in their approaches to their discipline and the world around them.

One Human Side of Science

What Does Biology Offer Society?Lot’s in terms of medicine, agriculture, maintaining a healthy environment, and basic understanding of ourselves and our world.

One of many recent examples of “good” biology.

Science and scientists of all kinds are poorly understood by the public and scientists tend to poorly understand the public

How Does Society Understand Biology and Biologists?

The Scope and Limitations of Science

Science acquires knowledge through examination of falsifiable hypotheses based on natural phenomena.

This sets a limit on science; science cannot speak directly to such issues as morality or religion.

The domain and limit of science are often misunderstood.

The Scope and Limitations of Science Are More Than An Academic Issue

The Scope and Limitations of Science Are More Than An Academic Issue

The Scope and Limitations of Science Are More Than An Academic Issue

Summary points of the December 20, 2005 Kitzmiller v. Dover Area School District ruling:

Is this the final word on evolution and alternatives in the classroom?

Hardly.

Scientific Method

A way to answer questions

Must be testable & repeatable, i.e., validity and reliability

Deductive Reasoning- general to specificreasoning from general theories to account for specific experimental results

(theory-data collection-analysis)

Inductive Reasoning- specific to generalreasoning from specific observations and experiments to more general theories

(data collection-analysis-theory)

January1992 in the North Pacific

                                                                                                                                            

Rubber Duckies and Ocean currents.

• Jim Ingram (NOAA scientist)- offered a reward

• He graphed and studied the data as it came in.

• Hypothesis: ocean currents were moving the ducks in about the same speed and direction that the currents were going!

Toy trekResearchers expect some 29,000 bath toys lost at sea in 1992 to make the ice-covered trek over the North Pole and to the North Atlantic by this summer.

Population cycles in Snowshoe Hares vs. Lynx • Scientists collected data between 1850 to 1930

on the population of hares and lynx. • Data was from # of pelts sold by trappers to the

Hudson Bay Company!

Scientists observed an oscillation of population density

• As the population of Snowshoe Hare increased or decreased, the population of Lynx increased or decreased too.

• Hypothesis: the populations of Snowshoe Hare and Lynx depended upon each other.

• Scientists made inferences from their observations (Inductive reasoning).

• However, further observations failed to support the current hypothesis.

• New data showed that populations of Snowshoe hare on islands without Lynx had similar population changes as those with Lynx!

• This means the Snowshoe hare population is not dependent upon the Lynx population. (However, the Lynx may be dependent upon the amount of Snowshoe Hare.)

• Thus the data was accurate, but the hypothesis wasn't.

Scientific Method

Observations

Question

Formulate Hypothesis

Conduct Experiment to test Hypothesis

Analyze Results

Conclusions

Discussion

Observation:

The car won’t start when I turn the ignition.

Question:

Hypothesis:

Test hypothesis:

Analyze Results:

Draw Conclusion:

New hypothesis:

Observation:

Question:

Hypothesis:

Test hypothesis:

Analyze Results:

Draw Conclusion:

Ben Franklin & the Gulf Stream

1996

1786

Scientific Method

• Observations– Suggest questions to investigate

• Question– Why does something happen

• Hypothesis– An educated guess– A testable explanation for an observation

Scientific Method• Conduct Experiment

– Process of testing a hypothesis or prediction by gathering data under controlled conditions

– Control vs Experimental GroupControl group: a group that has not been exposed to

some factor (variable)

Experimental group: a group that has been exposed to the factor (variable)

Independent variable (IV): the variable you manipulate that you believe will affect the DV

Dependent variable (DV): the outcome variable, i.e., variable you measure

• Collect, organize, analyze data– Determine whether data is reliable– Determine whether data supports or does

not support the hypothesis or prediction– May use statistics

• Compare data from other studies• Determine relationships• Determine experimental error

Scientific Method

• Theories– Unifying explanations for a broad range of

observations– Based on testing a collection of related

hypotheses– The solid foundation of science– Can be revised given new evidence

Scientific Method

• Drawing Conclusions – To understand something not previously

understood– To produce a model

• Construct a representation of an object, a system, or a process to help show relationships given the data

• A model is an explanation supported by data• Use the model to generate new hypotheses or

predictions

Scientific Method

Biased sampling

Confounding factors

Method for Reducing Bias:

Replication

Randomization

Experimental Design

Sample Size: A larger sample size tends to give you a closer estimate of the true population mean.

