Biology Chapter 18: Origin and History of Life (PDF)

Because learning changes everything. ® Biology Sylvia S. Mader...

Because learning changes everything. ® Biology Sylvia S. Mader Michael Windelspecht Chapter 18 Origin and History of Life Lecture Outline See separate FlexArt PowerPoint slides for all figures and tables pre-inserted into PowerPoint without notes. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.  Outline 18.1 The Origin of Life 18.2 The History of Life 18.3 Geological Factors that Influence Evolution © McGraw Hill LLC 2  18.1 Origin of Life The last universal common ancestor (LUCA) is common to all organisms that live, and have lived, on Earth since life began. Today, we say that “life only comes from life.” The molecules of living organisms, called biomolecules, are organic molecules. However, the first cells had to arise from nonliving chemicals, inorganic substances. Studies in chemistry, evolutionary biology, paleontology, microbiology, and other branches of science help scientists develop hypotheses about life’s origins. © McGraw Hill LLC 3  Origin of Life on Earth Life on Earth originated about 3.5–4 billion years ago. Earth’s atmosphere most likely consisted of: Water vapor Nitrogen Carbon dioxide Small amounts of hydrogen, methane, ammonia, hydrogen sulfide, and carbon monoxide Little free oxygen Originally too hot for liquid water to form As the Earth cooled, water vapor condensed to liquid water. © McGraw Hill LLC 4  Four Stages of the Origin of Life Stage 1: Organic monomers (amino acids, nucleotides, etc.) evolved from inorganic compounds. Stage 2: Organic monomers were joined to form organic polymers (DNA, RNA, proteins, etc). Stage 3: Organic polymers became enclosed in membranes to form protocells or protobionts. State 4: Protobionts acquired the ability to self-replicate. Access the text alternative for slide images. Figure 18.1 © McGraw Hill LLC 6  Stage 1: Evolution of Monomers Several hypotheses suggest how monomers evolved. 1. Monomers came from outer space. Comets and meteorites, perhaps carrying organic chemicals, have pelted Earth throughout history. Organic molecules could have seeded the chemical origin of life on Earth. Bacterium-like cells could have been carried to Earth on a meteorite or comet. 2. Monomers came from reactions in the atmosphere. 1. Oparin-Haldane hypothesis (early 1900s) Suggested organic molecules could be formed in the presence of outside energy sources using atmospheric gases 3. Monomers came from reactions at hydrothermal vents. © McGraw Hill LLC 7  Miller and Urey Conducted an experiment in 1953 to test the Oparin-Haldane hypothesis Showed that gases (methane, ammonia, hydrogen, and water) can react with one another to produce small organic molecules (amino acids, organic acids) Strong energy sources Rainfall would have washed organic compounds from the atmosphere into the ocean. They would have accumulated in the ocean, making it an organic soup. © McGraw Hill LLC 8  Stanley Miller’s Experiment Boiler with stopcock for withdrawing liquid is heated where gases move through the tube with stopcock for adding gases. The gases methane, ammonia, hydrogen and water with electric spark (from electrode) are passed to condenser ( with hot water out and cool water in). The liquid droplets form into small organic molecules leading back to boiler. Access the text alternative for slide images. Figure 18.2 © McGraw Hill LLC 9  Iron-Sulfur World Hypothesis: Chemical Evolution at Hydrothermal Vents Figure 18.3 © McGraw Hill LLC Source: Image courtesy of Submarine Ring of Fire 2006 Exploration, NOAA Vents Program 10  Stage 2: Evolution of Polymers In cells, monomers join to form polymers in the presence of enzymes. Iron–Sulfur World Hypothesis It suggests organic molecules reacted with amino acids to form peptides in the presence of iron-nickel sulfides. Protein-First Hypothesis It assumes that protein enzymes arose first. DNA genes came afterwards. Proteinoids are small polypeptides with catalytic properties. When proteinoids are placed in water, they form microspheres, structures made of proteins with many properties of a cell. © McGraw Hill LLC 11  Stage 2: Evolution of Polymers In cells, monomers join to form polymers in the presence of