Yesterday, November 24th was evolution day: the 150th anniversary of the publication of Charle’s Darwin’s revolutionary book, The Origin of Species.

Here’s the article. (H/T Neil Simpson)

Excerpt:

On one of the Galápagos islands whose finches shaped the theories of a young Charles Darwin, biologists have witnessed that elusive moment when a single species splits in two.

Well, that would be very interesting… if it were true. But whenever I’ve heard these finches mentioned, it turns out that what actually happened is that populations of different kinds of finches increase and decrease in response to changing environmental conditions. No finch’s beak actually changes size! Some finches with beaks more adapted to the environmental conditions survive and leave more offspring than other finches who are not as adapted. When conditions change, the changes in populations reverse themselves and return to equilibrium.

Evolution News explains:

The deeper problem with the Wired Science report is not its perpetuation of the legend of Darwin’s finches, but its false claim that biologists have now “witnessed that elusive moment when a single species splits in two.” This is not what Peter and Rosemary Grant reported in their scientific article in the Proceedings of the National Academy of Sciences. ⁶

According to the Grants, in 1981 they found an unusually large male medium ground finch (scientific name: G. fortis) on the island of Daphne Major that they labeled 5110. They inferred that it had probably immigrated from the nearby island of Santa Cruz—though they could not be certain. For 28 years, the Grants followed all known descendants of this presumed immigrant, and genetic analysis suggested that after 2002 the descendants of 5110 bred only with each other (and were thus “endogamous”). The inbred group had a distinctive song that may have contributed to its reproductive isolation from other medium ground finches that were in the same area (“sympatric”).

But the Grants did not go so far as to label the inbred descendants a new species. “We treat the endogamous group as an incipient species because it has been reproductively isolated from sympatric G. fortis for three generations and possibly longer.” But an “incipient species” is not the same as a new species. In The Origin of Species, Darwin wrote: “According to my view, varieties are species in the process of formation, or are, as I have called them, incipient species.” ⁷ But how can we possibly know whether two varieties (or races) are in the process of becoming separate species? Saint Bernards and Chihuahuas are two varieties that cannot interbreed naturally. The Ainu people of northern Japan and the !Kung of southern Africa are separated not only geographically, linguistically, and culturally, but also (for all practical purposes) reproductively. Are dog breeds and human races therefore “incipient species?”

There’s no way we can know, unless we observe varieties becoming separate species at a future date. Designating two reproductively isolated populations “incipient species” is nothing more than a prediction that speciation will eventually occur. It is a far cry from observing the origin of a new species.

Read the rest here. References to peer-reviewed literature are provided.

It’s pretty rare that biologists find an instance where speciation appears to have occurred right in front of their very eyes, but it appears that Peter and Rosemary Grant have looked closely enough over the course of a few decades to have seen it. As Allen writes on The EvolutionList, A New Species of Finch may have Evolved in the Galapagos:

Peter and Rosemary Grant have been studying the finches of Daphne Major, a small island in the Galapagos archipelago since 1973. In PNAS, they have proposed that a population of finches on Daphne Major may be on the verge of becoming a new species of finch. Here’s how their proposal was reported at Nature.com News:

“It was in 1981, that the Grants spotted an unusually heavy medium ground-finch (Geospiza fortis). At 29.7 grams, the male was more than 5 grams heavier than any they had seen on Daphne Major before. Genetic analysis showed that it probably came from the neighbouring island of Santa Cruz.

The Grants numbered the bird 5110 and followed it and all its known descendants over seven generations. Many of its descendants stuck out from the other G. fortis on Daphne Major: they had unusually shaped beaks and their songs differed from those of the other finches.

…

In the fourth generation, a severe drought hit the island and 5110’s descendants were reduced to one male and one female — a brother and sister. From then on the immigrant lineage isolated itself, breeding with no other G. fortis on the island….

Go check out the rest of Allen’s post for his analysis, and check out the article in PNAS as well. The Grants present the take-home message there in the final part of the abstract: “The study reveals additional stochastic elements of speciation, in which divergence is initiated in allopatry; immigration to a new area of a single male hybrid and initial breeding with a rare hybrid female.”

• The secondary contact phase of allopatric speciation in Darwin’s finches. Grant P.R. & Grant B.R. Proc. Natl Acad. Sci. USA, advance online publication (2009).

Here are a couple of odds and ends on this Thursday afternoon.

For those following the recent debate about species fixity on this blog, Todd Wood has added his own assessment of the situation. I meant to link to his comments earlier, but got waylaid with various other things. Basically Todd thinks WebMonk has a point in that the wider creationist movement has promoted fixity, but agrees with me that it’s unfair to associate young-age creationism exclusively with that position as though the two were synonymous. He concludes:

On the other hand, as Paul Garner, his other commenters, and I have documented, speciation has a long tradition in creationism stretching back even before Darwin. I also think Paul’s critique of Denis Alexander is right on the mark. For Alexander to equate young earth creationism with species fixity is preposterous and irresponsible. It’s a classic straw man argument. It would be nice if our critics actually criticized the things we really believe. Species fixity has not been a part of real creationism for decades. Get with the program.

Also somewhat belatedly, I thought John Woodmorappe’s paper on hardgrounds in the summer edition of the Creation Research Society Quarterly was worthy of an honourable mention (Woodmorappe 2009). Hardgrounds are synsedimentarily lithified carbonate sea-floors, often associated with well preserved faunas of encrusting and boring organisms, and they’re found throughout the Phanerozoic rock record. They pose something of a challenge to Flood geology because of the time thought to be required for their development. Woodmorappe has written on hardgrounds previously (Woodmorappe 2006; Woodmorappe and Whitmore 2004) and in this latest paper he suggests some alternative hypotheses for hardground formation during the Flood. Most of his proposals are highly speculative and obviously need to be tested in specific cases against field and experimental data, but, fair dues to Woodmorappe, he’s actually attempting to make sense of problematic geological data that creationists have tended to neglect over the years. Here’s his abstract:

Transport processes can potentially account for in situ hardgrounds in the sedimentary record. Steadily accumulating evidence undermines the certitude of life-position inferences of at least certain fossils. Some turbidity currents and debris flows allow for the contemplation of large-scale transport, imbrication, and coplanar deposition of large, flat slabs of antediluvian hardground origin. Modern volcanoes demonstrate that released gas can cause the flotation of large rock slabs. Finally, many in situ hardgrounds show evidences at least suggestive of a composite, allochthonous origin. A hardground-conduit hypothesis posits that hardgrounds formed in pseudokarstic-submarine (underwater cavelike) structures. This solves the apparent problems of time and stratigraphically superposed hardgrounds. The hardiness of hardground organisms is just one factor consistent with this hypothesis.

