Re: Macroevolution FAQ 2.1D


John Wilkins wrote:
> Macroevolution - its definition, philosophy and history
>
> John Wilkins
>
> Version 2.1 DELTA
>
> To be read in conjunction with Douglas Theobold's 29+ Evidences for
> Macroevolution FAQ.
>
> Contents
> ========
>
> What is Macroevolution?
>
> * The history of the concept of macroevolution
>
> * Confusions
>
> * Is macroevolution reducible to microevolution?
>
> * Species sorting/selection
>
> * Historical constraints/bauplans
>
> * Emergent properties
>
> * Barriers to macroevolution
>
> * Falsifying macroevolution
>
> * Conclusions
>
> * Notes
>
> * References
>
>
> What is macroevolution?
> =======================
>
> Creationists often assert that "macroevolution" is not proven, even if
> "microevolution" is, and by this they seem to mean that whatever evolution is
> observed is microevolution, but the rest is macroevolution. In making these
> claims they are misusing authentic scientific terms; that is, they have a
> non-standard definition, which they use to make science appear to be saying
> something other than it is. Evolution-proponents often say that creationists
> invented the terms. This is false. Both macroevolution and microevolution are
> legitimate scientific terms, which have a history of changing meanings that,
> in any case, fail to underpin creationism.
>
> In science, macro at the beginning of a word just means "big", and micro at
> the beginning of a word just means "small" (both from the Greek words). For
> example, a macrophage means a bigger than normal cell, but it is only a few
> times bigger than other cells, and not an order of magnitude bigger. Something
> can be "macro" by just being bigger, or there can be a transition that makes
> it something quite distinct.
>
> In evolutionary biology today, macroevolution is used to refer to any
> evolutionary change at or above the level of species. It means at least the
> splitting of a species into two (speciation, or cladogenesis , from the Greek
> meaning "the origin of a branch", see Fig. 1) or the change of a species over
> time into another (anagenetic speciation, not nowadays generally accepted
> [note 1]). Any changes that occur at higher levels, such as the evolution of
> new families, phyla or genera, are also therefore macroevolution, but the term
> is not restricted to those higher levels. It often also means long-term trends
> or biases in evolution of higher taxonomic levels.
>
> Microevolution refers to any evolutionary change below the level of species,
> and refers to changes in the frequency within a population or a species of its
> alleles (alternative genes) and their effects on the form, or phenotype, of
> organisms that make up that population or species. It can also apply to
> changes within species that are not genetic.
>
> Another way to state the difference is that macroevolution is between-species
> evolution and microevolution is within-species evolution. Sometimes,
> macroevolution is called "supraspecific evolution" (Rensch 1959, see Hennig
> 1966: 223-225).
>
> There are various views of the dynamics of macroevolution. Punctuated
> equilibrium theory proposes that once species have originated, and adapted to
> the new ecological niches in which they find themselves, they tend to stay
> pretty much as they are for the rest of their existence. Phyletic gradualism
> suggests that species continue to adapt to new challenges over the course of
> their history (see Fig. 1). Species selection and species sorting theories
> think that there are macroevolutionary processes going on that make it more or
> less likely that certain species will exist for very long before becoming
> extinct, in a kind of parallel to what happens to genes in microevolution.
>
> Figure 1: Anagenesis and cladogenesis. Species A anagenetically changes over
> time to become species B, while species B cladogenetically changes over time
> by splitting into species C and D, neither of which are very different from B
> or each other. The anagenesis axis represents change of form, either genetic
> or phenotypic. The cladogenetic axis represents isolation of species from each
> other (for example, reproductive isolation). Of course, cladogenesis and
> anagenesis can often go hand-in-hand as well.
>
>
>
> The history of the concept of macroevolution
> ============================================
>
> In the "modern synthesis" of neo-Darwinism, which developed in the period from
> 1930 to 1950 with the reconciliation of evolution by natural selection and
> modern genetics, macroevolution is thought to be the combined effects of
> microevolutionary processes.
>
> The terms macroevolution and microevolution were first coined in 1927 by the
> Russian entomologist Iuri'i Filipchenko (or Philipchenko, depending on the
> transliteration), in his German-language work Variabilitaet und Variation,
> which was an early attempt to reconcile Mendelian genetics and evolution.
> Filipchenko was an evolutionist, but as he wrote during the period when
> Mendelism seemed to have made Darwinism redundant, the so-called "eclipse of
> Darwinism" (Bowler 1983), he was not a Darwinian, but an orthogeneticist.
