Biology 20
Unit I – The Science of Life Review
Terms To Know
Analysis
Arm
Asexual reproduction
Autotroph
Base
Base unit
Biology
Body tube
Cell
Cell division
Coarse adjustment knob
Compound Light Microscope
Conclusion
Control group
Controlled experiment
Data
Dependent variable
Derived unit
Development
Diaphragm
Differentiation
DNA
Ecology
Ecosystems
Energy
Evolution
Experimental group
Experimentation
Fine adjustment knob
Gene
Growth
Heterotroph
Homeostasis
Hypothesis
Independent variable
Inference
Magnification
Measuring
Metabolism
Mirror
Model
Multicellular
Natural selection
Objective lens
Observation
Ocular lens
Organism
Photosynthesis
Power of Magnification
Prediction
Problem
Qualitative
Quantitative
Resolution
Revolving nosepiece
Sampling
Scanning Electron Microscope
Scientific method
Sexual reproduction
SI
Stage
Stage clip
Theory
Transmission Electron Microscope
Unicellular
Questions For Review (70 marks)
1. List six unifying themes of biology.
The six themes discussed in the chapter include cell structure and function;
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stability and homeostasis; reproduction and inheritance; evolution;
interdependence of organisms; and matter, energy, and organization.
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2. How do organisms produce offspring like themselves?
Organisms transmit hereditary information to their offspring in the form of
DNA.
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3. What are two of the driving forces behind the process of natural selection?
(a) Organisms in a population must compete for limited resources.
(b) Individuals in a population differ from one another. Some have traits
that allow them to reproduce more successfully than other organisms.
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4. Why do biologists say that living things are organized?
They have a high level of molecular and cellular organization, showing more
complex structure than nonliving things.
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5. Why are rainforests considered fragile environments that are vulnerable to
permanent destruction?
Rain forests typically support large numbers of plants and animals on a thin
layer of topsoil. Removal of vegetation leads to depletion of soil nutrients
and hardening of the soil, eliminating the possibility of reforestation.
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6. What is the difference between asexual reproduction and sexual
reproduction?
Sexual reproduction involves the combining of genetic material form
different individuals, while asexual reproduction does not.
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7. How do autotrophs differ from heterotrophs in obtaining energy?
Autotrophs synthesize the nutrients they need from simple substances, in
most cases using the energy they trap from the sun. Heterotrophs must
rely on other organisms in order to obtain the nutrients they need as their
energy source.
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8. Why do scientists say that the environment “selects” the traits that allow an
organism to survive and reproduce?
The traits that are helpful to an organism depend almost entirely on that
organism’s interaction with the environment.
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9. Name six characteristics that all living things share.
Cellular composition, organization, use of energy, homeostasis, growth, and
reproduction
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10. What are two levels of organization found in living things?
Molecular and cellular organization
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11. How does growth of a nonliving thing differ from growth of a living thing?
Some nonliving things, like rock crystals, grow by accumulating more of the
materials they are made of. Living things grow by cell enlargement and cell
division.
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12. Why is reproduction an important characteristic of life?
Reproduction is not vital to the survival of an individual, but it is vital to the
continuation of life.
13. Why are so many organisms yet to be discovered identified, and described?
There is a great diversity of life, and many organisms are relatively
inaccessible to scientists.
14. How are the processes of inferring and modeling useful to scientists?
Inferring enables scientists to draw conclusions without making direct
observations. Modeling enables scientists to understand the relationships
among data they have collected or observations they have made.
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15. What is the relationship between hypothesizing and experimenting in
science?
Hypothesizing is forming a testable statement about observable phenomena.
Experimenting is testing a hypothesis or prediction by gathering data under
controlled conditions.
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16. What is the relationship between a hypothesis and a prediction?
A hypothesis is a testable explanation of observable phenomena and data. A
prediction is a statement of expected results of testing the hypothesis.
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17. What role does communication play in science?
Communication enables scientists to build on each other’s work and findings.
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18. Explain why there is no single scientific method.
Scientists use a variety of methods, depending on the nature of their work.
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19. How does a theory differ from a hypothesis?
A hypothesis is a testable statement, based on observation. A theory is a
broad statement of what is thought to be true, based on the testing of many
hypotheses.
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20. How do microscopes differ in magnification and resolution?
Some light microscopes magnify up to 2,000 X, but as the power of
magnification increases, the resolution drops. A TEM microscope magnifies
up to 200,000 X and can distinguish the internal structure of specimens. An
SEM magnifies up to 100,000 X and provides three-dimensional images of
the surface of a specimen.
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21. How is the maximum power of magnification computed for a compound light
microscope?
The power of magnification of a microscope is the product of the power of
magnification of the ocular lens and that of the most powerful objective
lens.
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22. Describe the similarities and differences between a transmission electron
microscope and a scanning electron microscope.
A TEM transmits electrons through a thinly sliced specimen and magnifies
the image of the specimen up to 200,000X. An SEM scans the surface of a
specimen with a beam of electrons and magnifies the image of the surface
up to 100,000X.
23. If SI measurement is no more accurate than the English system, why do
scientists throughout the world use it?
Conversions among SI units are simple, allowing scientists to manipulate data
much more easily than if they were working with English units.
24. One of the first branches of biology to be developed was taxonomy, the
naming of organisms. Why is taxonomy important to communication about
biology?
Organisms had to be named or described before different scientists
studying them independently could accurately compare their results.
25. Scientists know that a disease-causing organism can cause overwhelming
illness or death very quickly. Why would it not be adaptive for a diseasecausing organism to kill its victims too quickly?
If it kills its host before it can multiply and be passed to another host, it
will die off.