MacroEvolution: Large Scale Changes Over Time Figure 25.1 What does fossil evidence say about where these dinosaurs lived?

Deep Sea Vents Figure 25.2 A window to early life?

Protobionts May Have Formed Spontaneously Glucose-phosphate Glucose-phosphate Phosphatase Starch Amylase Phosphate Maltose Figure 25.3 Laboratory versions of protobionts (a) Simple reproduction by liposomes Maltose (b) Simple metabolism

Sedimentary Rock Strata -- Fossils Present Rhomaleosaurus victor, a plesiosaur Dimetrodon 100 million years ago Casts of ammonites 175 200 270 300 4.5 cm Hallucigenia 375 Coccosteus cuspidatus 400 1 cm Figure 25.4 Documenting the history of life Dickinsonia costata 500 525 2.5 cm 565 Stromatolites 600 Tappania, a unicellular eukaryote Fossilized stromatolite 3,500 1,500

1/2 1/4 1/8 1/16 Radiometric Dating Accumulating “daughter” isotope Fraction of parent isotope remaining 1/2 Remaining “parent” isotope 1/4 Figure 25.5 Radiometric dating 1/8 1/16 1 2 3 4 Time (half-lives)

Evolution of Mammals Synapsid (300 mya) Temporal fenestra Key Articular Dentary Quadrate Squamosal Therapsid (280 mya) Reptiles (including dinosaurs and birds) Temporal fenestra EARLY TETRAPODS Dimetrodon Early cynodont (260 mya) Synapsids Temporal fenestra Very late cynodonts Earlier cynodonts Therapsids Figure 25.6 The origin of mammals Later cynodont (220 mya) Mammals Very late cynodont (195 mya)

Geologic Record Table 25.1

Geologic Time Table Humans Colonization of land Animals Ceno- zoic Meso- zoic Humans Paleozoic Colonization of land Animals Origin of solar system and Earth 1 4 Proterozoic Archaean Prokaryotes Figure 25.7 Clock analogy for some key events in Earth’s history Billions of years ago 2 3 Multicellular eukaryotes Single-celled eukaryotes Atmospheric oxygen

About 2.7 billion years ago, O2 began accumulating in the atmosphere and rusting iron-rich terrestrial rocks. Figure 25.8 Banded iron formations: evidence of oxygenic photosynthesis For the Discovery Video Early Life, go to Animation and Video Files.

Invagination of Plasma Membrane Cytoplasm Plasma membrane DNA Ancestral prokaryote Endoplasmic reticulum Nucleus Figure 25.9 A model of the origin of eukaryotes through serial endosymbiosis Nuclear envelope

Aerobic heterotrophic prokaryote Mitochondrion Ancestral heterotrophic Serial Endosymbiosis Aerobic heterotrophic prokaryote Mitochondrion Ancestral heterotrophic eukaryote Figure 25.9 A model of the origin of eukaryotes through serial endosymbiosis

Ancestral photosynthetic eukaryote Serial Endosymbiosis Photosynthetic prokaryote Mitochondrion Plastid Figure 25.9 A model of the origin of eukaryotes through serial endosymbiosis Ancestral photosynthetic eukaryote

Endosymbiotic Sequence: Cytoplasm DNA Ancestral Prokaryote Invagination of Plasma Membrane Endoplasmic reticulum Nucleus Nuclear envelope Serial Endosymbiosis: Aerobic heterotrophic prokaryote Photosynthetic prokaryote Mitochondrion Figure 25.9 A model of the origin of eukaryotes through serial endosymbiosis Mitochondrion Ancestral heterotrophic eukaryote Plastid Ancestral photosynthetic eukaryote

Cambrian Explosion Sponges Cnidarians 500 Annelids Molluscs Chordates Arthropods Echinoderms Brachiopods Early Paleozoic era (Cambrian period) Millions of years ago 542 Figure 25.10 Appearance of selected animal phyla Late Proterozoic eon

(a) Two-cell stage (b) Later stage 150 µm 200 µm Proterozoic Fossils that may be animal embryos (SEM) Figure 25.11 Proterozoic fossils that may be animal embryos (SEM) (a) Two-cell stage (b) Later stage 150 µm 200 µm

Earth - Plate Tectonics: Continental Drift North American Plate Eurasian Plate Crust Juan de Fuca Plate Caribbean Plate Philippine Plate Arabian Plate Indian Plate Mantle Cocos Plate Pacific Plate South American Plate Nazca Plate Outer core African Plate Australian Plate Inner core Figure 25.12 Earth and its continental plates Scotia Plate Antarctic Plate (a) Cutaway view of Earth (b) Major continental plates

History of Continental Drift Present Cenozoic North America Eurasia 65.5 Africa South America India Madagascar Australia Antarctica Laurasia 135 Mesozoic Millions of years ago Gondwana Figure 25.13 The history of continental drift during the Phanerozoic eon 251 Pangaea Paleozoic

(families per million years): Five Big Mass Extinctions 20 800 700 15 600 500 Number of families: (families per million years): Total extinction rate 10 400 300 5 200 100 Figure 25.14 Mass extinction and the diversity of life Era Period Paleozoic Mesozoic Cenozoic E O S D C P Tr J C P N 542 488 444 416 359 299 251 200 145 65.5 Time (millions of years ago)

Evidence of Meteroite Impact NORTH AMERICA Chicxulub crater Yucatán Peninsula Figure 25.15 Trauma for Earth and its Cretaceous life For the Discovery Video Mass Extinctions, go to Animation and Video Files.

