Darwin's finches

Darwin's finches (also known as the Galápagos finches) are a group of about fifteen species of passerine birds.[1][2][3][4] They are well known for their remarkable diversity in beak form and function.[5] They are often classified as the subfamily Geospizinae or tribe Geospizini. They belong to the tanager family and are not closely related to the true finches. The closest known relative of the Galápagos finches is South-American Tiaris obscurus.[6] They were first collected by Charles Darwin on the Galápagos Islands during the second voyage of the Beagle. Apart from the Cocos finch, which is from Cocos Island, the others are found only on the Galápagos Islands.

The term "Darwin's finches" was first applied by Percy Lowe in 1936, and popularised in 1947 by David Lack in his book Darwin's Finches.[7][8] Lack based his analysis on the large collection of museum specimens collected by the 1905–06 Galápagos expedition of the California Academy of Sciences, to whom Lack dedicated his 1947 book. The birds vary in size from 10 to 20 cm and weigh between 8 and 38 grams. The smallest are the warbler-finches and the largest is the vegetarian finch. The most important differences between species are in the size and shape of their beaks, which are highly adapted to different food sources. The birds are all dull-coloured.

A long term study carried out for more than 40 years by the Princeton University researchers Peter and Rosemary Grant has documented evolutionary changes in beak size affected by El Niño/La Niña cycles in the Pacific.[9]

Darwin's finches
Darwin's finches by Gould
Large ground finch, Medium ground finch
Small tree finch, Green warbler-finch
Scientific classification
Kingdom:
Phylum:
Class:
Order:
Family:
Genera

Geospiza
Camarhynchus/Platyspiza
Certhidea
Pinaroloxias

Darwin's theory

During the survey voyage of HMS Beagle, Darwin was unaware of the significance of the birds of the Galápagos. He had learned how to preserve bird specimens while at the University of Edinburgh and had been keen on shooting, but he had no expertise in ornithology and by this stage of the voyage concentrated mainly on geology.[10] In Galápagos he mostly left bird shooting to his servant Syms Covington.[11] Nonetheless, these birds were to play an important part in the inception of Darwin's theory of evolution by natural selection.

On the Galápagos Islands and afterward, Darwin thought in terms of "centres of creation" and rejected ideas concerning the transmutation of species.[12] From Henslow's teaching, he was interested in the geographical distribution of species, particularly links between species on oceanic islands and on nearby continents. On Chatham Island, he recorded that a mockingbird was similar to those he had seen in Chile, and after finding a different one on Charles Island he carefully noted where mockingbirds had been caught.[10] In contrast, he paid little attention to the finches. When examining his specimens on the way to Tahiti, Darwin noted that all of the mockingbirds on Charles Island were of one species, those from Albemarle of another, and those from James and Chatham Islands of a third. As they sailed home about nine months later, this, together with other facts, including what he had heard about Galápagos tortoises, made him wonder about the stability of species.[13][14]

Following his return from the voyage, Darwin presented the finches to the Zoological Society of London on 4 January 1837, along with other mammal and bird specimens that he had collected. The bird specimens, including the finches, were given to John Gould, the famous English ornithologist, for identification. Gould set aside his paying work and at the next meeting, on 10 January, reported that the birds from the Galápagos Islands that Darwin had thought were blackbirds, "gross-beaks" and finches were actually "a series of ground Finches which are so peculiar [as to form] an entirely new group, containing 12 species". This story made the newspapers.[15][16]

Finchadaptiveradiation
Seen here is adapted radiation of finch A. (Geospiza magnirostris) into three other species of finches found on the Galapagos Islands. Due to the absence of other species of birds, the finches adapted to new niches. The finches beaks and bodies changed allowing them to eat certain types of foods such as nuts, fruits, and insects.
  1. Geospiza magnirostris
  2. Geospiza parvula
  3. Certhidea olivacea
  4. Geospiza fortis

