Fossil Record

11 Key excerpts on "Fossil Record"

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  Extinctions

  Living and Dying in the Margin of Error

  • Michael Hannah(Author)
  • 2021(Publication Date)
  • Cambridge University Press

    (Publisher)

   A Short Detour: The Fossil Record and the Geological Time Scale      The Fossil Record is the primary source of information that we can use to document the history of life on Earth. But it is a biased record, and although it’s biased in a very predictable way, it does place limitations on the history we’re trying to extract. We need to understand why the biases are there and see what can be done to minimise the problem. Fossils are the remains of animals, plants, and other organisms preserved in rocks. They can be the body parts of animals, cellular material, tracks and trails left by ancient organisms, even faecal matter (although palaeontologists give that a better sounding name – coprolites). This record of the great panoply of life on Earth provides an astonishing amount of information. It can tell us about an organ- ism’s evolution, what extinct creatures looked like, how they behaved, and what sort of ecological setting they lived in. It docu- ments how dinosaurs changed into birds, and how organisms evolved eyes – all this and more, much more. In this book, we are interested in the historical patterns of biodiversity, and for this sort of analysis, the Fossil Record is all we have available. I like to compare the Fossil Record to a chain-link fence. The fence is strong, durable, and full of holes. The Fossil Record is strong: we have recovered many, many fossils. It’s durable: no one (despite repeated efforts) has ever been able to prove it inconsistent. The same sequence of fossils appears everywhere on the planet – there are no rabbits in the Precambrian. 1 But like the chain-link fence, the fossil 1 The story goes that someone once asked the British-born biologist J. B. S. Haldane what would disprove evolution. He reportedly replied: ‘Rabbits! Rabbits in the Precambrian!’ The Precambrian is a period of time between 540 million and 4.5 billion years ago – well before the evolution of bunnies. 

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  Introduction to Physical Geology

  • Charles Fletcher, Dan Gibson, Kevin Ansdell(Authors)
  • 2014(Publication Date)
  • Wiley

    (Publisher)

  It reveals that time is deep and great change has occurred in both geologi- cal environments and biological communities. The fossil re- cord provides strong evidence of the evolution of life. Tens of thousands of fossils define animal and plant lineages that fully document evolutionary changes. These fossils prove that evolution is responsible for Earth’s vast diversity of life forms. There are practical aspects to the study of Earth’s his- tory. Evolution guides understanding and treatment of med- ical problems. Geologists use fossils to identify the rocks that carry natural resources, such as oil, coal, and many others. Fossils tell us that significant environmental change leads to mass extinctions; that humans and other four-limbed ani- mals share a common ancestor; that chimpanzees are more closely related to humans than they are to gorillas; and that, ultimately, all living organisms are related in a great web of life. In the end, this story tells us that if we wish to live sus- tainably on this planet, we absolutely must see beyond the horizon defined by our short lives. 366 • CHAPTER 14 Earth’s History 14-1 Earth’s History Has Been Unveiled by Scientists Applying the Tools of Critical Thinking LO 14-1 Describe the forebears of geology and their contributions. U se of the dating tools we studied in Chapter 13 (“Geologic Time”) has led to fundamental advances in our knowledge of Earth’s history—a field known as historical geology. Many of these advances came through the efforts of pioneering scientists who, a century and a half ago, walked the land, studied natural materials, and formulated many of the principles that define the science of geology. Two significant contributions of these forebears have become hallmarks of science: the theory of evolution (changes in the in- herited traits of a biological population from one generation to the next) and the recognition that Earth is profoundly old, a characteris- tic that scientist and author Stephen J.

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  Introduction to Paleobiology and the Fossil Record

  • Michael J. Benton, David A. T. Harper(Authors)
  • 2020(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  This highlights an important point about the Fossil Record: that some missing data can be modeled. For example, known unknowns include ghost ranges and Lazarus taxa – these are gaps detected within taxon ranges. A species exists, then apparently disappears, and reappears again (like Lazarus in the Bible, who died and was raised again by Jesus). Lazarus taxa indicate known collection failures, and they can provide information on times that are less well sampled than others.

  All these studies are looking at our knowledge of the Fossil Record. There are three meanings of the term Fossil Record:

  1. 1 Our current knowledge of the fossils in the rocks (the usual meaning).
  2. 2 Our ultimate knowledge of the fossils in the rocks (when all fossils have been collected).
  3. 3 What actually lived in the past.

  As we have seen, many species never left fossils of any kind because they had no hard parts or lived in the wrong place. So, paleontologists can strive to fill the gaps in the Fossil Record, and that is demonstrably happening (see Figure 5.15 ), but how much closer does that bring us to an understanding of what actually lived at any time in the past?