References

Woodmorappe J. 2006. Hardgrounds and the Flood: the need for a re-evaluation. Journal of Creation 20(3):104-110.

Woodmorappe J. 2009. The universal deluge: alternative hypotheses for hardground origins. Creation Research Society Quarterly 46(1):7-14.

Woodmorappe J. and Whitmore J. 2004. Field study of purported hardgrounds of the Cincinnatian (Ohio, USA). TJ (now Journal of Creation) 18(3):82-92.

Straying far from familiar
this heat invaded a thought
made action,
and food.

This seemed complicated and
competent a thing to
consume, beneficial
to the taste.

When those two then
became one, piece by piece,
as the thrill passed and
an empty quiet remained,

I wonder if there was a mind to pass?
A thought to cross it?
And whether anyone will find a way to know
or if we will care then, or now.

A fruit fallen from the tree
a sweet smelling species then,
to one, consumed by another,
did the smell of murder then cause a hunt?

A hunted murderer
daunted inside this new world, this
real reality of impending death, or survival,
suddenly swirling with fear.

It stands there, begging the question.

On November 4 and Dec 2, we will be watching a DVD by Ralph Muncaster, “Creation vs. Evolution.”

Many of the brief segments of this video are available on YouTube if you are interested in watching them. The group had a lively discussion, as we don’t necessarily agree with this video on all details, but found many of the facts presented extremely helpful and interesting.

The December meeting will include the “Appendices” which are more technical and in-depth.

Perhaps in an effort to stir the pot so to speak, Corey at 10,000 Birds raised an interesting question a few days ago: Can Creationists Be Birders? The short answer is “Of course!” For most birders, the appreciation of birds does not extend much beyond the aesthetic beauty of the birds and the ability to match a bird with a name. That may be sufficient for some people just as knowing the names of their co-workers and acquaintances is sufficient, but when they’re finished, they know very little about the birds (or persons) themselves.

If you dig a layer deeper, a person can learn about the reproductive cycles and diets of the birds they watch. A person can also learn the geographical ranges of the birds that he or she knows. Or the quirky behaviors, flight styles, and habitat proclivities of those birds. Or all of the subtle hints that go into what birders call General Indicators of Size and Shape (GISS), which is often extended to include not just size and shape but any clue at all that can be used to distinguish what group or species of bird that may you glimpse.

An overlay of phylogeny and the biogeography for Monarch Flycatchers

First, the body of knowledge that has since formed the evidence for evolution was collected by creationists first and foremost. Creationism was still considered mainstream science during this golden age of studying taxonomy and morphology. Linnaeus, certainly no evolutionist, established the system of scientific classification that we use today, and his groupings were based upon shared physical characteristics. Only his groupings for animals remain to this day, and the groupings themselves have been significantly changed since Linnaeus’ conception, as have the principles behind them. Nevertheless, Linnaeus is credited with establishing the idea of a hierarchical structure of classification which is based upon observable characteristics — something that is entirely compatible with both the concepts of special creation and speciation.

Even Charles Lyell, who established a much older age for the Earth and paved the way for gradualism, had defended the thesis of “Centers of Creation.” These Centers offered a convenient argument for not only the periodic appearance of new species in the fossil record but also the observable differences between the floura and fauna of the continents, without really explaining how they got there. So, not only taxonomy but the observations of morphology and paleontology are compatible with either hierarchical organization of Earth’s flora and fauna.

In contrast, many of the greatest contributions to the growth of evolutionary thought sprang from observations of birds. It seems no coincidence that Darwin’s, Wallace’s and Mayr’s initial insights into the origins of species came from ornithology, and the biogeography of birds in particular. Evolution did not have a strong case until after Darwin’s Origin, which although it dealt little with the origin of species or birds, was instigated by a revelation gleaned from the puzzle of the Galapagos Mockingbirds, as Darwin’s meticulous notebooks revealed:

When I recollect the fact that [from] the form of the body, shape of scales and general size, the Spaniards can at once pronounce from which island any tortoise may have been brought; when I see these islands in sight of each other and possessed of but a scanty stock of animals, tenanted by these birds, but slightly differing in structure and filling the same place in nature; I must suspect they are only varieties. The only fact of a similar kind of which I am aware, is the constant asserted difference between the wolf-like fox of East and West Falkland Islands. If there is the slightest foundation for these remarks, the zoology of archipelagoes will be well worth examining; for such facts would undermine the stability of species.

So it was here, with this odd distribution of mockingbirds (as well as a few other details of island biogeography), that Darwin first thought that Lyell’s hypothesis of centers of creation and its principle conclusion – the fixity of species – had been undermined. He also later learned that many of the other birds that he thought to be wrens, warblers, etc., were in fact finches which provided the possibility of common ancestry between seemingly unrelated “kinds.” This is the case for a variety of phylogenies, such as the honeycreepers shown in the image below – an impressive display of diversity from a strange collection of birds that appear unrelated, but bear strong resemblances to one another upon closer inspection, that betray their common ancestry.

Similarly and quite independently, Alfred Russell Wallace made the same observations first across South American and then again in the Malaysian archipelago. And summarizing a career of collecting bird and insect specimens of tremendous variety – both between and within species – he proposed what became known as “Sarawak’s Law” in 1855: “Every species has come into existence coincident both in space and time with a pre-existing closely allied species.”

This simple enough explanation also defied arguments based on fixity of species or special creation. And, knowing this biological law, you can have some kind of inkling as to where the species of bird you may be looking at has come from. Even where the relationship of one taxon to others is unclear, it follows that it is simply unclear how that particular taxonomic group originated, not that it did not originate from a common ancestor with another group at all. In this way, denying speciation closes doors to understanding where a species of bird came from, or how it may be related to sister species or clades. Some well-studied examples may help illustrate this:

1. Single origin of a pan-Pacific bird group and upstream colonization of Australasia, by Christopher E. Filardi & Robert G. Moyle. (2005) Nature 438:216-219. (The paper on Monarch Flycatchers, shown in the image near the top of this post)
2. The Origin and Diversification of Galapagos Mockingbirds, by Brian S. Arbogast, Sergei V. Drovetski, Robert L. Curry, Peter T. Boag, Gilles Seutin, Peter R. Grant, B. Rosemary Grant, and David J. Anderson. (2006) Evolution 60(2):370-382. (Mentioned briefly above)
3. Clade-specific morphological diversification and adaptive radiation in Hawaiian songbirds, by Irby J Lovette, Eldredge Bermingham, and Robert E Ricklefs. (2001) Proceedings of the Royal Society of London: Biological Sciences 269:37-42.