Darwin had been in Cambridge at that time. In early March, he met Gould again and for the first time to get a full report on the findings, including the point that his Galápagos "wren" was another closely allied species of finch. The mockingbirds that Darwin had labelled by island were separate species rather than just varieties. Gould found more species than Darwin had expected,[17] and concluded that 25 of the 26 land birds were new and distinct forms, found nowhere else in the world but closely allied to those found on the South American continent.[16] Darwin now saw that, if the finch species were confined to individual islands, like the mockingbirds, this would help to account for the number of species on the islands, and he sought information from others on the expedition. Specimens had also been collected by Captain Robert FitzRoy, FitzRoy's steward Harry Fuller, and Darwin's servant Covington, who had labelled them by island.[18] From these, Darwin tried to reconstruct the locations from where he had collected his own specimens. The conclusions supported his idea of the transmutation of species.[16]

Text from The Voyage of the Beagle

At the time that he rewrote his diary for publication as Journal and Remarks (later The Voyage of the Beagle), he described Gould's findings on the number of birds, noting that "Although the species are thus peculiar to the archipelago, yet nearly all in their general structure, habits, colour of feathers, and even tone of voice, are strictly American".[19] In the first edition of The Voyage of the Beagle, Darwin said that

It is very remarkable that a nearly perfect gradation of structure in this one group can be traced in the form of the beak, from one exceeding in dimensions that of the largest gros-beak, to another differing but little from that of a warbler".[20]

By the time the first edition was published, the development of Darwin's theory of natural selection was in progress. For the 1845 second edition of The Voyage (now titled Journal of Researches), Darwin added more detail about the beaks of the birds, and two closing sentences which reflected his changed ideas:

Seeing this gradation and diversity of structure in one small, intimately related group of birds, one might really fancy that from an original paucity of birds in this archipelago, one species had been taken and modified for different ends."[21][22]

The remaining land-birds form a most singular group of finches, related to each other in the structure of their beaks, short tails, form of body and plumage: There are thirteen species, which Mr. Gould has divided into four subgroups. All these species are peculiar to this archipelago; and so is the whole group, with the exception of one species of the sub-group Cactornis, lately brought from Bow Island, in the Low Archipelago. Of Cactornis, the two species may be often seen climbing about the flowers of the great cactus-trees; but all the other species of this group of finches, mingled together in flocks, feed on the dry and sterile ground of the lower districts. The males of all, or certainly of the greater number, are jet black; and the females (with perhaps one or two exceptions) are brown. The most curious fact is the perfect gradation in the size of the beaks in the different species of Geospiza, from one as large as that of a hawfinch to that of a chaffinch, and (if Mr. Gould is right in including his sub-group, Certhidea, in the main group) even to that of a warbler. The largest beak in the genus Geospiza is shown in Fig. 1, and the smallest in Fig. 3; but instead of there being only one intermediate species, with a beak of the size shown in Fig. 2, there are no less than six species with insensibly graduated beaks. The beak of the sub-group Certhidea, is shown in Fig. 4. The beak of Cactornis is somewhat like that of a starling, and that of the fourth subgroup, Camarhynchus, is slightly parrot-shaped. Seeing this gradation and diversity of structure in one small, intimately related group of birds, one might really fancy that from an original paucity of birds in this archipelago, one species had been taken and modified for different ends. In a like manner it might be fancied that a bird originally a buzzard, had been induced here to undertake the office of the carrion-feeding Polybori of the American continent.[23]

Text from On the Origin of Species

Darwin discussed the divergence of species of birds in the Galápagos more explicitly in his chapter on geographical distribution in On the Origin of Species:

