4 Key excerpts on "Common Ancestry"

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  eBook - ePub

  Theistic Evolution

  A Scientific, Philosophical, and Theological Critique

  • J. P. Moreland, Stephen C. Meyer, Christopher Shaw, Ann K. Gauger, Wayne Grudem(Authors)
  • 2017(Publication Date)
  • Crossway

    (Publisher)

  As we shall see, the principle of continuity actually challenges the tree of life everywhere, not simply at its base. But common descent and continuity are themselves embedded in a wider scientific and philosophical context. How one evaluates the theory depends on the decisions one makes about that wider context—on questions such as the probability of the naturalistic origin of life (or abiogenesis), how many times abiogenesis occurred, and whether intelligent design is a live possibility. To paraphrase John Donne, no theory is an island, and common descent is no exception.

  The relevance of common descent to the subject of this book hardly needs elaborating. BioLogos, the leading organization in the United States promoting theistic evolution, states that “evolution” means (among other things) that “all the life forms on earth share a common ancestor”3 —i.e., common descent. To stress that no legitimate doubt exists about the theory, BioLogos adds,

  There is very little debate in the scientific community about this broad characterization of evolution (anyone who claims otherwise is either uninformed or deliberately trying to mislead). The observational evidence explained by Common Ancestry is overwhelming.4

  But serious questions about common descent have existed since Darwin’s time, and are even more significant today. Let’s abbreviate common descent as “UCD” (i.e., “universal common descent”): this will stand for Darwin’s idea that all organisms on Earth stemmed from a single common ancestor. We’ll use CD for hypotheses about the shared ancestry of particular groups of organisms, where UCD may or may not be presupposed.

  The scope of UCD includes all life on this planet, and even particular CD theories, such as the Common Ancestry of the animals, encompass enormous swaths of organismal diversity. Given this vast breadth, it is impossible in a single chapter, or even an entire book, to address every dimension of the problem (although, in chapter 11

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  Biodiversity and Evolution

  • Philippe Grandcolas, Marie-Christine Maurel(Authors)
  • 2018(Publication Date)
  • ISTE Press - Elsevier

    (Publisher)

  My goal is not to present Systematic case studies of biodiversity, but to highlight several significant points which Systematics can help us to understand or value regarding Biodiversity, and which are linked in a very interesting way to those uncovered by ecological approaches. The purpose of this presentation is obviously not to promote a discipline for its own sake, but to provoke reactions and reflections through the contrast between different points of views.

  3.2 Species: all different

  In the 1980s, the creation of the concept of Biodiversity and the advent of phylogenetic analysis made it possible to reintroduce in people’s minds a very valuable asset: the notion of diversity between species, which had faded away since the rise of General Biology

  1

  at the beginning of the 20th Century [GRA 17] .

  In fact, General Biology and what we still call today Life Sciences (with some components called Systems Biology

  2

  or Integrative Biology

  3

  ) appeared and developed with the idea of seeking and defining main general principles common to all organisms, like, for example, the “laws of heredity”. It is also at this time that model organisms, which were supposed to represent on their own entire sections of the living world, emerged, such as the Thale Cress Arabidopsis thaliana for plants or the common fruit fly Drosophila melanogaster for insects. From the moment we focus on the main constitution or functioning principles supposedly common to all organisms, we are concerned far less with their differences and diversity. General Biology thus contributes to the study of organism evolution, because it identifies general heredity or functioning mechanisms of organisms. However, it does not then study the evolutionary History of different groups of organisms in interaction with the environment, which is the source of Biodiversity.

  This eclipse of History (evolutionary History), as the systematist Dan Brooks and the ethologist Deborah McLennan called it [BRO 91] , then ended in the 1980s when the community of biologists became aware again of the importance of considering differences between species. At that time, the term biodiversity was coined by Thomas Lovejoy, Walter G. Rosen and Edward Osborne Wilson [WIL 88] . Phylogenetic analysis was formalized at the same time [WIL 81]

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  Old-Earth or Evolutionary Creation?

