Chapter 1 Biology notes
Biology is the study of life and can be used to both solve societal
problems and explain aspects of our daily lives.
Living things share the same 7 characteristics: cellular organization,
response to stimuli, homeostasis, metabolism, growth and
development, reproduction, and heredity (evolution).
Organization and Cells
Organization is the high degree of order within an organism’s internal
and external parts and in its interactions with the living world.
A cell is the smallest unit of an organism that can perform all life’s
Multicellular organisms are made up of many cells and show a
hierarchy of organization going from the organism to the atom.
Response to Stimuli
Organism’s can respond to a stimulus—a physical or chemical change in
the internal or external environment.
All living things have mechanisms that allow them to maintain stable
internal conditions. Homeostasis is the maintenance of a stable level of
internal conditions even though environmental conditions are
constantly changing.
Sum of all the chemical reactions that take in and transform energy and
materials from the environment.
Growth and Development
The growth of living things results from the division and enlargement of
Development is the process by which an organism becomes a mature
Living organisms pass on hereditary information from parents to
Populations of living organisms evolve or change through time.
Unity in the Diversity of Life
Life is diverse, or full of variety.
Life is unity, features that all living things have in common.
All living things have descended with modification from a single
common ancestor. Think of a branching tree
Three Domains of Life
The three domains of life are Bacteria, Archaea, and Eukarya.
The six kingdoms include Archaea, Bacteria, Protista, Fungi, Plantae,
and Animalia.
Interdependence of Organisms
Organisms interact with other organisms and the environment.
“Descent with modification”, is the process in which the inherited
characteristics within populations change over generations.
It explains how species came to exist, have changed over time, and
adapt to their environment.
Natural selection
Process by which organisms that have certain favorable traits are
better able to survive and reproduce successfully than organisms that
lack these traits (Survival of the fittest). It can lead to the evolution of
populations of species.
Section 1-2 Steps of the Scientific Method
Make observations, ask questions, form hypotheses, make predictions,
design experiments, analyze data, and draw conclusions.
Act of perceiving a natural occurrence that causes someone to pose a
question. The scientific process begins with an observation.
Proposed explanation for the way a particular aspect of the natural
world functions.
Used in testing a hypothesis. A prediction is what is expected to
happen if the hypothesis is true.
A controlled experiment compares an experimental group and a
control group and only has one variable.
The controlled group provides a normal standard against which can be
compared to results of the experimental group
The experimental group is identical to the control, except for one
factor, the independent variable
The independent variable can be manipulated
Scientists can measure the dependent variable (responding
variable) because it is affected by the independent variable.
Testing the Experiment
Controlled experiments should be conducted without bias, be able to
be repeated, and have enough data to find meaningful results.
Analyzing and Comparing Data
Scientists analyze data to draw conclusions about the experiment
Quantitative data can be measured in numbers
An experiment can also be measured by using one of your senses
Drawing Conclusions
An inference is a conclusion made on the basis of facts and previous
knowledge rather than on direct observations. It is not directly testable
Scientists often apply their findings about the natural world to solve
practical problems.
Scientists can also build models to represent or describe things
Constructing a Theory
A theory is a set of related hypotheses confirmed to be true many
times, and it can explain a great amount of data. Examples include the
cell theory or the theory of evolution
Publishing a Paper
Scientists submit research papers to scientific journals for publication.
There are 4 sections to a research paper: Introduction, Materials and
Methods, Results, and Discussion.
Honesty and Bias
Scientific methods and results must be accurate and true in order to
improve scientific ideas
A conflict of interest is the threat of a potential scandal based on
misleading data or conclusions is a powerful force in science that helps
keep scientists honest and fair to an extent.
States that all living things come from other living things (example
Spontaneous generation (17th century)
Spontaneous generation (17th century): Living things come from
nonliving things (example )
Disproving Spontaneous Generation
Francesco Redi’s Experiment (1650’s) Figure 1-8, page 9
Describe the experiment (control, experimental groups)
Lazzaro Spallanzani’s Experiment (1700’s) Figure 1-10, page 11
Describe the experiment (control, experimental groups)
Conclusion? (“vital force” = weak defense)
Louis Pasteur’s Award Winning Experiment (1850’s) Figure 1-11
pg. 12
Describe the experiment (control, experimental groups)
Conclusion? Microorganisms
Microscopes as Tools (Upcoming Lab)
A compound light microscope is a microscope that shines light through
a specimen and has two lenses to magnify an image.
There are four major parts of a compound light microscope are the
ocular lens, objective lens, stage, and light source.
The eyepiece magnifies the image.
The objective lens enlarges the specimen.
The stage is a platform that supports slides with specimens.
The light source is a light bulb that provides light for viewing images.
An electron microscope uses a beam of electrons to produce an
enlarged image of a specimen.
Electron microscopes have greater magnification and resolution than
light microscopes.
Scanning electron microscopes pass a beam of electrons over the
specimen’s surface for better viewing the external surface of a
specimen. They can magnify objects up to 100,000X (times).
Transmission electron microscopes transmit a beam of electrons
through a thinly sliced specimen for better viewing the internal
structures of a specimen. They can magnify objects up to 200,000X
Magnification and Resolution (Upcoming Lab)
Magnification is the increase of an object’s apparent size.(10 X 10 =
Resolution is the power to show details clearly in an image.
Units of Measurement
Scientists use a single, standard system of measurement, called
the metric system. The official name of the metric system is Système
International d’Unités or SI. (Hint, good bonus question!)
The metric system is a decimal system based on the powers of 10.
The metric system has seven base units. (Figure 1-23)
Review this Information!
Derived units are produced by a mathematical relationship between
two base units or two derived units. Examples include area and volume
Lab safety involves safe and common-sense habits. Read page 28.

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