The most striking and important fact for us in regard to the inhabitants of islands, is their affinity to those of the nearest mainland, without being actually the same species. [In] the Galapagos Archipelago ... almost every product of the land and water bears the unmistakable stamp of the American continent. There are twenty-six land birds, and twenty-five of these are ranked by Mr. Gould as distinct species, supposed to have been created here; yet the close affinity of most of these birds to American species in every character, in their habits, gestures, and tones of voice, was manifest. ... The naturalist, looking at the inhabitants of these volcanic islands in the Pacific, distant several hundred miles from the continent, yet feels that he is standing on American land. Why should this be so? Why should the species which are supposed to have been created in the Galapagos Archipelago, and nowhere else, bear so plain a stamp of affinity to those created in America? There is nothing in the conditions of life, in the geological nature of the islands, in their height or climate, or in the proportions in which the several classes are associated together, which resembles closely the conditions of the South American coast: In fact there is a considerable dissimilarity in all these respects. On the other hand, there is a considerable degree of resemblance in the volcanic nature of the soil, in climate, height, and size of the islands, between the Galapagos and Cape de Verde Archipelagos: But what an entire and absolute difference in their inhabitants! The inhabitants of the Cape de Verde Islands are related to those of Africa, like those of the Galapagos to America. I believe this grand fact can receive no sort of explanation on the ordinary view of independent creation; whereas on the view here maintained, it is obvious that the Galapagos Islands would be likely to receive colonists, whether by occasional means of transport or by formerly continuous land, from America; and the Cape de Verde Islands from Africa; and that such colonists would be liable to modification — the principle of inheritance still betraying their original birthplace.[24]

Polymorphism in Darwin's finches

Whereas Darwin spent just five weeks in the Galápagos, and David Lack spent three months, Peter and Rosemary Grant and their colleagues have made research trips to the Galápagos for about thirty years, particularly studying Darwin's finches.

Males are dimorphic in song type: songs A and B are quite distinct. Also, males with song A have shorter bills than B males. This is also a clear difference. With these beaks, males are able to feed differently on their favourite cactus, the prickly pear Opuntia. Those with long beaks are able to punch holes in the cactus fruit and eat the fleshy aril pulp, which surrounds the seeds, whereas those with shorter beaks tear apart the cactus base and eat the pulp and any insect larvae and pupae (both groups eat flowers and buds). This dimorphism clearly maximises their feeding opportunities during the non-breeding season when food is scarce.

If the population is panmixic,[25][26] then Geospiza conirostris exhibits a balanced genetic polymorphism and not, as originally supposed, a case of nascent sympatric speciation. The selection maintaining the polymorphism maximises the species' niche by expanding its feeding opportunity. The genetics of this situation cannot be clarified in the absence of a detailed breeding program, but two loci with linkage disequilibrium[27] is a possibility.

Another interesting dimorphism is for the bills of young finches, which are either 'pink' or 'yellow'. All species of Darwin's finches exhibit this morphism, which lasts for two months. No interpretation of this phenomenon is known.[28]

Taxonomy

Family

For some decades, taxonomists have placed these birds in the family Emberizidae along with the New World sparrows and Old World buntings (Sulloway 1982). However, the Sibley–Ahlquist taxonomy puts Darwin's finches with the tanagers (Monroe and Sibley 1993), and at least one recent work follows that example (Burns and Skutch 2003). The American Ornithologists' Union, in its North American check-list, places the Cocos finch in the Emberizidae but with an asterisk indicating that the placement is probably wrong (AOU 1998–2006); in its tentative South American check-list, the Galápagos species are incertae sedis, of uncertain place (Remsen et al. 2007).

Species

In 1981, a male Española cactus finch arrived at Daphne Major island. Its mating with local Galapagos finches has produced a new population that can exploit previously unexploited food due to its larger size. They do not breed with the other species on the island, as the females do not recognize the songs of the new males. Genetic evidence shows that now, after two generations, it lives in a complete reproductive isolation from the native species. According to professor Leif Andersson of Uppsala University, a taxonomist not aware of its history would consider it a distinct species.[29][30]

Molecular basis of beak evolution

Developmental research in 2004 found that bone morphogenetic protein 4 (BMP4), and its differential expression during development, resulted in variation of beak size and shape among finches. BMP4 acts in the developing embryo to lay down skeletal features, including the beak.[31] The same group showed that the development of the different beak shapes in Darwin's finches are also influenced by slightly different timing and spatial expressions of a gene called calmodulin (CaM).[32] Calmodulin acts in a similar way to BMP4, affecting some of the features of beak growth. The authors suggest that changes in the temporal and spatial expression of these two factors are possible developmental controls of beak morphology. In a recent study genome sequencing revealed a 240 kilobase haplotype encompassing the ALX1 gene that encodes a transcription factor affecting craniofacial development is strongly associated with beak shape diversity.[33][34] Moreover, these changes in the beak size have also altered vocalization in Darwin's finches.[5]

