
	Where results make sense

Topic: Sympatric

In the News (Mon 6 Jul 09)

Northern Trust

Marvin Harrison

Peter Chernin

Gary Locke

Match Play

Penelope Cruz

Mickey Rourke

AR Rahman

Danny Boyle

Hugh Jackman

	Sympatric/parapatric speciation, hybrid zones, and reinforcement (October 2002) (Site not responding. Last check: 2007-10-25)
		Morphological, behavioral, and genetic divergence of sympatric morphotypes of the treefrog Polypedates leucomystax in peninsular Malaysia.
		Sympatric morphs, populations and speciation in freshwater fish with emphasis on arctic charr.
		Evolution of reproductive isolation in allopatric and sympatric populations.
	www.eeb.uconn.edu /Courses/EEB449/449_sympatric.htm (9075 words)

	Sympatric speciation - Wikipedia, the free encyclopedia
		In complete contrast to allopatry, species undergoing sympatric speciation are not geographically isolated by, for example, a mountain or a river.
		There is also at least one well-known ecological phenomenon, allochrony, which offers some empirical evidence that sympatric speciation has taken place, as many examples exist of allochronic species which are each others' nearest relatives ("sister taxa").
		Sympatric speciation events are most common in plants when they double or triple the number of chromosomes, resulting in a condition called polyploidy.
	en.wikipedia.org /wiki/Sympatric_speciation (409 words)

	The Scientist : Mechanisms of Speciation
		Although Darwin acknowledged the existence of allopatric speciation, he believed that most separations occur sympatrically, which happens without geographic isolation, while the incipient species are still in physical contact and able to interbreed.
		Now, there are good examples of sympatric speciation, most notably the cichlids in East Africa, and much of the growing evidence in support of the back-to-Darwin approach comes from these newly acknowledged cases.
		The evidence has altered Mayr's views on sympatric speciation, although he still strongly believes that the allopatric method is the predominant mode and the only one to be found among the well-studied birds and mammals.
	www.the-scientist.com /2003/11/17/14/1 (2143 words)

	VARIATION OF THE SIPHONAL CHARACTERS IN SYMPATRIC POPULATIONS OF
		An investigation of sympatric populations of Aedes caspius and Ae.
		The aim of this paper is to establish differences in the characters of the respiratory siphon of 4th instar larvae in sympatric populations of Ae.
		Similar results were obtained in a morphological analysis of larvae of sympatric populations in France (Lambert et al., 1990); the number of branches of the siphonal seta ranging from 5 to 10 in Ae.
	www.uel.ac.uk /mosquito/issue2/pecten.htm (1200 words)

	The Scientist : Evidence for sympatric speciation
		To convincingly demonstrate sympatric speciation, the species must be true sister taxa that are reproductively isolated while occupying overlapping ranges.
		But he and Coyne, neither of whom contributed to either study, remain unconvinced that they are much more robust than a 1994 study of cichlids in Cameroonian crater lakes, to which they also did not contribute.
		The strength of that study, said Coyne, is that it involved a monophyletic group of several species from a single lake, which is harder to explain by multiple independent colonizations from a source population.
	www.the-scientist.com /news/display/23103 (723 words)

	MY LOGFILE (Site not responding. Last check: 2007-10-25)
		The review suggests that the sympatric speciation of cichlids are due to trophic differentiation, which I think means differentiation caused by utilization of different food sources, but not to sexual selection.
		Sympatric speciation is promoted if costs of being choosy are small (or absent) and if linkage between the loci experiencing disruptive selection and those controlling assortative mating is strong.
		This is another example for sympatric evolution of the species due to different host-race, and due to the selection of particular behavior that are beneficial for that particular host.
	home.wlu.edu /~barekeh/bio182/log.html (3490 words)

	Evolution - A-Z - Sympatric speciation (Site not responding. Last check: 2007-10-25)
		In sympatric speciation, a species splits into two without any separation of the ancestral species' geographic range.
		With the exception of hybrid speciations, it has been a source of recurrent controversy whether sympatric speciation ever happens.
		Sympatric speciation can be compared with the allopatric and parapatric theories of speciation.
	www.blackwellpublishing.com /ridley/a-z/Sympatric_speciation.asp (60 words)