enzymes. RNA-First Hypothesis It suggests only RNA was needed to progress toward formation of the first cell or cells. Some viruses have only RNA genes. DNA genes would have come afterwards. © McGraw Hill LLC 12  Stage 3: Evolution of Protocells Before the first true cell arose, there would have been a protocell or protobiont, the hypothesized precursor to the first true cells. A protocell would have an outer membrane and carry on energy metabolism. Figure 18.4 © McGraw Hill LLC 15  Structure and Growth of the First Plasma Membrane The first plasma membrane likely similar in structure to vesicles. (a) Vesicle cross- section shows fatty acid bilayer of a vesicle membrane. Micelles are spherical droplets formed by a single layer of fatty acids. (b) Under proper conditions, micelles can merge to form vesicles. Figure 18.5 © McGraw Hill LLC 17  Membrane-first hypothesis states first cell had to have a plasma membrane before any of its other parts. If lipids are made available to microspheres, lipids become associated with microspheres, producing a lipid-protein membrane. Lipids placed into water form cell-sized double- layered bubbles called liposomes. They may have provided the first membranous boundary. © McGraw Hill LLC 18  Protocell Nutrition The protocell would have had to carry on nutrition in order to grow. If organic molecules formed in the atmosphere and were carried into the ocean by rain, simple organic molecules could have served as food. According to this hypothesis, the protocell was a heterotroph, an organism that consumes preformed organic molecules. If the protocell evolved at hydrothermal events, it could have carried out chemosynthesis. Chemosynthesis is the synthesis of organic molecules by the oxidation of inorganic compounds. © McGraw Hill LLC 19  Protocell and Natural Selection Natural selection would have favored cells that could extract energy from carbohydrates to produce ATP. Oxygen was not available. The protocell may have carried on a form of fermentation. Scientists speculate that it took millions of years for glycolysis, a metabolic pathway that transforms high-energy chemical bonds into energy for a cell to do work, to evolve completely. © McGraw Hill LLC 20  Stage 4: Evolution of a Self- Replication System RNA-first hypothesis The first cell would have had an RNA gene that directed protein synthesis. Reverse transcription could have led to DNA genes. RNA was responsible for both DNA and protein formation. Eventually, protein synthesis would have been carried out according to the central dogma, with information flowing from DNA to RNA to protein. © McGraw Hill LLC 21  Stage 4: Evolution of a Self- Replication System Protein-first hypothesis The protocell would have developed a plasma membrane and enzymes. Then, DNA and RNA synthesis would have been possible. After DNA genes evolved, protein synthesis would have been carried out according to the central dogma. After DNA formed, the genetic code had to evolve. © McGraw Hill LLC 22  18.2 History of Life Fossils are the remains and traces of past life. Paleontology is the study of the fossil record. Most fossils are traces of organisms embedded in sediment. Sediment becomes a recognizable stratum (layer) in a stratigraphic sequence. Strata of the same age tend to contain the similar fossil assemblages (index fossils) that can be used for relative dating. This helps geologists determine relative dates of embedded fossils (relative dating). © McGraw Hill LLC 23  The History of Life Figure 18.6 Access the text alternative for slide images. © McGraw Hill LLC (a): Kenneth Murray/Science Source 24  Fossils Figure 18.7 (trilobite): Francois Gohier/Science Source; (ichthyosaur): R. Koenig/Blickwinkel/age fotostock; (fossil fish): Alan Morgan; (fern): George Bernard/NHPA/Photoshot; (ammonites): Sinclair Stammers/SPL/Science Source; (footprint): © McGraw Hill LLC fotocelia/iStockphoto/Getty Images 25  Geologic Timescale The geologic timescale divides the history of the Earth into: Eras Periods Epochs Derives from accumulation of data from the age of fossils in strata all over the world Life arose during the Precambrian time. © McGraw Hill LLC 27  Geologic Timescale: Cenozoic Table 18.1 The Geological Timescale: Major Divisions of Geological Time