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Ch 26: The Tree of Life-An Intro to Biological Diversity
What do you know about the origins of life on Earth? Earth is 4.6 billion yrs old (byo) Oldest rocks – 3.8 byo – Greenland Oldest fossils – 3.5 byo How was primitive Earth different than current Earth? Little O2, much H2O, CH4, CO, CO2 Lightning Volcanic activity UV radiation Meteorite bombardment How do we get “the living” from “the non-living?” 1920’s Oparin & Haldane postulated early Earth favored rxns that formed organic cmpds from inorganic cmpds 1953 Miller-Urey experiment test Oparin & Haldane’s hypothesis
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Figure 26.2 Can organic molecules form in a reducing atmosphere?
Repeated experiments have formed All 20 amino acids several sugars lipids purines & pyrimindines ATP (when phosphate is added) ALL MONOMERS
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Ch 26: The Tree of Life-An Intro to Biological Diversity
What do you know about the origins of life on Earth? How was primitive Earth different than current Earth? How do we get “the living” from “the non-living?” 1920’s Oparin & Haldane postulated early Earth favored rxns that formed organic cmpds from inorganic cmpds 1953 Miller-Urey experiment test Oparin& Haldane’s hypothesis How were monomers connected to make polymers? Sydney Fox dripped monomers on hot sand, clay or rocks Created proteinoids – polypeptides created by abiotic means What’s next? Protobionts – abiotically produced molecules surrounded by a membrane Primitive cells Coacervate – stable protobiont droplet that self-assembles when a suspension of macromolecules is shaken Imprecise reproduction Simple metabolism & excitability (similar to neurons) How does natural selection fit in? - Protobionts best suited to their environment could reproduce & create others best suited to their environment
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Figure 26.4 Laboratory versions of protobionts
20 m (a) Simple reproduction. This lipo- some is “giving birth” to smaller liposomes (LM). (b) Simple metabolism. If enzymes—in this case, phosphorylase and amylase—are included in the solution from which the droplets self-assemble, some liposomes can carry out simple metabolic reactions and export the products. Glucose-phosphate Phosphorylase Starch Amylase Maltose Phosphate
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Ch 26: The Tree of Life-An Intro to Biological Diversity
What do you know about the origins of life on Earth? How was primitive Earth different than current Earth? How do we get “the living” from “the non-living?” How were monomers connected to make polymers? What’s next? Protobionts – abiotically produced molecules surrounded by a membrane Primitive cells Imprecise reproduction Simple metabolism & excitability (similar to neurons) How does natural selection fit in? Protobionts best suited to their environment could reproduce & create others best suited to their environment What was the first genetic material? RNA – single stranded Ribozymes – can replicate RNA
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Figure 26.5 A ribozyme capable of replicating RNA
(RNA molecule) Template Nucleotides Complementary RNA copy 3 5 Collections of RNA molecules best suited for their environment replicate their RNA & reproduce mRNA, rRNA, tRNA
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Ch 26: The Tree of Life-An Intro to Biological Diversity
What do you know about the origins of life on Earth? How was primitive Earth different than current Earth? How do we get “the living” from “the non-living?” How were monomers connected to make polymers? What’s next? Protobionts – abiotically produced molecules surrounded by a membrane Primitive cells Imprecise reproduction Simple metabolism & excitability (similar to neurons) How does natural selection fit in? Protobionts best suited to their environment could reproduce & create others best suited to their environment What was the first genetic material? RNA – single stranded Ribozymes – can replicate RNA Natural selection over millions of years led to a diversity of the 1st prokaryotes Diversity of organisms led to classification
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Figure 26.22 One current view of biological diversity
Proteobacteria Chlamydias Spirochetes Cyanobacteria Gram-positive bacteria Korarchaeotes Euryarchaeotes, crenarchaeotes, nanoarchaeotes Diplomonads, parabasalids Euglenozoans Alveolates (dinoflagellates, apicomplexans, ciliates) Stramenopiles (water molds, diatoms, golden algae, brown algae) Cercozoans, radiolarians Red algae Chlorophytes Charophyceans Domain Archaea Domain Eukarya Universal ancestor Domain Bacteria Chapter 27 Chapter 28
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Chapter 29 Chapter 30 Chapter 28 Chapter 31 Chapter 32 Chapters 33, 34
Bryophytes (mosses, liverworts, hornworts) Plants Fungi Animals Seedless vascular plants (ferns) Gymnosperms Angiosperms Amoebozoans (amoebas, slime molds) Chytrids Zygote fungi Arbuscular mycorrhizal fungi Sac fungi Club fungi Choanoflagellates Sponges Cnidarians (jellies, coral) Bilaterally symmetrical animals (annelis, arthropods, molluscs, echinoderms, vertebrate) Chapter 29 Chapter 30 Chapter 28 Chapter 31 Chapter 32 Chapters 33, 34
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