1 Chapter 1 The Science of Biology. 2 1–1 What Is Science? Science is a process of inquiry, asking questions, the answers to which produce a body of knowledge,

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Chapter 1 The Science of Biology

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1–1 What Is Science?

• Science is a process of inquiry, asking questions, the answers to which produce a body of knowledge, which is subject to change and revision.

• The goal of science is to investigate and understand the natural world, to explain events in the natural world and to use those explanations to make useful predictions.

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• Science only deals with the natural world. Biology is a field in science that focuses on the study of life.

• An understanding of science and the scientific approach is essential to making intelligent decisions.

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• Scientists collect and organize information in a careful, orderly way, looking for patterns and connections between events.

• Scientists propose explanations that can be tested by examining evidence. Scientists try to explain events logically and analytically.

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• Scientific thinking begins with observation, the process of gathering information about events or processes in a careful, orderly way.

• Observation generally involves using the senses, particularly sight and hearing. The information gathered from observations is called data. Data consists of observations that do not differ whether collected by one person or another.

• Eg. Flame from a lighter/Candle Flame

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• Two types of data:– Quantitative data: expressed in numbers,

obtained by counting or measuring.– Qualitative data: descriptive and involves

characteristics that can’t usually be counted.

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• Scientists use data to make inferences, a logical interpretation based on prior knowledge or experience.

• After initial observations, a hypothesis is proposed. A hypothesis is a proposed scientific explanation for a set of observations.

• Scientific hypotheses must be proposed in a way that enables them to be tested.

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• Science is an ongoing process, knowledge is constantly being reevaluated, revised and updated because of new tools, techniques and discoveries.

• Good scientists are skeptics, questioning existing ideas and new hypotheses.

• Common steps for scientists to gather information and answer questions are known as scientific methods. Not every scientific investigation uses every method nor do all investigations lead to scientific theory.

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1-2 How Scientists Work

• While there are no fixed steps, generally the scientific method involves:

1) MAKE OBSERVATIONS: observations utilize the senses to gather information. Scientific discovery often takes place when a scientist observes something no one has noticed before.

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2) ASK A QUESTION: observations may lead to unanswered questions. (Research may provide information about previous investigations of the question or suggest appropriate approaches to the problem.)

3) FORM A HYPOTHESIS: an explanation for a question or a problem that can be formally tested. A good hypothesis predicts a relationship between cause and effect.

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4) SET UP A CONTROLLED EXPERIMENT: While we use the term experiment informally, a scientific experiment is an investigation that tests a hypothesis by the process of collecting information under controlled conditions. A controlled experiment involves two groups:

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a) Variable (Experimental) group: test group that receives experimental treatment. A variable is the factor of an experiment that can change. In a controlled experiment, only one variable is tested at a time. There are three types of variables:

– Controlled (constant) variables: same for both the control and variable group.

– Manipulated (independent) variable: variable that is deliberately changed.

– Responding (dependent) variable: changes in response to the manipulated variable (what happened).

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b) Control group: group that receives no experimental treatment, the standard against which results are compared.

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5) RECORD AND ANALYZE RESULTS: keeping a written record of observations and data. Data from an investigation can be considered confirmed only if repeating the investigation several times yields similar results.

6) DRAWING A CONCLUSION: Use evidence to determine whether the hypothesis was supported or refuted.

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7) REPORTING RESULTS: Results are only useful if they are made available to other scientists for peer review. Other scientists can try to verify the results by repeating the procedure.

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• It is not always possible to do an experiment to test a hypothesis.– Alternative investigations may utilize fieldwork or

surveys or large groups of subjects, controlling as many variables as possible.

• As evidence accumulates from scientific investigations, a particular hypothesis may become so well supported that scientists consider it a theory. A theory is a well-tested explanation that unifies a broad range of observations. – No theory is considered absolute truth. As new

evidence is uncovered, a theory may be revised or replaced.

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1 – 3 Studying Life

• The word biology means the study of life. A biologist is someone who uses scientific methods to study living things.

• Describing what makes something alive is not easy.

• No single characteristic is enough to describe a living thing.

• Some non-living things share one or more traits with living things.

Section 1-3

THE CHARACTERISTICS OF LIVING ORGANISMS

There are 7 characteristics:• Movement

• Respiration

• Sensitivity

• Growth

• Reproduction

• Excretion

• Nutrition

Movement

• An action by an organism or part of an organism causing a change of position or place.

