2 Biology - The Life Science
The word biology means, "the science of life", from the Greek bios, life, and logos, word
or knowledge. Therefore, Biology is the science of Living Things. That is why Biology is
sometimes known as Life Science.
The science has been divided into many subdisciplines, such as botany1 , bacteriology,
anatomy2 , zoology, histology, mycology, embryology, parasitology, genetics3 , molecular biol-
ogy4 , systematics, immunology, microbiology5 , physiology, cell biology6 , cytology, ecology7 ,
and virology. Other branches of science include or are comprised in part of biology studies,
including paleontology8 , taxonomy, evolution, phycology, helimentology, protozoology, en-
tomology, biochemistry, biophysics, biomathematics, bio engineering, bio climatology and
anthropology.
2.1 Characteristics of life
Not all scientists agree on the definition of just what makes up life. Various characteristics
describe most living things. However, with most of the characteristics listed below we can
think of one or more examples that would seem to break the rule, with something nonliving
being classified as living or something living classified as nonliving. Therefore we are careful
not to be too dogmatic in our attempt to explain which things are living or nonliving.
• Living things are composed of matter structured in an orderly way where simple
molecules are ordered together into much larger macromolecules.
An easy way to remember this is GRIMNERD C All organisms; - Grow, Respire, Interact,
Move, Need Nutrients, Excrete (Waste), Reproduce,Death, Cells (Made of)
• Living things are sensitive, meaning they are able to respond to stimuli.
• Living things are able to grow, develop, and reproduce.
• Living things are able to adapt over time by the process of natural selection.
• All known living things use the hereditary molecule, DNA9 .
1 http://en.wikibooks.org/wiki/botany
2 http://en.wikibooks.org/wiki/anatomy
3 http://en.wikibooks.org/wiki/genetics
4 http://en.wikibooks.org/wiki/Molecular%20Biology
5 http://en.wikibooks.org/wiki/microbiology
6 http://en.wikibooks.org/wiki/Cell%20Biology
7 http://en.wikibooks.org/wiki/ecology
8 http://en.wikibooks.org/wiki/paleontology
9 http://en.wikipedia.org/wiki/DNA
5
,Biology - The Life Science
• Internal functions are coordinated and regulated so that the internal environment of a
living thing is relatively constant, referred to as homeostasis10 .
Living things are organized in the microscopic level from atoms up to cells11 . Atoms are
arranged into molecules, then into macromolecules12 , which make up organelles13 , which
work together to form cells. Beyond this, cells are organized in higher levels to form entire
multicellular organisms. Cells together form tissues14 , which make up organs, which are
part of organ systems, which work together to form an entire organism. Of course, beyond
this, organisms form populations which make up parts of an ecosystem. All of the Earth's
ecosystems together form the diverse environment that is the earth.
Example:-
sub atoms, atoms, molecules, cells, tissues, organs, organ systems, organisms, population,
community, eco systems
2.2 Nature of science
Science is a methodology for learning about the world. It involves the application
of knowledge.
The scientific method deals with systematic investigation, reproducible results, the
formation and testing of hypotheses, and reasoning.
Reasoning can be broken down into two categories, induction (specific data is used to
develop a generalized observation or conclusion) and deduction (general information leads
to specific conclusion). Most reasoning in science is done through induction.
Science as we now know it arose as a discipline in the 17th century.
2.3 Scientific method
The scientific method is not a step by step, linear process. It is an intuitive process, a
methodology for learning about the world through the application of knowledge. Scientists
must be able to have an "imaginative preconception" of what the truth is. Scientists will
often observe and then hypothesize the reason why a phenomenon occurred. They use all
of their knowledge and a bit of imagination, all in an attempt to uncover something that
might be true. A typical scientific investigation might go like so:
You observe that a room appears dark, and you ponder why the room is dark. In an attempt
to find explanations to this curiosity, your mind unravels several different hypotheses. One
hypothesis might state that the lights are turned off. Another hunch might be that the
room's lightbulb has burnt out. Worst yet, you could be going blind. To discover the truth,
10 http://en.wikipedia.org/wiki/homeostasis
11 http://en.wikipedia.org/wiki/cell
12 http://en.wikipedia.org/wiki/macromolecule
13 http://en.wikipedia.org/wiki/organelle
14 http://en.wikibooks.org/wiki/General%20Biology%2FTissues
6
, Scientific method
you experiment. You feel your way around the room and find a light switch and turn it on.
No light. You repeat the experiment, flicking the switch back and forth. Still nothing. That
means your initial hypothesis, the room is dark because the lights are off, has been rejected.