  Without supernatural knowledge, that might seem hard to assess. On a good day, paleontologists believe the Fossil Record (meanings 1 or 2) actually does give us a good outline of the key events in the history of life. On a bad day, it is easy to despair of ever really understanding the history of life (meaning 3) because the fossils we have to hand are such a small remnant of what once existed.

  Nonetheless, paleontologists, and other scientists, mostly accept that the Fossil Record (meaning 1) does give us a broadly correct picture of the history of life (meaning 3). As evidence for this slightly optimistic view, they might point to the lack of surprises. If the fossils were wildly out of kilter with the history of life, we might expect to find human fossils in the Jurassic or dinosaur fossils in the Miocene. We do not (despite Charles Lyell's famous expectation in the 1830s that we might do just that, see Chapter 1 : Section “Progressionism and evolution

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  Arguing for Evolution

  An Encyclopedia for Understanding Science

  • Sehoya H. Cotner, Randy Moore(Authors)
  • 2011(Publication Date)
  • Greenwood

    (Publisher)

  However, not one fossilized flat- worm has been discovered. This lack of flatworms in the Fossil Record results not from their absence or extinction, but instead because the fos- silization of soft-tissue organisms is exceedingly rare. Indeed, the fossil re- cord of soft-bodied organisms is so poor that relatively few paleontologists study these organisms or can say much about their evolution. The incompleteness of the Fossil Record has also produced other prob- lems. Once fossils are uncovered, how should they be interpreted? What differences among fossils actually denote different species? Debates about this question have prompted paleontologists to reevaluate many fossils and the associated claims about life’s history. For example, in 2009, pa- leontologists determined that three dinosaurs— Dracorex, Stygimoloch, and Pachycephalosaurus—are actually the young, juvenile, and adult stages of the same species. Suddenly, because of a new interpretation, the fossils of three different species became different stages of just one species. The Fossil Record remains incomplete; for example, biologists have not yet found fossils of an organism that clearly “links” bats and their mam- malian predecessors. Nevertheless the Fossil Record comprises a vast li- brary that enables us to piece together the broad patterns of life’s history on Earth, much like forensic experts use incomplete historical evidence to determine what happened at a crime scene. Whereas Darwin spoke apolo- getically of “difficulties” with the Fossil Record, today’s Fossil Record pro- vides extensive, strong, and unequivocal evidence for evolution. The Fossil Record Can Be Matched with Geologic Evidence to Describe the History of Life on Earth By the 1890s, geologists knew that Earth’s history is written in rocks. Recall from Chapter 2 Steno’s Principle of Superposition—namely, that in 46 Arguing for Evolution undisturbed areas, younger layers of sediments always overlie older layers of sediments.

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  The Earth Through Time

  • Harold L. Levin, David T. King, Jr.(Authors)
  • 2016(Publication Date)
  • Wiley

    (Publisher)

  129 C H A P T E R 6 Life on Earth: What Do Fossils Reveal? Key Chapter Concepts • Fossils are the remains or indications of ancient organisms that are preserved in rock. A fossil can be an actual part of an organism (like a shell or bone), an imprint or cast of the organism, or a trace of the organism’s activity (like a footprint or burrow). • Three common processes by which fossils are preserved are replacement, permineralization, and carbonization. • Trace fossils are tracks, trails, burrows, and other markings made by ancient organisms in sediment. • The probability of preserving an ancient organ- ism is greater if the organism was buried rapidly and if it had hard parts. • In the 1700s, Carolus Linnaeus paved the way for classifying plants and animals. • To understand and study life, we divide it into three great domains: Archaea, Bacteria, and Eukarya. There are four taxonomic kingdoms within the Eukarya: Protista, Fungi, Plantae, and Animalia. Each of these in turn is divided into the categories phylum, class, order, family, genus, and species. • Lamarck’s hypothesis about lines of descent, introduced in the early 1800s, was an important step. However, it was flawed because it stated that organisms can transmit to their offspring traits acquired during their life span. • In the mid‐1800s, Charles Darwin explained how natural selection can control the direction of evolutionary change in organisms. • Natural selection operates through mutation and the rules of inheritance to cause variation in organisms. • New species can result from shifts to new envi- ronments or environmental change in a given location. The new species can then adapt and radiate as new generations exploit new environ- mental situations or life strategies.

