
	Where results make sense

Topic: Paedogenesis

In the News (Fri 27 Nov 09)

Northern Trust

Marvin Harrison

Peter Chernin

Gary Locke

Match Play

Penelope Cruz

Mickey Rourke

AR Rahman

Danny Boyle

Hugh Jackman

	Jason Hodin
		Paedogenesis in cecids involves the precocious growth and differentiation of the ovary in an otherwise larval form.
		Of the six independent instances of paedogenesis (defined broadly to include pupal reproduction, as seen in some chironomid midges), four of them are among the Diptera.
		I argue that the paucity of instances of paedogenesis outside of the "lower" Diptera represents a developmental constraint on the evolution of paedogenesis.
	raven.zoology.washington.edu /EvoDevo/jason.html (627 words)

	Interactive Fly, Drosophila
		Paedogenesis in gall midges involves the precocious growth and differentiation of the ovary in an otherwise larval form.
		Since the germ cells were already differentiating early in a hypothetical ancestral non-paedogenetic gall midge, the most important change necessary to evolve paedogenesis may have been the precocious activation of the ovarian somatic cell differentiation program.
		There may only be a limited set of possible ways to evolve this life cycle, and it may be essentially unavailable to many taxa due to the vagaries of evolutionary history (namely, which taxa have the appropriate pre-adaptations, such as parthenogenesis and early germ cell differentiation).
	www.sdbonline.org /fly/newgene/ecdysr2c.htm (4972 words)

	306 HETEROCHRONY AND PAEDOMORPHOSIS (Site not responding. Last check: 2007-10-08)
		The last of von Baer's contributions to the study of heterochrony (1866) may seem trifling compared with his earlier accomplishments: he gave the name Paedogenesis to a remarkable method of parthenogenetic reproduction in gall midges (Diptera, family Cecidomyiidae).
		Paedogenesis has arisen in at least four distinct groups of the Cecidomyiidae (Wyatt, 1967, p.
		There can be no doubt that these larval paedomorphs are progenetic rather than neotenic, for their development is markedly accelerated relative to the sexual phase of their life cycle.
	www.sjgarchive.org /library/text/ontogeny/p0306.htm (406 words)

	BioG 105/106 \| Autotutorial Introductory Biology
		The early onset of sexual maturity is a particular form of paedomorphosis called paedogenesis.
		If a sexually mature organism that resembled a larval tunicate was successful natural selection would have reinforced paedogenesis, ultimately eliminating metamorphosis entirely, and giving us something similar to the cephalochordates we see today.
		Despite their similarities, there are several reasons why cephalochordates are unlikely to be the direct ancestors of vertebrates, one of them being the lack of a complex brain and cephalic sense organs homologous to those of vertebrates.
	instruct1.cit.cornell.edu /courses/biog105/labs/deuts/cephalochordata.html (508 words)

	BIOLOGY 151 - GENERAL BIOLOGY I
		High probability that both lineages evolved thru a process known as paedogenesis.
		Paedogenesis= precocious development of sexual maturity in a larval form.
		Slight changes in developmental genes may have changed the timing of gonadal development, this would allow larval forms to reproduce.
	www.usd.edu /biol/genbio/151/kurt/lectures/kd3.html (1493 words)

	Introductory Biology Courseware (111)- Kingdom Animalia (Vertebrata) (Site not responding. Last check: 2007-10-08)
		is that the first vertebrates may have resulted from paedogenesis (precocious attainment of sexual maturity) taking place in urochordate larvae (in this group, chordate features are normally lost at metamorphosis).
		Paedogenesis is common among members of the group.
		Although amphibians exhibited modifications which enabled them to maneuver and survive in moist terrestrial environments, they were still dependent on the ready availability of water.
	tidepool.st.usm.edu /crswr/111vertebrates.html (3379 words)

