THE SCIENCE OF LIFE

Reference:Modern Biology

CHAPTER 1

•Biology is the Study of Life!

•Certain ‘themes’ unify all Biological Sciences.

•Living things, no matter how diverse, share common characteristics.

BIG IDEA

Biology - The Study of Life

BIOLOGY-the study of all living things (organisms like plants, animals, insects, bacteria, humans).

EXAMPLES of Biological Sciences:– Histology-the study cells and tissues– Genetics-the study of how traits are inherited– Microbiology-the study of microorganisms– Ecology-how organisms interact with each

other and their environment.

The study of Biology is unified by certain themes, or patterns that connect all living things:

1. Cell Structure and Function2. Stability & Homeostasis3. Reproduction and Inheritance4. Evolution5. Interdependence of organisms6. Matter, Energy & Organization

6 MAJOR THEMES OF BIOLOGY

SECTION 1-1 UNIFYING THEMES OF BIOLOGY

Cell Structure & FunctionStability & Homeostasis

Reproduction & Inheritance

EvolutionInterdependence of Organisms

Matter, Energy & Organization

All organisms are made of and develop from cells – the basic unit of life.•UNICELLULAR-made of only one cell (amoeba, paramecium)•MULTICELLULAR-made up of many different types of cells working together (tree, spider, dog)

1. CELL STRUCTURE & FUNCTION

1. CELL STRUCTURE & FUNCTIONUnicellular – Each new cell is identical to the parent. All developing organisms are exact clones of their parents.

Multicellular – Cells become different from each other as they multiply. All multicellular developing organisms are a combination of two parents, but are different from them – not clones.

DIFFERENTIATION

Cell - One Name, Many Types

•All cells, no matter what kind, have similarities, as well as differences.

•Certain cell structures determine the function of the cell.•Examples:•Red Blood Cells – carry oxygen•Plant cells – carry out photosynthesis•Unicellular Microorganisms – carry out ALL of life processes.

1. CELL STRUCTURE & FUNCTION

All living things must maintain stable internal conditions to survive.Homeostasis - stable level of internal conditions found in all living cells.

EXAMPLES:•temperature•water content•food intake•blood glucose levels•sleep

2. STABILITY & HOMEOSTASIS

All organisms come from existing organisms. They reproduce and transfer their hereditary information to their offspring.

2 Types of Reproduction:•ASEXUAL REPRODUCTION-heredity information is not combined - only one organism’s DNA is used. Offspring are identical to parent.

EXAMPLES: bacteria and other unicellular organisms

•SEXUAL REPRODUCTION- heredity information (DNA)from two organisms from the same species combine. Offspring are different from both parents and from any other offspring

EXAMPLE: monkey having a babyEgg and sperm zygote (fertilized egg).

3. REPRODUCTION & INHERITANCE

Organisms transfer their hereditary information to their offspring in the form of deoxyribonucleic acid (DNA) – the “book” of life.

A gene is a short segment of DNA that contains the instructions for a

single trait.

vs.

3. REPRODUCTION & INHERITANCE

Lung Cells vs. Thyroid Cell sEach “turn on” different genes

3. REPRODUCTION & INHERITANCE

4. EVOLUTIONPopulations of organisms evolve or change over time.Evolution -population of organism changes over generations (time).

Natural selection is the most important driving force behind evolution.

All living organisms interact with other living organisms and their non-living environment.

5. INTERDEPENDENCE OF ORGANISMS

The branch of biology concerned with these interactions is called Ecology.Ecology-the study of how organisms interact with each other and with their environment.

5. INTERDEPENDENCE OF ORGANISMS

All living organisms need a constant supply of energy.

How organisms obtain, use and transfer energy is a major topic of study in biology.ALL energy for life on earth comes from

the SUN.

