Supporting Evolution by Responding to “Missing Link” Arguments

2018 ◽  
Vol 80 (2) ◽  
pp. 100-104
Author(s):  
David Westmoreland
Keyword(s):  
Evolutionary Theory ◽  
Fossil Record ◽  
Evolutionary Transitions ◽  
Missing Link ◽  
Typical Response

The missing link argument is a common challenge raised by students to evolutionary theory; it notes that the majority of evolutionary transitions are not represented in the fossil record. A typical response is to present examples of fossils that have a combination of ancestral and derived traits, but I argue that this approach is largely ineffective because it does not address the broader question of whether the fossil record accords better with evolutionary theory than with creationist narratives. A better response is to agree that the fossil record is largely incomplete because fossilization is rare, and to direct the conversation toward addressing how a rich, yet incomplete, collection of evidence can be reasonably interpreted. Evolutionary theory and creationism pose starkly different expectations about trends in fossil diversity, and evolution is strongly supported while creationism is not.

Missing Links in the History of Life

2002 ◽  
Vol 11 ◽  
pp. 97-118
Author(s):  
Charles R. Marshall
Keyword(s):  
Evolutionary Theory ◽  
Fossil Record ◽  
Theory Of Evolution ◽  
History Of ◽  
Living Species

Ever since Darwin proposed his theory of evolution (or more correctly, theories; see Mayr, 1991) it has been assumed that intermediates now extinct once existed between living species. For some, the hunt for these so-called missing links in the fossil record became an obsession, a search for evidence thought needed to establish the veracity of evolutionary theory. Few modern paleontologists, however, search explicitly for ancestors in the fossil record because we now know that fossils can be used to chart the order of evolution regardless of whether they are directly ancestral either to extinct organisms or to those living today.

Missing Links in the History of Life

1999 ◽  
Vol 9 ◽  
pp. 119-144
Author(s):  
Charles R. Marshall
Keyword(s):  
Evolutionary Theory ◽  
Fossil Record ◽  
Theory Of Evolution ◽  
History Of ◽  
Living Species

Ever since Darwin proposed his theory of evolution (or more correctly, theories; see Mayr, 1991) it has been assumed that intermediates now extinct once existed between living species. For some, the hunt for these so-called missing links in the fossil record became an obsession, a search for evidence thought needed to establish the veracity of evolutionary theory. Few modern paleontologists, however, search explicitly for ancestors in the fossil record because we now know that fossils can be used to chart the order of evolution regardless of whether they are directly ancestral either to extinct organisms or those living today.

scholarly journals Cladogenesis and replacement in the fossil record of Microsyopidae (?Primates) from the southern Bighorn Basin, Wyoming

2021 ◽  
Vol 17 (2) ◽  
Author(s):  
Mary T. Silcox ◽  
Keegan R. Selig ◽  
Thomas M. Bown ◽  
Amy E. Chew ◽  
Kenneth D. Rose
Keyword(s):  
Fossil Record ◽  
Evolutionary Change ◽  
Local Extinction ◽  
Bighorn Basin ◽  
Early Eocene ◽  
Evolutionary Transitions ◽  
Continuous Record ◽  
Extinction Event ◽  
Nearly Continuous

The early Eocene of the southern Bighorn Basin, Wyoming, is notable for its nearly continuous record of mammalian fossils. Microsyopinae (?Primates) is one of several lineages that shows evidence of evolutionary change associated with an interval referred to as Biohorizon A. Arctodontomys wilsoni is replaced by a larger species, Arctodontomys nuptus , during the biohorizon interval in what is likely an immigration/emigration or immigration/local extinction event. The latter is then superseded by Microsyops angustidens after the end of the Biohorizon A interval. Although this pattern has been understood for some time, denser sampling has led to the identification of a specimen intermediate in morphology between A. nuptus and M. angustidens , located stratigraphically as the latter is appearing. Because specimens of A. nuptus have been recovered approximately 60 m above the appearance of M. angustidens , it is clear that A. nuptus did not suffer pseudoextinction. Instead, evidence suggests that M. angustidens branched off from a population of A. nuptus , but the latter species persisted. This represents possible evidence of cladogenesis, which has rarely been directly documented in the fossil record. The improved understanding of both evolutionary transitions with better sampling highlights the problem of interpreting gaps in the fossil record as punctuations.