Hawaiian honeycreepers radiated from an ancestral founder that was a cardueline finch.

So while discussing how creationists may “appreciate” something pertaining to the origins and diversity of birds can be fickle, there are clearly some things that they cannot explain with a denial of speciation. Clearly I’m not speaking to “theistic evolutionists” here, and I’m not criticizing religion per se (here, anyway). I want to challenge one specific religious view with a few puzzles from the natural world. Puzzles which speciation appears to answer, but special creation cannot:

1. How do you comprehend the ongoing debates in ornithology over adaptive “niche-filling” and geographical separation for the origins of new species?

Since Mayr’s 1942 book Systematics and the Origin of Species, there has been an ongoing debate in biology over speciation. That is, is natural selection and an empty “niche” sufficient for a new species to emerge, or do you need geographical isolation to allow for genetic drift? Most biologists tend to think the latter, because natural selection does not select for reproductive isolation, which is required for the species to remain distinct. The study of the Geospiza group of Galapagos ground finches (aka Darwin’s finches) is perhaps the best study of adaptive speciation. Ongoing since 1973, Peter and Rosemary Grant have been trekking to the Galapagos island of Daphne to track the fluctuations of disruptive selection and hybridization, and the outcome of the studies leaves a reader with the ambiguous nature of adaptive speciation. See the book Evolution on Islands and chapter 9 in particular for more on this subject (Amazon US/UK).

2. How do you understand why we say that the best places for seeing a diverse group of new birds (for the observer) is on remote islands and archipelagos?

This follows from #1: If speciation occurs and island isolation speeds it along, then most islands will be a great place to observe newer endemic species seen nowhere else in the world. The conclusion to this “If, then” statement may seem unremarkable to most people, but it is one that has puzzled biologists since the Voyage of the Beagle, and the observation that paved the way for The Origin of Species

3. And, how do you comprehend the arguments underlying debates among ornithologists and taxonomists over “lumping” versus “splitting?”

And finally, if you deny that speciation occurs, how do you follow the debates over whether separate populations of birds are the same or separate species? The ornithologists will be speaking from completely different theoretical arguments than any creationist, effectively shutting out creationists from the discussion.

The creationist can certainly identify a bird from his or her field guide just as well as an evolutionist, and appreciate its appearance and behavior, but they’re missing details regarding the origins and diversity of those birds that inform the rest of us.

Cronus

Bit of a strange one for you today, but here’s a post I hope you’ll enjoy.

My colleague, Barry Brook, and I recently published a paper in the very new and perhaps controversial online journal , the Journal of Cosmology. Cosmology? According to the journal, ‘cosmology’ is:

“the study and understanding of existence in its totality, encompassing the infinite and eternal, and the origins and evolution of the cosmos, galaxies, stars, planets, earth, life, woman and man”.

The journal publishes papers dealing with ‘cosmology’ and is a vehicle for those who wish to publish on subjects devoted to the study of existence in its totality.

Ok. Quite an aim.

Our paper is part of the November (second ever) issue of the journal entitled Asteroids, Meteors, Comets, Climate and Mass Extinctions, and because we were the first to submit, we managed to secure the first paper in the issue.

Our paper, entitled The Cronus hypothesis – extinction as a necessary and dynamic balance to evolutionary diversification, introduces a new idea in the quest to find that perfect analogy for understanding the mechanisms dictating how life on our planet has waxed and waned over the billions of years since it first appeared.

Gaia

In the 1960s, James Lovelock conceived the novel idea of Gaia – that the Earth functions like a single, self-regulating organism where life itself interacts with the physical environment to maintain conditions favourable for life (Gaia was the ancient Greeks’ Earth mother goddess). Embraced, contested, denounced and recently re-invigorated, the idea has evolved substantially since it first appeared. More recently (this year, in fact), Peter Ward countered the Gaia hypothesis with his own Greek metaphor – the Medea hypothesis. Essentially this view holds that life instead ‘seeks’ to destroy itself in an anti-Gaia manner (Medea was the siblicidal wife of Jason of the Argonauts). Ward described his Medea hypothesis as “Gaia’s evil twin”.

One can marvel at the incredible diversity of life on Earth (e.g., conservatively, > 4 million protists, 16600 protozoa, 75000-300000 helminth parasites, 1.5 million fungi, 320000 plants, 4-6 million arthropods, > 6500 amphibians, 10000 birds and > 5000 mammals) and wonder that there might be something in the ‘life makes it easier for life’ idea underlying Gaia. However, when one considers that over 99 % of all species that have ever existed are today extinct, then a Medea perspective might dominate.

Medea

Enter Cronus. Here we posit a new way of looking at the tumultuous history of life and death on Earth that effectively relegates Gaia and Medea to opposite ends of a spectrum. Cronus (patricidal son of Gaia overthrown by his own son, Zeus, and banished to Hades) treats speciation and extinction as birth and death in a ‘metapopulation’ of species assemblages split into biogeographic realms. Catastrophic extinction events can be brought about via species engineering their surroundings by passively modifying the delicate balance of oxygen, carbon dioxide and methane – indeed, humans might be the next species to fall victim to our own Medean tendencies. But extinction opens up new niches that eventually elicit speciation, and under conditions of relative environmental stability, specialists evolve because they are (at least temporarily) competitive under those conditions. When conditions change again, extinction ensues because not all can adapt quickly enough. Just as all individuals born in a population must eventually die, extinction is a necessary termination.

We think the Cronus metaphor has a lot of advantages over Gaia and Medea. The notion of a community of species as a population of selfish individuals retains the Darwinian view of contestation; self-regulation in Cronus occurs naturally as a result of extinction modifying the course of future evolution. Cronus also makes existing mathematical tools developed for metapopulation theory amenable to broader lines of inquiry.

