essential knowledge 1.b.2 – phylogenetic trees and cladograms are graphical representations...

Download Essential Knowledge 1.b.2 – Phylogenetic trees and cladograms are graphical representations (models) of evolutionary history that can be tested (26.1-26.3)

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Slide 2 Essential Knowledge 1.b.2 Phylogenetic trees and cladograms are graphical representations (models) of evolutionary history that can be tested (26.1-26.3). 1.d.2 Scientific evidence from many different disciplines supports models of the origin of life (26.6). Slide 3 Phylon = tribe, geny = genesis or origin The evolutionary history of a species or a group of related species Found in fossils and the fossil record Slide 4 Any preserved remnant or impression of a past organism. Types: 1. Mineralized 2. Organic matter 3. Trace 4. Amber Slide 5 Found in sedimentary rock. Minerals replace cell contents. Ex: bone, teeth, shells Retain the original organic matter Ex: plant leaves trapped in shale Comment can sometimes extract DNA from these fossils Slide 6 Footprints and other impressions No organic matter present Fossil tree resin Preserve whole specimen Usually small insects, etc Slide 7 Rare event Hard to find Fragmentary Dating Slide 8 1. Relative - by a fossil's position in the strata relative to index fossils 2. Absolute - approximate age on a scale of absolute time 2. 2 types: 1. Radioactive Estimated from half-life products Ex: Carbon 14, Potassium 40 2. Isomer Ratios Slide 9 That the geographical distribution of organisms has changed over time Reason? The land formations of the earth have changed through continental drift Slide 10 The movement of the earth's crustal plates over time Drift is correlated with events of mass extinctions and adaptive radiations of life Slide 11 250 million years ago One super continent Many life forms brought into contact with each other Result: Geographic isolation New environments formed, others lost As environments changed, so did life! Slide 12 Mass Extinctions The sudden loss of many species in geologic time May be caused by asteroid hits or other disasters Result: Area open for surviving species to exploit Rapid period of speciation (adaptive radiation) Many new species are formed in short amount of time Slide 13 The study of biological diversity. Uses evidence from the fossil record and other sources to reconstruct phylogeny. Goal: To have Taxonomy reflect the evolutionary affinities or phylogeny of the organisms. Slide 14 Areas of Systematics 1. Phylogeny- tracing of evolutionary relationships 2. Taxonomy- the identification and classification of species Slide 15 Natural to humans. Modern system developed by Linnaeus in the 18 th century. Includes: 1.Binomial nomenclature: naming system Ex: Homo sapiens 2.Hierarchical system: arranges life into groups Ex: Kingdom species Slide 16 Levels Kingdom Phylum Class Order Family Genus Species Slide 17 Question? How do we relate Taxonomy to evolution? Not all likeness is inherited from a common ancestor. Problem is of homology vs. analogy Slide 18 Homology and Analogy Homology likeness attributed to shared ancestry (divergent and parallel evolution) Ex: forelimbs of vertebrates Analogy likeness due to convergent evolution (not necessarily a shared ancestral lineage) Ex: wings of insects and birds Slide 19 Convergent Evolution When unrelated species have similar adaptations to a common environment Ex: Sharks and dolphins fins; wings of bats, butterflies and birds Slide 20 Taxonomy and Evolution We need methods to group organisms by anatomical similarities and phylogenies One possible method is Molecular Systematics Compares similarities at the molecular level Ex: DNA, Proteins Slide 21 DNA Comparisons A direct measure of common inheritance The more DNA in common, the more closely related Methods: Restriction Mapping DNA Sequencing Slide 22 Protein Comparisons Examines the Amino Acid sequence of homologous proteins. Ex: Cytochrome C Study Slide 23 Molecular Clock Compares molecular differences to fossil records Result is a way to estimate divergence in species where the fossil record is missing Slide 24 Chapter 25: The History of Life on Earth Slide 25 Essential Knowledge 1.a.4 Biological evolution is supported by scientific evidence from many disciplines, including mathematics (25.2). 1.b.1 Organisms share many conserved core processes and features the evolved and are widely distributed among organisms today (25.1, 25.3). 1.c.1 Speciation and extinction have occurred throughout the Earths history (25.4). Slide 26 Essential Knowledge, Continued 1.d.1 There are several hypotheses about the natural origin of life on Earth, each with supporting scientific evidence (25.1 & 25.3). 4.b.4 Distribution of local and global ecosystems changes over time (25.4). Slide 27 Fossil Record Earliest - 3.5 billion years old Earth - 4.5 billion years old Point - Life on earth started relatively soon after the earth was formed Slide 28 Chemical Evolution Def the evolution of life by abiogenesis Steps: 1. Monomer Formation 2. Polymer Formation 3. Protobiont Formation 4. Origin of Heredity Slide 29 Primitive Earth Conditions Reducing atmosphere present Simple molecules Ex: H 2 O, CH 4, H 2, NH 3 Complex molecule formation: Requires an energy source UV Radioactivity Heat Lightning/Electricity Slide 30 Oparin and Haldane, 1920s Hypothesized steps of chemical evolution from primitive earth conditions Slide 31 Miller and Urey, 1953 Tested Oparin and Haldanes hypothesis Experiment - to duplicate primitive earth conditions in the lab Results: Organic monomers formed (include amino acids) Slide 32 Other Investigator's Results All 20 Amino Acids found Others Sugars Lipids Nucleotides ATP Slide 33 Hypothesis Early earth conditions could have formed monomers for life's origins These early monomers eventually joined together to form large, complex polymers Slide 34 Genetic Information DNA RNA Protein Too complex for early life Were there other forms of genetic information? Slide 35 RNA Hypothesis RNA as early genetic information Rationale RNA polymerizes easily RNA can replicate itself RNA can catalyze reactions including protein synthesis Slide 36 Ribozymes RNA catalysts found in modern cells Could be a possible relic from early evolutionary processes Slide 37 DNA hypothesis Developed later as the genetic information Why? More stable than RNA Slide 38 Classification Kingdom: Highest Taxonomic category Old system: 2 Kingdoms 1. Plant 2. Animal Slide 39 5 Kingdom System R.H. Whittaker - 1969 System most widely used today Use three main characteristics to categorize: 1. Cell type 2. Structure 3. Nutrition mode Slide 40 Monerans Ex: Bacteria, Cyanobacteria Prokaryotic Ex: Amoeba, paramecium Eukaryotic cells Unicellular or colonial Heterotrophs Protists Slide 41 Fungi Ex: Mushrooms, Molds Eukaryotic Unicellular or Multicellular Heterotrophic - external digestion Cell wall of chitin Slide 42 Plantae Ex: Flowers, Trees Eukaryotic Multicellular Autotrophic Cell wall of Cellulose/Silicon Slide 43 Animalia Ex: Animals, Humans Eukaryotic Multicellular Hetrotrophic - internal digestion No cell wall Slide 44 Other Systems Multiple Kingdoms split life into as many as 8 kingdoms Domains a system of classification that is higher than kingdom Based on molecular structure for evolutionary relationships Gaining wider acceptance Slide 45 3 Domains 1. Bacteria prokaryotic 2. Archaea prokaryotic, but biochemically similar to eukaryotic cells 3. Eucarya the traditional eukaryotic cells Slide 46 Summary Identify the steps of Chemical Evolution Recognize the conditions on early Earth. Recognize the limitations of the fossil record. Recognize some of the key events in the history of Earth.