Experimental Design

Coral Reef Benthic Habitat Point and Area

AssessmentsKaneohe Bay, HI

• Large sample size• Random sampling

Mangrove Study

Do sponges affect mangrove root growth?

Select a large sample size

Randomly divide the sample into 2 groups

Treat the groups equally in all ways but one

Observe or make measurements

Compare results

Mangrove Study

Select a large number of appropriate subjects

Randomly divide the subjects into 2 groups

Treat the groups equally in all ways but one

Observe or make measurements

Compare results

What is difference between hypothesis, theory & law?

Hypothesis - “an educated guess”; a tentative explanation of phenomena.

Theory - a widely accepted explanation of natural phenomena; has stood up to thorough &

continual testing.

Law - a statement of what always occurs under certain conditions.

Theories

Evolution

Cell Theory

Laws

Biology: Mendelian Inheritance

Physics, Chemistry, Math- Lots!!!!

The Blind Men and the Elephant (Saxe; 1816-1887)

I.It was six men of Indostan

To learn much inclined,Who went to see the elephant

(Though all of them were blind), That each by observationMight satisfy their mind.

II.The First approached the elephant,

And happened to fallAgainst his broad sturdy side,

At once began to bawl:“Bless me!—but the Elephant is very like a wall!”

III.The Second, feeling of the tusk ,Cried, “Ho!—what have we here

So very round and smooth and sharp?To me ‘t is mighty clear

This wonder of an ElephantIs very like a spear!”

IV.The Third approached the animal,

And happening to takeThe squirming trunk within his hands,

Thus boldly up and spake:“I see,” quoth he, “the Elephant

Is very like a snake!”

V.The Fourth reached out his eager hand,

And felt about the knee.“What most this wondrous beast is like

Is might plain’” quoth he;“‘T is clear enough the Elephant

Is very like a tree!”

VI.The Fifth, who chanced to touch the ear,

Said, “E’en the blindest manCan tell what this resembles most;

Deny the fact who can,This marvel of an Elephant

Is very like a fan!”

VII.The Sixth no sooner had begun

About the beast to grope,Than seizing on the swinging tail

That fell within his scope,“I see,” quoth he, “the Elephant

Is very like a rope!”

VIII.And so these men of Indostan

Disputed loud and long,Each with his own opinionExceeding stiff and strong,

Though each was partly in the right,And all were in the wrong!

Moral.

So, oft in these theological wars

The disputants, I ween,

Rail on in utter ignorance

Of what each other mean,

And prate about an elephant

Not one of them has seen!

The Blind Men and the Elephant, Part 2,

I.They talked, those men from Indostan

While standing at the door,Of elephants and how they looked

(This talk was such a bore!),At last they agreed that the knowledge gained

Required something more.

II.Perhaps each one in his own way,

Did learn a bitOf the beast’s elusive mystery,

But just a part of itWith work, they thought, that they might see

The puzzle pieces fit.

III.‘Twas obvious to all of them

For learning to progress,That they must share in what they found—

Jointly sort out the mess.And seek to fully understand

Elephants, more or less.

IV.Some worked alone and some in teams,

In both the field and lab.Models were made: some soft, some hard

Some good, some pretty bad.But when they pooled the useful work,

And truth they made a grab.

V.They checked each other’s methods out,

Some kept, some put asunder.To use the ones which passed the test

Reduced the chance of blunder.Then they’d trust what they had learned

Of elephants’ fine wonders.

VI.They made great strides in what hey knew

Of the nature of the beast.Of what and where and how and why

They knew much more at least.For blind men learned how best to learn

And vision soon increased!

Questions:

1. A hypothesis is a _____________.2. In the mangrove experiment, the dependant

variable is the ________.3. The lynx were found to be _____ on the

presence of the hares, and the hares were ______ of the presence of the lynx.

4. A control group is used as a ________________.

5. Using the scientific method, the statement “Ships travel to England faster than in the other direction because there is a stream in the Atlantic Ocean” is a _________.