Chapter 1 The Science of Life
Holt Modern Biology, 2006 ed.
D. Dyer
Biology 10
Chapter 1 The Science of Life
Section 1.1 “The World of Biology”
I.
Introduction: Biology and Society
A. Biology: The Study of Life
B. Biology studies
1. Microscopic life to large organisms
2. Small to global interactions of organisms
3. Diversity of life
4. History of life
C. Biology is woven into the fabric of our society
1. In Magazines and Movies
a. Bird Flu
b. Climate Change
c. C.S.I. on TV
d. Jurassic Park/ March of the Penguins in movies
e. “Following the Trail of our DNA” by National Geographic
f. Fig. 1.1, p. 1.1 shows how biology affects us each day
2. In Cell Biology and Genetics
a. Medicines
b. Agriculture
3. In Molecular Biology (DNA)
a. Solve Crimes
b. Determine Ancestry
4. In Ecology
a. Interrelationships between all life and the environment
b. Helps us to manage environmental problems like global warming,
pollution, and extinction
5. In Neuroscience and Evolutionary Biology
a. Understanding psychology
b. Understanding social behavior (sociology)
D. Today exists the largest and best equipped scientists in world history
1. Solving problems of
a. Diseases like Cancer (cell development and function)
b. Energy and food needs (cell biology and genetics)
c. The environment and how we fit in it (ecology)
d. Diversity of life and how life has changed over time (evolution)
2. This course will cover Biology Essentials
a. Properties of Life
b. Scope (range) of Life
c. Evolution as a theme that unifies all of Biology
d. Biology as a process of inquiry
e. Connections between Biology and society
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Chapter 1 The Science of Life
Holt Modern Biology, 2006 ed.
II.
D. Dyer
Characteristics of Living Things
A. The Unity of Life (What are the Properties of Life?) (Fig. 1.2, p. 3)
1. Made of cells
2. Highly Organized from atoms to cells to the whole body
3. Homeostasis or the regulation of a stable internal environment
4. Growth and Development
5. Uses Energy
6. Responds to Stimuli from the environment
7. Reproduces
8. Evolves to fit an environment
B. Made of Cells
1. Cells
a. Found in all living organisms
b. Microscopic, living building blocks of all organisms
c. Basic unit of structure and function of life
· Lowest level that can perform all activities of life
· Organelles in the cell carry out specific life functions
2. Two Types of Cellular Organisms
a. Unicellular (one celled, microscopic)
b. Multicellular (made of groups of cells that can form tissues,
organs and organ systems)
3. Cell Division
a. Basis of all reproduction
b. Basis of growth and repair in multicellular organisms
4. Two Types of Cells
a. Prokaryotes (simple, very small and has no nucleus like bacteria)
b. Eukaryotes (larger, has DNA in a nucleus)
5. All cells share two common trait
a. DNA (deoxyribonucleic acid)
b. Same chemical language for inheritance in DNA
C. Highly Organized
1. At the Molecular Level (organized chemically)
2. At the Cellular Level (organized by function)
3. Life at Many Levels (Levels of Life) (Fig. 1.2 p. 6-7)
a. Biosphere (all environments on Earth that supports life)
b. Biomes (large areas of common life forms and environments)
c. Ecosystem (all life and the environment that affects them in a
given area within a Biome)
d. Community (all the different species living together in a given
area)
e. Population (all organisms of the same species living in a given
area)
f. Organism (individual)
g. Organ System (Sensory, circulatory, etc)
h. Organs (ear)
i. Tissues (nervous, muscular)
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Chapter 1 The Science of Life
Holt Modern Biology, 2006 ed.
D. Dyer
j. Cells (nerve)
k. Organelles (mitochondria)
l. Biological Molecules (lipids or fats)
m. Atoms
4. Why does the organization of humans into tissues and organs work
so well?”