For example, species as individuals with particular ‘mortality’ (extinction) rates, and lineages with particular ‘birth’ (speciation) rates, could interact and disperse among ‘habitats’ (biogeographical realms). ‘Density’ feedback could be represented as competitive exclusion or symbioses. As species dwindle, feedbacks such as reduced community resilience that further exacerbate extinction risk (Medea-like phase), and stochastic fluctuation around a ‘carrying capacity’ (niche saturation) arising when environmental conditions are relatively stable is the Gaia-like phase. Our Cronus framework is also scale-invariant – it could be applied to microbial diversity on another organism right up to inter-planetary exchange of life (panspermia).

What’s the relevance to conservation? We’re struggling to prevent extinction, so understanding how it works is an essential first step. Without the realisation that extinction is necessary (albeit, at rates preferably slower than they are currently), we cannot properly implement conservation triage, i.e., where do we invest in conservation and why?

We had fun with this, and I hope you enjoy it too.

CJA Bradshaw

Bradshaw, C.J.A., & Brook, B.W. (2009). The Cronus Hypothesis – extinction as a necessary and dynamic balance to evolutionary diversification Journal of Cosmology, 2, 201-209 Other: http://journalofcosmology.com/Extinction100.html

Cette leçon aborde premièrement la notion de théorie scientifique et montre qu’il ne s’agit pas de “suppositions”. Cet exposé est étendu à la théorie de l’évolution, qui est ensuite définie et brièvement expliquée. Le problème des “fossiles vivants” est finalement abordé par une activité.

Concepts abordés: théorie scientifique, théorie de l’évolution, spéciation, fossiles vivants, téléologie.

Domaines concernés: philosophie des sciences, histoire des sciences, biologie.

Plan

1. Introduction
2. Qu’est-ce qu’une théorie scientifique
3. Qu’est-ce que l’évolution biologique
4. Qu’est-ce que la théorie de l’évolution
5. Problème: les fossiles vivants

1. Introduction: seulement une théorie?

On présente le lieu commun suivant: “On ne dit pas ‘théorie de l’évolution’ pour rien. L’évolution est une théorie, pas un fait.” Les étudiants peuvent commenter l’affirmation. On annonce ensuite que l’évolution est à la fois un fait et une théorie. La leçon permettra de comprendre pourquoi.

2. Qu’est-ce qu’une théorie scientifique?

En sciences, les mots ont souvent un sens particulier qui n’est pas le sens employé dans la vie de tous les jours. Le mot théorie, en ce qui concerne les sciences, n’est pas un synonyme de supposition ou d’hypothèse. Une théorie scientifique est un ensemble structuré d’information, d’hypothèses confirmées, de données, de lois, d’outils d’observation, etc.

Le but d’une théorie est d’expliquer un aspect du monde réel. Il ne s’agit pas de spéculation. Lorsqu’une hypothèse est vérifiée par l’expérimentation, on l’intègre au modèle théorique.

Note: cette section peut être agrémentée d’une discussion concernant la nature de la science, selon la matière ayant déjà été étudiée.

3. Qu’est l’évolution biologique

L’évolution biologique désigne un changement dans le bassin génétique d’une population au fil du temps. Cela implique la descendance avec modification, incluant les variations à petite échelle (dans une même population) et à grande échelle (au bout de plusieurs générations).

‘évolution n’est pas un processus de remplacement d’une espèce par une autre “meilleure”. On aurait tendance à croire que, puisqu’il y a “survie du plus fort”, les espèces plus primitives devraient être éteintes aujourd’hui. On devrait en réalité parler de “survie de celui qui est assez fort”.

L’évolution n’affirme pas que les espèces doivent nécessairement changer au fil du temps dans une sorte de “marche du progrès”. L’évolution fonctionne par sélection naturelle, laquelle dépend de l’environnement. Du moment où il n’y a pas de contraintes environnementales suffisantes pour éliminer une espèce, celle-ci risque de demeurer.

Dans un environnement relativement stable, aucune variante morphologique ne sera favorisée. L’aspect général de l’espèce demeurera donc stable également. Attention, car cela ne signifie pas qu’il n’y a pas d’évolution à ce moment-là. La stabilité est également une adaptation, puisque l’environnement sélectionne alors à nouveau la variété qui était déjà majoritaire il y a quelques générations.

4. Qu’est-ce que la théorie de l’évolution

La théorie de l’évolution (on dit parfois aujourd’hui la théorie synthétique de l’évolution) est l’ensemble des données expliquant l’origine des espèces sur terre, principalement par sélection naturelle mais aussi par dérive génétique, mutations, extinctions, etc.

La théorie de l’évolution explique comment les espèces ont émergé via l’évolution biologique. Dans sa formulation actuelle, la théorie a pour nom exact théorie synthétique de l’évolution, ou théorie néo-darwinienne.

Il est important de comprendre que la théorie de l’évolution n’est pas un modèle de société, ou encore une théorie morale et éthique. La théorie de l’évolution décrit l’origine des espèces, et non la manière dont il faut se comporter et mener notre vie.

5. Problème: les fossiles vivants

Il existe des espèces vivantes qui semblent ne pas avoir changé depuis des millions d’années. Comme les spécimens vivants ressemblent beaucoup aux fossiles que l’on retrouve, on surnomme ces espèces des “fossiles vivants”.

Le coelacanthe et l’oryctérope sont deux exemple de fossiles vivants. L’étudiant devra, dans une activité, décrire un cas de fossile vivant et expliquer en quoi cela n’invalide pas la théorie de l’évolution.

A quick one. Evolution has nothing to do with where life came from. Abiogenesis is the study of how life could have arisen from non-living matter. Also, evolution does not explain how the universe came into existence. The cosmology deals with that.

What evolution does deal with is the change in genetic material of populations of organisms over generations. So, it explains how complex organisms like humans evolved from simpler life forms. It explains how populations of organisms develop new traits in order to adapt to their environment. And it explains how vestigial structures like the wings of ostriches fall out of use among other things. Overall, evolution explains speciation and the diversity of life on this planet very well.

link:

http://images.google.com.ph/imgres?imgurl=http://www.dwm.ks.edu.tw/bio/activelearner/19/images/ch19c2.jpg&imgrefurl=http://www.dwm.ks.edu.tw/bio/activelearner/19/ch19c2.html&usg=__km28ouLeRZFkwmPKpvPdjEw2bjY=&h=309&w=345&sz=21&hl=tl&start=1&tbnid=8Clkfzv2uwsVqM:&tbnh=107&tbnw=120&prev=/images%3Fq%3Dbehavioral%2Bisolation%26gbv%3D2%26hl%3Dtl

i hope these links will help you understand the concepts

While working on the Orders of the Birds and finding so many species of birds worldwide, I went looking for more information about them. I came across this interesting article at the ICR.org website. The bolding is mine. I trust you will find it worth the reading.