See also

Notes

  1. ^ Grant & Grant 2008, p. 3
  2. ^ Marsh, Geoff (11 February 2015). "Darwin's iconic finches join genome club". Nature. 518 (7538): 147. Bibcode:2015Natur.518..147M. doi:10.1038/518147a. PMID 25673391.
  3. ^ "Evolution of Darwin's finches and their beaks - Uppsala University, Sweden". www.uu.se. Archived from the original on 24 April 2018. Retrieved 24 April 2018.
  4. ^ Soons, Joris; Herrel, Anthony; Genbrugge, Annelies; Aerts, Peter; Podos, Jeffrey; Adriaens, Dominique; Witte, Yoni de; Jacobs, Patric; Dirckx, Joris (12 April 2010). "Mechanical stress, fracture risk and beak evolution in Darwin's ground finches (Geospiza)". Philosophical Transactions of the Royal Society B: Biological Sciences. 365 (1543): 1093–1098. doi:10.1098/rstb.2009.0280. PMC 2830229. PMID 20194171. Archived from the original on 17 October 2017. Retrieved 24 April 2018.
  5. ^ a b PODOS, JEFFREY; NOWICKI, STEPHEN (2004). "Beaks, Adaptation, and Vocal Evolution in Darwin's Finches". BioScience. 54 (6): 501. doi:10.1641/0006-3568(2004)054[0501:baavei]2.0.co;2.
  6. ^ Sato, Akie (2001). "On the Origin of Darwin's Finches". Oxford. Archived from the original on 2016-03-03.
  7. ^ Lack, David. 1947. Darwin's Finches. Cambridge University Press (reissued in 1961 by Harper, New York, with a new preface by Lack; reissued in 1983 by Cambridge University Press with an introduction and notes by Laurene M. Ratcliffe and Peter T. Boag). ISBN 0-521-25243-1
  8. ^ Steinheimer 2004, p. 300
  9. ^ Lewitt, Dan. "Galapagos Finch Evolution – Dan Lewitt – HHMI (2013)". Archived from the original on 7 November 2017. Retrieved 6 June 2017.
  10. ^ a b Grant, K. Thalia; Estes, Gregory B. (2009). Darwin in Galapagos: Footsteps to a New World. Princeton, NJ: Princeton University Press.
  11. ^ Steinheimer 2004, pp. 301–303
  12. ^ Keynes 2000, p. xix.
       Eldredge 2006
  13. ^ Chancellor, Gordon; Keynes, Randal (October 2006), Darwin's field notes on the Galapagos: 'A little world within itself', Darwin Online, archived from the original on 22 August 2011
  14. ^ Eldredge 2006
  15. ^ Desmond & Moore 1991, pp. 208–209
  16. ^ a b c Sulloway 1982, pp. 57–58
  17. ^ Desmond & Moore 1991, p. 248
  18. ^ Sulloway 2006
  19. ^ Darwin 1839, pp. 461–462
  20. ^ Darwin 1839, p. 462.
  21. ^ Darwin 1845, pp. 379–380
  22. ^ Darwin 1887
  23. ^ Darwin 1845, p. 380.
  24. ^ Darwin 1859, pp. 397–398.
  25. ^ B. Rosemary Grant and Peter R. Grant 1989. Evolutionary dynamics of a natural population: the large cactus finch of the Galápagos. Chicago, p241 first para.
  26. ^ Grant, Peter R. 1999. Ecology and evolution of Darwin's finches. Princeton NJ, p428 in Afterword.
  27. ^ Maynard Smith J. 1998. Evolutionary genetics. 2nd ed, Chapter 5, Oxford.
  28. ^ Grant, Peter R. 1999. Ecology and evolution of Darwin's finches. Princeton NJ. (see plate 7)
  29. ^ "Galapagos finches caught in act of becoming new species". BBC News. 23 Nov 2017. Archived from the original on 2017-11-30.
  30. ^ "A New Bird Species Has Evolved on Galapagos And Scientists Watched It Happen". ScienceAlert. 24 Nov 2017. Archived from the original on 2017-12-09.
  31. ^ Abzhanov, Arhat; Protas, Meredith; Grant, B. Rosemary; Grant, Peter R.; Tabin, Clifford J. (3 September 2004). "Bmp4 and Morphological Variation of Beaks in Darwin's Finches". Science. 305 (5689): 1462–1465. Bibcode:2004Sci...305.1462A. doi:10.1126/science.1098095. ISSN 0036-8075. OCLC 1644869. PMID 15353802.
  32. ^ Abzhanov, Arhat; Kuo, Winston P.; Hartmann, Christine; Grant, B. Rosemary; Grant, Peter R.; Tabin, Clifford J. (3 August 2006). "The calmodulin pathway and evolution of elongated beak morphology in Darwin's finches". Nature. 442 (7102): 563–567. Bibcode:2006Natur.442..563A. doi:10.1038/nature04843. ISSN 0028-0836. OCLC 1586310. PMID 16885984.
  33. ^ Andersson, Leif; Lamichhaney, Sangeet; Berglund, Jonas; Almén, Markus Sällman; Maqbool, Khurram; Grabherr, Manfred; et al. (11 February 2015), "Evolution of Darwin's finches and their beaks revealed by genome sequencing", Nature, 518 (7102): 563–567, Bibcode:2006Natur.442..563A, doi:10.1038/nature14181, ISSN 0028-0836, OCLC 1586310, PMID 25686609
  34. ^ "200 years after Darwin, this is how the iconic Galapagos finches are still evolving". 22 April 2016. Archived from the original on 31 May 2016.
  35. ^ Podos & Nowicki, Jeffrey & Stephen (2004). "Beaks, Adaptation, and Vocal Evolution in Darwin's Finches". BioScience. 54 (6): 501–510. doi:10.1641/0006-3568(2004)054[0501:baavei]2.0.co;2.