> Moreover, Russian biologists of the period had a history of rejecting Darwin's
> Malthusian mechanism of evolution by competition (Todes 1989).
>
> In Dobzhansky's founding work of the Modern Synthesis, Genetics and the Origin
> of Species, he began by saying that "we are compelled at the present level of
> knowledge reluctantly to put a sign of equality between the mechanisms of
> macro- and microevolution" (1937: 12), thereby introducing the terms into the
> English-speaking biological community (Alexandrov 1994). Dobzhansky had been
> Filipchenko's student and regarded him as his mentor. In science as in all
> academic disciplines, it is difficult to deny a major tenet of one's teachers
> due to filial loyalty, and Dobzhansky, who effectively started the modern
> Darwinian synthesis with this book, found it disagreeable to have to deny his
> teacher's views (Burian 1994).
>
> The term fell into limited disfavour when it was taken over by such writers as
> the geneticist Richard Goldschmidt (1940) and the paleontologist Otto
> Schindewolf to describe their orthogenetic theories. As a result, apart from
> Dobzhansky, Bernhardt Rensch and Ernst Mayr, very few neo-Darwinian writers
> used the term, preferring instead to talk of evolution as changes in allele
> frequencies without mention of the level of the changes (above species level
> or below). Those who did were generally working within the continental
> European traditions (as Dobzhansky, Mayr, Rensch, Goldschmidt, and Schindewolf
> are) and those who didn't were generally working within the Anglo-American
> tradition (such as John Maynard Smith and Richard Dawkins). Hence, use of the
> term "macroevolution" is sometimes wrongly used as a litmus test of whether
> the writer is "properly" neo-Darwinian or not (Eldredge 1995: 126-127).
>
> The term was revived by a number of mainly paleontological authors such as
> Stephen Jay Gould and Niles Eldredge, the authors of punctuated equilibrium
> theory (see Eldredge 1992), who argued that something other than
> within-species processes are causing macroevolution, although they disavow the
> orthogenetic view that evolution is progressive. Many paleontologists have
> held that what happens in evolution beyond the species level is due to
> processes that operate beyond the level of populations - for example, the
> notion of species selection (the idea that species themselves get selected
> similarly to the way alleles get selected within populations, see Grantham
> 1995, Rice 1995, and Stidd and Wade 1995 for reviews and discussions.
>
> The idea that the origin of higher taxa, such as genera (canines versus
> felines, for example), requires something special is often based on the
> misunderstanding of the way in which new lineages arise. The two species that
> are the origin of canines and felines probably differed very little from their
> common ancestral species and each other. But once they were taxonomically
> isolated from each other, they evolved more and more differences that they
> shared internally but that other lineages didn't. This is true of all lineages
> back to the first eukaryotic (nuclear) cell. Even the changes in the Cambrian
> explosion are of this kind, although some (e.g., Gould 1989) think that the
> genomes (gene structures) of these early animals were not as tightly regulated
> as modern animals, and therefore had more freedom to change.
>
> Confusions
> ==========
>
> The meaning modern authors give to the terms "macroevolution" and
> "microevolution" is often confusing, and varies according to what it is they
> are discussing. This is particularly the case when "large-scale" evolutionary
> processes are being discussed. For example, R. L. Carroll, in his
> undergraduate textbook (1997: 10) defines microevolution as "involving
> phenomena at the level of populations and species" and macroevolution as
> "evolutionary patterns expressed over millions and hundreds of millions of
> years". Eldredge says, "Macroevolution, however it is precisely defined,
> always connotes "large-scale evolutionary change" (1989: vii) and throughout
> his book speaks of macroevolution as roughly equivalent to the evolution of
> taxa that are of a higher rank than species, such as genera, orders, families
> and the like. In his book Evolution, Mark Ridley defines the terms thus (2004:
> 227):
>
> <bq>Macroevolution means evolution on the grand scale, and it is mainly
> studied in the fossil record. It is contrasted with microevolution, the study
> of evolution over short time periods, such as that of a human lifetime or
> less. Microevolution therefore refers to changes in gene frequency within a
> population .... Macroevolutionary events events are much more likely to take
> millions of years. Macroevolution refers to things like the trends in horse
> evolution ... or the origin of major groups, or mass extinctions, or the
> Cambrian explosion .... Speciation is the traditional dividing line between
> micro- and macroevolution.<eq>
>
> There are many papers published that use the term in this "higher category"
> way; why is that?