D. Use of Energy
1. Metabolism is the sum of all the chemical processes that occur in an
organism
a. Its all the processes living things use to convert nutrients into
chemical energy that the body can use to sustain life
· It involves chemical reactions
· Energy is required in order to make chemical cellular energy
2. Most organisms get their energy directly or indirectly from the Sun
a. Energy is required to maintain an organism’s molecular and
cellular organization
b. Energy is required for reproduction and growth
E. Homeostasis is the ability to maintain a stable internal environment.
1. All living things must maintain a stable, internal environment
2. Homeostasis acts like a thermostat for life functions
3. It maintains body temperature, water content, food intake, etc, at a
stable level
F. Growth and Development
1. Growth is by cell division (Fig. 1.3, p. 8)
2. Development is by repeated cell division and differentiation of cells
as in aging
3. Non living things, like a rock crystal, grow by accumulating more
material of which they are made
G. Reproduction and Inheritance
1. Reproduction is the process by which organisms transmit hereditary
information to offspring
a. It is not essential for the survival of an individual organism
b. It is essential for the survival of a species
2. Reproduction and inheritance involves DNA (deoxyribonucleic acid)
a. DNA is a large molecule that stores hereditary information
b. Its is found in the cell’s nucleus
c. It is identical in all cells of an organism
d. It has a twisted ladder shape (double helix) and is about 3 feet long
in a single cell
e. A gene is a segment of DNA that stores information for single trait
3. DNA gives instructions to cells to make structures and complex
chemicals for life
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Chapter 1 The Science of Life
Holt Modern Biology, 2006 ed.
D. Dyer
4. Two Types of Reproduction
a. Sexual Reproduction
b. Asexual Reproduction
5. Sexual Reproduction
a. Hereditary information comes from two parts of a single organism
(plants)
b. Hereditary information comes from two organisms of the same
species (animals)
c. Both processes involves a fertilized egg containing the both
parent’s genetic material
6. Asexual Reproduction
a. This process does not involve the transfer of hereditary material
b. Example: bacteria and other unicellular organisms simply divide
c. See Fig. 1.4, p. 9, “Why do some animals produce so many
fertilized eggs all at once?”
H. Change through Time (organisms evolve)
1. Individual organisms do not change genetically over a lifetime
2. Populations do change or evolve over many generations
a. Change in a population allows the species to adapt to changing
environments
b. Change in populations explains the great diversity of life on Earth
3. “Why is a growing salt crystal not alive?”
III.
Section 1.1 Review Questions, p. 9
A. How does biology affect a person’s daily life?
B. How does biology affect society?
C. Name the 8 characteristics shared by living things.
D. Summarize the hierarchy of organization found in complex multicellular
organisms.
E. What are the different functions of homeostasis and metabolism in living
organism?
F. Why is reproduction an important characteristic of life?
G. How does the growth among living and non living things differ?
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Chapter 1 The Science of Life
Holt Modern Biology, 2006 ed.
D. Dyer
Section 1.2 “Unifying Themes of Biology”
I.
Unifying Themes of Biology
A. Three Major Themes of biology that connects all life
1. Diversity and the Unity of Life
2. Interdependence of Organisms
3. Evolution of Life
B. Diversity and the Unity of Life
1. Diversity means variety of life (differences)
a. There are about 40 million species on Earth
b. Only 2 million have been identified and named
c. Only a few thousand have been studied
2. Why so little knowledge of species?
a. Many organisms are too small to observe (a gram of fertile soil
may have 2.5 billion unicellular organisms)
b. Many areas of the world are too difficult to explore and find
new organisms
c. Due to costs, we mostly study species that benefit or hurt humans
3. Unity of life means features common in all living things
a. Genetic Code is the chemical language of DNA in all cells
b. Organelles are in most cells and they carry out cellular activities
c. “Tree of Life” shows how life is connected (Fig 1.5, p. 10)
· It shows that life is connected genetically
· It forms a “tree” that relates and unites life’s diversity
o Organisms with more similar genes are placed on closer
branches or “lineages”
o It assumes all life on Earth descended, with modifications,
from common ancestor(s)
4. Three Domains of Life (appendix pp. 1078 – 1084)
a. Domain Bacteria – unicellular prokaryotes
b. Domain Archaea – unicellular prokaryotes similar to protists
c. Domain Eukarya – unicellular and multicellular Eukaryotes
divided into four kingdoms
· Kingdom Animalia
· Kingdom Plantae
· Kingdom Fungi
· Kingdom Protists
d. Fig 1.5, p. 10 shows the three Domains of Life
C. Interdependence of Organisms
1. Ecology
a. Ecology is the study of the interactions of organisms with one
another and with their environment
· It may involve one species and its environment
· It may involve an entire ecosystem (a community of many
species and their environment)
b. “It’s a recent branch of biology. Why?”
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Chapter 1 The Science of Life
Holt Modern Biology, 2006 ed.