References

External links

Adaptive radiation

In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches. Starting with a recent single ancestor, this process results in the speciation and phenotypic adaptation of an array of species exhibiting different morphological and physiological traits. The prototypical example of adaptive radiation is finch speciation on the Galapagos ("Darwin's finches"), but examples are known from around the world.

Camarhynchus

Camarhynchus is a genus of bird in the family Thraupidae; all species of Camarhynchus are endemic to the Galápagos Islands, and together with related genera they are collectively known as Darwin's finches. Sometimes classified in the bunting and American sparrow family Emberizidae, more recent studies have shown it to belong in the tanager family.

It contains the following species:

The vegetarian finch (Platyspiza crassirostris) is often also included in this genus.

Cocos finch

The Cocos finch or Cocos Island finch (Pinaroloxias inornata) is the only one of Darwin's finches not native to the Galápagos Islands, and the only member of the genus Pinaroloxias. Sometimes classified in the family Emberizidae, more recent studies have shown it to belong in the tanager family Thraupidae. It is endemic to Cocos Island, which is approximately 360 miles south of Costa Rica.

It is a chunky 12 cm long finch weighing around 12.5 g and with a black decurved pointed bill. The male is entirely black, while the female is a heavily streaked brown, with a paler underside. The young are similar but have yellow bills. The standard clutch is two brown-spotted white eggs, which are hatched in a roughly spherical nest built at the end of a tree branch.

The Cocos finch is the most abundant landbird on Cocos Island. It can be found in every habitat on the island and eats a wide range of plant and insects as food.

This species qualifies as Vulnerable because of its small range.

Cuban bullfinch

The Cuban bullfinch (Melopyrrha nigra) is a songbird species of the genus Melopyrrha. Recent studies have shown it to be part of the tanager family (Thraupidae). Therein, it belongs to the lineage of tholospizan "finches", which also includes the famous Darwin's finches.

It is found on and endemic to Cuba. The Grand Cayman bullfinch, formerly considered a subspecies (M. n. taylori), is now considered a full species by IUCN and BirdLife International. Its natural habitats are subtropical or tropical moist lowland forest, subtropical or tropical moist montane forest, and heavily degraded former forest. It is not considered a threatened species by the IUCN.

Cuban grassquit

The Cuban grassquit (Tiaris canorus) is a small bird. It is recognized as a tanager closely related to Darwin's finches. It is found in Bahamas, Cuba, and Turks and Caicos Islands.

