22.1 – 1
Which of the individuals discussed in
this section viewed species as fixed,
and which viewed species as being
able to change over time?
22.1 – 1
Aristotle, Linnaeus, and Cuvier
viewed species as fixed (though
Cuvier noted that the species
present in a particular location
could change over time). Lamarck,
Erasmus Darwin, and Charles
Darwin thought species could
change.
22.1 – 2
What was Lamarck’s theory of
evolution? Explain its significance.
22.1 – 2
Lamarck observed evidence of
changes in species over time and
noted that evolution could result in
organisms’ adaptations to their
environments, though his theory was
based on an incorrect mechanism for
evolution: that modifications an
organism acquires during its lifetime
can be passed to its offspring.
22.2 – 1
Describe how the following
concepts relate to Darwin’s theory
of evolution by natural selection:
overproduction of populations,
limited resources, and heritable
variation.
22.2 – 1
Species have the potential to produce more
offspring than survive (overproduction),
leading to a struggle for resources, which are
limited. Populations exhibit a range of
heritable variations, some of which confer
advantages to their bearers that make them
more likely to leave more offspring than less
well-suited individuals. Over time this natural
selection can result in a greater proportion of
favorable traits in a population (evolutionary
change).
22.2 – 2
Explain why an individual organism
cannot be said to evolve.
22.2 – 2
Though an individual may become
modified during its lifetime through
interactions with its environment,
this does not represent evolution.
Evolution can be measured only as a
change in proportions of heritable
variations from generation to
generation.
22.3 – 1
Explain why the following statement is
inaccurate: “Anti-HIV drugs have
created drug resistance in the virus.”
22.3 – 1
An environmental factor such as a
drug does not create new traits such
as drug resistance, but rather
selects for traits among those that
are already present in the population.
22.3 – 2
How does Darwin’s theory account for both the
similar mammalian forelimbs with different
functions of the human, cat, whale, and bat
(shown below left) and the similar lifestyles of the
Australian sugar glider and the North American
flying squirrel (shown below right).
22.3 – 2
Despite their different functions,
the forelimbs of different mammals
are structurally similar because they
all represent modifications of a
structure found in the common
ancestor. The similarities between
the sugar glider and flying squirrel
indicate than similar environments
selected for similar adaptations
despite different ancestry.
22.3 – 3
Explain how the fossil record can be
used to test predictions of evolutionary
theory.
22.3 – 3
If molecular biology of biogeography
indicates a particular branching patter of
descent from a single group of ancestral
organisms, representatives of the
ancestral group should appear earlier in
the fossil record than representatives of
later organisms. Likewise, the many
transitional forms that link ancient
organisms to present-day species are
evidence of descent with modification.