BIOLOGY CONCEPTS & 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 Chapters Tracing Evolutionary History Modules 15.1 – 15.5

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Macroevolution consists of the major changes in the history of life –The Earth is 4.6 billion years old –Life appeared 3.8 billion years ago: as single celled prokaryotic bacteria –Around 500 million years ago, simple marine animals and plants had evolved 15.1 The fossil record chronicles macroevolution MACROEVOLUTION

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –300 million years ago, reptiles, amphibians, and insects evolved on land –200 million years ago, dinosaurs and flowering plants evolved –65 million years ago: mammals and birds evolved from a common reptilian ancestor –20 million years ago, evolution of apes –100,000 years ago: the first humans 15.1 The fossil record chronicles macroevolution MACROEVOLUTION

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Radiometric (or carbon) dating is based on the measurement of certain radioactive isotopes Scientists can measure how much carbon is left in a fossil, and can then determine how old that fossil is Radiometric Dating

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Continental drift is the slow, incessant movement of Earth’s crustal plates on the hot mantle 15.3 Continental drift Figure 15.3A Pacific Plate North American Plate Nazca Plate South American Plate African Plate Eurasian Plate Split developing Indo-Australian Plate Edge of one plate being pushed over edge of neighboring plate (zones of violent geologic events) Antarctic Plate

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings This movement has influenced the distribution of organisms and greatly affected the history of life –Continental mergers triggered extinctions –Separation of continents caused the isolation and diversification of organisms Figure 15.3B Millions of years ago Eurasia CENOZOIC MESOZOIC PALEOZOIC North America Africa India South America Antarctica Australia Laurasia Gondwana Pangaea

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Continental drift explains the distribution of lungfishes –Lungfishes evolved when Pangaea was intact Figure 15.3C

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 15.3D NORTH AMERICA SOUTH AMERICA EUROPE AFRICA ASIA AUSTRALIA = Living lungfishes = Fossilized lungfishes

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Plate tectonics, the movements of Earth’s crustal plates, are also associated with volcanoes and earthquakes –California’s San Andreas fault is a boundary between two crustal plates 15.4 Plate tectonics Figure 15.4A San Andreas fault San Francisco Santa Cruz Los Angeles

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings By forming new islands, volcanoes can create opportunities for organisms –Example: Galápagos But volcanic activity can also destroy life –Example: Krakatau (destroyed an entire island rainforest) Figure 15.4B, C

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The Permian Extinction occurred 245 million years ago due to extreme climate change (global warming caused by volcanic activity). –95% of the species of plants and animals went extinct A large asteroid hit the Earth about 65 million years ago. –This caused the Cretaceous Extinction, the extinction during which all dinosaurs died –The crater left by this asteroid can be found in the Gulf of Mexico 15.5 Mass extinctions

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Every mass extinction reduced the diversity of life –But each was followed by a rebound in diversity –Mammals filled the void left by the dinosaurs

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A structure that evolved in one context and was later adapted to another function is referred to as exaptation. –Example: Dinosaurs evolved feathers as insulation against extreme temperatures, as birds evolved from small dinosaurs, feathers changed through natural selection to give flight Adaptations Figure 15.6

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Phylogeny is the evolutionary history of a group of organisms. Biologists construct phylogenic trees, which are diagrams that trace evolutionary relationships Phylogeny

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 15.9 Medium ground finch Cactus ground finch Small tree finch Large ground finch Small ground finch Large cactus ground finch Sharp-beaked ground finch Vegetarian finch Seed eaters Ground finches Cactus flower eaters Bud eaters Tree finches Insect eaters Medium tree finch Large tree finch Mangrove finch Woodpecker finch Green warbler finch Gray warbler finch Warbler finches Common ancestor from South America mainland

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Reconstructing phylogeny is part of systematics, the study of biological diversity and classification. Taxonomists assign a two-part name to each species (binomial nomenclature) –The first name, the genus, covers a group of related species (but they can’t breed!) Ex: Homo –The second name refers to a species within a genus Ex: sapiens –Another Example: Canis familiaris (italics, genus capitalized, species not) Systematists classify organisms by phylogeny