6. MATTER, ENERGY & ORGANIZATION

The MOST Important Factor Determining how many and what kind of organisms that can live in an environment is the amount of ENERGY Available. • Autotrophs-organisms that can get energy by

producing their own food.• EXAMPLES: plants and some

unicellular organisms• Heteroptrophs-organisms that must get energy

by eating other organisms• EXAMPLES: some unicellular organisms, all

animals and fungi

6. MATTER, ENERGY & ORGANIZATION

Take the Concept Review Quiz 1_1 …

The World of Biology

In your notebook, respond to the following:Suppose you discovered an unidentified object on your way home from school. How would you determine if it is a living or a nonliving thing?

DO NOW:

All organisms, no matter how different, have certain characteristics in common

THE CHARACTERISTICS OF LIFE !

THE CHARACTERISTICS OF LIFE

All living things are composed of cells…

1. MADE OF CELLS

All living things are highly organized…•They are organized at molecular and cellular level. •Cell structures (organelles) carry out specific functions.

2. ORGANIZED

Levels of Hierarchy of Biological Organization:Cells tissuesTissues organsOrgans systemsSystems ORGANISM

2. ORGANIZED

2. ORGANIZED

All living things use energy…•All organisms use energy to grow, reproduce and make repairs.•Metabolism-all of the chemical processes that take place in a living organism.

3. USE ENERGY

All Living things maintain stable internal conditions and respond to their environment.Remember: Homeostasis is maintaining internal balance.Response - reaction to input (stimulus) from the world.•May be simple or complex.•EXAMPLE: Bird fluffing its feathers to stay warm

4. HOMEOSTASIS

All living things grow and develop…

5. GROW & DEVELOP

Growth is the increase in the amount of livingmaterial in an organism.

Development is the series of changes an organism undergoes in reaching its final adult form.

5. GROW & DEVELOP

All living things reproduce…•Create more of their own species.•Essential to the survival of the species…NOT of the reproducing organism.

6. REPRODUCTION

Compare and Contrast:1. Make a chart that lists the six

characteristics of life.2. Watch the following video clip,

IS IT ALIVE…OR IS IT??3. Use the chart to help you

determine whether the object is living or non-living. Support your decision.

DO NOW

What is Science?Science is a process that produces a body of knowledge!•Science is carried out because people :

‐Wonder…‐Are Curious…‐Ask questions…

•That is the beginning of all scientific research.

SCIENCE – LEARNING ABOUT THE WORLD

Knowledge from science can be used to improve life.

Example: polio vaccine, penicillin, genetically enhanced food

SCIENCE – LEARNING ABOUT THE WORLD

Watch this VideoHow simple ideas lead to scientific discovery

Respond to the video in your

notebook.

BIOLOGY AS A SCIENCE

METHODS OF SCIENCEOne of the best ways to begin studying science is to examine how scientists try to solve a problem or answer a questionWhatever they study, all scientists use certain methods to get answers!

What is in here??

METHODS OF SCIENCE

METHODS OF SCIENCE

Scientist use certain methods in their work…

The Scientific MethodA group of strategies or steps used to help guide scientist to arrive at an answer to a question or problem.

The Scientific Method

The Scientific Method has approximately 6 steps:

1. Observation2. Asking Questions3. Collect Data

– Research

4. Hypothesis (explains their observations and can be tested!)

5. Experiment (testing your hypothesis, Collecting, Organizing & Analyzing Data)

6. Conclusion & Communication

The Scientific Method

Step 1 & 2- Observations & Questions

• 1- Use the 5 senses to perceive objects or events.

• 2 - Ask a question– Based on observations; one or more questions

are generated.

Step 3 – Research & Collect Data

Research – a methodical investigation into a subject in order to answer a question, discover facts and to develop a plan of action based on the facts discoveredData – any and all information gathered while researching an answer to a question

Step 4 – Forming a Hypothesis

Hypothesis-a possible explanation for what was observed and why it should be true.– It must be able to be tested and proven wrong– If/then statement-often written in this form.– Example: If giving a tomato plants “Tomato

Grow” plant food increases the size of the tomatoes they produce, then tomato plants feed “Tomato Grow” will produce larger tomatoes.