D. Dyer
2. Why We Need to Understand the Earth’s Ecology
a. To survive, all organisms need nutrients, water, and gases from
the environment
b. Well functioning and healthy organisms depends on the stability
of the environment
c. Humans have had an enormous effect on the environment for
1000’s of years
· Rain forests are fragile ecosystems that affect all life on Earth
yet we are destroying them (Fig. 1.6, p. 11)
· Silt runoff in streams, air pollution, forest roads also affects life
· Cheat Mountain Salamander – most notable endangered
species in W. Va., has been affected by forest roads
d. Knowing our ecology helps us to better manage the environment
D. Evolution of Life
1. Populations of organisms evolve or change over generations, not
individuals
2. Theory of Evolution
a. Inherited characteristics in a population change over time to
match a changing environment
b. Darwin described it as “Descent of a Species with Modifications”
· It helps us understand how the various branches of the “Tree
of Life” came into existence
· It helps to explain how organisms living today are related to
ancient organisms
· It helps to explain why organisms look and behave the way
they do
3. Natural Selection
a. Natural selection is the driving force in evolution or change
· Organisms with favorable traits are better able to survive and
reproduce (adaptation)
o Favorable (adapted) traits help an organism to survive and
reproduce more, passing those traits on to offspring
o The survival of favorable traits cause a gradual change in
a population (one species) over many generations
· Favorable traits (adaptations) help a population to adapt to
changing environmental stresses
b. Natural selection is driven in part by competition among
individuals
· Fig. 1.7a, p. 12 shows white, small eared rabbits surviving
better in a snowy environment from predators and frostbite ears
· Fig. 1.7b, p. 12 shows brown, long eared rabbits survive best in
desert environments from predators and heat (long ears radiate
away body heat)
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Chapter 1 The Science of Life
Holt Modern Biology, 2006 ed.
II.
D. Dyer
Section 1.2 Review Question, page 12
A. Name three unifying themes found in biology.
B. How is the unity and diversity in the living world represented?
C. Identify the three domains and the kingdoms found in each domain.
D. How are organisms interdependent?
E. Describe why evolution is important in explaining the diversity of life.
F.
Distinguish between evolution and natural selection.
G. According to the “tree” in figure 1.5, p. 10, which of these pairs are more
closely related: Archaea: Bacteria or Archaea: Eukarya.
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Chapter 1 The Science of Life
Holt Modern Biology, 2006 ed.
D. Dyer
Section 1.3 “The Study of Biology”
I.
Science as a Process
A. Scientific Method is the organized approach used by science to learn
about the natural world
B. Ways How “We Know What We Know “
1. Art – knowledge through pictures, music, words
2. Religion – knowledge through faith
3. Science – knowledge through inquiry or search
C. Two Principles
1. Events in the natural world have natural causes
2. Idea of Uniformity in which the Laws of Nature operate the same
way everywhere, today and in the past
D. Steps of the Scientific Method (Fig. 1.9, p.14-15)
1. Observations
a. Observing involves human senses “seeing” the natural world in
order to raise questions
· Care must be taken for the senses can fool the observer
· Like a magician, who can easily fools our senses, nature can
fool us also
b. Example: Owls can catch prey in near total darkness
2. Questions: How does an Owl detect prey in the dark?
3. Forming a Hypothesizing:
a. The hypothesis gives a possible answer and is testable
b. List of possible testable answers (3 Hypothesis):
· Owls hunt by keen vision in the dark
· Owls hunt by detecting body heat of prey in the dark
· Owls hunt by superb hearing in the dark
4. Predicting
a. It’s the observation you expect if hypothesis is true
· It states the predicted results after testing a hypothesis
· Statement is usually in the form of “if-then”
· It may be found wrong, but it can never be proven true beyond
any doubt
· In the above example, a “rustling decoy” (leaf) was tied to the
tail of the mice and dragged a distance back
b. Predicting hypothesis 1and 2 (vision and body heat):
· (If) In the presence of a rustling “decoy”, (then) the owls will
pounce only on the prey in both dark and light conditions.
· Both hypotheses above would get the same outcome and make
a conclusion of which is true, difficult.
c. Predicting hypothesis 3 (hearing):
· (If) In the presence of a rustling “decoy”, (then) the owls will
pounce on the prey in light, but closer to the “decoy” in dark.
· This outcome would be conclusive for this hypothesis
(hearing)
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Chapter 1 The Science of Life
Holt Modern Biology, 2006 ed.
D. Dyer
5. Designing an Experiment (The Controlled Experiment)
a. For an experiment to be valid, experiments must be controlled
b. In a controlled experiment, two groups must be compared
· All conditions (variables) must be the same for both groups
except for one variable to be tested.
