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© 2012 Pearson Education, Inc. Lecture by Edward J. Zalisko PowerPoint Lectures for Campbell Biology: Concepts & Connections, Seventh Edition Reece, Taylor,

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Presentation on theme: "© 2012 Pearson Education, Inc. Lecture by Edward J. Zalisko PowerPoint Lectures for Campbell Biology: Concepts & Connections, Seventh Edition Reece, Taylor,"— Presentation transcript:

1 © 2012 Pearson Education, Inc. Lecture by Edward J. Zalisko PowerPoint Lectures for Campbell Biology: Concepts & Connections, Seventh Edition Reece, Taylor, Simon, and Dickey Chapter 15 Tracing Evolutionary History

2 PHYLOGENY AND THE TREE OF LIFE © 2012 Pearson Education, Inc.

3  Phylogeny is the evolutionary history of a species.  Phylogeny can be inferred from –the fossil record, –morphological homologies, and –molecular homologies. Phylogenies based on homologies reflect evolutionary history © 2012 Pearson Education, Inc.

4  Homologies are similarities due to shared ancestry.  However, some similarities are analogies  due to similar adaptations favored by a common environment, a process called convergent evolution. Phylogenies based on homologies reflect evolutionary history © 2012 Pearson Education, Inc.

5 The Bones Are Homologous, the Wings Are Not

6  Systematics is a discipline of biology that focuses on –classifying organisms and –determining their evolutionary relationships.  Carolus Linnaeus introduced taxonomy, a system of naming and classifying species.  Biologists use phylogenetic trees to depict evolutionary history of species Systematics connects classification with evolutionary history © 2012 Pearson Education, Inc. Animation: Classification Schemes

7 Figure 15.15A Species: Felis catus Genus: Felis Family: Felidae Order: Carnivora Class: Mammalia Phylum: Chordata Kingdom: Animalia Domain: Eukarya Archaea Bacteria

8 TAXA Amnion Character Table Long gestation Long gestation Gestation Hair, mammary glands CHARACTERS FrogIguana Duck-billed platypus KangarooBeaver Gestation Hair, mammary glands Phylogenetic Tree Beaver Kangaroo Duck-billed platypus Iguana Frog 0 0 0 00001 0011 0111 1111 Reading and constructing phylogenetic trees Shared ancestral characters relate organisms to common ancestors. Derived characters distinguish new lineages and form the branch points in the tree of life

9  A clade is a monophyletic group of species that includes the ancestral species and all of its descendants. Reading and constructing phylogenetic trees © 2012 Pearson Education, Inc. TAXA Amnion Character Table Long gestation Long gestation Gestation Hair, mammary glands CHARACTERS FrogIguana Duck-billed platypus KangarooBeaver Gestation Hair, mammary glands Phylogenetic Tree Beaver Kangaroo Duck-billed platypus Iguana Frog 0 0 0 00001 0011 0111 1111

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12  The phylogenetic tree of reptiles shows that crocodilians are the closest living relatives of birds. –They share numerous features, including –four-chambered hearts, –“singing” to defend territories, and –parental care of eggs within nests. –These traits were likely present in the common ancestor of birds, crocodiles, and dinosaurs. Phylogenetic trees allow us to make hypotheses about evolutionary relationships © 2012 Pearson Education, Inc.

13 Figure 15.16B Common ancestor of crocodilians, dinosaurs, and birds Lizards and snakes Crocodilians Pterosaurs* Ornithischian dinosaurs* Saurischian dinosaurs* Birds

14  Phylogeny is the evolutionary history of a species or group of species.  Phylogeny can be inferred from –the fossil record, –morphological homologies, and –molecular homologies. Phylogenies based on homologies reflect evolutionary history © 2012 Pearson Education, Inc.

15  Molecular homologies: DNA or protein sequences are compared to establish ancestry.  More recently two species are related the more similar their DNA sequences should be.  More distantly related, the more their DNA should have diverged.  Advantage of molecular homologies:  Can sort out relationships among closely related, or distantly related species when morphologies alone are difficult or not sufficient Using molecular homologies to establish evolutionary relationships © 2012 Pearson Education, Inc.

16 Amino Acid Sequences of Cytochrome c

17 Amino Acid Sequence Alignment

18 Figure 15.17 Red panda Weasel Raccoon Giant panda Spectacled bear Sloth bear Sun bear American black bear Asian black bear Polar bear Brown bear Pleistocene Pliocene MioceneOligocene Millions of years ago 353025201510

19  Different genes evolve at different rates. –DNA coding for ribosomal RNA (rRNA) –changes slowly and –is useful for investigating relationships between taxa that diverged hundreds of millions of years ago. –Example: fungi vs animals; relationships among prokaryotes –In contrast, DNA in mitochondria (mtDNA) –evolves rapidly and –is more useful to investigate more recent evolutionary events. –Example: hominid and primate evolution Using molecular homologies allows us to understand both close and distant relationships © 2012 Pearson Education, Inc.

20 Figure 15.17 Red panda Weasel Raccoon Giant panda Spectacled bear Sloth bear Sun bear American black bear Asian black bear Polar bear Brown bear Pleistocene Pliocene MioceneOligocene Millions of years ago 353025201510

21  Molecular clocks –Assumption: genes exhibit a constant rate of change –Must be calibrated by graphing the number of nucleotide differences against the dates of evolutionary branch points known from the fossil record Assigning time to evolutionary events © 2012 Pearson Education, Inc.

22 A Molecular Clock of the Protein Hemoglobin

23 Figure 15.UN05 Outgroup


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