Download Honors Biology Ch. 14 Notes The Origin of Species Concepts of species

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 allele frequency in
a population.
macroevolution: the broader pattern of evolutionary change
over long periods of time including speciation.
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
Mrs. Loyd 
[email protected]
Page 1 of 3
http://loydbiology.weebly.com
5/25/2017
http://www.mybiology.com
Mechanisms of Speciation
14.4 Explain how geologic processes can fragment
populations and lead to speciation.
Allopatric Speciation: “In another place”
14.5 Explain how sympatric speciation can occur, noting
examples in plants and animals.
Sympatric Speciation: A new species arises within the same
geographic area as a parent species.
Polyploidy:
 genetic isolation by hybridization + failure at cell
division.
 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, isolating
gene pools.
Sexual selection:
 Females 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:
 Extinction of dinosaurs.
 Many niches opened up.
 Mammals underwent dramatic adaptive radiation.
Isolated Island chains with physically diverse habitats are often
the sites of explosive adaptive radiations.
 Colonizers may undergo multiple allopatric and sympatric
speciation events
 Producing species that are found nowhere else on Earth
o Example:

Galapagos Archipelago

Great showcase of adaptive radiation

Each island produced by volcanic
activity

Ocean currents and winds brought stray
plants, animals, microorganisms.
Mrs. Loyd 
[email protected]
Page 2 of 3
http://loydbiology.weebly.com
5/25/2017
http://www.mybiology.com
14.11 Compare the gradualism model and the punctuated
equilibrium model of evolution. Explain how each model
applies to the fossil record.
Punctuated: many fossils appear suddenly in fossil record
and then…
Equilibria: persist essentially unchanged through several
layers (strata) until…
Punctuated: disappearing as suddenly as they appeared.
One would not expect many transitional fossils in the record.
Punctuated Equilibrium
Gradualism:
 Other fossil species appear to have diverged gradually
over long periods of time.
 Differences gradually evolve in populations as they
become adapted to their local environments
Gradualism
Mrs. Loyd 
[email protected]
Page 3 of 3
http://loydbiology.weebly.com
5/25/2017
http://www.mybiology.com