THE SCIENCE OF BIOLOGY

THE SCIENCE OF

BIOLOGY

C H A P T E R O N E

Chapter 1 – The Science of Biology

• Biology is the study of living things

• Living things are diverse

• There are enough similarities among some living things that they can be grouped into the same kingdom

• Members of different kingdoms are usually very different from each other

KINGDOMS

• Life on planet Earth is broken down into six groups called Kingdoms .

• Bacteria

• Archaea

• Protista

• Fungi

• Plantae

• Animalia

Bacteria Archaea Protista Plantae Fungi Animalia

BACTERIA ARCHAEA EUKARYA

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© The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Archaea. This kingdom of prokaryotes

(the simplest of cells that do not have nuclei) includes this methanogen, which manufactures methane as a result of its metabolic activity.

Bacteria. This group is the second of the two prokaryotic kingdoms. Shown here are purple sulfur bacteria, which are able to convert light energy into chemical energy.

Protista. Most of the unicellular eukaryotes

(those whose cells contain a nucleus) are grouped into this kingdom, and so are the multicellular algae pictured here.

Fungi. This kingdom contains nonphotosynthetic organisms, mostly multicellular, that digest their food externally, such as these mushrooms.

Plantae. This kingdom contains photosynthetic multicellular organisms that are terrestrial, such as the flowering plant pictured here.

Animalia. Organisms in this kingdom are nonphotosynthetic multicellular organisms that digest their food internally, such as this ram.

(Achaea): © R. Robinson/Visuals Unlimited; (bacteria): © Alfred Pasieka/Science Photo

Library/Photo Researchers; (protista, plantae): © Corbis RF; (fungi, animalia): © Getty RF

4

DIVERSITY OF LIFE

• The living world is very diverse – many different types of living organisms – but all living things share many key properties.

PROPERTIES OF LIFE

• What does it mean to be alive?

• Complexity (computers are complex)

• Movement (clouds, ocean waves move)

• Response to stimulation (soap bubble pops if touched)

• Let ’ s look at five more properties of life:

PROPERTIES OF LIFE

• Cellular Organization – All living things are composed of one or more cells.

• Cell – tiny compartment surrounded by a membrane.

• Cells may have simple or complex interiors.

• All can grow and reproduce.

PROPERTIES OF LIFE

• Metabolism – All living things use energy.

• Energy comes from the sun.

• Energy is captured by plants and algae.

• Plants turn energy from the sun into a form that can be used by the plants and by organisms that eat the plants.

• The chemical process that extracts energy from a food source is called metabolism .

PROPERTIES OF LIFE

• Homeostasis – All living things maintain stable internal conditions.

• Environment is variable.

• Organisms keep interior relatively constant – homeostasis.

• Body temperature is one example.

PROPERTIES OF LIFE

• Reproduction – All living things reproduce.

• The simplest organisms (bacteria) simply split in two.

• More complex organisms have more complicated forms of reproduction.

PROPERTIES OF LIFE

• Heredity – All organisms possess a genetic system that is based on the replication and duplication of a long molecule called DNA

(deoxyribonucleic acid).

• The order of the subunits that make up DNA provide the information needed to determine what an organism will be like.

PROPERTIES OF LIFE

• Each set of instructions within the DNA is called a gene .

• Transmission of characteristics from parent to offspring is a process called heredity .

THE ORGANIZATION OF LIFE

• Organisms function and interact with each other on many levels.

