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Chapter 3. The Diversity of Life. 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? . Fossils.
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Chapter 3 The Diversity of Life
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?
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
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.
Fossils • Hard parts may be completely replaced by minerals • This crinoid’s CaCO3 skeleton has been completely replaced by pyrite (fool’s gold).
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
Fossils • Fossil need not be skeletal • Mold • 3-D negative imprint Brachiopod fossils (left): S = shell M = mold
Fossils • Impressions • 2-D preservation of outlines and surface features • Carbonization (left) • Concentrated residue of remaining carbon
Fossils • Trace fossils • Tracks/trackways • Trails • Burrows • Provides behavioral information about extinct animals (how?)
Fossils • Fossils provide biased view of biota • Not all organisms are preserved (over-/under-represented) • 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.
The Current Hotspot American/Mongolian team excavating an ankylosaur fossil in the Gobi Desert in Mongolia.
Buy Fossils Now! • eBay http://www.ebay.com • http://www.arizonaskiesmeteorites.com/Dinosaur_Fossils_For_Sale/
Human Genealogy (Who else is hanging around in your family tree?)
Taxonomic Scheme • Kingdom • Phylum • Class • Order • Family • Genus • Species
Taxonomic Scheme • Karl • Plays • Cards • Only • For • Green • Stamps
Taxonomic Scheme • Kids • Prefer • Candy • Over • Fat • Gooey • Snails
Taxonomic Scheme • Kingdom - Animal • Phyum - Chordate • Sub-phylum - Vertebrate • Class - Mammal • Order - Primate • Family - Hominid • Genus - Homo • Species - Homo sapiens
Animalia Chordata Vertebrata Mammalia Primata Hominid Homo Homo sapiens Ana Caught Vince Making Piping Hot Ham Sandwiches More Mnemonics
A chocolate valentine may produce hot and heavy sweethearts Animalia Chordata Vertebrata Mammalia Primata Hominid Homo Homo sapiens
A crystal vase might possibly hold hybrid sunflowers Animalia Chordata Vertebrata Mammalia Primata Hominid Homo Homo sapiens
Amy cutout valentines for Ma, Pa, her husband and sister Animalia Chordata Vertebrata Mammalia Primata Hominid Homo Homo sapiens
Primates Prosimian Baboon
Other Hominids? Bigfoot Sasquatch Jersey Devil Abominable Snowman
Other Hominids? Neanderthal Homo habilis Homo erectus
Taxonomic Groups • Six kingdoms • Prokaryotes • Archaeobacteria • Eubacteria • Eukaryotes • Plantae-producers • Fungi-consumers • Animalia-consumers • Protista
Taxonomic Groups • Taxonomy • Study of composition and relationship of the taxonomic groups • Taxonomic groups • The six kingdoms and their subordinate groups • Taxon/taxa
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
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
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.
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
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
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
Prokaryotes • Archaeobacteria • Can tolerate extreme conditions-extremophiles • very high temperatures • hot springs • low or no oxygen • acidic conditions
Prokaryotes • Eubacteria • divided by structure of cell walls • Cyanobacteria • photosynthetic • spherical or filamentous • can form mats or scum
Protista • Many single celled organisms • Some simple multicellular organisms • Includes Algae • “seaweeds” Amoeba
Protista • Protozoans • Animal-like protists • Amoebas • change shape; no rigid form • Flagellates • flagellum for locomotion • Ciliates • cilia for locomotion
Protista • Unicellular algae • plant-like protists • Dinoflagellates • Diatoms • Calcareous nannoplankton • Originated in the Mesozoic Era • among the most important marine producers
Protista • Dinoflagellates • two flagella for locomotion • drift • dormancy • armor in a cyst • often fossilized as cysts
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
Protista • Calcareous Nannoplankton • Small spherical cells • Armored • overlapping plates of calcium carbonate • Mostly marine plankton • Accumulations can produce chalk
Protista • Multi-cellular algae • Much drifts • Some attaches to seafloor • Some red and green algae secrete calcium carbonate skeletons • limestone
Protista • Protozoans with skeletons • Foraminifera • Chambered skeleton of calcium carbonate • Very abundant • Useful for dating rocks and sediments