Cormorant Tree by Dan

Do ‘New Species’ Demonstrate Darwinism?
by Various Authors
Frank Sherwin, M.A., and Brian Thomas, M.S.*

“That species undergo change in this grand system called earth is apparent, but those changes do not occur the way Charles Darwin envisioned. Living things do shift behaviors and physiologies in response to environmental (and other) pressures, but can these minor changes completely rework a creature’s essential form (a concept referred to as “macroevolution”)? Decades of research emphatically say no.

Often, small changes within a kind are referred to as “microevolution,” which has been defined as “evolution resulting from a succession of relatively small genetic variations that often cause the formation of new subspecies.”1 Creation scientists agree that small variations occur, both because they can be observed, and because it is reasonable that a wise Creator would equip His creatures with survival-enhancing capabilities. But these variations do not lead to large-scale changes between kinds. Indeed, “there is no agreement [among evolutionists] as to whether macroevolution results from the accumulation of small changes due to microevolution, or whether macroevolution is uncoupled from microevolution.”2

The confusing array of definitions for the word “species” can obscure deficiencies in Darwinian evolution. As leading scientists have admitted, “The very term ’species’ is deeply ambiguous.”3 Harvard’s Steven Palumbi said in 1994 that “the formation of species has long represented one of the most central, yet also one of the most elusive, subjects in evolutionary biology.”4

If different species are described as essentially those forms which cannot interbreed, then new species do arise, a process called “speciation.” They do so, however, because of a loss of information–the opposite direction to what Darwinian evolution requires. “…..

To see the complete article – CLICK HERE

Adaptation of the Drake Equation for determining probability of speciation in populations

A while back, I broke a personal rule of mine and got involved in a debate at work over a controversial subject. Evolution in particular. I wouldn’t let myself get involved except that it was after 5pm, and thus I was off the clock. I’ll add that I have a great deal of respect for the intelligence of the person I was debating. We went back and forth for about 45 minutes as I explained how DNA works, and how cells reproduce, etc etc. In the end I had convinced him that something like evolution does happen, but he was still not sold on the entire theory.

In particular, he was hung up on the notion of speciation. He was fine with a wolf evolving into a dog, or dogs coming to have many breeds. What he didn’t subscribe to was the notion that tiny little changes could carry a species all the way from an amphibian to a horse, or a snake, or a human. So that’s where I left the debate. It was actually the first day of summer and I was already at work an hour later than I needed to be. On the way home I tried to think if there was a way to demonstrate how small changes in a population could become significant over time.  It was then that I recalled something vaguely similar from “Cosmos” by Carl Sagan.

In one chapter regarding extra-terrestrial life, he referred to the Drake Equation. This is a big but simple equation that tells you how many civilizations there are in the universe that can communicate with Earth. Now, of course it doesn’t actually tell you the answer to the question. The idea though, is that you feed the equation certain variables and play around with it. You can tell it your estimates for how many stars might have planets, and how likely a civilization is to try to communicate. You can feed in whatever crazy numbers you want, and see if there’s still a few planets out there.

I figured I could do something similar regarding the likelihood of speciation. Speciation is defined as the evolutionary process by which new species arise. After a number of failed attempts at doing it via computer programming, I remembered one of my own programming tips: “If at all possible, do it in Excel”.

So here’s my Equation. Perhaps it could be called the Darwin Equation. Mostly because Darwin is the name of a guy who, like Drake, has the letters D, A, and R in the first part of his last name.

N = [A / (B * V * W * X * Y)] * Z
(years per each new trait in population), times (the number of traits needed to be adopted)

N = years before speciation occurs

A = time between generations in years
B = number of new offspring per generation
V = chance of any mutation occurring in an individual
W = chance for any mutation to be beneficial
X = chance of beneficial mutation being passed to offspring
Y = chance of inherited beneficial mutation becoming prevalent in population
Z = number of mutations in population before speciation will have occurred

Here’s a link to a spreadsheet that lets you plug in values: Darwin Equation.xls
and if that doesn’t work, or you don’t have Excel, click here to see it in Google Doc’s (The text formatting’s a bit weird).

Perhaps you notice some weird flaws in my reasoning. There’s actually a number of them, but this equation is still useful. First it assumes that all these mutations happen one at a time. Also, it makes broad generalizations about things that aren’t known. It’s a vast oversimplification in all respects -But that’s the entire point.

The beauty of this equation is that one can simply plug in the numbers as desired and play around with the results. Ok, so one hundred new mutations isn’t speciation, then how about a one hundred thousand new mutations? Is that enough?

I’ve been playing around with it myself. Consider a species generating ten thousand offspring every 10 years, and 1/100 odds for each V, W, X, and Y variables, and requiring one hundred new mutations to occur. This works out to ten million years needed for speciation. Don’t like it? Plug your own values in. I don’t like it either. Ten million seems like a lot. Though if mammals first evolved about 200 million years ago, that leaves time for twenty speciation events to have occurred, each being a major step away from where that group started.

Now I know it didn’t really happen that way. This system is way too linear, it’s not meant to actually model how a species changes, it’s meant to model the numbers behind these changes. It allows one to give the most generous possible allowances in support of their own beliefs and see what’s comes of it. I’m a big fan of “upper bounds”. See my boat making notes, and my Whopper combinations. Upper bounds are relatively easy to determine, and are usually useful even with a good amount of error. As with the original Drake Equation, this algorithm smooshes together very large numbers and very small numbers. One in a million chances of a mutation, billions of members in the population. If a girl is one in a million, then there over a thousand of her in China. Some of whom may have beneficial mutations.

Yet another person thinks evolution and creationism can live side-by-side.

The image of the Virgin Mary is reported to have been seen on a tree stump in the village of Rathkeale, and thousands of people have flocked there. And yes, this is quite absurd.

But is it more preposterous to believe that that piece of timber, and the willow tree from which it came, and the eye that beheld the wood, arrived in this world entirely by accident?