• Hierarchy of increasing complexity

• Within cells

• Within multicellular organisms

• Among organisms

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CELLULAR LEVEL

(Hydrogen, carbon, nitrogen)


CELLULAR LEVEL


2

Molecule

(Adenine)


CELLULARLEVEL

FIG. 1.4LEFT-3


2

Molecule

(Adenine)

3

Macromolecule

(DNA)


CELLULARLEVEL

FIG. 1.4LEFT-4


2

Molecule

(Adenine)

3

Macromolecule

(DNA)

4

Organelle

(Nucleus)


CELLULARLEVEL


2

Molecule

(Adenine)

3

Macromolecule

(DNA)

4

Organelle

(Nucleus)

5

Cell

(Nervecell)


CELLULARLEVEL

1

Atoms


2

Molecule

(Adenine)

3

Macromolecule

(DNA)

4

Organelle

(Nucleus)

5

Cell

(Nervecell)

ORGANISMAL LEVEL

6

Tissue

(Nerve tissue)


CELLULARLEVEL

1

Atoms


2

Molecule

(Adenine)

3

Macromolecule

(DNA)

4

Organelle

(Nucleus)

5

Cell

(Nervecell)


6

Tissue

(Nerve tissue)

7

Organ

(Brain)


CELLULARLEVEL

1

Atoms


2

Molecule

(Adenine)

3

Macromolecule

(DNA)

4

Organelle

(Nucleus)

5

Cell

(Nervecell)


6

Tissue

(Nerve tissue)

7

Organ

(Brain)

8

Organ system

(Nervous system)

CELLULARLEVEL


1

Atoms


2

Molecule

(Adenine)

3

Macromolecule

(DNA)

4

Organelle

(Nucleus)

5

Cell

(Nervecell)


6

Tissue

(Nerve tissue) 9

Organism

7

Organ

(Brain)

8

Organ system

(Nervous system)

POPULATIONAL LEVEL


FIG. 1.4RIGHT-1

(goose & crane): © Jim Bailey; (geese on lake): © Raymond Gehman/Corbis; (cranes on lake): © Corbis RF;

(ecosystem): © Winfried Wisniewski/zefa/Corbis



FIG. 1.4RIGHT-2

10 Population

11 Species





FIG. 1.4RIGHT-3

10 Population

11 Species

12 Community





FIG. 1.4RIGHT

10 Population

11 Species

12 Community



13 Ecosystem

ORGANIZATION OF LIFE

• At higher levels of the living hierarchy, new properties become apparent that were absent at the lower levels

• These emergent properties result from the interaction of diverse but simpler components

• Many higher order processes that are hallmarks of life are emergent properties

• metabolism

• consciousness

BIOLOGICAL THEMES

• Evolution – The change in species over time.

Charles Darwin proposed the mechanism by which this change takes place – natural selection .

• Organisms that are better able to respond to challenges in the environment are more likely to survive, reproduce, and pass on their genes to the next generation.

EVOLUTION

• Artificial Selection

• Darwin was familiar with variation in domestic animals and that breeders select animals with desired characteristics and breed them to obtain offspring with the desired or exaggerated characteristics.

EVOLUTION

• The characteristics selected are passed on through the generations because DNA is transmitted from parent to offspring.

• Darwin extended the idea of artificial selection to the natural world.

• Thus, the many forms of life we see today reflect a long history of natural selection.

BIOLOGICAL THEMES

• The flow of energy – All organisms require energy for the activities of living.

• All of the energy used by most organisms originally comes from the sun.

• This energy gets used up as it passes through an ecosystem.

THE FLOW OF ENERGY

• Green plants and photosynthetic protists

(algae, seaweed) capture energy from the sun using a process called photosynthesis .

• Plants serve as the energy source for the animals who eat them.

THE FLOW OF ENERGY

• Other animals eat the plant-eaters.

• At each stage, some energy is used, some is transformed, and much is lost.

THE FLOW OF ENERGY

• The flow of energy is very important in shaping ecosystems:

• What kind of organisms live there?

• How many of each?

BIOLOGICAL THEMES

• Cooperation has played a critical role in the evolution of life on Earth.

• Coevolution of insects

& flowering plants

• Fungi helped plants first invade land from the sea.

• Barnacles living on gray whales are carried around exposing them to fresh supply of food.

BIOLOGICAL THEMES

• Structure determines function

– At every level of organization, structures are well suited to their functions.

BIOLOGICAL THEMES

• Homeostasis – maintaining a relatively constant internal environment is essential for complex organisms.