Step 5- ExperimentingA hypothesis is often tested by carrying out an experiment.Most experiments in Biology are controlled experiments– performed to test your hypothesis

(confirm or disprove it)– Based on a comparison of a control group

with an experimental group.• Used to gather data under controlled

conditions.» Data-bits of information gathered during the

experiment.

To have a controlled experiment, two groups must be tested: Control Group- the group where

all the variables remain constant the "normal group”

Experimental Group- the group exposed to the experimental factor (independent variable – what is being tested), but is otherwise IDENTICAL to the control group.

Step 5 - Experimenting

All factors in the control group and the experimental group are identical except for one: INDEPENDENT VARIABLE (input)• what is being tested

During the experiment, observations and measurements are taken from both groups, looking specifically at another factor or variable: DEPENEDENT VARIABLE (output)

– dependent because it is driven by/or results from the effect of the independent variable.

Step 5 - Experimenting

For example, if we were setting up an experiment to test our hypothesis about

“Tomato Grow” plant food, we would set up the experiment using two groups of identical tomato plants. One group, our experimental group would receive the food, while the other group, the control group would not. All other variables would remain constant. The plant food would be considered the independent variable, and only given to the experimental group. In this case, the size of the tomatoes would be the dependent variable, as this factor is dependent upon the manipulation and effect of the independent variable.

• What factors must remain the same in both groups to ensure that the results you observe are due to changes resulting from the variable being tested ONLY?

~ FYI ~

If you said one or more of the following, you are correct!–Type and number of plants–amount of water given–the temperature of the environment–amount of sunlight the plants receive–The pH of the soil–etc.

~ FYI ~

Control Group Experimental Group

Tomato Grow

pH 7 pH 7

Collecting & Organizing Data:– Involves placing observations and

measurements (data) in order.• Charts, tables, graphs or maps.

Step 5 - Experimenting

Analyzing data– Determine if the data has meaning– Is the data reliable (trustworthy)?

• If Yes---run the experiment again…and again!• If NO---make a new hypothesis and run

experiment again.

Step 5 - Experimenting

Step 6 – Conclusion & Communication

A conclusion is a summary of the experiment's results. The results are often represented in the form of a model.– A MODEL is an explanation supported by data– It can be visual, verbal or mathematical– Should support the hypothesis– Should be re-testable

Step 6 – Conclusion & Communication

A conclusion is sometimes drawn from an Inference. – made on the basis of premise and previous knowledge rather than direct observations.– It is still an explanation supported by data– Unlike a Hypothesis, an inference is not directly testable…

Scientists communicate the results of their studies with other scientists (peers).

•Publish findings in journals•Present their findings at scientific meetings

Scientists must be unbiased•Should not tamper with their data•Only publish & report tested & proven ideas that can be re-tested & produce the sameresults.

Step 6 – Conclusion & Communication

Step 6 – Conclusion & Communication

Hypothesis Theory Law

No hypothesis or explanation in science is ever really final.

Science is an ongoing process which is constantly revised and improved as new evidence is found.

But many hypotheses have held up over time.

A Hypothesis that has ‘stood the test of time’ (even with minor revisions) may led to

Theories & Laws

Step 6 – Conclusion & Communication

Forming a TheoryA theory may be formed after many hypotheses have been tested and supported – not speculation! What is thought to be true!– supported by much evidence, data– A comprehensive statement of an explanation of a

particular phenomenon– CAN BE PROVEN WRONG!

Step 6 – Conclusion & Communication

Hypothesis Theory Law

LAWS:Theories are explanations of observations.On the other hand, LAWS are statements about events that always occur in nature.A LAW doesn’t explain why something happens, it just merely states that it does happen…

– Accepted to be true– Universal– Is usually expressed as a math equation

e.g. E=mc2

– Scientists use laws to explain theories…

The Scientific Method

Microscopes:Sometimes we need to see thingssmaller than we can see with our eyes.