You devise more experiments to test your hypotheses, utilizing a flashlight to prove that
you are indeed not blind. In order to accept your last remaining hypothesis as the truth,
you could predict that changing the light bulb will fix the problem. If all your predictions
succeed, the original hypothesis is valid and is accepted. In some cases, however, your
predictions will not occur, in which you'll have to start over. Perhaps the power is off.
Figure 1 How Science is Done
A diagram that illustrates scientific investigation
Scientists first make observations that raise a particular question. In order to explain the
observed phenomenon, they develop a number of possible explanations, or hypotheses. This
is the inductive part of science, observing and constructing plausible arguments for why
7
, Biology - The Life Science
an event occurred. Experiments are then used to eliminate one of more of the possible
hypotheses until one hypothesis remains. Using deduction, scientists use the principles of
their hypothesis to make predictions, and then test to make sure that their predictions are
confirmed. After many trials (repeatability) and all predictions have been confirmed, the
hypothesis then may become a theory.
Quick Definitions
Observation - Quantitative and qualitative measurements of the world.
Inference - Deriving new knowledge based upon old knowledge.
Hypotheses - A suggested explanation.
Rejected Hypothesis - An explanation that has been ruled out through experimentation.
Accepted Hypothesis - An explanation that has not been ruled out through excessive
experimentation and makes verifiable predictions that are true.
Experiment - A test that is used to rule out a hypothesis or validate something already
known.
Scientific Method - The process of scientific investigation.
Theory - A widely accepted hypothesis that stands the test of time. Often tested, and
usually never rejected.
The scientific method is based primarily on the testing of hypotheses by experimentation.
This involves a control, or subject that does not undergo the process in question. A scientist
will also seek to limit variables to one or another very small number, single or minimum
number of variables. The procedure is to form a hypothesis or prediction about what you
believe or expect to see and then do everything you can to violate that, or falsify the
hypotheses. Although this may seem unintuitive, the process serves to establish more firmly
what is and what is not true.
A founding principle in science is a lack of absolute truth: the accepted explanation is the
most likely and is the basis for further hypotheses as well as for falsification. All knowledge
has its relative uncertainty.
Theories are hypotheses which have withstood repeated attempts at falsification. Common
theories include evolution by natural selection and the idea that all organisms consist of
cells. The scientific community asserts that much more evidence supports these two ideas
than contradicts them.
8
The word biology means, "the science of life", from the Greek bios, life, and logos, word
or knowledge. Therefore, Biology is the science of Living Things. That is why Biology is
sometimes known as Life Science.
The science has been divided into many subdisciplines, such as botany1 , bacteriology,
anatomy2 , zoology, histology, mycology, embryology, parasitology, genetics3 , molecular biol-
ogy4 , systematics, immunology, microbiology5 , physiology, cell biology6 , cytology, ecology7 ,
and virology. Other branches of science include or are comprised in part of biology studies,
including paleontology8 , taxonomy, evolution, phycology, helimentology, protozoology, en-
tomology, biochemistry, biophysics, biomathematics, bio engineering, bio climatology and
anthropology.
2.1 Characteristics of life
Not all scientists agree on the definition of just what makes up life. Various characteristics
describe most living things. However, with most of the characteristics listed below we can
think of one or more examples that would seem to break the rule, with something nonliving
being classified as living or something living classified as nonliving. Therefore we are careful
not to be too dogmatic in our attempt to explain which things are living or nonliving.
• Living things are composed of matter structured in an orderly way where simple
molecules are ordered together into much larger macromolecules.
An easy way to remember this is GRIMNERD C All organisms; - Grow, Respire, Interact,
Move, Need Nutrients, Excrete (Waste), Reproduce,Death, Cells (Made of)
• Living things are sensitive, meaning they are able to respond to stimuli.
• Living things are able to grow, develop, and reproduce.
• Living things are able to adapt over time by the process of natural selection.
• All known living things use the hereditary molecule, DNA9 .
1 http://en.wikibooks.org/wiki/botany
2 http://en.wikibooks.org/wiki/anatomy
3 http://en.wikibooks.org/wiki/genetics
4 http://en.wikibooks.org/wiki/Molecular%20Biology
5 http://en.wikibooks.org/wiki/microbiology
6 http://en.wikibooks.org/wiki/Cell%20Biology
7 http://en.wikibooks.org/wiki/ecology
8 http://en.wikibooks.org/wiki/paleontology
9 http://en.wikipedia.org/wiki/DNA
5
,Biology - The Life Science
• Internal functions are coordinated and regulated so that the internal environment of a
living thing is relatively constant, referred to as homeostasis10 .