  Discussing Origins with Reasons to Believe and BioLogos

  • Kenneth Keathley, J. B. Stump, Joe Aguirre(Authors)
  • 2017(Publication Date)
  • IVP Academic

    (Publisher)

  Biological evolution, simply put, is descent with modification. This definition encompasses small-scale evolution (changes in gene frequency in a population from one generation to the next) and large-scale evolution (the descent of different species from a common ancestor over many generations). Evolution helps us to understand the history of life. . . .

  Biological evolution is not simply a matter of change over time. Lots of things change over time: trees lose their leaves, mountain ranges rise and erode, but they aren’t examples of biological evolution because they don’t involve descent through genetic inheritance.

  The central idea of biological evolution is that all life on Earth shares a common ancestor, just as you and your cousins share a common grandmother.

  Through the process of descent with modification, the common ancestor of life on Earth gave rise to the fantastic diversity that we see documented in the fossil record and around us today. Evolution means that we’re all distant cousins: humans and oak trees, hummingbirds and whales.1

  This summary says nothing about whether there is or is not a Creator in whom the process is based and whose ongoing presence is required for it to proceed. It says nothing about purpose, nor does it encroach on the issue of whether a Creator has influenced (or may still be influencing) the process in ways that are undetectable through the tools of scientific investigation. Evolutionary theory is silent about all of these issues.

  The two poles of misrepresentation. Despite what most would agree is a good consensus statement of the meaning that biologists attach to the term evolution, a number of spokespersons drastically overinterpret its meaning. Besides the stridency of books by “new atheists,” the literature is full of statements by scientists whose writings may not be characterized by militant atheism, but who write nonetheless as though the theory of evolution has disproven theism. For example, in his book The Accidental Species, Henry Gee states, “It is clear that evolution has no plan. It has neither memory nor foresight. No vestige of cosmic strivings from some remote beginning; no prospect of revelatory culmination in some transcendent end. Rather than being at the pinnacle of creation, human beings are just one species on the tangled bank of Darwin’s imagination.”2

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  Should Christians Embrace Evolution?

  Biblical and Scientific Responses

  • (Author)
  • 2013(Publication Date)
  • IVP

    (Publisher)

  9. Interpretation of Scientific evidence 9A. Homology

  Norman C. Nevin

  Difficulties over the theory of evolution have centred on evidences such as homology. A leading evolutionist, Ernst Mayr, defined homology as: ‘[a] feature in two or more taxa is homologous when it is derived from the same (or corresponding) feature in the common ancestor’.126 Scientists before Darwin considered that such homologous structures were due to a common plan. Darwin, however, claimed that homology was best explained by descent with modification from a common ancestor: ‘If we suppose that an early progenitor – the archetype as it may be called – of all mammals, birds and reptiles, had its limbs constructed on an existing pattern...the similar framework of bones in the hand of a man, the wing of a bat, fin of a porpoise, and the leg of the horse...at once explain themselves on the theory of descent with slow and slight modification.’127 Indeed, he considered homology a central tenet of his theory, and as powerful evidence of inheritance from a common ancestor. He wrote:

  We have seen that the members of the same class independently of their habits resemble each other in general plan of their organisation. This resemblance is often expressed by the term ‘unity of type’; or by saying that several parts and organs in different species of class are homologous...is it not powerfully suggestive of true relationship, of inheritance from a common ancestor.128

  Some evolutionary biologists cite homology as providing one of the most compelling lines of evidence for evolution. Indeed recently, Shubin et al . define traditional homology as ‘a historical continuity in which morphological features in related species are similar in pattern or form because they evolved from a corresponding structure in a common ancestor’.129

  The similarities of bone structure conform to a basic pattern. However, Darwin went further and considered the homologies were best explained by descent with modification from a common ancestor. Advocates of common descent conclude that homologous anatomical structures originated in a common ancestor and were modified by random mutations and natural selection. Frequently, they point to the persistence of the five-digit pentadactyl pattern of fore- and hind-limbs of quadrupeds as evidence of homology.

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