Transcript Chapter 3
Chapter 3 The Diversity of Life 1 Guiding Questions • What are fossils? • How do scientists arrange organisms in natural groups? • What is the most fundamental taxonomic division of life? • What kinds of organisms constitute the Protista and Fungi? 2 Fossils • Tangible remains or signs of ancient organisms • Found mostly in sedimentary rocks (why?) or sediments, especially marine sediments • Thousands to millions of years old Nautilus 3 Fossils • Most fossils are hard parts of organism – – – – Teeth, skeleton Earthworm setae Insect mandibles Crinoid (left)- ‘sea lily’ that is actually an animal with a CaCO3 skeleton. 4 Fossils • Hard parts may be completely replaced by minerals • This crinoid’s CaCO3 skeleton has been completely replaced by pyrite (fool’s gold). 5 Fossils • Fossilization of soft parts is rare – Requires oxygen-poor environment – Burial in fine-grained sediment • Permineralization – Infilling of woody tissue by inorganic materials – Petrified wood 6 Petrified Wood 7 Fossils • Fossil need not be skeletal • Mold – 3-D negative imprint Brachiopod fossils (left): S = shell M = mold 8 Fossils • Impressions – 2-D preservation of outlines and surface features • Carbonization (left) – Concentrated residue of remaining carbon 9 Fossils • Trace fossils – Tracks/trackways – Trails – Burrows • Provides behavioral information about extinct animals (how?) 10 Fossils • Fossils provide biased view of biota – Not all organisms are preserved (over-/underrepresented) • Rare organisms • Lacking hard parts – Not all skeletal material is preserved • Scavengers • Transport and abrasion • Post-burial alteration of rock – Not all fossils are exposed at the surface – Some are destroyed by plate tectonics, metamorphism, etc. 11 Putative Jellyfish fossils 12 The Current Hotspot American/Mongolian team excavating an ankylosaur fossil in the Gobi Desert in Mongolia. 13 Buy Fossils Now! • eBay http://www.ebay.com • http://www.arizonaskiesmeteorites.com/Din osaur_Fossils_For_Sale/ 14 Taxonomy 15 Human Genealogy (Who else is hanging around in your family tree?) 16 Taxonomic Scheme • • • • • • • Kingdom Phylum Class Order Family Genus Species 17 Taxonomic Scheme • • • • • • • Karl Plays Cards Only For Green Stamps 18 Taxonomic Scheme • • • • • • • Kids Prefer Candy Over Fat Gooey Snails 19 Taxonomic Scheme • • • • • • • • Kingdom Phyum Sub-phylum Class Order Family Genus Species - Animal - Chordate - Vertebrate - Mammal - Primate - Hominid - Homo - Homo sapiens 20 More Mnemonics • • • • • • • • Animalia Chordata Vertebrata Mammalia Primata Hominid Homo Homo sapiens • • • • • • • • Ana Caught Vince Making Piping Hot Ham Sandwiches 21 • • • • • • • • Animalia Chordata Vertebrata Mammalia Primata Hominid Homo Homo sapiens • • • • • • • • A chocolate valentine may produce hot and heavy sweethearts 22 • • • • • • • • Animalia Chordata Vertebrata Mammalia Primata Hominid Homo Homo sapiens • • • • • • • • A crystal vase might possibly hold hybrid sunflowers 23 • • • • • • • • Animalia Chordata Vertebrata Mammalia Primata Hominid Homo Homo sapiens • • • • • • • • Amy cutout valentines for Ma, Pa, her husband and sister 24 Chordates 25 Fish Amphibian 26 Reptile Mammal 27 Birds 28 Primates Baboon Prosimian 29 The Pinnacle of Evolution? 30 Other Hominids? Bigfoot Sasquatch Jersey Devil Abominable Snowman 31 Other Hominids? Neanderthal Homo habilis Homo erectus 32 Taxonomic Groups • Six kingdoms – Prokaryotes • Archaeobacteria • Eubacteria – Eukaryotes • • • • Plantae-producers Fungi-consumers Animalia-consumers Protista 33 Taxonomic Groups • Taxonomy – Study of composition and relationship of the taxonomic groups • Taxonomic groups – The six kingdoms and their subordinate groups – Taxon/taxa 34 Taxonomic Groups • Linnaean taxa range from broad (phylum) to narrow (species) – Phylum-one of the major categories of organisms – Species • Group of individuals that can interbreed • Name includes genus • Italicized or underlines • Class Mammalia – Order primates 35 Taxonomic Groups • Phylogeny – “tree of life” – structure formed by branches of species • Cluster into groups with similar traits, equivalent to taxa – Genus (genera) • small clusters 36 Taxonomic Groups • Clade – Cluster of species that share a common ancestry and have homologous structures – All species within each clade must be traceable to a common ancestor; must be monophyletic • Cladistics • Homologous-structures derived from the same “blueprint” of common ancestry. 