	The Evolution of the
		Due to their morphologic and embryonic similarities, modern day researchers have hypothesized that the cephalochordate is the closest relative to the vertebrate (Campbell et al.
		It is possible that both vertebrates and cephalochordates evolved from a common ancestor through paedogenesis, the "development of sexual maturity in the larva," and that small changes in the gene controlling development altered the timing of development events (Campbell et al.
		While it can be predicted that the cephalochordate and vertebrate evolved from a common ancestor, it is also important to recognize the difference brought about by their evolutionary divergence.
	www.personal.psu.edu /students/c/l/clm278/evolution.htm (533 words)

	newt glossary - bethnewt (Site not responding. Last check: 2007-10-08)
		Neotenics are generally much larger than terrestrial salamanders; a neotenic Ambystoma tigrinum can be 30 inches long, while the terrestrial form rarely exceeds 10 inches.
		Sometimes used as a synonym for "neoteny," paedogenesis is the phenomenon neotenics are capable of: reproducing while otherwise physically immature.
		See the FAQ for the difference between newts and salamanders.
	www.loxosceles.org /newts/glossary.shtml (286 words)

	Research on Soybean aphid, Aphis glycines Matsumura, in Jilin Province
		These nymphae which had nymphae embryo was only 14.5% in all the instar 2 aphids collected from filed.
		This can prove that soybean aphis have the phenomenon of deformed paedogenesis.
		However, whether the aphides of nymphae pregnancy and mature pregnancy have the same number of instar in one generation need research further.
	www.k-state.edu /issa/aphids/reporthtml/trans32.htm (865 words)

	131exam3 (Site not responding. Last check: 2007-10-08)
		Why was the formation of the amniotic egg a major step in vertebrate evolution?
		Compare and contrast heterochrony, paedogenesis, peadomorphosis, allometric growth and homeotic genes?
		What role did paedogenesis play in chordate lineage?
	voyager.dvc.edu /~rgoralka/131exam3.html (225 words)

	[No title]
		After the bag is closed, the male pupates and will eventually emerge as a flying moth.
		Bagworms are unusual because they use an uncommon form of reproduction called paedogenesis in which the female larva reproduces.
		The female larva never pupates, but produces mature sexual organs during the last larval instar.
	www.oznet.ksu.edu /hfrr/hnewslet/2003/ksht0333.htm (1561 words)

	practice2
		Give two examples of chordates other than vertebrates.
		Describe the tunicate (sea squirt, Urochordate) and explain why vertebrates are hypotheszied to have evolved from a Urochordate-like ancestor that underwent paedogenesis.
		Name the seven classes of vertebrates and describe them in terms of jaws, appendages, skeletal material, vertebral column, gill slits, lungs, skin, eggs, and endothermy.
	www.sou.edu /BIOLOGY/Courses/PrinBi/BI212/practice3.htm (399 words)

	Florida Entomologist, v. 84, n. 1, p. 159
		Larvae develop in moist decaying hardwoods and can go through several stages and shapes in their development, appearing as caraboid, cerambycoid, and curculionoid larval types.
		The complicated lifecycle involves paedogenesis and several types of parthenogenesis (thelytoky, amphitoky, and arrhenotoky) (for details see Barber 1913a, b; Pringle 1938; Scott 1936, 1938, 1941).
		The classification of this species has undergone much discussion and controversy.
	www.fcla.edu /FlaEnt/fe84p159.htm (884 words)

	Vol. 11, no1 (Site not responding. Last check: 2007-10-08)
		Variability among paedotypic populations was found to be lower than intrapopulation variability of metamorphosed individuals.
		Key words: Triturus alpestris, morphological differentiation, taxonomy, paedogenesis, Balkan Peninsula
		Predator-induced behavioural responses: Tadpoles of the neotropical frog Phyllomedusa tarsius do not respond to all predators
	biology.bangor.ac.uk /~bss166/HJ/v11no1.html (872 words)

Try your search on: Qwika (all wikis)