and Some of the Major Evolutionary Events of Each Time Period Millions of Years Ago Era Period Epoch (MYA) Plant Life Animal Life Cenozoic Quaternary Holocene Current Humans influence plant life. Age of Homo sapiens Significant Extinction Event Underway Cenozoic Quaternary Pleistocene 0.01 Herbaceous plants spread and Ice age mammals and diversify. modern humans appear. Cenozoic Neogene Pliocene 2.6 Herbaceous angiosperms First hominids appear. flourish. Cenozoic Neogene Miocene 5.3 Grasslands spread as forests Apelike mammals and contract. grazing mammals flourish; insects flourish. Cenozoic Neogene Oligocene 23.0 Many modern families of Browsing mammals and flowering plants evolve; monkeylike primates appear. grasses appear. Cenozoic Paleogene Eocene 33.9 Subtropical forests with heavy All modern orders of rainfall thrive. mammals are represented. Cenozoic Paleogene Paleocene 55.8 Flowering plants continue to Ancestral primates, diversify. herbivores, carnivores, and insectivores appear. Mass Extinction: 50% of all species, dinosaurs and most reptiles © McGraw Hill LLC 28  Geologic Timescale: Mesozoic and Paleozoic Table 18.1 The Geological Timescale: Major Divisions of Geological Time and Some of the Major Evolutionary Events of Each Time Period Millions of Years Ago Era Period Epoch (MYA) Plant Life Animal Life Mesozoic Cretaceous 65.5 Flowering plants spread; Placental mammals appear; conifers persist. modern insect groups appear. Mesozoic Jurassic 145.5 Flowering plants appear. Dinosaurs flourish; birds appear. Mass Extinction: 48% of all species, including corals and ferns Mesozoic Triassic 199.6 Forests of conifers and First mammals appear; first cycads dominate. dinosaurs appear; corals and molluscs dominate seas. Mass Extinction (“The Great Dying”): 83% of all species on land and sea Paleozoic Permian 251.0 Gymnosperms diversify. Reptiles diversify; amphibians decline. Paleozoic Carboniferous 299.0 Age of great coal-forming Amphibians diversity; first forests; ferns, club mosses, reptiles appear; first great and horsetails flourish. radiation of insects occurs. Mass Extinction: Over 50% of coastal marine species, corals © McGraw Hill LLC 29  Geologic Timescale: Paleozoic Table 18.1 The Geological Timescale: Major Divisions of Geological Time and Some of the Major Evolutionary Events of Each Time Period Millions of Years Ago Era Period Epoch (MYA) Plant Life Animal Life Paleozoic Devonian 359.2 First seed plants appear; seedless First insects and first vascular plants diversify. amphibians appear on land. Paleozoic Silurian 416.0 Seedless vascular plants appear. Jawed fishes diversify and dominate the seas. Mass Extinction: Over 57% of marine species Paleozoic Ordovician 443.7 Nonvascular land plants appear. Invertebrates spread and diversify; first jawless and then jawed fishes appear. Paleozoic Cambrian 488.3 Marine algae flourish. All invertebrate phyla are present; first chordates appear. 630 First soft-bodied invertebrates evolve. 1,000 Protists diversify. 2,100 First eukaryotic cells evolve. 2,700 O2 accumulates in atmosphere. 3,500 First prokaryotic cells evolve. 4,570 Earth forms. © McGraw Hill LLC 30  Precambrian The Precambrian includes about 87% of the geological timescale. Little or no atmospheric oxygen in the early atmosphere Lack of an ozone shield allowed UV radiation to bombard Earth. The first cells came into existence in aquatic environments. Prokaryotes appeared about 3.5 BYA. Cyanobacteria fossils have been found in ancient stromatolites. Photosynthetic cyanobacteria added oxygen to the atmosphere. Aerobic bacteria proliferated in the oxygen-rich atmosphere. © McGraw Hill LLC 31  Prokaryote Fossils of the Precambrian a. Stromatolites b. Primaevifilum Figure 18.8 © McGraw Hill LLC (a): Francois Gohier/Science Source; (b, photo): ©Dr. J. William Schopf 32  Eukaryotic Cells Arise About 2.1 BYA Most are aerobic Contain a nucleus as well as other membranous organelles Endosymbiotic Theory Mitochondria were probably once free-living aerobic prokaryotes. Chloroplasts were probably once free-living photosynthetic prokaryotes. A nucleated cell probably engulfed these prokaryotes that became various organelles. © McGraw Hill LLC 33  Endosymbiotic Theory Present-day mitochondria and