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  Physical Geology

  The Science of Earth

  • Charles Fletcher(Author)
  • 2017(Publication Date)
  • Wiley

    (Publisher)

  These fos- sils prove that evolution is responsible for Earth’s vast diversity of life-forms. There also are practical aspects to the study of Earth’s history. Evolution guides our understanding and treatment of medical problems, for example. And geologists use fossils to identify the rocks that carry natural resources, such as oil, coal, and many others. Fossils tell us that significant environmental change leads to mass extinctions; that humans and other four- limbed animals share a common ancestor; that chimpanzees are more closely related to humans than to gorillas; and that, ulti- mately, all living organisms are related in the great web of life. In the end, this story tells us that if humans are to continue to live sustainably on this planet, it is absolutely crucial that we look far beyond the horizon defined by our short lives. LO 13.1 Name the forebears of geology and describe their contributions. We owe our understanding of Earth history to the discov- eries and insights of several pioneering scientists. Earliest fossils 4.6 Billion Years Ago 3.5 2.5 1.5 0.5 0 2 1 4 3 Moon formation Oldest zircon crystal 4.4 billion years old First sedimentary evidence for oceans and earliest isotopic evidence for life Formation of Earth Rise in atmospheric oxygen Oldest rock First cells with nucleus Dinosaurs Rise of flowering plants Assembly of Pangaea Rise of mammals Humans First hard-shelled animals Formation of core FIGURE 13.1 Earth’s history is characterized by the evolution of life from simple early forms to highly diverse modern ecosystems. This history includes tectonic events that have built mountain systems, split and assembled continents, and formed oceans. Formulate a hypothesis that describes long-term changes in living organisms over geologic time. How would you test this hypothesis? This chapter takes you on a walk through deep time to examine the major tectonic and biologic events of the Precambrian and Phanerozoic eons (Figure 13.1).

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  The Handy Geology Answer Book

  • Patricia Barnes-Svarney, Thomas E Svarney(Authors)
  • 2004(Publication Date)
  • Visible Ink Press

    (Publisher)

  The real reason lies in the information they provide. Without fossils, the history of life on our planet—spanning over hundreds of millions of years—would remain unknown to us. We would have no idea how life began and what shapes it took. There would be no record of the numerous catastrophes and extinc- tions that have befallen life on our planet. We would have no clues that large and diverse reptiles called dinosaurs once roamed the Earth, or that the conti- nents have been (and are) continuously moving, changing the face of our plan- et, the climate, and the flora and fauna. Without the Fossil Record of how life has changed over millions of years, there would be no concept of evolution, the fundamental principle that governs the growth and change of all living things. And we would have no knowledge how our species, Homo sapiens, came to exist on this planet. Chemofossils —Chemofossils are chemical signatures of life in rock. They may be organic chemical compounds (also called biomarkers) indicative of certain organisms, or trace elements that are the result of biological processes. How did trace fossils form? Trace fossil are evidence that animals ran, walked, crawled, burrowed, or hopped across land, usually in soft sediment such as sand or mud. For example, dinosaurs walking along a river left their footprints in soft sand; small animals dug branching tunnels in the mud of a lake bed in search of food. These traces then filled with sedi- ment and were buried under layer upon layer of sediment over millions of years, even- tually solidifying into rock. When the rock is exposed and collected, the trace evidence of the organisms can be seen

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  Events of Increased Biodiversity

  Evolutionary Radiations in the Fossil Record

  • Pascal Neige(Author)
  • 2015(Publication Date)
  • ISTE Press - Elsevier

    (Publisher)

  The aim of this program is to facilitate access to all of the natural history specimens – including paleontological artifacts – conserved in France. Via its Internet portal (http://recolnat.org), it is possible to consult objects, set up one’s own virtual laboratory, add comments or indeed suggest new determinations. An important point of that Website is the use of a participative science system to improve knowledge of the collections. 2.5 Yes, the Fossil Record can be used to study the history of biodiversity Ultimately, the paleontological databases, the techniques used to sample the Fossil Record and the tools employed to examine the resulting samples mean we can be reasonably optimistic about the use of that Fossil Record, with a view to exploring the history of biodiversity. As we have seen, the transition from collecting fossils in the field to constructing a graph illustrating biodiversity through the geological ages is a lengthy task. It is lengthy, but doable, with the conditions required to produce robust results (reproducibility, potential bias testing, etc.). It is not possible to find an answer to every scientific question we can come up with: the Fossil Record is, by nature, incomplete, and its sampling is sometimes not sufficient to furnish an answer to a given question. However, some questions certainly can be resolved. In the following pages (particularly in Chapter 4), we shall explore some of these questions – specifically targeted at analysis of the events of extension of biodiversity.

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  An Introduction to Forensic Geoscience

  • Elisa Bergslien(Author)
  • 2012(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  When most people think of fossils, the first thing that probably comes to mind is bones, like dinosaur bones. However, the most common types of fossils do not look anything like bones. There are several different types of fossils that vary from easily recognizable material to very odd-looking impressions. Technically, fossils can be either the physical remains of organisms or evidence of the behavior of organisms preserved in the rock record. Virtually all fossils are found in sediment or sedimentary rock, as the temperatures and pressures associated with igneous and most metamorphic processes destroy organic material. Fossils are typically found in depositional environments, reaching highest abundance in marine sediments, though they can be preserved in terrestrial depositional environments as well.