>
> Science is not always consistent in its use of terms; this is the source of
> much confusion. Sometimes this is carelessness, and sometimes this is because
> of the way in which terms are extended over time. When biologists and
> paleontologists talk about macroevolution in the sense of "large-scale"
> evolution, they are strictly speaking meaning only a part of the phenomena the
> term covers, but it is the most interesting part for those specialists. That
> is, they are talking about the patterns of well-above-species-level evolution
> (Smith 1992).
>
> In order to have a pattern you have to be able to compare three or more
> species (Fig. 2). On its own, species A forms no patterns, and so long as the
> changes within it do not result in a new species, evolution is
> microevolutionary. If a new species B splits from A, then you have
> macroevolution, but no patterns. For there to be a pattern, you need to be
> able to say that one species is more closely related to another than a third
> is (in this case, that A is closer to B than it is to C).
>
>
> Figure 2: If only two species or higher taxa are identified (red set) there is
> no pattern. If three or more (blue set) are included, then you are able to say
> that one is more closely related, evolutionarily speaking, to another than the
> third - in this case A and B are more closely related to each other than
> either is to C, which split off earlier than the A/B split.
>
> The sorts of patterns that people are interested in when discussing
> macroevolution tend to involve very many species, either as a single large
> group ("higher taxon") or individually. This is why many authors use the term
> "macroevolution" to mean "large-scale evolution". However, just like
> anagenetic speciation, "large-scale" is an arbitrary and often subjective
> term, and the objective meaning of macroevolution is evolution at or above the
> level of species [note 2]. Hence, Carroll's "definition" is mistaken, despite
> his prominence in the field, and this sort of confusion is to be avoided.
>
> A more considered definition is that of Levinton: "I define the process of
> macroevolution to be... the sum of those processes that explain the
> character-state transitions that diagnose evolutionary differences of major
> taxonomic rank" (Levinto 2001:2). Here, Levinton is trying to define
> macroevolution in a way that is not prejudicial for the debate. It focuses on
> the characters of taxa, and is neutral about what level of taxa are involved.
> He denies the "species level" definition because he thinks, I believe wrongly,
> that it makes macroevolution the study of speciation. But if the "pattern"
> analysis above is right, then macroevolution includes the study of speciation,
> but it is hardly restricted to it. The scope of macroevolution rises very far
> above that level. It's worth observing, though, that higher taxonomic levels
> are artificial, constructed for convenience by systematists. Conclusions about
> evolution that rely upon taxonomic levels like genera or families (e.g.,
> Raup's and Sepkoski's work on extinction, Raup and Sepkoski 1986, Sepkoski
> 1987, Raup 1991) must be taken with a grain of salt, since the taxon levels
> are not the "same" across phylogenetically distant groups, because they are
> not "natural". Incidentally, the study of speciation has taken off
> significantly in recent years with some solid theoretical work that suggests
> many macroevolutionary effects are indeed the result of population level
> processes (Gavrilets 2003, 2004, Gavrilets and Gravner 1997).
>
> Is macroevolution reducible to microevolution?
> ==============================================
>
> From a philosophical perspective, one might say macroevolution is just a
> bunch of microevolution. It's also just a bunch of chemistry. And physics.
> These are unhelpful answers, so we might find it worthwhile to ask how
> scientific domains relate to each other. Whenever a scientist or philosopher
> asks if two theories are reducible one to the other, there are several answers
> that can be given. One is if the first theory being reduced A is adequately
> captured by the reducing theory B. Another is that A is not entirely captured
> by B. A third is that A and B each have overlapping areas, and areas only they
> capture. This is called the problem of theory reduction.
>
> Reduction has been a philosophical problem with respect to science for about
> 60 years. It comes in three main varieties: methodological reduction, which is
> the notion that one ought to try to explain wholes in terms of the parts and
> their interactions; ontological reduction, which is the notion that all the
> units or entities of one theory are composed of units or entities of another;
> and metaphysical reduction, which is the claim that only one kind of thing
> exists. Ontological reduction includes reducing all the laws and dynamic
> generalisations of the A theory to laws and dynamic generalisations of the B
> theory. In philosophy of science, the case is often put in just these terms,
> but increasingly philosophers are attending to the objects of scientific
> theories as well as the models.