	Evolution - Speciation
		Sympatric speciation describes the splitting into two of a species without any separation of the ancestral species' geographic range.
		The general conditions for sympatric speciation are therefore that the genotypes are adapted to different resources and the limited resources generate frequency-dependent selection.
		Then if the resources are not in the frequencies of the genotypes generated by random mating, sympatric speciation becomes a possibility.
	www.blackwellpublishing.com /ridley/tutorials/Speciation10.asp (323 words)

	Frontiers in Zoology \| Full text \| Reticulate sympatric speciation in Cameroonian crater lake cichlids
		Recent empirical data and theoretical advances suggest that the diversity of complex species assemblages is based at least partially on the hybridization of numerous ancestral allopatric lineages that formed hybrids upon invasion of new environments [1-5].
		In this study, we tested hypotheses about sympatric speciation with a focus on hybridization by applying a combination of mitochondrial DNA-sequencing and AFLP-genotyping as well as a set of recently proposed analytical tools [20] to the phylogenetic analysis of a complete and complex species flock.
		Our results demonstrate that the sympatric origin of a diverse and complex species flock was aided substantially by reticulate evolution among lineages that emerged in a much smaller primary radiation.
	www.frontiersinzoology.com /content/1/1/5 (6135 words)

	Sympatric White-lipped Peccary and Collared Peccary - Ecology of Peccaries
		Sympatric White-lipped Peccary and Collared Peccary - Ecology of Peccaries
		Haemig PD Sympatric White-lipped Peccary and Collared Peccary.
		White-lipped and collared peccaries are therefore sympatric in much of South America and in the humid tropical forests of Mexico and Central America.
	www.ecology.info /ecology-peccaries.htm (2047 words)

	Allopatric vs
		Therefore, sympatric speciation is not only possible, but likely contributes to much of the diversity seen in nature.
		Furthermore, empirical studies have demonstrated that sympatric speciation can cause the divergence of a population in a relatively short amount of time; allopatric speciation requires much more time, especially in large populations.
		The importance of sympatric relative to allopatric speciation is still unclear.
	evotutor.org /Author/Research/Paper-EG2-Speciation.htm (983 words)

	Speciation
		Some of the spectacular radiation of African cichlid fishes is probably also a result of sympatric speciation, perhaps driven by a combination of ecological and sexual selection (Schliewen et al.
		Sympatric speciation can occur more readily in plants (Savolainen et al., 2006), because plants can change their chrosome number (polyploidy) and persist or spread by asexual reproduction.
		Sympatric speciation in palms on an oceanic island.
	www.uwyo.edu /dbmcd/molmark/lect2a.html (3205 words)

	Sympatric speciation in Nicaraguan crater lake cichlid fish : Nature (Site not responding. Last check: 2007-10-25)
		Sympatric speciation in Nicaraguan crater lake cichlid fish
		Sympatric speciation, the formation of species in the absence of geographical barriers, remains one of the most contentious concepts in evolutionary biology.
		Here we present a convincing case of sympatric speciation in the Midas cichlid species complex (Amphilophus sp.) in a young and small volcanic crater lake in Nicaragua.
	www.nature.com /nature/journal/v439/n7077/abs/nature04325.html (273 words)

	Sympatric speciation in palms on an oceanic island: Nature (Site not responding. Last check: 2007-10-25)
		Claims of sympatric speciation must demonstrate species sympatry, sister relationships, reproductive isolation, and that an earlier allopatric phase is highly unlikely
		Here we provide clear support for sympatric speciation in a case study of two species of palm (Arecaceae) on an oceanic island.
		This case study of sympatric speciation in plants provides an opportunity for refining theoretical models on the origin of species, and new impetus for exploring putative plant and animal examples on oceanic islands.
	www.nature.com /nature/journal/v441/n7090/abs/nature04566.html (351 words)

