THE SCIENCE OF LIFE

Modern BiologyCHAPTER 1

In your notebook, respond to the following questions:

“Why do we study Biology?”

“What is the goal of science?”

DO NOW:

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.

SCIENCE – LEARNING ABOUT THE WORLD

SECTION 1-1 UNIFYING THEMES OF BIOLOGY

Biology - The Study of Life

BIOLOGY-the study of all living things.EXAMPLES OF SPECIFIC AREAS:–Histology-the study cells and tissues–Genetics-the study of how traits are

inherited–Molecular biology-how organisms

function on the molecular level–Ecology-how organisms interact.

Biology - The Study of Life

ORGANISMS-living things• EXAMPLES:–Plants–Insects–Humans–Bacteria

Biology is unified by certain themes (patterns that connect living things)

1. Evolution2. Reproduction and Inheritance3. Development4. Cell Structure and Function5. Matter, energy and organization6. Interdependence of organisms

*Science & Society

6 MAJOR THEMES OF BIOLOGY

Evolution-population of organism changes over generations (time).

1. EVOLUTION

All organisms come from existing organisms.Transfer hereditary information in the form of deoxyribonucleic acid (DNA).Can be:

ASEXUAL REPRODUCTION-only one organism’s DNA is used. Offspring is identical to parent.

EXAMPLE: bacteria dividingSEXUAL REPRODUCTION-DNA from 2 organisms is combined. Offspring is different from both parents and from any other offspring

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

2. REPRODUCTION & INHERITANCE

This baby has inherited some traits from its mom and some from its dad…it may look similar to one or both of them, but its DNA is a combination of the two!

2. REPRODUCTION & INHERITANCE

All organisms are made of cells.

UNICELLULAR-made of only one cell (amoeba, paramecium)MULTICELLULAR-made up of many different types of cells working together (tree, spider, shark).

DEVELOPMENT-process where a zygote (combined sperm and egg) becomes a mature (adult) individual.

3. CELL STRUCTURE & FUNCTION

3. CELL STRUCTURE & FUNCTION

The structure (way an organism is put together) is connected to its function (how it works).

EXAMPLE:Bird’s wingHuman handStomachMuscle cell

**The Cell is the basic unit of life.

All organisms are made of and develop from cells.

3. CELL STRUCTURE & FUNCTION

The structure (way an organism is put together) is connected to its function (how it works).

EXAMPLE:Bird’s wingHuman handStomachMuscle cell

**The Cell is basic unit of life. All organisms are made of and develop from cells.

3. CELL STRUCTURE & FUNCTION

3. CELL STRUCTURE & FUNCTION

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

4. STABILITY & HOMEOSTASIS

All organisms obtain, use and transfer energy.ALL energy comes from the SUN.

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

5. MATTER, ENERGY & ORGANIZATION

Ecology-the study of how organisms interact with each other and with their environment.All organisms need substances (nutrients, water, gases) from their environment.

6. INTERDEPENDENCE OF ORGANISMS

Knowledge from science can be used to improve life.

Example: polio vaccine, penicillin.

SCIENCE & SOCIETY

IS IT ALIVE…OR IS IT??

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:

SECT 1-2 THE WORLD OF BIOLOGY

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…•Organized at cellular and molecular level. •Cell structures (organelles) carry out specific functions.•Multicellular organisms may contain many types of cells, each type carrying out one job (Specialized-carry out one set of functions).

2. ORGANIZATION

In multicellular organisms, cells and groups of cells (tissues) are organized by their function

Cells tissuesTissues organsOrgans systemsSystems ORGANISM

2. ORGANIZATION

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

3. ENERGY USE

All living things respond to their environment… Response-reaction to input from the world.May be simple or complex.

EXAMPLE: gazelle runs away from a lion.

4. RESPOND TO ENVIRONMENT

All living things grow and develop…As cells divide and get larger, the organism becomes bigger.

5. GROWTH

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

6. REPRODUCTION

All living things maintain stable internal conditions…(Homeostasis)

EXAMPLE: water balance, ph, gas exchange…birds feathers fluffing up in cold weather•.

7. MAINTAIN HOMEOSTASIS

Compare an icicle to a carrot. Make a chart that lists the characteristics of life. Decide which of them that each meets and use the chart to decide which is alive and which is not. Explain.

CHECK FOR UNDERSTANDING

SECTION 1-3 SCIENTIFIC METHODS

Watch this at HomeHow simple ideas lead to scientific discovery

Do NowRespond to the following

in your notebook:

How do we investigate and acquire knowledge in

science?

What do you see in this picture?

The Scientific MethodWhat is it??Scientific Methoda systematic way of developing an answer to a question or problem through experimentation.

The Scientific MethodThe Scientific Method has 6 steps:

1. Observation (Asking questions & collecting data)

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

3. Experiment (testing your hypothesis)4. Organizing Data5. Conclusion6. Communication

The Scientific Method

Step 1 - Observation• Use the 5 senses to perceive objects or

events.• Asking a question– Based on observations; one or more questions

are generated.

