Chapter 1: Chapter 1: Biology and YouBiology and You

Chapter 1: Chapter 1: Biology and YouBiology and You

Section 1-1: The Nature of

Science

Key Ideas:

• How can someone practice scientific

thoughts?

• What are universal laws in science?

• How do ethics apply to science?

• Why should someone who is not

planning to become a scientist study

science?

• The goal of science is to help us

understand the natural world

and improve people’s lives.

Thinking like a scientist can help

you solve problems and think

critically about your world.

What Is Scientific Thought?

• Scientific Thought- involves making

observations, using evidence to

draw conclusions, being skeptical

about ideas, and being open to

change when new discoveries are

made.

• Scientists observe the world around them

and then ask questions about what they

observe. This process of making

observations and asking questions is the

basis of scientific thought. Scientific thought

also requires skepticism- a habit of mind in

which a person questions the validity of

accepted ideas. Scientists require

• evidence, not opinions, to support

ideas.

• Ex: People once thought stress

caused stomach ulcers. However,

a group of researchers found that

bacteria Helicobacter pylori in the

stomachs of people with ulcers.

Studies confirmed that the

bacteria caused ulcers.

• Scientific discoveries can change

the way people view the world.

Many scientific discoveries lead to

new technologies and medical

treatments. For example,

discovering that bacteria cause

stomach ulcers led to prescribing

antibiotics for patients with ulcers.

In summary, scientific thought involves:

• Making observations

• Being skeptical about ideas

• Using evidence to draw conclusions

• Being open to change when new

discoveries are made

What are Universal laws?

• Universal Laws- Science is governed

by truths that are valid everywhere in

the universe.

• These truths are called universal

laws.

• Though branches of science address

different aspects of the natural world,

universal laws apply to all branches of

science and every person.

• Ex: All objects in the universe are

affected by gravity. Whether

scientists are studying birds, stars,

or landscapes, they must all

understand the law of gravity.

Birds must overcome gravity to

fly. Stars are formed when gravity

pulls a mass of gases together.

Why Are Ethics Important In Science?• Ethics are a system of moral

principles and values.

• Scientific experimentation and

discovery can have serious ethical

implications, scientific investigations

require ethical behavior.

Ethics cont’d• Scientists performing investigations must

report only accurate data, be willing to

allow their peers to review their work, and

behave ethically with the people involved in

the investigations. If the data or claims by

a scientist are false or misleading the

people relying on this discovery/information

could be in real danger.

• Ex: A scientist falsely claims he

found a cure for diabetes; those

individuals with diabetes change

how they manage their condition to

take advantage of the new

discovery. Since the information is

false those individuals with

diabetes can suffer serious

consequences.

Why is it important that scientific investigations

be done ethically?

Why Study Science?

• Scientific thinking is not just for

scientists.

• An understanding of science can

help you take better care of your

health, be a wiser consumer,

and become a better-informed

citizen.

Why Study Science?• You can do this by asking questions about

certain claims, be skeptical about what

you read, and be ready for discovery and

change.

• You can use science to investigate a

problem in your community and discover

helpful solutions. You can also use science

to improve the world around you.

Key Ideas:• How can someone practice scientific thoughts?

– Scientific thought involves making

observations, using evidence to draw

conclusions, being skeptical about ideas, and

being open to change when new discoveries

are made.

• What are universal laws in science?

– Science is governed by truths that are valid

everywhere in the universe. These truths are

called universal laws.

Key Ideas:• How do ethics apply to science?

– Since scientific experimentation and discovery

can have serious ethical implications, scientific

investigations require ethical behavior.

• Why should someone who is not planning to

become a scientist study science?

– An understanding of science can help you take

better care of your health, be a wiser consumer,

and become a better informed citizen.

Section 1-2: Scientific method

Key Ideas:

• How do scientists know how to begin an

investigation?

• What are two types of experiments that

scientists can use to test hypotheses?

• What is the difference between a theory

and a hypothesis?

How Do Scientific Investigations Begin?

Step 1: Making Observations

• Most scientific investigations begin

with observations that lead to

questions.

• Observation is the act of studying

objects or events using your senses

(sight, hearing, touch, taste, and

smell).

Making Observations cont’d

• Scientists use both direct and

indirect observations to study the

world around them.

• Tools, such as microscopes, can also

help you make observations. Many

observations lead to questions.

• Ex: Direct observation: The TV in my

room can be seen

• Indirect observation: The force of

gravity cannot be seen; scientists

observe gravity indirectly by

observing the effects of gravity on

objects that can directly be observed.

Step 2: Formulating a Hypothesis

• Scientists formulate hypotheses to

answer these questions. A

hypothesis is a possible

explanation that can be tested by

observation or experimentation.

Hypotheses are NOT guesses!