Evolution of mammalian biology

2004 ◽  
Author(s):  
T.S. Kemp
Keyword(s):  
Fossil Record ◽  
Vertebral Column ◽  
The Body ◽  
Evolutionary Transitions ◽  
Highly Sensitive ◽  
Jaw Musculature ◽  
Very High ◽  
Insight Into ◽  
Biological Differences ◽  
Considerable Insight

There are large biological differences between the mammals and the primitive living amniotes as represented by turtles, lizards, and crocodiles ● Differentiated dentition with occluding post-canine teeth, and radical reorganisation of jaw musculature to operate them ● Differentiation of vertebral column and limb musculature, and repositioning of limbs to bring feet under the body, increasing agility of locomotion ● Relatively huge brain and highly sensitive sense organs ● Endothermic temperature physiology, with very high metabolic rates, insulation, and high respiratory rates ● Precise osmoregulatory and chemoregulatory abilities using loops of Henle in the kidney and an array of endocrine mechanisms Incomplete as it is, the fossil record of the mammal-like reptiles, or ‘non-mammalian synapsids’ permits the reconstruction of a series of hypothetical intermediate stages that offers considerable insight into how, when, and where this remarkable transition occurred. Deriving these stages starts with a cladogram of the relevant fossils that is then read as an evolutionary tree, with hypothetical ancestors represented by the nodes. The characters that define a node, plus the characters of the previous nodes, constitute the reconstruction. The differences in characters between adjacent nodes represent the evolutionary transitions that by inference occurred, and the whole set of successive nodes generates all that can be inferred about the sequence of acquisition of characters. If a hypothetical ancestral synapsid is placed at the base of the cladogram, and a hypothetical ancestral mammal as the final node, then the set of nodes in between represents everything the fossil record is capable of revealing about the pattern by which mammalian characters evolved: the sequence of their acquisition, the correlations between characters, and possibly the rates of their evolution. Of course, the inferred pattern of evolution of characters is only as reliable as the cladogram which generated it, and that in turn is only as realistic as the model of evolution used in its construction from the character data. And of course, there must have been many intermediate stages in the transition than cannot be reconstructed for want of appropriate fossil representation of those particular grades. Nevertheless, limited as it may be, this is what can be known from the fossil record.

scholarly journals A unique winged euthycarcinoid from the Permian of Antarctica

2017 ◽  
Vol 91 (5) ◽  
pp. 987-993
Author(s):  
Joseph H. Collette ◽  
John L. Isbell ◽  
Molly F. Miller
Keyword(s):  
Fossil Record ◽  
Trace Fossil ◽  
Morphological Similarity ◽  
Evolutionary Transitions ◽  
Body Segments ◽  
Rapid Transition ◽  
Proglacial Lake ◽  
High Degree ◽  
Freshwater Environments

AbstractEuthycarcinoid arthropods (Cambrian–Triassic) were likely the first animals to transition from oceanic to freshwater and emergent environments. Although their basic bauplan is well known, they have a poor fossil record because their non-sclerotized exoskeleton was rarely preserved. Euthycarcinoids’ unusual morphology (varying numbers of body segments, seemingly dichotomous possession of either mandibles or a labrum, specialized or generalized limbs, and possession by some euthycarcinoid species of sternal pores—structures possibly analogous to coxal vesicles in myriapods) contribute to uncertainty regarding their relationship to other arthropod groups; while their poor fossil record masks the evolutionary transitions within and between the separate realms they inhabited (marine, freshwater, emergent). A new euthycarcinoid from a Permian polar proglacial lake is described herein that is morphologically unlike all other euthycarcinoids, and interpreted as being well adapted for a nekton-benthic lifestyle. Antarcticarcinus pagoda n. gen. n. sp. possesses a pair of large wing-like processes that project laterally from the preabdominal dorsal exoskeleton. A trace fossil from the overlying Mackellar Formation, cf. Orbiculichnus, which was previously interpreted as having been produced by insects taking off or landing on wet sediments, is reinterpreted herein as being produced by A. pagoda n. gen. n. sp. due to the high degree of morphological similarity between traces and body fossils. This occurrence indicates that euthycarcinoids were able to adapt to life in temperate freshwater environments, while possible subaerial adaptations hint at an ability to breathe air. Indeed, if euthycarcinoids could breathe air, Cambrian terrestrial forays and rapid transition (by the Ordovician) into freshwater environments might be explained.

Evolutionary paleoecology: recent contributions to evolutionary theory

Paleobiology ◽  
1985 ◽  
Vol 11 (1) ◽  
pp. 91-104 ◽  
Author(s):  
Jennifer A. Kitchell
Keyword(s):  
Evolutionary Theory ◽  
Fossil Record ◽  
Differential Rate ◽  
Faunal Turnover ◽  
The Past ◽  
The Individual ◽  
Evolutionary Consequences ◽  
Theoretical Issues ◽  
Species Ecology

In the past decade, evolutionary paleoecology has shifted away from corroborative research of the “me-too-ecology” type toward its proper domain—the evolutionary consequences of ecological properties, roles, and strategies at the individual, population, community, and species levels. The science of evolutionary paleoecology tests for linkage between a species' ecology and its macroevolutionary history. Do the ecological characters of species within clades influence differential rate dynamics, particularly rates of faunal turnover and diversification? Intellectual coequality, once hampered by the misunderstanding that the role of paleoecology is to find examples of past ecology imperfectly entombed in the fossil record, is strengthened by the increasing number of evolutionary ecologists who have called for explicit paleontological contributions to resolve theoretical issues. The fossil record provides a necessary perspective to an understanding of process.