	Frontiers in Zoology \| Full text \| Immune response to sympatric and allopatric parasites in a snail-trematode ...
		Therefore, even though the defense was induced to the same degree by both sympatric and allopatric parasites, the defense was less effective against the locally adapted sympatric parasites.
		Previous studies have shown that parasites from these same two lakes are adapted to infect their sympatric host populations [19].
		In addition, in a meta-analysis of multiple studies on this system, we found that 32 of 33 parasite populations (in either space or time) were more successful at infecting local snails than snails collected from allopatric locations [21].
	www.frontiersinzoology.com /content/2/1/8 (4063 words)

	[No title]
		ORIGIN OF SYMPATRIC SPECIES Species which live together in the same area at the same time, i.e., that are sympatric and synchronic, tend to be clearly differentiated in morphology, ecology and reproductive behavior.
		So common are congeneric species (closely related species which are included in the same genus) which are always sympatric that some biologists have argued that they must have evolved while part of the same species population (sympatric speciation).
		An alternative view of the origin of sympatric species relies on the theory of allopatric speciation wherein a daughter species evolved from a parental species as an allopatric population and secondarily came into contact with the parental species through migration into its home range.
	www.holycross.edu /departments/biology/whealy/notes_text/bp.text (877 words)

	American Scientist Online - How Species Arise (Site not responding. Last check: 2007-10-25)
		The sharpest critiques in the book are of sympatric modes, which the authors consider to be possible but probably of minor importance.
		Coyne and Orr note that "parapatric and sympatric modes of speciation require that the evolutionary forces causing populations to diverge must be stronger than the gene flow causing them to fuse," whereas there are few roadblocks to allopatric speciation.
		Polyploid speciation (based on chromosomal dysfunction), reinforcement (in which incipient isolation is enhanced by natural selection when populations become sympatric), and natural selection versus genetic drift are all considered in analytical detail.
	www.americanscientist.org /template/AssetDetail/assetid/37202 (1545 words)

	Male pregnancy in seahorses may affect formation of new species
		Driving the sympatric speciation process in seahorses is the fish’s size-similar mating practice imposed by male pregnancy, extended male parental care and monogamy, Jones said.
		A third line of evidence for sympatric speciation came from the phylogeny, or family tree, of seahorses, which are found in coastal and ocean habitats throughout the world, except in extreme latitudes.
		Further research on sympatric speciation could reveal patterns of genetic variation in species pairs that researchers suspect might have undergone sympatric speciation.
	www.eurekalert.org /pub_releases/2003-05/giot-mpi050503.php (922 words)

	Evidence for sympatric speciation by host shift in the sea
		Using a combination of genetic, ecological, and biogeographic studies, researchers have found that a new species of reef fish might have evolved when some individuals of the ancestral population began inhabiting a novel species of coral and that this "host shift" could have happened without geographic isolation of the new population.
		Although various mechanisms of speciation are possible, the authors show that sympatric speciation by host shift is the simplest explanation for the pattern of habitat use and current-day geographic range of the new species.
		The ecology of coral-dwelling gobies closely matches that of leaf-eating insects, another group of animals for which sympatric speciation by host shift has been reported, thus providing support for a general set of ecological conditions that favor sympatric speciation by host shift.
	www.eurekalert.org /pub_releases/2004-08/cp-efs081704.php (305 words)

	Sympatric Jaguar and Puma. Ecology of Big Cats of North and South America.
		In this article, we compare the habits of sympatric jaguar and puma, and examine the many important ways that they differ from each other.
		The best places to study sympatric jaguar and puma are in wilderness areas where neither of these big cats, nor the animals they prey upon, have been reduced in numbers by hunting, poaching or trapping.
		Maxit IE (2001) Prey Use by Sympatric Jaguar and Puma in the Venezuelan Llanos.
	www.ecology.info /ecology-jaguar-puma.htm (2224 words)

	evolgen archive: A Few Words on Speciation
		In this framework two sympatric population are essentially one single population with complete migration between them (m=0.5).
		Even the sympatric nature of the Rhagoletis system has been called into question -- traditionally by the argument that host shifts due not really constitute sympatric speciation, and more recently by molecular studies that show the genetic potential for speciation originated allopatrically (defined geographically).
		This new framework provides two plausible modes of speciation (rather than the extremely unlikely entirely sympatric speciation), but the mechanisms of speciation would still differ between the two modes so the dichotomy is biologically meaningful.
	evolgen.blogspot.com /2005/12/few-words-on-speciation.html (619 words)

