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Chapter 14
The Origin of Species
PowerPoint Lectures for
Biology: Concepts and Connections, Fifth Edition
– Campbell, Reece, Taylor, and Simon
Lectures by Chris Romero
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
14.0 Mosquito Mystery
- Speciation
- the emergence of
- how do we know that a distinctly new
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
In London
- two populations of mosquitoes exist with very
little
In the United States
- the two species appeared to hybridize into one
species, which
How could the mosquitoes behave like two species
on one continent and
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
14.1 The origin of species
- is the source of
Microevolution
- gradual adaptation of a species to
- does not produce
Speciation
- the origin of new species, is at the
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
CONCEPTS OF SPECIES
14.2 Taxonomy
- branch of biology naming and
- the binomial system was introduced by
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
The biological species concept
– defines a species as a
– whose members can interbreed and
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
14.3 Reproductive barriers
- isolate a species' gene pool and
Pre-zygotic barriers
-prevent mating or
• Temporal isolation: species breed
• Behavioral isolation: there is no sexual attraction
between
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Mechanical isolation: female and male sex
organs or gametes
• Gametic isolation: after copulation, gametes
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
MECHANISMS OF SPECIATION
14.4 Geographic isolation
- can lead
In allopatric speciation
- a population is
- barriers include
- emergence of a
- subsidence of
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Geographic isolation in
- led to allopatric
- the isolated populations
Video: Galápagos Marine Iguana
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
14.5 Adaptive radiation
- the evolution of many new species from
- occurs when mass extinctions provide
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Island chains with
- are often sites of
- 14 species of Galápagos finches differ in
- evidence indicates that all 14 species evolved
from a single small population of
Video: Galapágos Islands Overview
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
TALKING ABOUT SCIENCE
14.6 Evolution of Darwin's finches
- natural selection acting on populations of
- finch beaks adapted to different food sources
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14.7 Gradualism model
- new species evolve by the gradual
accumulation of changes
- not well supported by
most new species seem to appear suddenly
in rock strata without
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
14.8 Punctuated equilibrium model
-periods of rapid
- interrupted by long periods of
Fossil record shows species changing most as
they
-and then relatively little for
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
14.9 Human evolution
Large skull & long childhood provide humans with:
- more
- more
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Juvenile physical traits
- may make adults more
- ex: "evolution" of
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
14.10 Evolutionary trends
- do not imply an intrinsic
- if environmental conditions change,
an apparent
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings