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Topic: Amniotic egg

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In the News (Tue 19 Mar 19)

  The Amniotic Egg
Which is an egg that if you really look at it in the big sense of the thing, what this egg isdoing is allowing vertebrate animals to produce larger newborn young than they would be able toproduce otherwise.
When we look at a fish egg, for example, or an amphibian egg, what we will see is thatthese eggs, which are -- I'm using these because these are representative of the ancestors fromwhich the amniotic egg evolved, these eggs have one structure which is called a extra embryonicmembrane that provides for nutrition.
So in an amniotic egg, the water is provided by one of the extra embryonicmembranes, which is called the "amnion." This is the membrane that gives the egg its name.
www.csupomona.edu /~dfhoyt/classes/zoo138/EGG.HTML   (1975 words)

  Dinosaur Nests Reinterpreted
Considering the eggs in light of the possible sequence of events which occurred during their laying (Figure 6), egg 1 was laid and prior to the time eggs 2 and 3 were laid, approximately 12 to 15 cm of sediment, (half the diameter of egg 1), were deposited.
Eggs are positioned in the substrate as though their final positions were determined by the viscosity of wet sediments into which they were dropped.
Eggs are found with pieces of hatching windows lying inside the lower portion of the shells, usually with the concave surface upward, indicating breakage by causes other than the hatching of young and also indicating negligent treatment of the eggs when they were laid.
www.creationresearch.org /crsq/articles/41/41_2/Dinotests.htm   (7658 words)

 [No title]
The development of the amniotic egg is considered one of the major evolutionary events, heralding full independence from water and the conquest of land by vertebrates.
The egg is supported on a cushion of modeling clay to hold it in the desired orientation, and therefore an approximation may be made that only the top surface of the egg is exposed directly to the crushing force.
The dome coefficient for the side of the egg is 1/2 the short axis length divided by the long axis, and 1/2 the long axis length divided by the short axis length for the top of the egg.
www.sicb.org /dl/rtfview.php3?file=30.1.rtf   (1900 words)

 Chicken or Egg
The chicken or the egg is a reference to the causality dilemma which arises from the expression "which came first, the chicken or the egg?".
Since both the chicken and the egg create the other in certain circumstances (a chicken emerges from an egg; an egg is laid by a chicken) it is ambiguous which originally gave rise to the other.
Evolutionary scientists believe the first hard shell egg was the amniotic egg laid around 300 million years ago, and was laid by the animal who was the link between amphibians and reptiles.
eggchickenfirst.blogspot.com   (1183 words)

Each of the corners of the egg case is drawn out into a long coiled filament, or tendril, that wraps around rocks, kelps, or other materials on the sea floor, preventing the egg case from being carried away by currents and exposed to possible predation.
Mollusk eggs vary from those of the squid, which are laid in a number of cylindrical cases attached to one another like the strands of a mop, to the eggs of certain snails of the genus Bulimus, which have hard shells and resemble pigeons' eggs in size and shape.
The eggs of insects are characterized by a great variety of egg and egg case forms as well as by the intricate markings on the eggshells of many species.
members.fortunecity.com /phylcage/past/wonders/egg.htm   (1179 words)

 Amniotic Egg - Picture - MSN Encarta
A critical evolutionary development for terrestrial animals is the reptilian amniotic egg, now also characteristic of birds and some mammals.
Wastes are released to the allantois, an extension of the embryonic gut.
Oxygen diffuses easily through the thin outer shell of the egg; its passage to the embryo is regulated by the chorion.
encarta.msn.com /media_461517464_761563418_-1_1/Amniotic_Egg.html   (84 words)

 Amniotic sac Summary
The amniotic cavity is filled with amniotic fluid, in which the embryo floats.
Amniotic fluid is the watery liquid surrounding and cushioning a growing fetus within the amnion.
A rare and often fatal obstetric complication is an amniotic fluid embolism, which causes Disseminated intravascular coagulation.
www.bookrags.com /Amniotic_sac   (1011 words)

 For Review
Amniotic egg: The evolution of the amniotic egg was critical in helping the vertebrates successfully colonize land.
Amniotic eggs protect the developing embryo from drying out in the terrestrial environment and also supply the necessary nutrients, water, and oxygen while removing or storing waste materials.
Amniotic eggs first evolved in the reptiles, and are also found in birds and monotremes.
www.mhhe.com /biosci/genbio/biolink/student/olc2/chap56review.html   (424 words)

 Amniote - Wikipedia, the free encyclopedia
Their eggs were small and covered with a membrane, not a hard shell like most modern amniote eggs.
One can assume the ancestors of the amniotes laid their eggs in moist places, as such modest-sized animals wouldn't have too many difficulties in finding depressions under fallen logs or other suitable places in the ancient forests, and dry conditions were probably not the main reason why the soft shell emerged.
Bigger eggs meant bigger offspring, and bigger adults meant bigger eggs, which meant the amniotes had gotten the opportunity to grow bigger than their ancestors.
en.wikipedia.org /wiki/Amniotic_egg   (628 words)