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Genera are grouped into progressively larger categories Table 15.10

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A review of taxonomy Taxonomy is the system of classifying living organisms. Kings = Kingdom (Anamalia) Play = Phylum (Chordata) Chess = Class (Mammalia) On = Order (Primates) Funny = Family (Hominidae) Green = Genus (Homo) Squares = Species (sapiens)

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure SPECIES Felis catus (domestic cat) Mephitis mephitis (striped skunk) Lutra lutra (European otter) Canis familiaris (domestic dog) Canis lupus (wolf) Felis GENUS FAMILY ORDER MephitisLutraCanis CanidaeMustelidaeFelidae Carnivora

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Homologous structures are evidence that organisms have evolved from a common ancestor (human arm, whale flipper) In contrast, analogous similarities are evidence that organisms from different evolutionary lineages have undergone convergent evolution (shark and dolphin) –Their resemblances have resulted from living in similar environments –Example: A bat wing and a bee wing (they are NOT homologous, they are analogous) Homology vs. Analogy

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Systematists increasingly use molecular techniques to –classify organisms –develop phylogenetic hypotheses –Protein sequences, DNA, and RNA of different organisms are compared to determine relationships Molecular Biology Figure 15.12B HumanChimpanzeeGorillaOrangutan

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Clades are evolutionary branches that consist of a common ancestor and all the organisms that evolved from it. A phylogenic tree based on cladistic analysis is called a cladogram Cladistic Analysis

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Quick Review Key terms Phylogeny is the evolutionary history of a species or group of species. Systematics is the analytical approach to understanding the diversity and relationships of organisms. Molecular Systematics compares DNA and RNA of different organisms to determine evolutionary relationships

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings For several decades, systematists have classified life into five kingdoms THE DOMAINS OF LIFE Figure 15.14A MONERAPROTISTAPLANTAEFUNGIANIMALIA Earliest organisms: Bacteria

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 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 BACTERIAARCHAEAEUKARYA Earliest organisms

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The mammalian order Primates includes: humans, apes, monkeys, and lemurs –We all share a common ancestor that lived 65 million years ago PRIMATE DIVERSITY

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 19.1E Millions of years ago PROSIMIANSANTHROPOIDS MONKEYSAPES Lemurs, lorises, and pottos Tarsiers New World monkeys Old World monkeys Gibbons Orangutans Gorillas Chim- panzees Humans ANCESTRAL PRIMATE

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Reproductive Barriers Reproductive Barriers prevent members of different species from producing viable, fertile offspring. (there are 2 types) 1. Prezygotic barriers: impede mating or hinder fertilization if mating does occur (BEFORE zygote forms) 2.Postzygotic barriers: prevent a hybrid zygote from developing into a viable, fertile adult (AFTER zygote forms)

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Prezygotic Barriers 1. Habitat isolation: 2 species live in different habitats and don’t see each other 2. Temporal isolation: 2 species breed at different times of the day or year 3. Behavioral isolation: courtship rituals are species specific, and don’t attract other species 4. Mechanical isolation: the sexual pieces don’t fit together 5. Gametic isolation: even if sex occurs, the egg and sperm can’t meet

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Postzygotic barriers 1. Reduced hybrid viability: hybrid babies die before reaching reproductive age 2. Reduced hybrid fertility: hybrid babies are sterile and can’t reproduce 3. Hybrid breakdown: first generation babies can breed, but their children are infertile (F2)

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings How do new species form? Allopatric speciation: “other country,” a population is geographically divided into 2 isolated subpopulations, which eventually become 2 new species Sympatric speciation: “same country,” 2 new species develop in the same area –Mutations such as polyploidy (extra set of chromosomes) –Habitat differentiation –Sexual selection

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Adaptive Radiation Adaptive radiation: the evolution of many diversely adapted species from a common ancestor upon introduction to various new environmental opportunities and challenges Example: Hawaiian plants

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Extras Punctuated equilibrium: lots of new species appear all at once in history (Cambrian explosion) Heterochrony: an evolutionary change in the rate or timing of developmental events