Its natural habitats are subtropical or tropical moist lowland forest, subtropical or tropical moist montane forest, subtropical or tropical dry shrubland, and heavily degraded former forest.

Daphne Major

Daphne Major is a volcanic island just north of Santa Cruz Island and just west of the Baltra Airport in the Archipelago of Colón, commonly known as the Galápagos Islands. It consists of a tuff crater, devoid of trees, whose rim rises 120 m (394 ft) above the sea.

Though easily accessible to most visitors to the Galápagos, the national park service has highly restricted visits to this island, and it is primarily used for scientific research. An intensive study of Darwin's finches was conducted here by biologists Peter and Rosemary Grant over a period of 20 years. They examined the behaviour and life cycles of finches, demonstrating the role of natural selection in producing biological evolution. Their efforts were documented in the Pulitzer Prize–winning book The Beak of the Finch.

Daphne is home to a variety of other birds including Galápagos martins, blue-footed booby, Nazca booby, short-eared owls, red-billed tropicbirds and magnificent frigatebirds.

David Lack

David Lambert Lack FRS (16 July 1910 – 12 March 1973) was a British evolutionary biologist who made contributions to ornithology, ecology, and ethology. His 1947 book, Darwin's Finches, on the finches of the Galapagos Islands was a landmark work as were his other popular science books on Life of the Robin and Swifts in a Tower. He developed what is now known as Lack's Principle which explained the evolution of avian clutch sizes in terms of individual selection as opposed to the competing contemporary idea that they had evolved for the benefit of species (also known as group selection). His pioneering life-history studies of the living bird helped in changing the nature of ornithology from what was then a collection-oriented field. He was a longtime director of the Edward Grey Institute of Field Ornithology at the University of Oxford.

Divergent evolution

Divergent evolution or divergent selection is the accumulation of differences between closely related populations within a species, leading to speciation. Divergent evolution is typically exhibited when two populations become separated by a geographic barrier (such as in allopatric or peripatric speciation) and experience different selective pressures that drive adaptations to their new environment. After many generations and continual evolution, the populations become unable to interbreed with one another. The American naturalist J. T. Gulick (1832-1923) was the first to use the term "divergent evolution", with its use becoming widespread in modern evolutionary literature. Classic examples of divergence in nature are the adaptive radiation of the finches of the Galapagos or the coloration differences in populations of a species that live in different habitats such as with pocket mice and fence lizards.The term can also be applied in molecular evolution, such as to proteins that derive from homologous genes. Both orthologous genes (resulting from a speciation event) and paralogous genes (resulting from gene duplication) can illustrate divergent evolution. Through gene duplication, it is possible for divergent evolution to occur between two genes within a species. Similarities between species that have diverged are due to their common origin, so such similarities are homologies. In contrast, convergent evolution arises when an adaptation has arisen independently, creating analogous structures such as the wings of birds and of insects.

Dull-coloured grassquit

The dull-coloured grassquit (Tiaris obscurus) is a small bird. It is recognized as a tanager closely related to Darwin's finches.

It is found in northwestern Argentina, Bolivia, Colombia, Ecuador, Peru and western Venezuela. It is a vagrant to Paraguay and central Brazil.

Its natural habitats are subtropical or tropical moist lowland forest, subtropical or tropical moist montane forest, subtropical or tropical moist shrubland, subtropical or tropical high-altitude shrubland, and heavily degraded former forest.

Española cactus finch

The Española cactus finch (Geospiza conirostris), is a species of bird in the tanager family Thraupidae. It is one of Darwin's finches, and is endemic to the Galápagos islands, where it is restricted to Española, Genovesa, Darwin and Wolf Islands. This rather dark bird resembles the smaller and finer-beaked common cactus finch, but the two species do not co-inhabit any island.

Its natural habitat is dry shrubland and it is commonly seen on the ground. Its main food source is the cactus Opuntia.

Genovesa cactus finch

The Genovesa cactus finch (Geospiza propinqua) is a species of bird in the tanager family Thraupidae. It is one of Darwin's finches, and is endemic to the Galápagos islands, Ecuador, where it is restricted to Genovesa Island.