Step 2 – Forming a Hypothesis

• Once a specific question has been asked, a scientist can think about possible answers to the question.

• Hypothesis-a possible explanation for what was observed that must be able to betested.

– May be disproven as new data is collected.– If/then statement-often written in this form.– Example: If the amount of sunlight is affecting the

growth of my plants, then plants receiving more sunlight should grow at a faster rate.

Step 3 - Experimenting• A test of the hypothesis by gathering

data under controlled conditions.– Conducting a controlled experiment.– Data-observation and measurements gathered

during the experiment.

• Based on a comparison of a control group with an experimental group.

Step 3 - Experimenting– Both are identical except for one

factor (independent variable).–Observations and measurements

are taken for a particular factor (dependent variable) in both groups.• Driven by/or results from independent

variable.

The Scientific MethodWhat are the parts of an experiment?• Control Group- in an experiment, the group is

the standard of comparison with the other group, does not receive the experimental factor, the “normal” group.

• Experimental Group- in an experiment, group exposed to the experimental factor, but is otherwise IDENTICAL to the control group.

The Scientific MethodWhat are the parts of an experiment?

Independent Variable-the factor deliberately changed by the scientist; the one factor different between the groups.

**Independent variable causes a change in what you are measuring – the dependent variable**

Dependent Variable-the one thing that is measured in the experiment, directly influenced by the independent variable.• Outcome variable measured each time the independent variable is changed.

Step 4 – Organizing Data• Involves placing observations and

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

Step 4 – Organizing Data• Analyze 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 - Conclusion• Conclusions are made on the

basis of facts, not observations–Often drawn from data gathered

from a study or experiment–Should support the hypothesis–Should be re-testable

• Scientists must share 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

Step 6 - Communication

• Sharing of information is essential to scientific process

• Subject to examination and verification by other scientists

• Allows scientists to build on the work of others

Step 6 - Communication

TheoriesA theory may be formed after many relatedhypotheses have been tested and supported

withexperimental evidence– A broad and comprehensive statement of

what is thought to be true– Supported by considerable evidence– Ties together related hypotheses

Type:

LawsA Statement of fact that concisely explains

an action or group of actionse.g. Law of Gravity– Accepted to be true– Universal– May be expressed as a math equation

e.g. E=mc2

Observation: I notice that some plants in my yard are not growing at the same rate. Some plants seem to grow faster than others. The plants that are growing faster seem to be exposed to more sunlight that the other plants.Question: Why are some growing faster?

EXAMPLE : SCIENTIFIC METHOD

Check For Understanding:I love to garden, but always seems to kill the plants. I am especially jealous of my son, Nicholas, because everything he plants grows. This summer I bought a special plant food to see if it will help my plants to grow faster.

Question/Observation:Hypothesis (If/then):Parts of the experiment:

control group:experimental group:independent variable:dependent variable:constants:

EXAMPLE : SCIENTIFIC METHOD

Respond to the following in your notebook:

What constitutes evidence? What makes a question scientific?

DO NOW

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

Microscope-instrument that produces a larger image of an object.WHAT DOES A MICROSCOPE DO?

Produces a larger image of an object.Magnification-the amount an object’s size is increasedResolution-the power to show details clearly

MICROSCOPY & MEASUREMENT

SECTION 1-4 : MICROSCOPY & MEASUREMENT

Compound Light Microscope•Specimen mounted on aglass slide•Must be thinly sliced or very small•Pair of lenses•Ocular lens (eye piece)•Objective lens (nose piece)

•Can be used to study LIVE specimens•Magnification determined by multiplying power of both lenses•Eyepiece 10X times Objective power (20X, 40X…)•Highest Maximum magnification is around 1000X

MICROSCOPY & MEASUREMENT

Electron Microscopes•Transmission EM (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

MICROSCOPY & MEASUREMENT

Scanning EM (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

MICROSCOPY & MEASUREMENT

•Conversions within the metric system

WATCH THIS AT HOME:

• Scientists use one system of measurements.

• Called Systeme International d’Unites (SI), aka The Metric System– Base Units

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

Microscopy & Measurement

•Not everything you measure is 1 meter or 1 gram•US- inch, feet, yard, mile, ounce, pound, ton

•In SI, prefixes are added to the base unit (meter, gram, liter).•Prefixes are multiples of 10•Kilo-k- 1,000•Hecta-h-100•Deca-da-10•Deci-d-0.10•Centi-c-0.01•Milli-m-0.001

MICROSCOPY & MEASUREMENT

This makes conversions easier!

1 mile=1760 yards=5280 feet=63,360 inches1km=1,000m=100,000 cm

MICROSCOPY & MEASUREMENT

Mass vs. Weight

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

A QUICK SIDE NOTE…