chloroplasts are similar in size to bacteria. Mitochondria and chloroplasts have their own DNA and make some of their own proteins. Mitochondria and chloroplasts divide by binary fission. Mitochondria and chloroplasts are surrounded by two membranes. © McGraw Hill LLC 34  The Tree of Life Figure 18.9 Access the text alternative for slide images. © McGraw Hill LLC 35  Multicellularity Arises About 1.4 BYA Early multicellular organisms lacked internal organs and could have absorbed nutrients from the sea. It’s possible that they practiced sexual reproduction. © McGraw Hill LLC 36  Ediacaran Fossils Ediacaran invertebrates lived from about 630 to 545 MYA. Figure 18.10 © McGraw Hill LLC (a): Sinclair Stammers/Science Source; (b): DeAgostini/SuperStock 37  The Paleozoic Era It begins with the Cambrian period. It lasted over 300 million years. It includes three major mass extinction events. An extinction is the total disappearance of all members of a species or higher taxonomic group. Mass extinction: Disappearance of a large number of taxa Occurred within a relatively short time interval, a few million years (compared to geological time scale) © McGraw Hill LLC 38  Cambrian Animals The abundance of fossils of animals of the Cambrian period may be due to the evolution of outer skeletons. The ancestry of all modern animals can be traced to the Cambrian period. Figure 18.11 Sea Life of the Cambrian Period © McGraw Hill LLC 39  Invasion of Land Began around 500 MYA Plants Seedless vascular plants date back to the Silurian period. They later flourished in Carboniferous period. Invertebrates Arthropods were the first animals on land. Outer skeleton and jointed appendages pre-adapted them to live on land. Vertebrates Fishes first appeared in the Ordovician period. Amphibians first appeared in the Devonian period and diversified during the Carboniferous period. A mass extinction occurred at the end of the Permian period. © McGraw Hill LLC 41  Swamp Forests of the Carboniferous Period Figure 18.12 Access the text alternative for slide images. © McGraw Hill LLC (a): Richard Bizley/Science Source; (b): powerofforever/iStock/Getty Images; (c): ©Ablestock.com/Jupiterimages 42  The Mesozoic Era Triassic Period Nonflowering seed plants became dominant. Jurassic Period Dinosaurs achieved enormous size. Mammals remained small and less conspicuous. Cretaceous Period Dinosaurs declined at the end of the Cretaceous period due to a mass extinction. Mammals: Began an adaptive radiation Moved into habitats left vacated by dinosaurs © McGraw Hill LLC 43  Dinosaurs of the Cretaceous Period Figure 18.13 © McGraw Hill LLC Chase Studio/Science Source 44  The Cenozoic Era Mammals continued adaptive radiation. Flowering plants were already diverse and plentiful. Primate evolution began: Some primates adapted to living in trees for protection from predators and to obtain food in the form of fruit. Ancestral apes appeared during the Oligocene epoch. Megafauna during Pleistocene epoch © McGraw Hill LLC 45  Mammals of the Oligocene Epoch Figure 18.14 © McGraw Hill LLC Chase Studio/Science Source 46  Woolly Mammoths of the Pleistocene Epoch Figure 18.15 © McGraw Hill LLC Leonello CalvettiScience Photo Library/Alamy Stock Photo 47  18.3 Geological Factors that Influence Evolution Continental drift: The positions of continents and oceans are not fixed. Plate tectonics Earth’s crust consists of slablike plates. Tectonic plates float on a lower, hot mantle layer. Movements of plates result in continental drift. Modern mammalian diversity results from isolated evolution on separate continents. © McGraw Hill LLC 48  Continental Drift Figure 18.16 Access the text alternative for slide images. © McGraw Hill LLC 49  Biogeography of the fern Glossopteris Supports Continental Drift Figure 18.17 © McGraw Hill LLC 50  Mass Extinctions of Species Mass extinctions Permian occurred at the end of 251 MYA the following periods: 90% of species disappeared Ordovician Triassic 444 MYA 200 MYA 75% of species disappeared 60% of species disappeared Devonian Cretaceous 360 MYA 66 MYA 70% of marine 75% of species disappeared invertebrates disappeared © McGraw Hill LLC 51  Mass Extinctions Figure 18.18 Access the text alternative for slide images. © McGraw Hill LLC 52