• Body temperature

• Ph

• Water balance

THE NATURE OF SCIENCE

• Science is a particular way of investigating the world.

DEDUCTIVE REASONING

• Deductive reasoning involves making individual decisions by applying accepted general principles.

• Math

• Philosophy

• Politics

• Ethics

DEDUCTIVE REASONING

An Accepted General Principle

When traffic lights along city streets are "timed “ to change at the time interval it takes traffic to pass between them, the result will be a smooth flow of traffic.

DEDUCTIVE

REASONING

Using a General

Principle to

MakeEveryday

Decisions

Traveling at the speed limit, you approach each

Intersection anticipating that the red light will turn green as your each the intersection.

THE NATURE OF SCIENCE

• Where do these general principles come from?

• Religious & ethical principles may have a religious foundation.

• Political principles reflect social systems.

• Some general principles come from observing the world around us.

• Science is based on this type of general principle

INDUCTIVE REASONING

INDUCTIVE REASONING

Observations of

Specific Events

Driving down the street at the speed limit, you observe that the red traffic light turns green just as you approach the intersection.

Maintaining the same speed, you observe the same event at the next several intersections: the traffic lights turn green just as you approach the intersections. When you speed up, however, the light doesn't change until after you reach the intersection.

INDUCTIVE

REASONING

Formation of a General Principle

You conclude that the traffic lights along this street are "timed “ to change in the time it takes your car, traveling at the speed limit, to traverse the distance between them.

• Science is devoted to discovering general principles that govern the operation of the physical world.

• Discovering general principles by careful examination of

specific cases is called inductive reasoning.

INDUCTIVE REASONING

• 400 years ago Isaac Newton, Francis Bacon, and others began conducting experiments and inferring general principles about how the world works from their results.

• Simple observations (such as Newton ’ s apple) are very important in science.

INDUCTIVE REASONING

• Newton started by simply dropping an apple from his hand.

• He then performed other simple experiments.

• Using his results, Newton inferred that all objects fall toward the center of the Earth.

• This is a hypothesis about how the world works.

INDUCTIVE REASONING

• Today, scientists still formulate hypotheses to explain how the world works.

• Observations are the materials that they use to build their hypotheses.

HOW SCIENCE IS DONE

• Scientists start by making observations concerning a particular problem.

• A hypothesis is then formed.

• Hypothesis – a proposition that might be true, an educated guess.

• Experiments are performed to eliminate alternate hypotheses.

HOW SCIENCE IS DONE

• Hypotheses that are not rejected are retained because they fit known facts.

• Hypotheses are often revised or replaced as new data become available.

• Hypotheses that are well supported by many experiments over time are known as theories .