  Fossils are divided into two primary categories: body fossils that are part of the original organism and trace fossils (also called ichnofossils ), which are the preserved physical marks of the behavior of an organism. Microfossils are fossils that are too small to be studied without the aid of a microscope and include both the complete remains of microscopic organisms and microscopic small parts of larger organisms. The scientists who study fossils and the evolution of life on Earth are called paleontologists .

  Body fossils can be preserved in a variety of ways. In general, only organisms with hard parts such as shells, bones, or teeth are preserved. Hard parts are typically formed from one of the following materials: calcium carbonate (CaCO3 or calcite and aragonite), produced by corals, oyster shells, and starfish; silica (SiO2 or cryptocrystalline quartz), produced by diatoms, radiolarians and some sponges; calcium phosphates (such as hydroxyapatite), which includes vertebrate bones and teeth; or one of a variety of complex organic materials such as cellulose , produced by plants and some algae; chitin , most commonly found with arthropods (think insects); and spongin , which is produced by types of sponges like the one you might have in your bathtub (a “natural sponge,” not a Luffa , which is a type of plant). Organisms’ hard parts are not solid materials, but are porous

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  Prehistoric Life

  Evolution and the Fossil Record

  • Bruce S. Lieberman, Roger L. Kaesler(Authors)
  • 2010(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  One way that we search for overarching processes in paleontology and evolutionary biology is by studying different groups of animals, plants, or other life forms and searching for commonalities that they share. Really the scientific method in paleontology involves studying the history of different things and then seeing if there are any similarities in the patterns and details of that history. By way of an example, consider the individual events, the history if you will, Outline Introduction The Earliest Evidence for Life in the Geological Record The Time of Pond Scum and the Rise of Oxygen For Billions of Years Organisms Have Been Modifying the Atmosphere and Their Environment More Effects of Rising Oxygen Levels The Evolution of the Eukaryotic Cell Concluding Remarks Additional Reading Prehistoric Life: Evolution and the Fossil Record . 1st edition. By Bruce S. Lieberman and Roger Kaesler. Published 2010 by Blackwell Publishing. Prehistoric Life 254 of any one person’s life: you are born; you go to elementary school; you go to college; you get a job; and so on. That is just one person’s history of course and it is hard to extract any general principles from that. Now, however, imagine we trace the history of several people. We may find there are general processes or principles that recur in every human individual’s life such that we don’t have to view any life in isolation. Maybe junior high school, or college, is a time when we all experience similar things, some of them trying. Thus, from single individual histories we can reconstruct processes that repeatedly occur, and we can extract generalities. This is what the scientific approach in paleontology is all about, extracting the generalities from a set of historical patterns. Through the study of several repeated events that occur throughout the history of life we can extract generalities and processes.

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  Understanding Fossils

  An Introduction to Invertebrate Palaeontology

  • Peter Doyle(Author)
  • 2014(Publication Date)
  • Wiley

    (Publisher)

  354 Understanding Fossils important in accurately demonstrating evolutionary stasis, gradualism and a stepped extinction pattern which might otherwise have been lost. This is also bound up in the nature of the sampling procedure utilised, which was at the level of centimetre accuracy for all these examples. • Determining the range in variation within a given species at a given time interval is essential in order to be able to demonstrate the nature of the evolu- tionary changes within a species through time. In Metrarabdotos, for example, the range in morphology was determined within a species, and its rate of change through time assessed. In this case, the rate of change exceeded that occurring within the species, and was rapid, punctuating static episodes. In Sheldon's Ordovician trilobites, there was a constant rate of change within the lineages studied. Determination of the nature of the variation helped demon- strate the presence of periodic reversals in trends. • Understanding the nature of the data compilation is extremely important in examining broad-scale patterns. In the case of the observed periodicity of ex- tinctions, the nature of the original data source was of variable quality, includ- ing some 'families' of dubious biological value. Rigorous reassessment of some data sources suggests that the use of strictly monophyletic families creates a non-periodic pattern. Studies i 22 Palaeoenvi ronmental Analysis In this chapter the application of fossils in palaeoenvironmental analysis and palaeobiogeography is examined. 22.1 GENERAL CONSIDERATIONS OF PALAEOECOLOGY AND PALAEOENVIRONMENTS In seeking to determine the nature of ancient ecologies and interpret the factors which control them, five elements are of importance: determination of auto- chthonYi recurrence of association; taxonomic uniformitarianismi population structure; and comparison with other data sources.

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