The Nature of Life Chapter 1-3 & 1-4 The Science of Biology.
Chapter 1: Biology and You. Section 1-1: The Nature of Science.
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Transcript of Chapter 1: Biology and You. Section 1-1: The Nature of Science.
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.
Click
• 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.