Living things are organized in the microscopic level from atoms up to cells11 . Atoms are
arranged into molecules, then into macromolecules12 , which make up organelles13 , which
work together to form cells. Beyond this, cells are organized in higher levels to form entire
multicellular organisms. Cells together form tissues14 , which make up organs, which are
part of organ systems, which work together to form an entire organism. Of course, beyond
this, organisms form populations which make up parts of an ecosystem. All of the Earth's
ecosystems together form the diverse environment that is the earth.
Example:-
sub atoms, atoms, molecules, cells, tissues, organs, organ systems, organisms, population,
community, eco systems
2.2 Nature of science
Science is a methodology for learning about the world. It involves the application
of knowledge.
The scientific method deals with systematic investigation, reproducible results, the
formation and testing of hypotheses, and reasoning.
Reasoning can be broken down into two categories, induction (specific data is used to
develop a generalized observation or conclusion) and deduction (general information leads
to specific conclusion). Most reasoning in science is done through induction.
Science as we now know it arose as a discipline in the 17th century.
2.3 Scientific method
The scientific method is not a step by step, linear process. It is an intuitive process, a
methodology for learning about the world through the application of knowledge. Scientists
must be able to have an "imaginative preconception" of what the truth is. Scientists will
often observe and then hypothesize the reason why a phenomenon occurred. They use all
of their knowledge and a bit of imagination, all in an attempt to uncover something that
might be true. A typical scientific investigation might go like so:
You observe that a room appears dark, and you ponder why the room is dark. In an attempt
to find explanations to this curiosity, your mind unravels several different hypotheses. One
hypothesis might state that the lights are turned off. Another hunch might be that the
room's lightbulb has burnt out. Worst yet, you could be going blind. To discover the truth,
10 http://en.wikipedia.org/wiki/homeostasis
11 http://en.wikipedia.org/wiki/cell
12 http://en.wikipedia.org/wiki/macromolecule
13 http://en.wikipedia.org/wiki/organelle
14 http://en.wikibooks.org/wiki/General%20Biology%2FTissues
6
, Scientific method
you experiment. You feel your way around the room and find a light switch and turn it on.
No light. You repeat the experiment, flicking the switch back and forth. Still nothing. That
means your initial hypothesis, the room is dark because the lights are off, has been rejected.
You devise more experiments to test your hypotheses, utilizing a flashlight to prove that
you are indeed not blind. In order to accept your last remaining hypothesis as the truth,
you could predict that changing the light bulb will fix the problem. If all your predictions
succeed, the original hypothesis is valid and is accepted. In some cases, however, your
predictions will not occur, in which you'll have to start over. Perhaps the power is off.
Figure 1 How Science is Done
A diagram that illustrates scientific investigation
Scientists first make observations that raise a particular question. In order to explain the
observed phenomenon, they develop a number of possible explanations, or hypotheses. This
is the inductive part of science, observing and constructing plausible arguments for why
7
, Biology - The Life Science
an event occurred. Experiments are then used to eliminate one of more of the possible
hypotheses until one hypothesis remains. Using deduction, scientists use the principles of
their hypothesis to make predictions, and then test to make sure that their predictions are
confirmed. After many trials (repeatability) and all predictions have been confirmed, the
hypothesis then may become a theory.
Quick Definitions
Observation - Quantitative and qualitative measurements of the world.
Inference - Deriving new knowledge based upon old knowledge.
Hypotheses - A suggested explanation.
Rejected Hypothesis - An explanation that has been ruled out through experimentation.
Accepted Hypothesis - An explanation that has not been ruled out through excessive
experimentation and makes verifiable predictions that are true.
Experiment - A test that is used to rule out a hypothesis or validate something already
known.
Scientific Method - The process of scientific investigation.
Theory - A widely accepted hypothesis that stands the test of time. Often tested, and
usually never rejected.
The scientific method is based primarily on the testing of hypotheses by experimentation.
This involves a control, or subject that does not undergo the process in question. A scientist
will also seek to limit variables to one or another very small number, single or minimum
number of variables. The procedure is to form a hypothesis or prediction about what you
believe or expect to see and then do everything you can to violate that, or falsify the
hypotheses. Although this may seem unintuitive, the process serves to establish more firmly
what is and what is not true.
A founding principle in science is a lack of absolute truth: the accepted explanation is the
most likely and is the basis for further hypotheses as well as for falsification. All knowledge
has its relative uncertainty.
Theories are hypotheses which have withstood repeated attempts at falsification. Common
theories include evolution by natural selection and the idea that all organisms consist of
cells. The scientific community asserts that much more evidence supports these two ideas
than contradicts them.
8