‘Hurrah for the missing link!’: a history of apes, ancestors and a crucial piece of evidence

2011 ◽  
Vol 65 (1) ◽  
pp. 83-98 ◽  
Author(s):  
Peter C. Kjærgaard
Keyword(s):  
Nineteenth Century ◽  
Natural Selection ◽  
Human Evolution ◽  
Fossil Record ◽  
Animal Kingdom ◽  
Missing Link ◽  
Origin Of Species ◽  
Theory Of Evolution ◽  
History Of ◽  
Evolution By Natural Selection

In the nineteenth century the idea of a ‘missing link’ connecting humans with the rest of the animal kingdom was eagerly embraced by professional scientists and popularizers. After the publication of Charles Darwin's Origin of Species in 1859, many tied the idea and subsequent search for a crucial piece of evidence to Darwin and his formulation of the theory of evolution by natural selection. This article demonstrates that the expression was widely used and that the framework for discussions about human's relation to the apes and gaps in the fossil record were well in place and widely debated long before Origin of Species became the standard reference for discussing human evolution. In the second half of the century the missing link gradually became the ultimate prize in palaeoanthropology and grew into one of the most powerful, celebrated and criticized icons of human evolution.

It's a protist-eat-protist world: recalcitrance, predation, and evolution in the Tonian–Cryogenian ocean

2018 ◽  
Vol 2 (2) ◽  
pp. 173-180 ◽  
Author(s):  
Phoebe A. Cohen ◽  
Leigh Anne Riedman
Keyword(s):  
Molecular Clock ◽  
Fossil Record ◽  
Critical Role ◽  
Indirect Evidence ◽  
Tree Of Life ◽  
Current Understanding ◽  
Evolutionary Transitions ◽  
Ecological Interaction ◽  
Fossil Evidence ◽  
Multiple Metrics

Predation, and how organisms respond to it, is an important ecological interaction across the tree of life. Much of our understanding of predation focuses on modern metazoa. However, predation is equally important in single-celled eukaryotes (commonly referred to as protists). In the fossil record, we see evidence of protists preying on other protists beginning in the Tonian Period (1000–720 Ma). In addition, the first evidence of eukaryotic biomineralization and the appearance of multiple unmineralized but recalcitrant forms are also seen in the Tonian and Cryogenian (720–635 Ma), potentially indirect evidence of predation. This fossil evidence, coupled with molecular clock analyses, is coincident with multiple metrics that show an increase in the diversity of eukaryotic clades and fossil assemblages. Predation, thus, may have played a critical role in the diversification of eukaryotes and the evolution of protistan armor in the Neoproterozoic Era. Here, we review the current understanding of predation in the Tonian and Cryogenian oceans as viewed through the fossil record, and discuss how the rise of eukaryotic predation upon other eukaryotes (eukaryovory) may have played a role in major evolutionary transitions including the origins of biomineralization.

Evolutionary Patterns Within Fossil Lineages: Model-Based Assessment of Modes, Rates, Punctuations and Process

2008 ◽  
Vol 14 ◽  
pp. 117-131 ◽  
Author(s):  
Gene Hunt
Keyword(s):  
Fossil Record ◽  
Morphological Evolution ◽  
Phenotypic Change ◽  
Relative Importance ◽  
Phenotypic Evolution ◽  
Evolutionary Patterns ◽  
Evolutionary Transitions ◽  
Direct View ◽  
Great Progress ◽  
Evolutionary Mode

Patterns of phenotypic change documented in the fossil record offer the only direct view scientists have of evolutionary transitions arrayed over significant durations of time. What lessons should be drawn from these data, however, has proven to be rather contentious. Although we as paleontologists have made great progress in documenting the geological record of phenotypic evolution with greater thoroughness and sophistication, these successes have been limited by the use of verbal models of how phenotypes change. Descriptive terms such as “gradual” have been understood differently by different authors, and this has led to completely incompatible summary statements about the fossil record of morphological evolution. Here I argue that the solution to this ambiguity lies in insisting that different evolutionary interpretations be represented as explicit, statistical models of evolution. With such an approach, the powerful machinery of likelihood-based inference can be help resolve long-standing paleontological questions.Here I first review this approach and some aspects of its implementation. Then, I show how this approach leads to new traction on important issues in evolutionary paleobiology, including: understanding modes of evolution and determining their relative importance, separating evolutionary mode from tempo, assessing the evidence for hypotheses of punctuated change, and detecting adaptive evolution in the fossil record.

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