Its natural habitat is dry shrubland and it is commonly seen on the ground. Its main food source is the cactus Opuntia.

Geospiza

Geospiza is a genus of bird in the family Thraupidae. All species in the genus are endemic to the Galápagos Islands. Together with related genera, they are collectively known as Darwin's finches. Although in the past, they were classified in the bunting and American sparrow family Emberizidae, more recent studies have shown they belong in the tanager family.

Icons of Evolution

Icons of Evolution is a book by Jonathan Wells, an intelligent design advocate and fellow of the Discovery Institute, in which Wells criticized the paradigm of evolution by attacking how it is taught. The book includes a 2002 video companion. In 2000, Wells summarized the book's contents in an article in the American Spectator. Several of the scientists whose work is sourced in the book have written rebuttals to Wells, stating that they were quoted out of context, that their work has been misrepresented, or that it does not imply Wells' conclusions.Some in the scientific community have criticized the book and regard it as pseudoscientific. It was criticised for its claims that schoolchildren are deliberately misled, and its conclusions as to the evidential status of the theory of evolution, which is considered by scientists to be the central unifying paradigm of biology. Kevin Padian and Alan D. Gishlick wrote a review in Quarterly Review of Biology which said: "In our view, regardless of Wells’s religious or philosophical background, his Icons of Evolution can scarcely be considered a work of scholarly integrity."

Gishlick wrote a more detailed critique for the National Center for Science Education in his article "Icon of Evolution? Why much of what Jonathan Wells writes about evolution is wrong." Nick Matzke reviewed Wells' work in the talk.origins article Icon of Obfuscation, and Wells responded with A Response to Published Reviews (2002).

Large ground finch

The large ground finch (Geospiza magnirostris) is a species of bird. One of Darwin's finches, it is now placed in the family Thraupidae and was formerly in the Emberizidae. It is endemic to the Galapagos Islands, and is found in the arid zone of most of the archipelago, though it is absent from the southeastern islands (Floreana, Española, San Cristóbal and Santa Fé). It is the largest species of Darwin's finch both in total size and size of beak. It has a large, short beak for cracking nuts to get food.

List of things named after Charles Darwin

Several places, concepts, institutions, and things are namesakes of the English biologist Charles Darwin:

PlacesCharles Darwin National Park

Charles Darwin Foundation

Charles Darwin Research Station

Charles Darwin University

Darwin College, Cambridge

Darwin, Falkland Islands

Darwin, Northern Territory

Darwin Glacier (California)

Darwin Guyot, a seamount in the Pacific Ocean

Darwin Island, Galapagos Islands

Darwin Island (Antarctica)

Darwin Sound (Canada)

Mount Darwin (California)

Mount Darwin (Tasmania)Things named after Darwin in relation to his Beagle voyageCordillera Darwin

Darwin's finches

Darwin's frog

Darwin Sound

Mount Darwin (Andes)Scientific names of organismsSome 250 species and several higher groups bear Darwin's name; most are insects.

Darwinilus, a rove beetle

Darwinius, an extinct primate

Darwinopterus, a genus of pterosaur

Darwinula, a genus of seed shrimp

Darwinivelia, a water treader genus

Darwinysius, a seed bug

Darwinomya, a genus of flies

Darwinella, a sponge genus

Darwinsaurus, a dinosaur

Darwinhydrus, a diving beetle

darwini (multiple species)

darwinii (multiple species)

Ingerana charlesdarwini, a frogPhilosophiesDarwinism

Social DarwinismOtherDarwin, a unit of evolutionary change

Darwin, an operating system

Darwin (ESA) (a proposed satellite system)

Darwin Awards

Darwin Medal

Darwin fish

Division of Darwin, a former electoral division in Australia

1991 Darwin, a stony Florian asteroid

Darwin (lunar crater) a lunar crater

Darwin (Martian crater) a martian crater

Peter and Rosemary Grant

Peter Raymond Grant, , , and Barbara Rosemary Grant, , , are a British couple who are evolutionary biologists at Princeton University. Each currently holds the position of emeritus professor. They are known for their work with Darwin's finches on Daphne Major, one of the Galápagos Islands. Since 1973, the Grants have spent six months of every year capturing, tagging, and taking blood samples from finches on the island. They have worked to show that natural selection can be seen within a single lifetime, or even within a couple of years. Charles Darwin originally thought that natural selection was a long, drawn out process. The Grants have shown that these changes in populations can happen very quickly.