World-Wide Adaptive Radiations Ancestral mammal Monotremes (5 species) ANCESTRAL CYNODONT Marsupials (324 species) Eutherians (placental mammals; 5,010 species) Figure 25.17 Adaptive radiation of mammals 250 200 150 100 50 Millions of years ago

Hawaiian Islands -- Regional Adaptive Radiations Close North American relative, the tarweed Carlquistia muirii KAUAI 5.1 million years MOLOKAI 1.3 million years Dubautia laxa MAUI OAHU 3.7 million years Argyroxiphium sandwicense LANAI HAWAII 0.4 million years Figure 25.18 Adaptive radiation on the Hawaiian Islands Dubautia waialealae Dubautia scabra Dubautia linearis

Allometric Growth Figure 25.19 Relative growth rates of body parts Newborn 2 5 15 Adult Age (years) (a) Differential growth rates in a human Figure 25.19 Relative growth rates of body parts Chimpanzee fetus Chimpanzee adult Human fetus Human adult (b) Comparison of chimpanzee and human skull growth

Gills Paedomorphosis - Juvenile Gills Retained by Adult Salamander Figure 25.20 Paedomorphosis

Hypothetical vertebrate ancestor (invertebrate) Hox Genes Alterations Hypothetical vertebrate ancestor (invertebrate) with a single Hox cluster First Hox duplication Hypothetical early vertebrates (jawless) with two Hox clusters Second Hox duplication Figure 25.21 Hox mutations and the origin of vertebrates Vertebrates (with jaws) with four Hox clusters

Hox gene 6 Hox gene 7 Hox gene 8 Ubx About 400 mya Drosophila Artemia Changes in developmental genes can result in new morphological forms Hox gene 6 Hox gene 7 Hox gene 8 Ubx About 400 mya Figure 25.22 Origin of the insect body plan Drosophila Artemia

Evolution: new forms arise by the slight modification of existing forms Pigmented cells (photoreceptors) Pigmented cells Epithelium Nerve fibers Nerve fibers (a) Patch of pigmented cells (b) Eyecup Fluid-filled cavity Cellular mass (lens) Cornea Epithelium Optic nerve Pigmented layer (retina) Optic nerve (c) Pinhole camera-type eye (d) Eye with primitive lens Figure 25.24 A range of eye complexity among molluscs Cornea Lens Retina Optic nerve (e) Complex camera-type eye

Horse Evolution Figure 25.25 The branched evolution of horses Recent (11,500 ya) Equus Hippidion and other genera Pleistocene (1.8 mya) Nannippus Pliohippus Pliocene (5.3 mya) Hipparion Neohipparion Sinohippus Megahippus Callippus Archaeohippus Miocene (23 mya) Merychippus Anchitherium Hypohippus Parahippus Miohippus Oligocene (33.9 mya) Figure 25.25 The branched evolution of horses Mesohippus Paleotherium Epihippus Propalaeotherium Eocene (55.8 mya) Pachynolophus Orohippus Key Grazers Hyracotherium Browsers

The appearance of an evolutionary trend does not imply that there is some intrinsic drive toward a particular phenotype 1.2 bya: First multicellular eukaryotes 535–525 mya: Cambrian explosion (great increase in diversity of animal forms) 500 mya: Colonization of land by fungi, plants and animals 2.1 bya: First eukaryotes (single-celled) 3.5 billion years ago (bya): First prokaryotes (single-celled) 500 4,000 3,500 3,000 2,500 2,000 1,500 1,000 Present Millions of years ago (mya)

You should now be able to: Define radiometric dating, serial endosymbiosis, Pangaea, snowball Earth, exaptation, heterochrony, and paedomorphosis. Describe the contributions made by Oparin, Haldane, Miller, and Urey toward understanding the origin of organic molecules. Explain why RNA, not DNA, was likely the first genetic material.

Describe and suggest evidence for the major events in the history of life on Earth from Earth’s origin to 2 billion years ago. Briefly describe the Cambrian explosion. Explain how continental drift led to Australia’s unique flora and fauna. Describe the mass extinctions that ended the Permian and Cretaceous periods. Explain the function of Hox genes.