chapter 15 tracing evolutionary history

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


• 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


• “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


• 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


• 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


• 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


Figure 15.8


• Phylogeny is the evolutionary history of a group of organisms

15.9 Phylogenetic trees strive to represent evolutionary history


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


• 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


• Genera are grouped into progressively larger categories

Table 15.10


• Taxonomists often debate the particular placement of organisms in categories as they strive to make their categories reflect evolutionary relationships


Figure 15.10

SPECIES

Feliscatus

(domesticcat)

Mephitismephitis(stripedskunk)

Lutralutra

(Europeanotter)

Canisfamiliaris(domestic

dog)

Canislupus(wolf)

FelisGENUS

FAMILY

ORDER

Mephitis Lutra Canis

CanidaeMustelidaeFelidae

Carnivora


• 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


• Example: California ocotillo and allauidia of Madagascar

Figure 15.11


• 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


• 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


• Homologous features are used to compare organisms

• Cladistic analysis attempts to define monophyletic taxa

15.13 Systematists attempt to make classification consistent with phylogeny


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


• 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


• 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


• 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

chapter 15 tracing evolutionary history

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