For in this, the 150th anniversary of the publication of ‘The Origin of Species’, that is what we’ve been endlessly told this year.

Before Darwinian dogmatists sneer the words ‘intelligent design’ and ‘creationism’, let me declare that I embrace neither concept. But nor do I reject them.

There it is. I’ve been talking about it for awhile now, and here’s a prime example. It’s a New Creationist

I’ve been reading up on this subject recently, especially Ernst Mayr, Dawkins and Darwin, and what strikes me most is the sheer act of Darwinian faith which is required for us to accept that natural selection was the prime engine that conjured the vast complexity of modern life from its birthplace in the methanogenic oceans of the pre-Cambrian.

It actually doesn’t take any faith whatsoever. There is ample evidence for evolution, and specifically for natural selection. The only way the author of this piece would think it took faith to accept evolution would be if he was really a sneaky, coy creationist.

Now life as we know it depends on proteins. But even a relatively simple molecule such as insulin, consists of 51 conjoined amino-acids, with a molecular weight of 5808: nearly 6,000 times the weight of a hydrogen atom. And an average living cell contains 100 million protein molecules, involving perhaps 20,000 varieties of protein.

Do you remember those problems back in grammar school where you’d need to pick out the irrelevant part? Suzy and Tom went to the store at 7 in the morning. Tom got 2 packs of gum and a soda. They both returned at 4:30 later that day. For how long were Suzy and Tom gone? It isn’t important that Tom bought anything. No one cares. So in turn, one wonders why the author told us the weight of insulin, not to mention that weight versus a particular atom. Maybe he’s trying to compare complexity. If so, he failed.

Moreover, there are several hundred thousand types of protein, all of them impossibly complex. How were these made by accident? To say that such order is implicit in all of nature — as some scientists do — is begging the question, the equivalent of saying matter is intrinsic to materials.

There’s the problem. This guy thinks it was all “by accident”. He also seems to think, as creationists commonly do, that complex molecules have always existed in the form in which we see them. That is not the case. Evolution is a slow, gradual process. Until creationists understand that – and they usually willfully do not – no progress can be made with these people.

This logically means that there must have been many competing proto-life forms. Just one — apparently the one that depends upon DNA — survived. But how did the dear old double helix come into existence? For DNA doesn’t function at all unless complete. It’s either the final, impossibly complex but useful article, or it’s incomplete and utterly useless. So, no simple evolution here.

Competing lifeforms would not last long in an environment where other lifeforms already exist. That’s one reason we don’t see life spontaneously come into existence – the formation of any molecules will be quickly used up by existing life.

This guy goes on to state the common creationist idea that life must exist complexly immediately upon its inception. Again, no. Interestingly, this all seems like a non-sequitur: many life forms should exist, but only one does, so how did it come into existence, it couldn’t because it’s complex. Weird.

Human-triggered speciation has never occurred, despite separations of thousands of years. The dingo of the Australian desert is five millennia removed from the Arctic wolf; yet they can still interbreed. Similarly, Northern Dancer could have bred with a Connemara.

Dogs? Or all this?

Plumage variations of the monarch flycatcher. (Photo/Courtesy J. Albert Uy)

How do you measure the instant one species becomes two? Well, in the Solomon Islands, biologist J. Albert Uy is trying to pick a fight with monarch flycatchers to find the answer. That tipping point is a bunch of feathers, and it’s allowing scientists to capture a snapshot of evolution in action.

A territorial flycatcher (Monarcha castaneiventris castaneiventris) aggressively responding to a taxidermy mount during our mount presentation experiment. (Photo/Courtesy J. Albert Uy)

Flycatcher males are territorial and will launch an avian smackdown towards perceived rivals trespassing on their turf. But a flip of a single gene is turning the monarch flycatcher into a bird of a different color, and in the process changing the social dynamics of rival birds.

It seems that though they are technically still the same species, the black-feathered flycatcher didn’t get the memo about their chestnut-bellied kin, and vice versa. Uy tested this by invading flycatcher territory with dummy birds. What he’s found is that the two don’t see each other as rivals, and are therefore probably more interested in mating with their like-feathered counterparts.

At least in the case of the monarch flycatcher, this single gene and spot of color heralds the birth of an entire new species.

J. Albert Uy (Photo/ C. Low, courtesy J. Albert Uy)

We often hear about species being lost, but rarely do we learn of one being created. Uy’s work provides a glimpse of the “fork in the evolutionary road” as it happens in real-time, and what that could mean for our understanding of bird life.

Uy’s work appears in the current edition of American Naturalist, and you can read more about monarch flycatchers in the 2005 New York Times article, “In Give and Take of Evolution, a Surprising Contribution from Islands.”

Credit: Robert Moyle

The late Ernst Mayr, a famous Harvard University evolutionary biologist, was the first to notice the speciation potential of flycatcher birds in the South Pacific’s Solomon Islands. During the 1940s, he described differences in the body size and plumage of several populations of the flycatcher (Monarcha castaneiventris) and asserted that there existed at least five subspecies. Evolutionary biologist J. Albert Uy of Syracuse University in New York state and colleagues decided to see just how different two of these subspecies were. One lives on a larger island and has a reddish-brown belly with an iridescent blue-black back and head, and the other, which is all blue-black, lives on smaller islands about 10 kilometers away.

To track down the gene underlying the color change, Uy and his colleagues took a cue from black sheep and pigs. These animals have a mutation in the gene for the melanocortin-1 receptor, a protein that helps control how much black pigment is produced. The researchers sequenced part of that gene from 28 black birds and 19 brown-bellied ones. They found a few differences but only one that mattered: a genetic change that altered a single amino acid in the resulting protein. It seems this change permanently activates the protein so that more black than brown pigment is produced.

Next, the researchers evaluated whether this color change might make any difference to the birds. They put stuffed birds of either color into the territories of live flycatchers. Flycatchers are not bothered by most foreign birds, but they will attack potential rivals of the same species. Black bird decoys drew angry responses from black birds but little reaction from brown-belly birds and vice versa, Uy and his colleagues report in the August issue of The American Naturalist.