WHAT DOES A MICROSCOPE DO?Produces a larger image of an object. Uses a glass lens and a beam of light.Magnification-the amount an object’s size is increasedResolution-the power to show details clearly

Microscopes vary in powers of magnification and resolution.

TOOLS OF THE TRADE

*Compound Light Microscope•Specimen mounted on aglass slide•Must be thinly sliced or very small•Pair of lenses

o Ocular lens (eye piece)o Objective lens (nose piece)

•Can be used to study LIVE specimens•Magnification determined by multiplying power of both lenses

o Eyepiece 10X times Objective power (10X, 20X, 40X…)

•Highest Maximum magnification is around 1000X

LIGHT MICROSCOPES

LIGHT MICROSCOPES

*Transmission Electron Microscope (TEM)•Uses a beam of electrons to produce an enlarged image of very thinly sliced specimen on screen or photographic plate•Image focused by magnetic lenses•200,000X magnification•Cannot be used to view living specimens

ELECTRON MICROSCOPES

*Scanning Electron Microscope (SEM)

•3D image•Specimens not sliced for viewing•Surface sprayed with fine metal coating•Also uses electron beam and fluorescent screen or photographic plates•100,000X magnification•Cannot be used to view living specimens

ELECTRON MICROSCOPES

The International System of Measurement, or SI is the one

system of measurements scientists use.

Named after the French – ‘Systeme International d’Unites’

and formerly known as:The Metric System

Tools of the trade

The Metric System• Major advantages:– It is a decimal system based on multiples or

fractions of 10’s– Commonly used among all scientists– Easy to convert between prefixes:

– Kilo – 1000– Deci – 1/10th – Centi – 1/100th

– Milli – 1/1,000th – Micro – 1/1,000,000th …of the base UNIT

Tools of the trade

The Metric System– Uses Base Units -

• Describe what you are measuring.» Length-meter (m)» Volume-liter (L)» Mass-gram (kg)» Temperature-Celsius (C)» Time-second (s)

Tools of the trade

BASE UNIT MEASURES

Meter Length

Liter Volume

Gram Mass

In SI, prefixes are added to the base unit (meter, gram, liter).•The prefixes help us to understand the amount more easily•Prefixes are multiples of 10…

•So 1 kilogram is 1000 X larger than a gram or 1000 grams•1 centimeter is 1/100th of a meter or 100 X smaller than a meter•1 milliliter is 1/1000th of a liter, or 1000 X smaller than a liter

TOOLS OF THE TRADEPREFIX …PLUS BASE UNIT

Kilo – 1/1000th Kilo+gram = Kilogram

Hecto – 1/100th Hecto+liter = hectoliter

Deka – 1/10th Deka+gram = dekagram

Deci - 10 Deci+liter = deciliter

Centi - 100 Centi+meter = centimeter

Milli - 1000 Milli+meter = milliliter

The SI System makes conversions easier!

•1 mile=1760 yards=5280 feet= 63,360 inches – Ugh!!•Because all of the unit relationships in the metric system are based on multiples of 10, it is easy to convert between prefix units - just multiply or divide by 10!•100,000 cm = 1000 meters = 1 kilometer•1 kilometer = 1000 meters = 100,000 cm

TOOLS OF THE TRADE

For example:• Centimeters are 10 times larger than

millimetersSo..• 1 centimeter = 10 millimeters

1 10 100 1000.10.01.001

Kilo- Hecto- Deka-BASE UNITMeterGramliter

Deci- Centi- Milli-

Tools of the trade

1 centimeter = 10 millimeters

1 mm

1 mm

1 mm

1 mm

1 mm

1 mm

1 mm

1 mm

1 mm

1 mm

1 cm

40

41

41

40

Tools of the trade

US Conversions within theMetric System

TOOLS OF THE TRADE

Mass vs. Weight(Not the same!)

Mass-How much matter (particles) you are made of.Weight-How much gravity pulls on you.

A QUICK SIDE NOTE…