	Role reversal may affect formation of new seahorse species
		But some seahorses likely diversify in a process called sympatric speciation, in which new species arise from a single population that has no geographic barriers to inhibit gene flow, according to a paper published this week in the Proceedings of the National Academy of Sciences (PNAS).
		Indeed, researchers noted two examples of species that are close relatives that are sympatric over part or all of their range.
		The case for sympatric speciation will be stronger if we can find recent events - something that occurred in the past 50,000 years.
	gtresearchnews.gatech.edu /newsrelease/seahorse.htm (1003 words)

	Evolution 101: Speciation (Site not responding. Last check: 2007-10-25)
		Unlike the previous modes, sympatric speciation does not require large-scale geographic distance to reduce gene flow between parts of a population.
		This means that gene flow between parts of the population that mate on different types of fruit is reduced.
		This host shift from hawthorns to apples may be the first step toward sympatric speciation—in fewer than 200 years, some genetic differences between these two groups of flies have evolved.
	evolution.berkeley.edu /evosite/evo101/VC1eSympatric.shtml (338 words)

	evolgen: Nick Barton and Jerry Coyne Don't Like Your Sympatric Speciation
		However, one of our best examples of sympatric speciation via chromosomal inversions is actually allopatric speciation with reinforcement.
		Also, the other explanation used to explain away sympatric speciation is sequential invasions and ecological character displacement.
		This is a lot like sympatric speciation too and often leads to reproductive isolation that didn't exist BEFORE, of course reproductive isolation is not directly selected for here as it is with reinforcement.
	scienceblogs.com /evolgen/2006/09/nick_barton_and_jerry_coyne_do.php (646 words)

	Host Fidelity is an Effective Premating Barrier Between Sympatric Races of the Apple Maggot Fly -- Feder et al. 91 ...
		Models of sympatric speciation for phytophagous insects posit a central role for host plant-associated mating as a premating isolating mechanism in lieu of geographic barriers to gene flow.
		Genetically based differences in host preference, adult eclosion under the "correct" host species, and allochronic isolation contribute to host fidelity in various degrees in the races.
		The study also represents one of the few or perhaps only example in animals where the intra-specific isolating effects of specific phenotypes have been quantified in nature.
	www.pnas.org /cgi/content/abstract/91/17/7990 (628 words)

	Speciation - Wikipedia, the free encyclopedia
		There are four modes of natural speciation, based on the extent to which speciating populations are geographically isolated from one another: allopatric, peripatric, parapatric, and sympatric.
		Examples of sympatric speciation are found in insects which become dependent on different host plants in the same area.
		If their reproductive isolation is incomplete, then further mating between the populations will produce hybrids, which may or may not be fertile.
	en.wikipedia.org /?title=Speciation (1546 words)

	sympatric - Search Results - MSN Encarta
		In sympatric speciation, isolating mechanisms may be triggered by differences in habitat, sexual reproduction, or heredity.
		Sometimes two subpopulations of the same species do not produce offspring with one another, even though they come into breeding contact.
		Evolution : Origin of New Species : Sympatric Speciation
	encarta.msn.com /sympatric.html (97 words)

	Franklin \| News
		Also part of the research were geneticist Dr. John Avise of the University of Georgia and DeEtte Walker, research coordinator in his lab.
		“ If there had been sympatric speciation and it was based on assortative mating by size, then when speciation occurs, the result should be a large species and a small species that live in the same place,” Jones explained.
		The case for sympatric speciation will be stronger if we can find recent events – something that occurred in the past 50,000 years.
	www.franklin.uga.edu /news/2003/article27.htm (915 words)

	Evidence for Inversion Polymorphism Related to Sympatric Host Race Formation in the Apple Maggot Fly, Rhagoletis ...
		Evidence for Inversion Polymorphism Related to Sympatric Host Race Formation in the Apple Maggot Fly, Rhagoletis pomonella -- Feder et al.
		of sympatric speciation are predicated on such an association
		a major tenet of sympatric host race formation would be verified.
	www.genetics.org /cgi/content/full/163/3/939 (6347 words)

Try your search on: Qwika (all wikis)