In 1994, they were awarded the Leidy Award from the Academy of Natural Sciences of Philadelphia. The Grants were the subject of the book The Beak of the Finch: A Story of Evolution in Our Time by Jonathan Weiner, which won the Pulitzer Prize for General Non-Fiction in 1995.

In 2003, the Grants were joint recipients of the Loye and Alden Miller Research Award. They won the 2005 Balzan Prize for Population Biology. The Balzan Prize citation states:

Peter and Rosemary Grant are distinguished for their remarkable long-term studies demonstrating evolution in action in Galápagos finches. They have demonstrated how very rapid changes in body and beak size in response to changes in the food supply are driven by natural selection. They have also elucidated the mechanisms by which new species arise and how genetic diversity is maintained in natural populations. The work of the Grants has had a seminal influence in the fields of population biology, evolution, and ecology.The Grants are both Fellows of the Royal Society, Peter in 1987, and Rosemary in 2007. In 2008 the Grants were among the thirteen recipients of the Darwin-Wallace Medal, which is bestowed every fifty years by the Linnean Society of London. In 2009 they were recipients of the annual Kyoto Prize in basic sciences, an international award honouring significant contributions to the scientific, cultural and spiritual betterment of mankind. In 2017, they received the Royal Medal in Biology "for their research on the ecology and evolution of Darwin’s finches on the Galapagos, demonstrating that natural selection occurs frequently and that evolution is rapid as a result".

Philornis downsi

Philornis downsi is a species of fly (Diptera, Muscidae) that was first recorded in Trinidad and Brazil in the 1990s. It has been accidentally introduced to the Galapagos Islands (Ecuador). Adult P. downsi feed on fruit. Eggs are laid in bird nests and hatch into parasitic larvae which reside in the nest material and emerge at night to feed both internally and externally on the blood and flesh of developing nestlings. The parasite is causing significant mortality in Darwin's finch nestlings and threaten the survival of some rarer species such as the mangrove finch (Camarhynchus heliobates) and the medium tree finch (C. pauper). In order to protect the threatened finch populations, insecticide-laced cotton has been supplied as nesting material for the finches, with the results being highly successful in combating P. downsi infestations.

Scalesia

Scalesia is a genus in the family Asteraceae endemic to the Galapagos Islands. It contains fifteen species that grow as shrubs or trees. This is unusual, because tree species are uncommon in Asteraceae. The genus Scalesia resulted from a blunder by Arnott who named it in honour of "W. Scales Esq., Cawdor Castle, Elginshire" but discovered after publication that the name should have read 'Stables', after Scottish botanist, William Alexander Stables (1810–1890).All of the species have soft, pithy wood. Scalesia species have been called "the Darwin's finches of the plant world" because they show a similarly dramatic pattern of adaptive radiation.

One of the largest and most widespread species is Scalesia pedunculata – a large tree which grows up to 15 to 20 metres tall, reaching maturity in a few years time. These trees typically grow in dense stands of the same species and age. They die around the same time, and then a new generation of seedlings grows up in the same place. The largest stands of Scalesia pedunculata are found on the humid windward sides of Santa Cruz, San Cristóbal, Santiago and Floreana islands, at an altitude of 400–700 m. The best known and most visited stand is on Santa Cruz Island, and is crossed by a road.

Scalesia atractyloides and S. stewartii are two small tree species, very similar to each other.

Vegetarian finch

The vegetarian finch (Platyspiza crassirostris) is a species of bird in the Darwin's finch group of the tanager family Thraupidae. It is monotypic within the genus Platyspiza. It is endemic to the Galápagos Islands. Its natural habitats are subtropical or tropical dry forests and subtropical or tropical moist montane forests.

Birds (class: Aves)
Anatomy
Behaviour
Evolution
Fossil birds
Human interaction
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Neornithes

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