Respiration

• The chemical reactions that break down nutrient molecules in living cells to release energy

Sensitivity

• The ability to detect or sense changes in the environment (stimuli) and to make responses.

Growth

• A permanent increase in size and dry mass by an increase in cell number or cell size or both.

Reproduction

• The processes that make more of the same kind of organism

Excretion

• The removal from organisms of toxic materials, the waste products of metabolism (chemical reactions in cells including respiration) and substances in excess of requirements.

Nutrition

• The taking in of nutrients which are organic substances and mineral ions, containing raw materials or energy for growth and tissue repair, absorbing and assimilating them.

Summary:Write down the terms

• Movement

• Respiration

• Sensitivity

• Growth

• Reproduction

• Excretion

• Nutrition

Quiz

Guess which characteristic is being demonstrated by the following

animations:

Question 1

Question 2

Question 3

Question 4

Question 5

Which two characteristics are shown by this animation:

Question 6

Other than movement, which characteristics are shown by this animation:

Question 7

So far you should have named a total of five different characteristics.

However there are 7 characteristics in total.

Name the two remaining characteristics.

Answers:

How well did you do?

Question 1: Excretion

Question 2: Nutrition

Question 3: Movement

Question 4: Reproduction

Question 5: Sensitivity and Movement

Which two characteristics are shown by this animation:

Question 6: Sensitivity and Nutrition

Other than movement, which characteristics are shown by this animation:

Question 7: Growth and Respiration

So far you should have named a total of five different characteristics.

However there are 7 characteristics in total.

Name the two remaining characteristics.

Now you should be able to

Define the characteristics of living organisms

Copyright Pearson Prentice Hall

1-4 Tools and 1-4 Tools and ProceduresProcedures


A Common Measurement System

What measurement system do most scientists use?



Most scientists use the metric system when collecting data and performing experiments.



Because the metric system is based on multiples of 10, it is easy to use.


1 meter (m) = 100 centimeters (cm)1 meter = 1000 millimeters (mm)1000 meters = 1 kilometer (km)

1 kilogram (kg) = 1000 grams (g)1 gram = 1000 milligrams (mg)1000 kilograms = 1 metric ton (t)

00C = freezing point of water1000C = boiling point of water

1 liter (L) = 1000 milliliters (mL)1 liter = 1000 cubic centimeters (cm3)


Microscopes

How are light microscopes and electron microscopes similar? How are they different?


Microscopes

MicroscopesMicroscopes are devices that produce

magnified images of structures that are too small to see with the unaided eye.


MicroscopesLight Microscopes

The most commonly used microscope is the light microscope.

Light microscopes produce clear images of objects at a magnification of about 1000 times.


Microscopes

Compound light microscopes allow light to pass through the specimen and use two lenses to form an image.


MicroscopesElectron Microscopes

To study even smaller objects, scientists use electron microscopes.


Laboratory Techniques

Laboratory TechniquesCell Cultures

A single cell is able to reproduce so that a group of cells, called a cell culture, develops from the single original cell.


Laboratory Techniques

Cell FractionationBiologists often use a technique known as

cell fractionation to separate the different cell parts.


Working Safely in Biology

Follow safe practices.• Study the safety rules.• Read all the steps and safety precautions.• Follow your teacher’s instructions and textbook

directions exactly.• If in doubt, ask your teacher for an explanation.• Wash your hands thoroughly with soap and

warm water after every scientific activity.


1-4A single measurement system is

commonly used in science because• it allows scientists to easily replicate

one another’s experiments.• basic units of mass, length, and

volume are unrelated to one another.

• more kinds of measurements can be made.

• computers can store large amounts of scientific data.


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Compared to a light microscope, an electron microscope is used to observe

• larger objects with less detail.• larger objects with more detail.• smaller objects with more detail.• smaller objects with less detail.


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A device that separates cell parts is a • centrifuge.• cell culture.• light microscope.• electron microscope.


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A technique in which cells are grown in a nutrient solution is known as

• staining.• cell fractionation.• cell culturing.• cell fertilizing.


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When you work in a biology laboratory situation, your first priority should be to

• make sure all materials are available.

• modify any instructions that do not make sense.

• familiarize yourself with all safety rules before beginning to work.

• know ahead of time what kinds of results to expect.

END OF SECTIONEND OF SECTION

Documents

1 Chapter 1 The Science of Biology. 2 1–1 What Is Science? Science is a process of inquiry, asking questions, the answers to which produce a body of knowledge,