Observation

01.04 Scientific Method

Slide number: 2

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Observation

Question


Slide number: 3


Observation

Question

Hypothesis 1

Hypothesis 2

Hypothesis 3

Hypothesis 4

Hypothesis 5

Potential hypotheses


Slide number: 4



Observation

Question

Hypothesis 1

Hypothesis 2

Hypothesis 3

Hypothesis 4

Hypothesis 5


Experiment

Slide number: 5



Observation

Question

Hypothesis 1

Hypothesis 2

Hypothesis 3

Hypothesis 4

Hypothesis 5


Experiment

Reject hypotheses

1 and 4

Slide number: 6



Observation

Question

Hypothesis 1

Hypothesis 2

Hypothesis 3

Hypothesis 4

Hypothesis 5


Experiment

Hypothesis 5

Hypothesis 3

Hypothesis 2

Remaining possible hypotheses

Reject hypotheses

1 and 4

Slide number: 7



Observation

Question

Hypothesis 1

Hypothesis 2

Hypothesis 3

Hypothesis 4

Hypothesis 5


Experiment

Hypothesis 5

Hypothesis 3

Hypothesis 2


Reject hypotheses

1 and 4

Experiment

Slide number: 8



Observation

Question

Hypothesis 1

Hypothesis 2

Hypothesis 3

Hypothesis 4

Hypothesis 5


Experiment

Hypothesis 5

Hypothesis 3

Hypothesis 2


Reject hypotheses

1 and 4

Experiment

Reject hypotheses

2 and 3

Slide number: 9



Observation

Question

Hypothesis 1

Hypothesis 2

Hypothesis 3

Hypothesis 4

Hypothesis 5


Experiment

Hypothesis 5

Hypothesis 3

Hypothesis 2


Reject hypotheses

1 and 4

Experiment

Hypothesis 5

Reject hypotheses

2 and 3

Last remaining possible hypothesis

Slide number: 10



Observation

Question

Hypothesis 1

Hypothesis 2

Hypothesis 3

Hypothesis 4

Hypothesis 5


Experiment

Reject hypotheses

1 and 4

Hypothesis 5

Hypothesis 3

Hypothesis 2


Experiment

Hypothesis 5

Reject hypotheses

2 and 3

Last remaining possible hypothesis

Predictions

Experiment 1 Experiment 2 Experiment 3 Experiment 4

Slide number: 11

Predictions confirmed


THE SCIENTIFIC PROCESS

• Scientific investigations can be broken down into six stages.

OBSERVATION

• Observation is the key to any successful scientific investigation.

• Scientists take note of many details and keep careful records of these details.

OBSERVATION - SCIENCE IN ACTION: A

CASE STUDY

• Example – Scientists in the Antarctic kept careful record of temperature, light and levels of chemicals. They realized the level of ozone was dropping.

HYPOTHESIS

• A hypothesis is a guess that might be true – a potential explanation for the observations that have been made.

• Antarctic scientists guessed that CFCs may be responsible for ozone depletion.

• Chlorine from the CFCs reacts with O

O

2

.

3 producing

HYPOTHESIS

• Scientists form several alternate hypotheses when they have more than one guess about what they observe.

PREDICTIONS

• If a hypothesis is correct, several consequences might be predicted.

• Prediction – what you would expect to happen if a hypothesis is true.

PREDICTIONS

• If the CFC hypothesis is true, it should be possible to detect CFCs in the upper

Antarctic atmosphere as well as the chlorine released from CFCs that attack the ozone.

TESTING

• The next step is to verify the prediction.

• A test of a hypothesis is an experiment .

TESTING

• To test the CFC hypothesis, atmospheric samples were collected 6 miles over the

Antarctic.

• CFCs were found as predicted.

• Free chlorine & fluorine were also found confirming breakdown of CFCs.

• These results support the hypothesis.

CONTROLS

• A factor that might influence a process that we are interested in is called a variable .

• To evaluate alternative hypotheses about one variable, all others must be held

constant so that we are not misled.

CONTROLS

• Carry out 2 experiments in parallel:

• In one, a variable is altered in a known way to test a particular hypothesis.

• In the other, the variable is not altered. This is called a control experiment .

• The two experiments are identical in every way except for the one variable under consideration.

CONTROLS

• In our example, scientists set up experiments reconstructing conditions in the upper atmosphere.

• In one set-up they added CFCs.

• In the other they added no CFCs.

• Ozone levels only dropped in the set-up containing the added CFCs.

CONCLUSION

• A hypothesis that has been tested and not rejected is tentatively accepted.

• A collection of related hypotheses that have been tested many times is called a theory .

CONCLUSION

• The hypothesis that CFCs released into the atmosphere are destroying the Earth ’ s protective ozone shield is now supported by a great deal of experimental evidence and is widely accepted as a theory.

THEORY AND CERTAINTY

• Hypotheses that are often tested and never rejected are sometimes combined into general statements called theories .

• A Theory is a unifying explanation for a broad range of observations.

• Theory of gravity

• Theory of evolution

• Theory of the atom


• Theories represent the ideas of which scientists are most certain.

• There is no absolute truth in science, only varying degrees of certainty.

• It is always possible that new information will surface causing a theory to be revised.


• Very active areas of science are often full of controversy.

• Not a sign of poor science.

• Push & pull that is the heart of the scientific process.

• Example – global warming due to excessive production of CO

2

.

