Chapter 1:
The Study of Life
Introduction to Biology
Objectives for section 1:
• Define Biology
• Identify possible benefits from
studying biology
• Summarize the characteristics of
living things
The Science of Biology
• Biology: The science of life
(the study of Life and living organisms)
• Biology gives us an organized way of
studying living things
– how they interact and function
- their origins and history;
- develop concepts, principles and
theories that allow people to
understand their environment.
What
Biologists Do
• Study the diversity of life
• Research diseases
• Develop technologies
• Improve agriculture
• Preserve the environment
(Basically they study problems
and propose solutions)
Characteristics
of Life
An organism is anything that has or once had all of
these characteristics:
1) Living things are made of one or more cells
Unicellular -- one-celled (bacteria, protists)
Multicellular -- many-celled (humans, plants)
Cells are the basic units of structure and function
in all living things.
Characteristics of Life
2) Living things display organization
• specialized parts perform particular
functions, like in a factory
celltissueorganorgan systemorganism
Characteristics of Life
3.All living things grow and develop
growth – an ability to increase in size; either by
increasing cell size or by adding on other cells
- increase in amount of living material, forming new
structures
development: all change during life of an organism
Characteristics of Life
4) Living things Reproduce
reproduction; production of
offspring
• necessary for the continuation
of a species
• Offspring are not identical to
the parent (mutations)
• Change over time (evolution)
species - a group of similar
looking organisms that can
interbreed successfully (fertile)
Characteristics of living things
5) Living things adjust to their
environment
environment: living things interface with
surroundings
stimulus: condition in environment
which requires an organism to
adjust
response: reaction to a stimulus
adaptation: structure, behavior, or
internal process enables an
organism to respond to stimuli and
better survive (are inherited)
6. Living things require energy.
a. Energy: the ability to do work or make things move;
1. powers life, homeostasis, movement, growth,
reproduction, bioluminescense
2. flows through communities (one way)
b. Organisms either make food for themselves (Producers =
plants) or have to find and eat food for energy (Consumers
= animals)
7. Living things maintain homeostasis:
regulation of an animal’s internal environment to
maintain conditions suitable to their environment
- examples:
- Regulate blood sugar levels
- Regulate calcium levels in bloodstream
- Regulate body temperature
(energy is important here!)
8. Living things have adaptations that evolve
over time…
Certain features make them better able to
survive and reproduce.
Adaptations are any inherited characteristic
that results from evolution
example: drip tips on the leaves of
rainforest trees.
evolution: gradual change in the
characteristics of species over time
How do you know if an
organism is living?
• Some living things do not display all 8 of the
characteristics of life…
• Certain bacteria and fungi do not seem to
respond to their environment
• Mules (hybrid of donkey + horse) cannot
reproduce, they do not produce viable germ
cells. a sterile mule cannot pass on its genes, even if the genes
are well adapted. Some individuals never develop to full term and
never survive outside of the mothers womb. Furthermore, some
offspring are able to pass on their genes, but over the course of
multiple generations, in a small population, mutations begin to
accumulate and second or third generations are not able to pass on
their genes, ending the line of descent.
The Nature of Science
Section Objectives:
• Explain the characteristics of science
• Compare something that is scientific
with something that is pseudoscientific
• Describe the importance of the metric
system and SI
What is science?
• A body of knowledge
based on the study of
nature.
• The essential
characteristic is
scientific inquiry, which
can be both a creative
process as well as rooted
in unbiased observations
and experimentation.
Science relies on evidence
• We combine what we already know with
consistent evidence gathered from MANY
observations and experiments
Theory:
- different from what common folk say.
An explanation of natural phenomenon that
is supported by a large body of scientific
evidence obtained from many different
experiments and observations over time
• CELL THEORY
Examples:
• This theory says that new cells are formed from other existing cells,
and that the cell is a fundamental unit of structure, function and
organization in all living organisms.
• THEORY OF EVOLUTION
• The change in groups of living things over time. Evolution is the
process of inheritable differences becoming more common or rare
within large groups (populations) of organisms.
- based on countless experiments and observations
- have extensive supporting evidence
- allows scientists to predict new facts &
relationships
Have you ever read your
horoscope in the newspaper?
• How was it
determined?
• Was it based on
sound scientific
methods
Astrology is
PSEUDOSCIENCE!
Pseudoscience:
• Areas of study that try to imitate science
• Often driven by cultural or commercial
goals
• They do NOT provide science-based
explanations about the natural world
Examples: astrology, horoscopes, psychic
readings, tarot cards, face reading
(Physiognomy), head reading (Phrenology),
palmistry.
Expands scientific
knowledge
• A constant re-evaluation of what is known
• This often leads to new info
• Nearly every new finding leads to further
questioning and research
(with pseudoscience, little research is
done… new questions or research is NOT
WELCOMED)
Scientists challenge report of one Argentine ant
supercolony flooding California
Challenges accepted
theories
A team of California scientists made headlines
four years ago when it reported finding one of the
largest insect colonies in the world -- a 600-milelong subterranean network of Argentine ants
stretching from Northern California to the
Mexican border. According to the researchers,
this "supercolony" is made up of billions of
closely related workers -- all direct descendants
of a small group of Argentine ants that were
accidentally introduced into California more than
a century ago.