Hypothesis Visual Concept

Step 3: Scientific Experiment

• In science, an experiment is a set of

planned steps, or a procedure that is

carried out under controlled

conditions to test a hypothesis.

Different hypotheses require different

kinds of testing. Therefore, not all

experiments have the same format.

Scientific Experiment cont’d

• Experiments can be either

quantitative or qualitative. The

results of a quantitative

experiment can be measured in

numbers. The results of a

qualitative experiment are

generally described in words.

Scientific Experiment cont’d

• Scientists generally use quantitative

experiments in situations in which they

can control all the factors that affect

the experiment. For example, a

scientist may carry out a quantitative

experiment to learn how temperature

affects a chemical reaction.

Scientific Experiment cont’d

• Scientists generally use qualitative

experiments in situations in which they

cannot control all the factors that affect

the experiment.

• Using radio collars to track animals in a

natural habitat is an example of a

qualitative experiment.

Example of the results of aquantitative experiment

Example of the results of aqualitative experiment

The plant given fertilizer grew 10 cm. The plant given no fertilizer grew 2 cm.

The trees near the road look less healthy than the trees farther from the road.

CONTROL AND EXPERIMENTAL GROUPS

• Many scientific experiments use control groups

and experimental groups that test one factor

at a time, this is called a controlled

experiment.

• A control group is a group in an experiment

that receives no experimental treatment.

• Scientists try to make everything about the

control and experimental groups the same

except for one factor, or variable.

• This variable, which scientists change

during the experiment, is called the

independent variable.

• Variables that change as a result of changes

in the independent variable are called

dependent variables.

• In many experiments, scientists try to learn

how changes in the independent variable

affect the dependent variables.

Variables Visual Concept

• There are often cases in which

experiments are not possible or not

ethical.

• In these cases, researchers perform

studies.

• In a study, researchers gather data about

a system by making observations rather

than manipulating independent

variables.

• After conducting an experiment

researchers analyze their results to

learn whether their results support

their hypothesis or not.

• Scientists draw conclusions that

explain the results of their experiments.

• Scientists verify their conclusions by

conducting their experiments.

• Every person has his or her own

point of view.

• A particular point of view is called a

bias.

• Scientists try to prevent bias from

affecting their work, but bias can still

influence an experiment.

• Sources of funding, personal

involvement in a product, and other

conflicts of interest can affect an

experiment.

• It is wise to view all scientific claims

in their context and think critically

about them.

What Is a Scientific Theory?

• In everyday speech, people often use

the word theory to mean “a guess.”

• However, in science, a theory is much

more than just a guess.

• A scientific theory is a generally

accepted explanation for a large

amount of data and observations.

• The quantum theory, the cell theory,

and the theory of evolution are

examples of scientific theories.

• The figure below shows how

observations, questions, hypotheses,

and experiments, can lead to the

formation of a scientific theory.

Scientific Method Visual Concept

Key Ideas:• How do scientists know how to begin an

investigation?

– Most scientific investigations begin with

observations that lead to questions.

• What are two types of experiments that scientists

can use to test hypotheses?

– Scientists conduct controlled experiments

or perform studies in order to test a

hypothesis.

Key Ideas:• What is the difference between a theory and

a hypothesis?

– The main difference between a theory

and a hypothesis is that a hypothesis

is a specific, testable prediction for a

limited set of conditions and a theory

is a general explanation for a broad

range of data.

Section 1-3: Tools and

Techniques

Key Ideas:

• Why do scientists use the SI system

of measurement?

• What are some tools and techniques

that scientists use in the laboratory?

• What can you do to stay safe during

an investigation?

What Is SI?• Scientists from all around the world

share data. However, different units

of measurement are commonly used

in different countries.

• Therefore, scientists use a common

measurement system called the

International System of Units (SI).

• By using SI units, scientists can easily

understand and test the results of other

scientists.

• Scientists also use SI because each SI

unit can be organized into smaller or

larger units based on powers of 10.

• This makes it easy for scientists to

convert between large and small

measurements.

• Most SI units have a prefix that indicates the

relationship between the unit and a base

unit.

• For example, the base unit for length is the

meter.

• The prefix kilo- means 1,000. Therefore, a

kilometer is equal to 1,000 meters.

• The tables on the next pages show common SI

base units and prefixes.

Common SI Units

Some SI Prefixes

Metric Units of Lengths and Equivalents

What Tools and Techniques Do Scientists Use?

• When conducting investigations, scientists

always make precise measurements and keep

detailed notes.

• Many scientists also use special tools to boost

their senses.

• For example, scientists use microscopes to

observe objects that are too small to see with

the unaided eye, such as, bacteria.

• Two common kinds of microscopes

are light microscopes and electron

microscopes.

• In a light microscope, light passes

through one or more lenses to

produce an enlarged image of an

object.