· The Control Group provides the known normal standard that
can be compared to the Experimental Group to be tested
· The Experimental Group is identical to the Control Group
except for the one independent variable that the experimenter
can manipulate.
c. Experimental Setup
· Room with the owl has a trap door that lets the mouse enter
o Lights in the room can be turned on or off
o Mouse has a rustling leaf attached to its tail, trailing about
one foot
o Mouse will be released into the room under light and dark
conditions
o Experiment will be videotaped for analysis
· Control Group – owls hunting in the light
· Experimental Group – owls hunting in the dark
o Independent Variable
§ The one variable the scientist is testing, or manipulates
§ In this experiment it is the presence or absence of light
o Dependent Variable
§ The variable responding to the Independent Variable
§ It’s the results or what happens in an experiment
§ In this experiment, it is the distance from the owl’s
strike to the mouse’s head.
· Testing the Experiment
o Without testing, opinions remain just opinions
o Must Eliminate Experimenter Bias: Testing must be
“blind” to the person collecting data. They should not
know which is the control or experimental group
o Experiment Must Be Repeatable: Living systems are
variable. What’s true for one owl may not be for another.
o Collect Ample Data: Results from only one test may not
be accurate
6. Collect and Analyzing Data
a. Measuring
· Quantitative data – countable data such as the number of
organisms or your weight
· Qualitative data – descriptive, non-countable data such as
color, smell, or relative size (large/small or high/low)
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Chapter 1 The Science of Life
Holt Modern Biology, 2006 ed.
D. Dyer
b. Sampling – taking a small part of a population to represent a
whole population
· Example 1: “How many students attend Wayne High
School?”
o This class is a sample of the school’s population. (Hint:
there are about 30 classrooms)
o At least 3 samples should be collected and averaged in
order to increase the chance of a representative sample
o If three samples average 20 students per class, than 20
students x 30 classrooms = 600 students
· Example 2: “What is the height of a typical WHS student?”
o Measure student heights from class and get a class average
o Is average representative?” “Why or why not?”
o Graph (bar) the average height of each student group.
o “Is an average or median height more representative?
“Why or why not?”
7. Organizing Data
a. Placing measurements and observations into some logical order
b. Use Tables, Charts, Graphs (Fig 1.10, p. 16)
8. Analyzing Data
a. Support for the hypothesis is determined here
b. Data reliability is determined
· Statistics used to determine if data is reliable or happened just
by chance
· Determine sources of error – room not totally dark,
uncontrolled noises in the room with owl, owl had bad eyes or
ears, measuring errors, etc
9. Drawing Conclusions
a. Sheds light on the unknown
b. Fig 1.10, p. 16, shows that leaf strikes (misses) were greater in the
dark than in the light
c. Conclusion: owls hunt by sound more than by sight or body heat
· Acceptance of a hypothesis is tentative
· Experiment can disprove a hypothesis (vision/body heat) but
not prove a hypothesis (hearing)
· New evidence can latter disprove the hearing hypothesis for
another possibility such as smell
d. Inferring from data
· Conclusion is based on facts or premises and not by direct
observation
· Inferences cannot be tested directly
· Results of the Owl study inferred that owls detect prey from a
distance
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Chapter 1 The Science of Life
Holt Modern Biology, 2006 ed.
D. Dyer
e. Modeling
· Constructed representations of an object, system, or process
that helps to show a relationship among data
o Explanation must be supported by the data
o It can be a visual, verbal, or mathematical model
· Models may help make a new hypothesis
10. Forming a Theory
a. Theory – statement of what is thought to be true
b. Theories are highly tested – based on results from many tests on
many hypothesis
· Laypeople use the term “theory” for their opinion or idea
· Opinions and ideas are just a hypothesis
11. Communicating Ideas
a. Publishing or presenting experimental results
b. Four Parts of a Paper
· Introduction – states problem and hypothesis to be
investigated
· Materials and Methods – what was used and how
· Results – Findings using graphs, tables, charts
· Discussion – conclusion, error sources, significance of
experiment, and future needs are discussed
c. Paper submitted for Peer Review
a. Errors, conflict of interest and honesty is checked
b. Allows science a method to self-correct mistakes
E. Implementing the Scientific Method
1. The scientific method is used to solve problems
2. It is not an exact process
a. Some scientists may combine different aspects of the scientific
process to solve their specific problem
b. It is used to communicate findings in a standard form so that they
can be verified by others
3. No Experiment is a Failure
a. If negative results occur, a scientist can show that a certain
hypothesis is not valid
b. An experiment can be successful even if it shows that a hypothesis
is not consistent with observations
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Chapter 1 The Science of Life
Holt Modern Biology, 2006 ed.