>
> Consider atoms, as an example. At the time Dalton proposed atoms, he was
> trying to explain larger things in terms of smaller things with properties
> that added up to the properties of the whole. He did this because he felt it
> was a good rule to follow, explaining wholes in terms of parts. So he was a
> methodological reductionist, explaining things in terms of ontological
> reduction. He wasn't a metaphysical reductionist, though, if he allowed that
> reality comprised stuff other than atoms - such as gravity or light. A
> parallel case is genetic reductionism, in which behaviours are "reduced" to
> genes - it is both methodologically and ontologically reductionist in the
> domain of behaviour and biology. It doesn't assert that everything is genetic,
> though, because we know that how genes are expressed is affected by
> non-genetic factors, such as the availability of food during crucial phases of
> development.
>
> The reductive relation between microevolution and macroevolution is hotly
> debated. There are those who, like Dobzhansky, say that macroevolution reduces
> to microevolution. We can break this down to three claims: within the
> "universe" of biology, one might say that everything biological is best
> explained by microevolution (methodological), or that all entities and
> processes of macroevolution are microevolutionary (usually genetic - this is
> ontological), or that everything that happens (in biology) is genetic
> (metaphysical). In the metaphysical case, genes acquire an almost mystical
> significance, and no serious biologist makes this claim, although opponents
> accuse (particularly Dawkins) some of doing so.
>
> The two reductive claims we will consider now are the methodological and the
> ontological.
>
> The methodological claim that macroevolution (Ma) reduces to microevolution
> (Mi) is a claim that the optimal solution for investigating evolution is to
> apply modelling and testing genetic techniques. And this has been very
> successful. However, it has not been an unqualified success - developmental
> biology is not easily reducible to genetics, nor is ecology. Cell division,
> specialisation and signalling explain development, and the relationship
> between genes and these processes is equivocal - that is, some genes play a
> role in many developmental processes, and many genes play a role in pretty
> well all processes. Moreover, there are many other things involved in
> development: epigenetic factors (para-genetic inheritance and environmental
> modulation of genetic effects), cytological inheritance (organelles, cell
> membranes, ribosomes and enzymes from parent cells, and parent organisms). So
> genes on their own are not enough to explain why evolution occurs along the
> pathways that it has. One reaction to methodological reductionism in biology
> has been to assert that genes are merely "bookkeeping" entities for
> evolutionary investigation (Gould 2002). The methodological reduction is not
> sufficient, even if genes turn out to be the only significant "players" in
> evolution.
>
> It is this assumption that antireductionists challenge in the ontological
> reductionist case. There are entities and processes, they say, that affect
> macroevolutionary dynamics which are not in their nature microevolutionary.
> What could these be?
>
> Well, a list that Mi-reductionists would accept includes climate change,
> geomorphological processes like mountain building, tectonic isolation and
> drift, vulcanism, extraterrestrial influences like bolide impacts, galactic
> wobble, precession of the earth's axial rotation, and possibly even local
> stars approaching and changing the impact on the earth of comets and other
> bolides in a cycle averaging around 13 million years. The point the
> Mi-reductionists would make, though, is that everything that these things
> affect is microevolutionary - only the frequencies of genes in populations,
> and so on. They serve as the environment in which genes change their frequency
> (or fail to, and the species goes extinct). What the "player" is in Mi is the
> population, comprising organisms, traits and genes; in short, the gene pool.
> Nothing else is important.
>
> Ma-nonreductionists will argue, however, that there are emergent processes and
> entities in macroevolution that cannot be captured ontologically. There are
> several candidates for these, each challenged by Mi-reductionists. The basis
> for this is a view of evolution as a series of inclusive hierarchical levels,
> each of which is somewhat independent of the lower levels.
>
> Figure 3.The hierarchical relations between Macroevolution (Ma) and
> Microevolution (Mi), and the Environment (E). Mi consists of Organisms (O) and
> their Interactions (I) together with factors from the Environment. Examples
> A-G illustrate the levels of environmental influence: A. Mutation caused by
> thermal or radioactive interference. B. Heat shock on developing zygotes. C.
> Local adaptation to a niche. D. Climatological change causing migration. E.
> Geographical isolation. F. Environmental changes that cannot be adapted to for
> historical or developmental reasons (causing extinction). G. Changes that
> affect speciation rates and type.
>
> Species selection/sorting
> -------------------------
>
> Elisabeth Vrba (Vrba 1985, Gould and Vrba 1993) proposed that species come
> into being and go extinct in a biased way. Generalist species (eurytopes) tend
> to survive longer - when one food source is unavailable, they switch to
> another until it comes back, thus avoiding predator-prey cycles known as
> Lotka-Volterra cycles (such as fox numbers dropping dramatically when rabbits
> are over-predated). Specialist species (stenotopes), though, are sensitive to
> the contingent changes forced by climate changes - even long droughts. But
> specialists tend to speciate more frequently, even if they go extinct more
> frequently, too, as they adapt to loss of degradation of their food resources.