37 Taxonomic Groups • Primitive traits – appear early in evolutionary history; relatively unchanged – hagfish group traits • Derived traits – evolved later; often much changed from ancestral forms – present only in some subgroups – jaws, lungs, claws or nails, feather, fur, and mammary glands 38 Taxonomic Groups • Horse ancestry – Detailed phylogeny due to abundant fossil record • Three clades – Subfamilies • All members of the modern horse family belong to Equus and originated in North America 39 Prokaryotes • Bacteria (bacterium), as a group, gain nutrition in a variety of ways – photosynthetic – chemosynthetic – consumers • As a group, at least 3 billion years old 40 Prokaryotes • Archaeobacteria – Can tolerate extreme conditions-extremophiles • very high temperatures – hot springs • low or no oxygen • acidic conditions 41 Prokaryotes • Eubacteria – divided by structure of cell walls – Cyanobacteria • photosynthetic – spherical or filamentous • can form mats or scum 42 Protista • Many single celled organisms • Some simple multicellular organisms • Includes Algae – “seaweeds” Amoeba 43 Protista • Protozoans – Animal-like protists • Amoebas – change shape; no rigid form • Flagellates – flagellum for locomotion • Ciliates – cilia for locomotion 44 Protista • Unicellular algae – plant-like protists • Dinoflagellates • Diatoms • Calcareous nannoplankton • Originated in the Mesozoic Era – among the most important marine producers 45 Protista • Dinoflagellates – two flagella for locomotion • drift – dormancy • armor in a cyst • often fossilized as cysts 46 Protista • Diatoms – Two-part skeleton of opal (SiO2) • Halves fit together – Freshwater and marine • Most planktonic • Some benthic – Accumulations can produce diatomaceous earth and chert 47 Protista • Calcareous Nannoplankton – Small spherical cells – Armored • overlapping plates of calcium carbonate – Mostly marine plankton • Accumulations can produce chalk 48 Protista • Multi-cellular algae – Much drifts – Some attaches to seafloor • Some red and green algae secrete calcium carbonate skeletons – limestone 49 Protista • Protozoans with skeletons – Foraminifera • Chambered skeleton of calcium carbonate • Very abundant • Useful for dating rocks and sediments 50 Protista • Protozoa with skeletons • Radiolarians – Skeleton made out of opal (SiO2) – Related to foraminifera 51 Fungi • Decomposers – Obtain nutrients from dead organisms • Diverse – Yeast – Mushroom • Poor fossil record 52 Plants • Differ from multicellular green algae – Internal fertilization of egg – Tissue • Vascular – Vessels for transport of water, dissolved nutrients, food • Non-vascular – Transportation of materials by diffusion • moss 53 Plants • Seedless Vascular Plants – Evolved first – Psilotum • Simplest vascular plant • No leaves or roots • Similar to earliest fossil forms 54 Plants • Ferns – Roots and leaves – Alternation of generations • Spore-producing then spermproducing generation – Spores • One set of chromosomes • Fertilized by sperm • Requires moisture – Vast Late Paleozoic swamps led to coal formation 55 Plants • Gymnosperms – “Naked seed” plants – Conifers • Cone-bearing plants • Eggs are fertilized in cone by pollen – Pollen bears sperm; carried by wind • Dominant in the Mesozoic • Angiosperms – Flowering plants • Pollen carried by pollinators (animals) 56 Animals • Two groups – Vertebrates • Possess a