The Scientific

“

Method

”

• A scientist does not follow a fixed method to form a hypothesis.

• Judgment and intuition are also very important to the process of science.

LIMITATIONS OF SCIENCE

• Scientific study is limited to organisms and processes that we are able to observe and measure.

• Supernatural and religious phenomena are completely outside the realm of science.

LIMITATIONS OF SCIENCE

• Science can point us toward solutions to problems only when those solutions exist.

• Science can not restore extinct animals.

• Science may not be able to fix all problems created by polluting the environment and using up resources.

FOUR THEORIES UNIFY BIOLOGY AS A

SCIENCE

• 1 . The Cell Theory

• 2. The Gene Theory

• 3. The Theory of Heredity

• 4. The Theory of Evolution

THE CELL THEORY:

ORGANIZATION OF LIFE

• Robert Hooke, 1665

• Discovered cells

• Anton van Leeuwenhoek, 1670s

• Discovered single-celled life

• Matthias Schleiden & Theodor Schwann, 1839

• All living organisms are composed of cells

• Cells are the basic units of life

• Later the third tenet of the theory was added

• All cells come from other cells

THE GENE THEORY: MOLECULAR

BASIS OF INHERITANCE

• Genetic information is encoded in molecules of deoxyribonucleic acid (DNA)

• Genes can encode specific proteins or RNA, or they can act to regulate other genes

• The proteins and RNA encoded by an organism ’ s genes determine what it will be like in terms of form and function

FIGURE 1.12

THE GENE

THEORY


1

A human body contains over 100 different kinds of cells.

INTESTIONAL CELL

MACROPHAGE

Nucleus

5

All cells contain the same set of genes, but different kinds of cells use different genes.The

production of specific proteins coded for by these genes determines what the cell is like.

MUSCLE CELL

Chromosomes

NERVE CELL

Genes being used 2

A human cell has 46 chromosomes, containing some 3 billion nucleotides of DNA.

Chromosome Gene 3

A typical human chromosome can contain up to a thousand genes, arrayed along a linear piece of DNA.

Nucleotides

DNA double helix 4

Each gene is composed of a sequence of several hundred to many thousands of DNA nucleotides and functions as a discrete unit of information.

THE THEORY OF HEREDITY: UNITY

OF LIFE

• Genes are passed down in generations as discrete units.

• Mendel ’ s theory of heredity gave rise to the field of genetics.

• The chromosomal theory of inheritance located

Mendelian genes on chromosomes.

THE THEORY OF EVOLUTION: DIVERSITY

OF LIFE

• Charles Darwin ’ s theory of evolution explains the unity and diversity of life as “ descent with modification”.

• Advances in genetics have helped scientists understand precisely how changes in genes can result in adaptation and evolution.

THE SCIENCE OF BIOLOGY

THE SCIENCE OF

BIOLOGY

Chapter 1 – The Science of Biology

ORGANIZATION OF LIFE

OBSERVATION - SCIENCE IN ACTION: A

CASE STUDY

“

”

FOUR THEORIES UNIFY BIOLOGY AS A

SCIENCE

THE CELL THEORY:

ORGANIZATION OF LIFE

THE GENE THEORY: MOLECULAR

BASIS OF INHERITANCE

THE THEORY OF HEREDITY: UNITY

OF LIFE

THE THEORY OF EVOLUTION: DIVERSITY

OF LIFE

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THE SCIENCE OF BIOLOGY

THE SCIENCE OF

BIOLOGY

Chapter 1 – The Science of Biology

ORGANIZATION OF LIFE

OBSERVATION - SCIENCE IN ACTION: A

CASE STUDY

“

”

FOUR THEORIES UNIFY BIOLOGY AS A

SCIENCE

THE CELL THEORY:

ORGANIZATION OF LIFE

THE GENE THEORY: MOLECULAR

BASIS OF INHERITANCE

THE THEORY OF HEREDITY: UNITY

OF LIFE

THE THEORY OF EVOLUTION: DIVERSITY

OF LIFE

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