Presumably, during the isolation of these flycatcher populations to different islands of the Solomon chain, the founder effect introduced different proportions of certain alleles. Competition for territory and for mates could have set up the conditions for sexual selection for or against alternative alleles. Or simple genetic drift in small island populations could have eliminated an allele on one island’s population where that allele was rare, but preserved it against alternative alleles in another population where it was common. And eventually, the populations adjacent islands cease to recognize each other as members of the same species – geographically isolated populations become reproductively isolated.

This study, finding putative speciation occurring through a single mutation, raises some questions about speciation itself. That is, it seems reminiscent of saltation or the ‘Hopeless Monster‘ hypothesis to me, and I’m not quite sure how to explain why the findings of this study fit better with allopatric speciation than with saltation. I’m not an evolutionary biologist, afterall. I suspect however that the difference lays in the assumption that this mutation would not have laid the groundwork for possible reproductive isolation for in a single generation, nor would it have done so in the absence of geographic isolation.

But the full article isn’t published yet, so I haven’t read the paper, only it’s synopsis. If the only way of observing whether this change in appearance made any difference to the birds themselves was their specific territorial responses to stuffed birds, and no indication of whether the color had any impact on mating preferences, then the researchers can’t (yet) claim that they’re reproductively isolated. Can they?

Trudging along the paths of Bill Yeck Park, I was thinking about God’s command to us in Genesis 1:28 to “be fruitful and multiply.”  So much thought has gone into the rest of the verse about subduing the earth and filling it and having dominion over every living thing that moves on the earth.  God the creative Creator whose making of the cosmos in Genesis 1 is done with poetic license (the word “made” in Gen 1:1 in Greek is the same word that our word poem or poetry comes from), endows humans with creativity as well.  In Genesis 2:19, God awaits to see what the human will call each animal which God has made – it is left to the human to creatively name the animals, God does not tell Adam their names nor how to name them, but watches as his human creates names and words just like God formed words which created all things.  Thus God imbues humans with a creative nature like His own, except we do not create out of nothing – we creatively name the creatures which in biblical thinking gives us some mastery over them.   “Hippopotamus,” says the man.  “Interesting,” says God.  Would God have thought of that name Himself?  (In the Quran God is overpoweringly omnipotent not leaving any room for human creativity or error, for Allah does not let the human create names, but rather tells the human their names and then tests the human to see if he remembers – the human cannot freely choose, he can only obey and his every act is under judgment.  Thank God for Genesis 2 and the freedom and creativity with which He entrusts us!)

“Be fruitful and multiply…”  {A joke comes to mind:  Why did all of the children in the Christian fundamentalist school refuse to do any division in math?  Because God only commanded them to be fruitful and to multiply.}

“Be fruitful and multiply… fill the earth…”   The creativity that God bestows upon us includes making use of the time He has given us.   We have to fill our time, not just the earth.  We are to be creative and to make beauty just as the Lord did – poetry, art, music, imagining, paintings, sculpting, prose, dance, photography, graphics and animation are among the ways humans are given by God to create beauty in time.   Boredom and wasting time are lost chances to create beauty and to fill time itself with things which give glory to God.   Creativity is a gift from God and a way to use time.

I came upon a plant which I could not identify but the shape of the leaves caught my attention because it showed such imaginative form.  What variety in the leaves of plants – shapes, colors textures.  It seems to me one could spend days on end just photographing the different shapes and sizes of plant leaves, in that alone is there a multiplication of life as God commanded the earth to do (Gen 1:11).  There is a question which is hotly debated today between believers in God and believers in evolution.  Some believers in God claim all the species on earthy – plant and animal had to have been created by God in the six days of creation.  Believers in evolution say not so, plant life continues to evolve with some new species being formed and some others becoming extinct.  Those believers in God say new species cannot form from old ones since God commanded that plants and animals bring forth new life “according to their kind.”  Yet for me, as I read Genesis, I see God saying, let the earth bring forth the herb, the grass the plant bearing seed and the trees.  It doesn’t seem to me that God put any time limit on that.  The earth and the waters are continuously to bring forth life of all and varied kinds.  The text doesn’t say that God made every species, He commanded the earth and the waters to become creative and life giving.  God bestowed upon His creation the ability to creatively bring forth life. Nothing in His command forbids speciation and in fact God seems to value the goodness He sees in the earth and the waters creativity.  Besides if one understands speciation, even if the seed created by any plant species are in fact a new species they do bear the DNA of their parent plants, so they are of the same kind as their parents.  Speciation is not in opposition to what Genesis says – it is in fact the multiplication of which God commanded all living things – not only offspring but new species as well.    With the amazing variety of life we can already find in creation, why would God be opposed to new varieties or variations?  Why some feel the need to limit God’s ability to bring forth new things is beyond me.   Speciation is another form of miracle and a means for God to actually intervene in creation with something new.  He is the Lord and giver of life after all!

These are not the hobbits we're talking about.

A while back very odd human-like remains were found and sparked off all sorts of controvery as to their origins.  Some thought they were an as yet undiscovered branch of past human development, some thought they were past humans with some sort of genetic afflication, some thought other things which completely made no sense.  The lastest findings on the case are actually very interesting and almost settle the matter, though more questions have been raised.

Ancient ‘hobbits’ a new species after all

Diminutive humans whose remains were found on the remote Indonesian island of Flores in 2003 truly are a new species, and not pygmies whose brains had shrivelled with disease, researchers say.

Anthropologists have been arguing about the identity and origins of Homo floresiensis – dubbed “the hobbit” due to its small size – since it was unearthed by an Australian-led research team.

Measuring about a metre tall and weighing in at 30 kilograms, the tiny, tool-making hunters may have roamed the island for which they were named as recently as 8,000 years ago. The fossils are about 18,000 years old.

Many scientists have said H. floresiensis were prehistoric humans descended from Homo erectus, stunted by natural selection over millennia through a process called insular dwarfing.

Others countered that even this evolutionary shrinking, well known in island-bound animals, could not account for the hobbit’s chimp-sized grey matter of barely more than 400 cubic centimetres, a third the size of a modern human brain.

And how could such a being have been smart enough to craft its own stone tools?

The only plausible explanation, they insisted, was that the handful of specimens found suffered from a genetic disorder resulting in an abnormally small skull or – a more recent finding – that they suffered from “dwarf cretinism” caused by deficient thyroids.

Two new studies in the British journal Nature go a long way toward settling this debate, even as they raise new quandaries that are sure to stoke further controversy.

A team led by William Jungers of the Stony Brook University in New York tackled the problem from the other end by analysing the hobbit’s foot.