• Debate is welcomed
• Conferences and meetings
• Disagreements occur, lead to
Graduate student Nicole
Heller, left, andexperimentation
additional
biological sciences Professor Deborah Gordon
discussed the Jasper Ridge project in Gordon's
office. The project analyzed the DNA from ants in
the biological preserve and found obvious
genetic differences among some of them,
suggesting that the ants came from different
colonies. Photo: L.A. Cicero
Questions results
• Any observations or data that are not
consistent with current scientific
understanding are of interest…
• These lead to further investigation
• Example: bats used to be grouped with
birds due to wings, but later were found
more related to mammalian limbs.
(pseudoscience discards or ignores
observations that are inconsistent with
beliefs)
Tests claims
• Science-based claims are based upon a
large amount of data and observations
• This data is from unbiased
investigations and carefully controlled
experimentation.
• Conclusions are reached from the
evidence,
(pseudoscience makes claims that cannot
be tested, mix fact and opinion.
Undergoes peer review
• Work is reviewed before it is made
public.
• Review is done by scientists in the
same field or who are conducting
similar research
• They evaluate the procedures used and
the results
Uses metric system
• A system that has units with divisions
that are all powers of 10.
• Unit standard were established in 1960
• Called SI, or International System of
Units
Meter
Gram
Liter Second
Length
Mass
Volume
Time
Science Literacy
• Forensics = study that
applies science to
matters of legal
interest
• Literacy
• It is important that you
are able to understand
science and its process
with reasoning and
thinking skills.
• Ethics = the study of what is right or wrong
- science ethical issues affect politics,
moral, social
- once research is done it is people of
society make a decision
•
Section 1.3:
observation Methods of
Science
Describe the difference between an
and an inference
• Differentiate among control,
independent variable, and
dependent variable
• Identify the scientific methods a
biologist uses for research
1. Ask a question
Observation = a direct method of gathering
info about a natural phenomenon in an
orderly way.
Inferences = combining what you already
know with what you have learned to
begin making logical conclusions.
(an assumption based upon prior
experiences)
Ex: when we see smoke, we infer fire
Observation
Observation: when
studying something
describe only facts that
you can see, touch,
smell and hear. You
are not making any
guesses.
THIS IS NOT AN
OPINION!!
Ohh… This liquid
is green and it is
leaking from a
brown can. I
also smell it.
Inference
Inference: using your
observations to make a
guess about an object or
an outcome
THIS CAN BE A
SCIENTIFIC OPINION
Based on my
observations, I think
that this can is old and is
leaking a toxic
substance.
Scientific Methods:
A series of problem-solving
procedures that might include:
•
•
•
•
•
observations
forming a hypothesis
Experimenting
Gathering and analyzing data
Drawing conclusions
Important to note…
• This is the way scientific method is usually
shown on diagrams or reported in journals
• This is not how science is actually
conducted.
• Science often proceeds in a cyclical
manner with one question raising another
and one observation… and one
experiment…
• It is not always linear.
2. Form a hypothesis
• Hypothesis: testable explanation for a
question, problem, or situation.
- Scientists are able to hypothesize by
making inferences using their background
experience, reading, lab work,
imagination, logic, curiosity
• Serendipity: the occurrence of accidental
or unexpected, but fortunate results…
scientists who made breakthroughs that
they were not even looking for
. Collect the Data:
Experiment: to investigate a phenomenon in
a controlled setting to test a hypothesis.
• Controlled experiments = have:
1) a control group – a group used for
comparison, do not have the experimental
variable
2) an experimental group – the group
exposed to the factor that is being tested
Collect the Data:
• Experimental design:
independent variable – the tested factor, it
might affect the outcome of the experiment,
what is being manipulated or changed
dependent variable – what is measured, this
results from or depends on the changes made
to the independent variable
constant – a factor that remains fixed (also
called control factor)
In summary:
• Independent variables answer the question
"What do I change?”
• Dependent variables answer the question
"What do I observe?”
• Controlled variables answer the question
"What do I keep the same?”
• Constant variables (control factors) answer
the question "What uninteresting variables
might influence the effect of the IV on the
DV?"
Collect the Data: Data Gathering
• Data = information gained from
observations, many experiments use both:
Quantitative = numerical data that is easy to
analyze statistically (averages, graphs)
measurements of time, temp.,length,
mass, area, volume, density, etc…
Qualitative = descriptions from 5 senses,
give a more in depth and rich description
(sometimes is the only data you can get)
Collect the Data:
• Investigations – what we call it when the
procedure involves observation and
collection of data rather than controlled
manipulation of variables (this is not using
a control group…)
Examples:
• using computers to model natural behavior
of organisms & systems
• discovering and identifying new species
4. Analyze the Data:
• Has my hypothesis been supported?
• Are more data needed?
• Are different procedures needed?
• Display data in graph or table, this helps to
look for patterns or trends
• Meetings are held with other biologists to
examine for avoiding bias, repeating their
trials, and if sample size is large enough
• You also learn from an unsupported
hypothesis
5. Report Conclusions:
• Findings/conclusions are
reported in scientific journals
• First is peer reviewed for
• Originality
• Competence of scientific method
used
• Accuracy
• Then is published for review by
public and other scientists
(ex: journal of the american
medical association)
6. Student Scientific Inquiry:
• You will have some
opportunities to design your
own experiments
• Lab safety – there are
specific lab safety symbols
to help alert you to specific
dangers.
• Make sure you are aware of
all lab safety equipment and
how to use it