Honors Biology
Ch. 14 Notes
The Origin of Species
Concepts of species
14.1 Define and distinguish between microevolution and
macroevolution.
microevolution: the changes over time in _____frequency in
a population.
macroevolution: the broader pattern of evolutionary change
over _____________________________ .
14.2 Compare the definitions, advantages, and
disadvantages of the different species concepts.
Species
Concept
Biological
Morphological
Ecological
Phylogenetic
definition
A group of populations
whose members have the
potential to interbreed in
nature and produce fertile
offspring.
Based on observable and
measurable physical traits
such as shape, size, and
other features of
morphology (form).
Focuses on niches and
unique adaptations to
particular roles in a
biological community.
The smallest group of
individuals that shares a
common ancestor and
that forms one branch on
the tree of life.
advantages
disadvantages
Using reproductive isolation
as the sole criteria is
straightforward.
A. Extinct organisms with
only fossil evidence.
B. Useless for prokaryotes
(asexual)
Most common.
Can be applied to asexual
organisms and fossils.
Relies on subjective
criteria.
May look similar but
distinguishable based on diet
and location in environment.
Requires close
examination of behavior
and habitat.
History is traced by comparing
its characteristics, such as
morphology or DNA
sequences, with those of
other organisms.
Agreeing on the amount of
difference required to
distinguish separate
species remains a
problem.
14.3 Describe five types of prezygotic barriers and three
types of postzygotic barriers that prevent
populations belonging to closely related species
from interbreeding. table 14.3 p. 280
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Mechanisms of Speciation
14.4 Explain how geologic processes can fragment
populations and lead to speciation.
Allopatric Speciation: “In another ________”
14.5 Explain how sympatric speciation can occur, noting
examples in plants and animals.
Sympatric Speciation: A new species arises ____________
_____________________________as a parent species.
14.6 Polyploidy:
 genetic isolation by ____________+ failure at
_________ ________________.
 Less likely than the other two.
Habitat differentiation:
 subgroups of original population evolved adaptations
for exploiting different food sources.
 If in different habitats, mating between the two
specializing populations would become rare,
___________ the gene pools.
Sexual selection:
 F_______________ choose based on different
factors.
14.10 Describe the circumstances that led to the adaptive
radiation of the Galapagos finches.
Adaptive Radiation: The evolution of many diverse species
from a common ancestor. Example: Darwin’s Finches
Typically occurs when a few organisms colonize new,
unexploited areas or when environmental changes cause
numerous extinctions, opening up a variety of opportunities for
the survivors.
 Example:
 __________________________________
 Many niches opened up.
 _______________ underwent dramatic adaptive
radiation.
Isolated ___________ __________ with physically diverse
habitats are often the sites of explosive adaptive radiations.
 Colonizers may undergo multiple ___________and
__________________ speciation events
 Producing species that are found nowhere else on Earth
o Example:

G_________________ Archipelago

Great showcase of adaptive radiation

Each island produced by __________
_______________

Ocean currents and winds brought stray
plants, animals, microorganisms.
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14.11 Compare the gradualism model and the punctuated
equilibrium model of evolution. Explain how each model
applies to the fossil record.
Punctuated: many _________appear suddenly in fossil
record and then…
Equilibria: ________ _________ ____________through
several layers (strata) until…
Punctuated: disappearing as __________ as they appeared.
One would not expect many _____________ ______________
in the record.
Punctuated Equilibrium
Gradualism:
 Other fossil species appear to have diverged _______
___________________________________________ .
 D_________________ gradually evolve in populations as
they become adapted to their local environments
Gradualism
Mrs. Loyd 
cloyd@waukee.k12.ia.us
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