> Selection is a process of differential survival correlated with ecological
> success, so proponents of selection of this kind consider this to be a
> selection process on species. Others refer to it as a species "sorting"
> process (see Grantham 1995 for a review) because species are not sufficiently
> like organisms/individuals. Gould published an extensive discussion shortly
> before his death (Gould 2002: 644-673). It is worth noting here that if
> species are selected, it is more like asexual evolution than the evolution of
> sexual organisms, as species rarely evolve by recombining lineages, or at
> least animal species don't. Plant species often do (at about 5-10% of new
> species), and we have insufficient evidence about other groups to generalise.
>
> Historical constraints/bauplans
> -------------------------------
>
> Some "Non-Synthesis" or post-Synthesis evolutionists think that the processes
> that cause speciation are of a different kind to those that occur within
> species. That is, they admit that macroevolution occurs, but think that normal
> genetic change is restricted by such proposed mechanisms as developmental
> constraints. This view is associated with the names of Schmalhausen and
> Waddington, who were often characterised as being non-Darwinians by the modern
> synthesis theorists. However, with the recent rise of the field known as
> "evo-devo", or evolutionary developmental biology, many of the ideas proposed
> by Waddington and others have been revisited (Schlichting and Pigliucci 1998,
> Amundson 2005, Levinton 2001).
>
> There are several kinds of constraints upon evolution. The best known is of
> course selective constraints: some forms are just not viable, one way or
> another. But developmental constraints have been proposed to explain why, for
> example, in centipedes the segment number is always an odd number (Arthur
> 2003). In these cases, the constraint is the nature of the developmental
> system itself. Others (Schlichting and Pigliucci 1998) consider this as much a
> case of selection as anything else; the developmental system - indeed, the
> ability to evolve - is subjected to selection as well. Historical constraints
> form a kind of "you can't get there from here" class. Once something has
> evolved, any state that requires reversing the evolution of that trait to get
> somewhere else is vanishingly unlikely. So the dynamics of the evolution of
> that trait are constrained by what has evolved already.
>
> The notion of a bauplan - a German word meaning "blueprint" or "builder's
> plan" - has been applied to evolution most notably by Gould and Lewontin
> (1979). Bauplans (the word takes the English plural in this context) are the
> body plans of phyla, the second highest Linnaean taxonomic level. Since
> Georges Cuvier named them in the early 19th century, phyla (singular phylum)
> have been seen as distinct and natural groupings within animals (arguably not
> in plants, where the level is Division). Bauplans have been tied into the
> notion of a developmental and a historical constraint. There have been
> criticisms of the notion of a bauplan as being mystical in its causal power.
> Others see it as something that cannot be easily modified by the processes of
> within-species (Mi) evolution.
>
> Emergent Properties
> -------------------
>
> One of the claims made by Ma-nonreductionists is that evolution occurs on
> emergent properties. An emergent property is one in which the property of a
> higher level system or object cannot be reduced to the properties of its
> constituent elements, but instead it "emerges" from the interactions between
> them (O'Connor and Wong 2002, Man*** 2004). Emergent properties were first
> proposed by, coincidentally, a friend of Darwin's, G. H. Lewes, in the field
> of psychology, but the idea goes back to J. S. Mill in 1843. It is often
> sloganised as "the whole is more than the sum of its parts". Emergence was
> made an issue when applied, ironically enough, to evolution in the 1920s by
> Jan Smuts and C. D. Broad.
>
> In evolution, a species is considered by some Ma-nonreductionists as being a
> system that has properties above the level of the individual, the kin, or the
> deme (breeding population), based somewhat on Mayr's definition of a species
> as being a protected breeding gene-pool (Mayr 1996). This has been challenged
> on various grounds, not least being that usually species appear to have no
> systematic interactions between all its parts, and that the appropriate level
> is the population.
>
> In this writer's opinion, an emergent property is simply a property that we
> have trouble computing or predicting from a knowledge of the constituent
> parts, but this simple dismissal is insufficient. We have to identify the
> following aspects of the matter:
>
> E: The environmental factors in which a species exists - for example,
> geological and climatological changes
>
> O: the properties of the organisms - for example their traits and capacities
> severally
>
> I: the interactions between the organisms - for example, the lineages of
> heredity at the gene, haplotype, genome and developmental levels of
> organization. Also, the issue of organisms changing their environment through
> a process known as "niche construction" affects both E and I (Oyama et al.2000).