backbone – Invertebrates • Coelom – Body cavity housing internal organs • Protostomes – First opening becomes the mouth • Deuterostomes – First opening becomes the anus 57 Animals • Sponges – Simple invertebrates – Suspension feeds • Strain particles from water • Mostly eat bacteria • Flagella pump water through internal canals – Calcium carbonate or silica spicules support structure • Cambrian - modern 58 Cnidarians • Jellyfish and corals • Radial symmetry • Inner and outer body layer – Jelly-like layer in between • Use tentacles to catch prey – Stinging cells • Sexual and asexual reproduction 59 Protostome Invertebrate • Segmented worms – Fluid-filled coelom • Primitive skeleton – Each segment has own coelomic cavity • Expand, contract for movement 60 Arthropods • Insects, crabs, spiders, lobsters, trilobites • Trilobite – Three-lobed body • Central, left-and rightlobed – External skeleton – Gill-like structure for respiration – Legs – Primitive eyes • Common in Cambrian 61 Arthropods • Crustaceans – Head of five fused segments – Thorax and abdomen – Weakly calcified exoskeleton • Insects – – – – Head, thorax, abdomen Two pairs of wings Poor fossil record Precede angiosperms 62 Arthropods • Onychophorans – Intermediate between segmented worms and arthropods – Early forms • Marine • Nearly to base of Paleozoic – Modern forms • terrestrial 63 Mollusks • Clams, snails, octopuses – Shell of aragonite, calcite, or both – Mantle • Fleshy, sheetlike organ • Secretes shell – Radula • File-like structure for food – Base of Cambrian • Monoplacophorans – Primitive mollusks 64 Mollusks • Gastropods – Snails – Marine and freshwater – Terrestrial • Lung – Most grazers • Some suspension feeders – Beginning of Paleozoic 65 Mollusks • Cephalopods – Squids, octopuses, chambered nautiluses – Swim in the sea • Jet propulsion • Eyes – Carnivores • Catch with tentacles • Eat with strong beak • Chambered nautilus – Buoyancy due to gas in shell • Common in Phanerozoic 66 Mollusks • Clams, mussels, oysters, scallops – – – – Shell divided into two valves No head or radula Muscles pull shell together Suspension feeders mostly 67 Lophophores • Brachiopods – Shell divided into two valves – Lampshells – Lophophores • Pump water • Strain food – Inarticular brachiopods • Lack hinge teeth • Lingula – Articulate brachiopods 68 Bryozoans • Moss animals • Colonial • Closely related to brachiopods – Lophophore extended from skeleton to feed – Calcified skeleton • Ordovician 69 Echinoderms • Spiny-skinned form • Five-fold symmetry – Starfishes • Predators • Lower Paleozoic – Sea urchins • Regular sea urchins – Radially symmetrical bodies • Irregular sea urchins – Bilaterally symmetric – Burrowers 70 Echinoderms • Crinoids – Sea lilies – Sieve food using arms • Pass food to mouth with tube feet – May swim – May be attached by flexible stalk – Disk-shaped plates from stalk 71 Chordates • Notochord – Flexible, rodlike structure • Runs length of body • Supports body – For some part of lifecycle – Spinal cord • Runs next to notochord • Primitive Chordate – Lancet • Notochord is skeleton • Can swim • Usually rests 72 Vertebrates • Notochord develops into vertebral column – Usually bony – Cartilage in sharks 73 Conodonts • “Cone-teeth” – Originally thought to be teeth of a marine animal • Later determined to be eel-like fish and a vertebrate 74 Vertebrates • Fishes – Ray-finned fishes • Fins supported by thin bones radiating from body – Lobe-finned fishes • Evolved into amphibians • Coelacanth – Discovered in 1939 • Amphibians – First to live on land as adults – Metamorphosis 75 Vertebrates • Reptiles – Eggs with protective shells – Ectothermic • Environment controls internal body temperature • Dinosaurs • Birds – Endothermic 76 Vertebrates • Mammals – Endothermic; Hair – Bear live young – Montreme • Lay eggs – Marsupial • Offspring develop in pouch – Placental • Therapsids – Ancestral mammals – Arose in Mesozoic 77 78 79