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BIOLOGYCONCEPTS & CONNECTIONS
Fourth Edition
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor
From PowerPoint® Lectures for Biology: Concepts & Connections
CHAPTER 15Tracing Evolutionary History
Modules 15.6 – 15.14
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Adaptations that have evolved in one environmental context may be able to perform new functions when conditions change
– Example: Plant species with catch basins, an adaptation to dry environments
15.6 Key adaptations may enable species to proliferate after mass extinctions
Figure 15.6
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• “Evo-devo” is a field that combines evolutionary and developmental biology
• Major adaptations may arise rapidly if mutations occur in genes that control an organism’s early development
15.7 “Evo-devo:” Genes that control development play a major role in evolution
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• Paedomorphosis, the retention of juvenile characteristics in the adult, seems to have played a role in human evolution
Figure 15.7A, B
Chimpanzee fetus Chimpanzee adult
Human fetus Human adult
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Stephen Jay Gould argued that there was a connection between our juvenile physical traits and our long period of dependency– The youthful features of Mickey Mouse
elicit affectionate, parental responses
Figure 15.7C
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• Evolutionary trends may reflect unequal speciation or survival of species on a branching evolutionary tree
15.8 Evolutionary trends do not mean that evolution is directed toward a goal
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Figure 15.8
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• Phylogeny is the evolutionary history of a group of organisms
15.9 Phylogenetic trees strive to represent evolutionary history
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Figure 15.9
Mediumground finch
Cactusground finch
Smalltree finch
Largeground finch
Smallground finch
Large cactusground finch
Sharp-beakedground finch
Vegetarianfinch
Seedeaters
Ground finches
Cactus flowereaters
Budeaters
Tree finches
Insecteaters
Mediumtree finch
Largetree finch
Mangrovefinch
Woodpeckerfinch
Greenwarbler finch
Graywarbler finch
Warbler finches
Common ancestor fromSouth America mainland
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• Reconstructing phylogeny is part of systematics
– the study of biological diversity and classification
• Taxonomists assign a two-part name to each species
– The first name, the genus, covers a group of related species
– The second name refers to a species within a genus
15.10 Systematists classify organisms by phylogeny
SYSTEMATICS AND PHYLOGENETIC BIOLOGY
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• Genera are grouped into progressively larger categories
Table 15.10
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Taxonomists often debate the particular placement of organisms in categories as they strive to make their categories reflect evolutionary relationships
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 15.10
SPECIES
Feliscatus
(domesticcat)
Mephitismephitis(stripedskunk)
Lutralutra
(Europeanotter)
Canisfamiliaris(domestic
dog)
Canislupus(wolf)
FelisGENUS
FAMILY
ORDER
Mephitis Lutra Canis
CanidaeMustelidaeFelidae
Carnivora
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• Homologous structures are evidence that organisms have evolved from a common ancestor
• In contrast, analogous similarities are evidence that organisms from different evolutionary lineages have undergone convergent evolution
– Their resemblances have resulted from living in similar environments
15.11 Homology indicates common ancestry, but analogy does not
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• Example: California ocotillo and allauidia of Madagascar
Figure 15.11
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Systematists increasingly use molecular techniques to
– classify organisms
– develop phylogenetic hypotheses
15.12 Molecular biology is a powerful tool in systematics
Figure 15.12B
Human Chimpanzee Gorilla Orangutan
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• A phylogenetic tree based on molecular data
Figure 15.12A
Pleistocene
Pliocene
Mio
ce
ne
Oli
go
ce
ne
Brown bearPolarbear
Asiaticblack bear
Americanblack bear
Sunbear
Slothbear
Spectacledbear
Giantpanda
RaccoonLesserpanda
Ursidae
Procyonidae
Common ancestralcarnivorans
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• Homologous features are used to compare organisms
• Cladistic analysis attempts to define monophyletic taxa
15.13 Systematists attempt to make classification consistent with phylogeny
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Figure 15.13A
Outgroup(Reptiles)
TAXA
Ingoup(Mammals)
Eastern boxturtle
Duck-billedplatypus
Red kangaroo North Americanbeaver
CHARACTERS
Long gestation
Gestation
Hair, mammary glands
Vertebral column
Long gestation
1
Vertebral column
2
Hair, mammary glands
3
Gestation
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• Cladistic analysis is often a search for the simplest hypotheses about phylogeny
– Phylogenetic tree according to cladistic analysis
Figure 15.13B, C
Lizards Snakes Crocodiles Birds
Lizards Snakes Crocodiles Birds
– Phylogenetic tree according to classical systematics
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• For several decades, systematists have classified life into five kingdoms
15.14 Arranging life into kingdoms is a work in progress
THE DOMAINS OF LIFE
Figure 15.14A
MONERA PROTISTA PLANTAE FUNGI ANIMALIA
Earliestorganisms
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• A newer system recognizes two basically distinctive groups of prokaryotes
– The domain Bacteria
– The domain Archaea
• A third domain, the Eukarya, includes all kingdoms of eukaryotes
Figure 15.14B
BACTERIA ARCHAEA EUKARYA
Earliestorganisms