>
> Ma is therefore the result of the union, in some way, of E, O and I. This can
> be massively complex and give rise to "sudden" changes [note 3], or hold the
> evolutionary process in a state of stasis for long periods. Whether or not one
> wants to call this "repeated rounds of microevolution" or not (Erwin 2000) is
> open to debate. And even if it is, we still need to know the models for how
> they relate, and what Mi covers.
>
> Barriers to macroevolution?
> ===========================
>
> It is a common claim of antievolutionists that there is a limit to the amount
> of change that can be made. Creationists, like Gish (1979) claim that there is
> some limitation within "basic kinds", without being able to express exactly
> what basic kinds might be, or why change is restricted within them. Others,
> such as Johnson (1991:18) claim that the limit lies in the availability of
> genetic variety, and that when that limit is reached change ceases, although
> he does accept that "Darwinists" have "some points to make" - although he is
> hardly fair when he says that variation "might conceivably be renewed by
> mutation, but whether (and how often) this happens is not known" (p19). Of
> course it is known. We have had experimental evidence of rates of mutations
> since the 1910s, and modern research both mathematically and empirically
> confirms that rates of mutation occur at around 0.1-1.5 per zygote, which is
> to say every embryo has around 1/1000th to 1.5 mutations (Crow 1997). The
> average mutation rate - that is the average rate of persisting mutations in a
> population - is 2.2 x 10-9 (Kumar and Subramanian 2002). Further, genes aren't
> identical in their evolution to the species; a field known as coalescence
> genetics covers the ability of novel genes to persist across speciation, so
> that the variability is "available" when it is selectively advantageous (Hey
> and Walkley 1997). Note that this is not to say that variation is maintained
> in order to be available. It's just that it is available when selective
> pressures change some of the time.
>
> Creationists often say that species cannot be evolved from each other because
> chromosome numbers are different. Humans, for example, have 46 chromosomes,
> while chimpanzees have 48. But the human chromosome 2 is the result of what is
> called a Robertsonian fusion - the ancestral ape chromosomes 2p and 2q appear
> to have fused at their ends (telomeres) to form the human chromosome 2
> (Williams, not dated), and other species that have large chromosomal
> differences can still interbreed (Nevo et al. 1994). DNA aligns according to
> local sequence rather than large-scale chromosome structure, and this is why
> inversions and translocation in parts of the sequence still allow interbreeding.
>
> There appears to be no single amount of genetic variation common between
> closely related species that prevents interbreeding. In some, only a few are
> sufficient. In others, much variation, such as the large chromosomal
> difference in Nevo's mole rats, fails to prevent interbreeding. Introgression,
> or the leakage of genes across species boundaries, has been observed in
> lizards, plants, birds, and fish.
>
> In summary, there is no barrier to species forming. This may not be enough to
> show that large-scale macroevolution occurs, though, according to writers like
> Johnson and Hitching (1982), but the logic here implies some causal force
> actively preventing change, rather than a problem with change occurring. For
> if there is enough change to form new species, and each species is slightly
> different from its ancestor, then simple addition shows that many speciation
> events can cause large-scale evolution over enough time. A journey of a
> thousand miles begins with a single step. Conversely, many single steps can
> traverse long distances. There is no evidence of any kind of barriers to
> large-scale change (Brauer and Brumbaugh 2001).
>
> Falsifying macroevolution
> =========================
>
> Antievolutionists try to make out that macroevolution is a tautology, the way
> they claim that natural selection is a tautology. The implication is that
> macroevolution cannot be tested and shown to be wrong, and therefore it is not
> science.
>
> To clarify this, consider what it is that scientists test when they test a
> hypothesis. Let's suppose that we are testing the idea that global warming is
> caused by a rise in CO2 in the atmosphere. There are two parts to this - one
> is that CO

You also might want ot point out that many YECs claim that all original
animal "kinds" were vegetarian. And carnivorous animals originated from
microevolution with vegetarian ancestors since the first human sin
around 6,000 years ago. And you can point out that such YEC
microevolution exceeds the wildest imagination of evolutionary theory.

Here are most of the ideas on the subject from both AiG and ICR:
http://www.answersingenesis.org/home/area/faq/bad_things.asp

.