Transcript All of 14 2012

BIOLOGY
CONCEPTS & CONNECTIONS
Fourth Edition
Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor
CHAPTER 14
The Origin of Species
Modules 14.1 – 14.2
From PowerPoint® Lectures for Biology: Concepts & Connections
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
The origin of species
– A species is a group of organisms able to
successfully breed and produce fertile offspring.
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
CONCEPTS OF SPECIES
14.1 What is a species?
• Linnaeus used
physical appearance to
identify species when
he developed the
binomial system of
naming organisms
– This system
established the basis
for taxonomy, animal
classification
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– King: Kingdom
– Philip: Phylum
– Cried: Class
– Out: Order
– For: Family
– Good: Genus
– Soup: Species
Human Taxonomy
• Kingdom: Animalia
• Phylum: Chordata
• Class: Mammalia
• Order: Primate
• Family: Hominidae
• Genus: Homo
• Species: sapiens
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Every living thing has a scientific name, given
through binomial nomenclature, that is made
up of its genus and species names.
• Humans: Homo sapiens
• Dogs: Canis familiaris
• Wolves: Canis lupus
• Cats: Felis catus
Figure 14.1A
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14.2 Reproductive barriers keep species separate
• Prezygotic and
postzygotic
reproductive
barriers prevent
individuals of
different species
from
interbreeding
Table 14.2
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Prezygotic Barriers: Egg and sperm never meet
• Temporal isolation: two species breed at different times of
the year
• Habitat Isolation: two species live in the same area but in
different kinds of places (near the coast or inland in desert
regions)
• Behavioral isolation: mating behavior of males does not
attract females of another species
• Mechanical isolation: male and female sex organs don’t
work together (mostly in plants)
• Gametic isolation: gametes cannot unite and form a zygote
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Postzygotic barriers: babies don’t work
• Hybrid inviability: hybrid zygotes either don’t
develop or die too young to reproduce
• Hybrid sterility: hybrids are sterile (mules)
• Hybrid breakdown: offspring produced by
hybrids are weak or infertile (ligers)
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MECHANISMS OF SPECIATION
14.3 Geographic isolation can lead to speciation
• How do new species evolve?
– An isolated population may become genetically
unique as its gene pool is changed by natural
selection, genetic drift, or mutation
– This is called allopatric speciation
Figure 14.3
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14.4 Islands are living laboratories of speciation
• On the Galápagos
Islands, repeated
isolation and adaptation
have resulted in adaptive
radiation of 14 species of
Darwin’s finches
• Adaptive radiation is
when numerous species
evolve from a common
ancestor due to new
environments.
Figure 14.4A
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Peter and Rosemary Grant
• Studied finches on the
Galapagos for 30 years
• Observed the evolution
of a new species of finch
through natural
selection
• Showed that evolution
can happen both rapidly
and slowly depending on
environmental stresses
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
14.5 New species can also arise within the same
geographic area as the parent species
• In sympatric speciation, a new species may arise
without geographic isolation
– This is usually caused by spontaneous genetic
mutation.
Parent species
Zygote
Meiotic
error
Selffertilization
2n = 6
Diploid
Offspring may
be viable and
self-fertile
4n = 12
Tetraploid
Unreduced diploid gametes
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Figure 14.5A