In some ways it is very human. The big toe is aligned with the others and the joints make it possible to extend the toes as the body’s full weight falls on the foot, attributes not found in great apes.

But, in other respects, it is startlingly primitive: far longer than its modern human equivalent, and equipped with a very small big toe, long, curved lateral toes, and a weight-bearing structure closer to a chimpanzee’s.

Recent archeological evidence from Kenya shows that the modern foot evolved more than 1.5 million years ago, most likely in Homo erectus.

So unless the Flores hobbits became more primitive over time – a more-than-unlikely scenario – they must have branched off the human line at an even earlier date.

For Dr Jungers and colleagues, this suggests “that the ancestor of H floresiensis was not Homo erectus but instead some other, more primitive, hominin whose dispersal into southeast Asia is still undocumented,” the researchers conclude.

Companion studies, published online in the Journal of Human Evolution, bolster this theory by looking at other parts of the anatomy, and conjecture that these more ancient forebear may be the still poorly understood Homo habilis.

Either way, their status as a separate species would be confirmed.

Even this compelling new evidence, however, does not explain the hobbit’s inordinately small brain.

That’s where hippos come into the picture.

Eleanor Weston and Adrian Lister of the Natural History Museum in London compared fossils of several species of ancient hippos found on the island of Madagascar with the mainland ancestors from which they had evolved.

They were surprised to find that insular dwarfing – driven by the need to adapt to an island environment – shrank their brains far more than had previously been thought possible.

“Whatever the explanation for the tiny brain of H floresiensis relative to its body size, our evidence suggests that insular dwarfing could have played a role in its evolution,” they conclude.

While the new studies answer some questions, they also raise new ones sure to spark fresh debate, notes Harvard professor Daniel Lieberman in a comment, also published in Nature.

Only more fossil evidence will tell us whether the hobbits of Flores evolved from Homo erectus, whose traces have been found throughout Eurasia, or from an even more ancient lineage whose footsteps have not yet been traced outside Africa, he said.

In either case, however, it now seems unlikely that they were cretins, in any sense of the word.

March 2007

Interesting article in Science looking at the role of latitude in extinction and speciation. The authors conclude: ” most efforts have aimed at identifying the geological, climatic, and ecological factors that might have elevated tropical speciation rates, our results suggest that both speciation and extinction vary with latitude and contributed importantly to the latitudinal diversity gradient.” You or your institution will need a subscription to get past the abstract.

Question: Is there any legitimacy to the giant humans found outside Virginia city?

Answer: Short answer is — nope. I am assuming you are talking about the large, vaguely human-shaped footprints found in the late 1800’s when the Nevada State Prison was being built. The best information I could find online gives a pretty good explanation for the footprints and why they are unlikely to be human.

Question: What about Archaeopteryx and whales with rudimentary legs.  Do these point to macro-evolution?

Answer: Archaeopteryx fossils have been one of those “Creation killers” that people often throw out as bullet-proof evidence of evolutionary transitions. The problem is, it in fact has fully functional feathers that are very similar to modern bird feathers. The regions of the brain needed for flight appeared to be fully there, unlike  the much smaller and underdeveloped brain of dinosaurs. So the bird-like features are pretty much fully developed in Archaeopteryx, not transitonary. You might also read a couple articles on Caudipteryx and perhaps Answers in Genensis’s take on the issue. I tend to think that Archaeopteryx was really a bird with some dinosaur-like features. Remember though, that common features does not automatically mean common decent.

As far as whale legs go, while the idea that whales started out as land mammals that just sort of liked the water better is somewhat appealing as a simplistic story, I think there are still some issues such as bone structure and the ramifications of aquatic life that must be addressed as well.

Question: Is adaptation of species the same thing as mutation leading to new species?

Answer: No, they are a bit different. Adaptation is basically the process of natural selection making the organism or species better suited to their environment. Think of your pupils adapting to the change in light intensity as you walk outside. That is  adaptation by an individual. Another example would be the famous Peppered Moths. As tree trunks got darkened by industrial pollution, the light-colored variety of the months stuck out more and consequently got eaten more often than the dark-colored variety. That would be a species adapting. What’s important to notice is that the light-colored moths did not turn into the dark-colored moths (i.e. the dark color did not appear out of thin air), rather there was a shift in the relative amounts in the existing population.

Mutations are genetic mistakes, and by themselves they do not create new species. The vast majority of mutations are harmful, if not fatal. In order for the few beneficial ones that happen to create a new species they would have to cause such large changes that the part of the population which has the mutation could no longer breed with the part of the population that does not. We just do not see that in practice. What we are more likely to see is a part of a population is somehow cut off from the rest (usually via geographic isolation such as volcanic eruptions, flooding that creates a new river, etc.) and gradually that sub-population loses enough genetic variation (through mutation and adaptation) that it can no longer breed with the original population and the original species has split into two distinct species.

Question: What do you think of cloning?

Answer: This somewhat of a tricky question because “cloning” is a bit of a loaded term. Generically, in biology cloning means making identical copies of DNA (molecular cloning), cells, or organisms. I think there is little controversy or debate over molecular or cellular cloning. In that sense I think cloning can be a very cool and useful tool. The controversial parts are human cloning methods such as research/therapeutic cloning and the potential for reproductive cloning. They are controversial because they use somatic cell nuclear transfer, which is essentially creating a new organism (a human embryo) either to harvest for research or make a genetic duplicate. I feel harvesting human beings for research is highly unethical from a Christian perspective. Sacrificing the life of some people for possible gains for others is totally against traditional medical ethics in  the United States (and much of the world).

Reproductive cloning has even broader issues. For instance, if a person is cloned, who has the “rights” or ownership of the genetic code since both people have identical DNA? DNA evidence would become virtually useless in criminal courts. Since cloned human beings would be perfect organ donors, will there be pressure  or even requirements that they donate? Will “identical” copies become “better” copies via genetic engineering? Even beyond these issues there is the problem that cloning is a rather inefficient process. For instance, Dolly the famous cloned sheep was the only survivor among 3 that were born from 29 embryos which came from 277 eggs. The first cloned horse had a similar story, the only survivor of 14 embryos coming from 841 eggs. At least initially, the vast majority of cloned humans would suffer from terrible birth defects and many would not survive infancy.

I believe science must be tempered with ethics. Just because we can do something does not mean we should.