II.
D. Dyer
Section 1.3 Review Questions, p. 19
A. What two principles make the scientific method a unique process?
B. Define the roles of observation and hypothesis in science.
C. Summarize the parts of a controlled experiment.
D. Summarize how we make conclusions about the results of an experiment.
E. Why is the phrase “it’s just a theory” misleading?
F.
Give another example of a conflict of interest.
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Chapter 1 The Science of Life
Holt Modern Biology, 2006 ed.
D. Dyer
Section 1.4 “What is Microscopy?”
I.
Microscopes
A. Light Microscope (Fig. 1.13, p. 21 and pp. 1070-71)
1. The light microscope uses lenses to magnify or enlarge specimens
2. It shines light through a specimen and uses two lenses to view it
3. Four Major Parts
a. Light Source – at the microscope’s base, it shines light upward
through specimen on the Stage
b. Stage – platform where specimen or microscope slide is placed
c. Objective Lens – usually two lens: light passes through specimen
and enters objective lens, where its magnified (Fig. 1.14a, p. 22)
· Nosepiece – structure holding several objective lens
· Objective lens magnifies 10X to 100X or more
d. Eyepiece (Ocular Lens) – viewing port that magnifies 10X to 20X
B. Two Main Features Magnification and Resolution
1. Magnification
a. Increases the size of the specimen
b. Power of Magnification – product of eyepiece and objective lens
magnification
c. Example: Total Magnification
· Eyepiece magnifies 15X and Objective magnifies 40X.
· Total Magnification equals 600X or (15 x 40 = 600X)
2. Resolution
a. Power to show clarity or more details
· Resolution differs from focus
o Resolution refers to the number of points or pixels of detail
in an image
o Focus refers to the lining up of the points and lines
· It’s the difference between looking through wax paper vs.
cellophane).
b. Magnifies beyond 2000X, where light microscopes get “fuzzy”
C. Electron Microscope
1. Magnification above 2000X
a. Uses beam of electrons rather than light
b. Specimens placed in a vacuum chamber, so specimen always dies
2. Two Types of Electron Microscopes
a. Transmission Electron Microscope (TEM)
· Specimen is thinly sliced and electrons are passed through it
· Great resolution of details (Fig. 1.14c, p. 22)
· 200,000X
b. Scanning Electron Microscope (SEM)
· Specimen is covered with a metal coating
· Electrons bombard the specimen, which the metal emits back
· Photograph of emitted electrons give a striking 3-D image
· 100,000X
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Chapter 1 The Science of Life
Holt Modern Biology, 2006 ed.
D. Dyer
II.
Units of Measurements (Lab Skills, pp. 1072 – 1073)
A. Metric System
1. Decimal system based on powers of 10
2. International standard system of measurements, so its called SI units
3. It’s a universal standard that makes comparison of results easier
B. Seven Base Units
1. Describes length, mass, time, etc
2. Designated by prefixes (Table 1.1 and 1.2, p. 23)
3. Example: meters (m), kilograms (kg), seconds (s)
C. Derived Units
1. Combinations of two base units (Table 1.3, p. 23)
2. Combinations of two derived units
3. Example: volume and density
a. Volume = length x width x height (1 m3 or 1 cubic meter)
b. Density = mass/volume (grams/milliliters or g/ml)
III.
Safety in the Lab
A. Everyone should be aware of good lab practices (Fig. 1.15, p. 24)
B. A safety lab will be done
C. Read Lab Skills, pp. 1066 to 1069 before the lab
IV.
Section 1.4 Review Questions, p. 24
A. List the four parts of a compound microscope.
B. What is the difference between the magnification and resolution of an
image under a microscope?
C. Compare the function of a transmission electron microscope with that of a
scanning electron microscope.
D. What is the importance of scientists using a common SI system of
measurement?
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Chapter 1 The Science of Life
Holt Modern Biology, 2006 ed.
D. Dyer
E. How would you convert kilometers to millimeters?
F.
Name the safety symbols used in this textbook. (p. 24)
G. A virus is much smaller than a cell. Which type of microscope is most
likely to be used to view the internal structure of a virus?
H. How would you convert cubic meters to cubic centimeters?
I.
On a light microscope, an objective lens magnifies the view of some pond
water 25 times, and the ocular lens (eyepiece) magnifies it 10 times
further. What is the final magnification of the image?
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