• An electron microscope forms an

image of an object by using a beam

of electrons to magnify extremely

small objects.

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• Scientists also use special procedures

in the lab.

• For example, they may use a technique

called sterile technique to prevent

samples from being contaminated.

• In addition, scientists can also collect

data remotely, using remote tracking

devices on released animals.

How Can You Stay Safe in the Lab?

• Studying science can be exciting, but

it can also be dangerous. Here are

some guidelines for working safely in

the lab:

– Follow the instructions your teacher

gives you.

– Read your lab procedure carefully before

beginning.

• Do not skip any steps in your lab

procedure.

• Always wear safety equipment in the lab.

• Measure chemicals carefully and precisely.

• Ask your teacher how to get rid of any

extra chemicals or materials at the end of a

procedure.

• Never taste or smell any materials

or chemicals in lab unless your

teacher instructs you to do so.

• Do not use any damaged or broken

equipment.

• Keep your lab area clean and

organized.

• Be careful when you place

something on the lab bench.

• Make sure that the object will not

fall or tip over.

• Walk carefully in the lab.

• If you are working outside, be aware

of your surroundings.

• Avoid poisonous plants and

dangerous animals that live in the

area.

• Wear sunscreen and a hat that shades

your neck and ears.

• Before a lab begins, be sure you know where

the safety equipment is located and how to

use it.

• If an accident occurs in the lab, stay calm.

• Make sure that you are safe and that no one

else is in danger.

• Then, inform your teacher right away.

• Follow all the instructions your teacher gives

you.

Key Ideas:• Why do scientists use the SI system of

measurement?

• The international System of Units is used

by all scientists because scientists need

to share a common measurement

system. SI is also preferred by scientists

because it is scaled by multiples of 10,

which makes the system easy to use.

• What are some tools and techniques that

scientists use in the laboratory?

• In the lab, scientists always keep

detailed and accurate notes and

perform precise measurements. Many

scientists also used specialized tools,

such as, microscopes, and specialized

procedures, such as, sterile technique.

• What can you do to stay safe during an

investigation?

– Scientists must use caution when

working in the lab or doing field

research to avoid dangers such as,

chemical burns, exposure to radiation,

exposure to infectious disease, animal

bites, or poisonous plants.

Section 1-4: What Is Biology?

Key Ideas:

• What are some of the branches of

biology?

• What do biologists study?

• What are eight characteristics that

all living things share?

What Is Biology?

• Biology is the study of life. Life is

extremely diverse.

• There are many branches of biology,

such as, biochemistry, ecology, cell

biology, genetics, evolutionary theory,

microbiology, botany, zoology, and

physiology.

• Biologists study the characteristics of

organisms, or living things. They

also study how organisms interact

with their environment. Living

things share eight characteristics,

shown below, that separate them

from nonliving things.

Characteristic

Description

Cellular Organization

A cell is the smallest unit capable of all life functions. A cell is a highly organized structure that is surrounded by a thin covering called a membrane. The basic structure of cells is the same in all organisms.

Homeostasis All living organisms must maintain a stable internal environment in order to function properly. The maintenance of stable internal conditions in spite of changes in the external environment is called homeostasis.

Metabolism Organisms carry out many chemical reactions to obtain energy. Organisms use energy to grow, to move, and to process information. Metabolism is the sum of all the chemical reactions carried out in an organism. Almost all of the energy used by living things originally comes from the sun. Plants, algae, and some bacteria capture this energy and use it to make molecules.

Responsiveness

In addition to maintaining a stable internal environment, living organisms also respond to their external environment. Plants bend toward sunlight. Birds fluff their feathers to insulate their bodies during cold weather.

Reproduction Most organisms can reproduce. Reproduction is the process by which organisms make more of their own kind.

Heredity/Genetics

When an organism reproduces, it passes on its own characteristics, or traits, to its offspring. This is called heredity.

Evolution

A species is a group of organisms that can mate to produce offspring. Their offspring can also reproduce. Individuals with traits that help them survive tend to reproduce in larger numbers. They pass along the helpful traits to their offspring. As a result, these helpful traits become more common in the species. Evolution is the change in the inherited traits of a species over many generations (time).

Growth All living organisms grow. As organisms grow, many change. This process is called development. Development differs from evolution because development refers to change in a single individual during that individual’s life.

Both the man and the Sequoia tree that he is standing on are

living organisms.

Key Ideas:• What are some of the branches of biology?

– Biology includes biochemistry,

ecology, cell biology, genetics,

evolutionary theory, microbiology,

botany, zoology, and physiology.

• What do biologists study?

– Biologists study the characteristics

of organisms, or living things.

• What are eight characteristics that all

living things share?

– The eight properties of life are:

cellular organization,

homeostasis, metabolism,

responsiveness, reproduction,

heredity, evolution, and growth.