 Darwinism Refuted.com
One of the inconsistencies in the amphibian-reptile evolution scenario is the structure of the eggs.
Amphibian eggs, which develop in water, have a jelly-like structure and a porous membrane, whereas reptile eggs, as shown in the reconstruction of a dinosaur egg on the right, are hard and impermeable, in order to conform to conditions on land.
There are hardly two eggs in the whole animal kingdom which differ more fundamentally… The origin of the amniotic egg and the amphibian - reptile transition is just another of the major vertebrate divisions for which clearly worked out evolutionary schemes have never been provided.
www.darwinismrefuted.com /natural_history_1_10.html   (867 words)

 ZOO 138 The Amniotic Egg
Which is an egg that if youreally look at it in the big sense of the thing, what this egg isdoing is allowing vertebrate animals to produce larger newbornyoung than they would be able to produce otherwise.
And the reason is that the amniotic egg satisfies some basicrequirements of any living organism in a different way thanamphibian and fish eggs.
It's taking a sample of this amniotic fluid, which because itcompletely bathes the embryo, it has embryonic cells in it.They'll do this process, an amniocentesis, take a bit of thisamniotic fluid out and then they'll culture the cells and theycan test for genetic difficulties that may be occurring in theembryo.
www.csupomona.edu /~dfhoyt/classes/zoo138/old_transcripts/OLD_EGG.HTML   (1892 words)

The amniotic egg, together with a penis for internal fertilization, loss of a free-living larval stage in the life cycle, and the ability to bury their eggs, enabled amniotes to escape the bonds that confined their ancestors' reproductive activities to aquatic environments.
It has been suggested that the original function of the extra-embryonic membranes of the amniotic egg was to facilitate interactions between the mother and the embryo (Lombardi, 1994), but this hypothesis is not supported by the distribution of extended embryo retention in vertebrates, according to most proposed phylogenies (Laurin & Girondot, 1999).
Placental mammals, for example, have suppressed the egg shell and yolk sac, and elaborated the amniotic membranes to enable nutrients and wastes to pass directly between mother and embryo.
tolweb.org /Amniota/14990   (2591 words)

 Chicken-egg problem - EvoWiki
This is the paradoxical question: "Which came first, the chicken or the egg?" This presumes all chickens come from chicken eggs, and all chicken eggs come from chickens.
One simplistic response is that a not-quite-chicken produced a mutated gamete (egg or sperm), the mutant gamete then fused with another not-quite-chicken gamete, but the mutation was expressed, and the resulting animal was the first recognizable chicken.
This dilemma also ignores the fossil record which suggests the amniotic vertebrate egg originated some time in the late Carboniferous period, with the transition from amphibians to reptilomorphs, long before the advent of the domestic chicken, some 3 thousand years ago.
wiki.cotch.net /index.php/Chicken-egg_problem   (170 words)

 Chapter Synopsis
Eggs of most higher vertebrates (excluding mammals, except for the oviparous forms), are telolethical, and cleavage is meroblastic, or partial, resulting in a large amount of yolk, with the embryo undergoing cleavage lying on top.
Cleavage may be radial-cleavage is oriented either parallel or perpendicular to the animal-vegetal axis of the egg as it is in the deuterostomes, or spiral-cleavage is oblique to the animal-vegetal axis as it is in the protostomes.
Development of the embryo may be within an egg in oviparous animals, within an egg retained in the body of the female (ovoviviparous animals), or nourished within the oviduct or uterus of the female (viviparous animals).
www.mhhe.com /biosci/pae/zoology/hickman11/student/olc/chapter08-synopsis.mhtml   (1442 words)

 Amniotic Egg Shell In Reptiles
The Cleidoic (Self-Contained) Amniotic Egg of Reptiles and Birds - The Cleidoic (Self-Contained) Amniotic Egg of Reptiles and Birds...
the amniotic egg, in which the developing embryo is protected by a series of membranes and a hard...
Amniotic egg – the amniotic egg with a shell allowed the reptiles to complete their life...
www.snakefriends.com /amniotic-egg-shell-in-reptiles.html   (760 words)

 Home Labs: Structure of the Egg Lab
To identify the parts of an egg and examine how the egg is adapted to support an embryo.
The egg is a self-contained, watery environment which frees the parent from the burden of carrying its developing offspring.
In this lab activity, the student will be able to examine how the amniote egg promotes the development of the embryo.
www.troy.k12.ny.us /thsbiology/labs_online/home_labs/egg_lab_home.html   (232 words)

 Reptiles: scales and the amniotic egg
Egg has several special extra-embryonic membranes, which allow it to develop on land independent of water.
When the amniotic folds fuse, the two membranes are formed, with the amnion next to the embryo and the chorion next to the shell.
Egg allowed reptiles to move into habitats far from water, lay eggs on land.
www.sfu.ca /biology/courses/bisc316/outlines/Scaleegg.html   (679 words)

 Notes 3: Pre-Dinosaur Reptiles
Prior to the development of the amniotic egg, amphibians were "chained" to the ocean or some other large body of water, because they had to lay their eggs in water.
With all these features, an amniotic egg can be buried in the sand, or placed in a nest in a tree or wherever, and still survive.
The amniotic egg opened up any portion of the earth's land suitable for reptiles for their colonization.
faculty.plattsburgh.edu /thomas.wolosz/pre-dino.htm   (2343 words)

 Sex Glossary
A diagnostic procedure in which amniotic fluid is withdrawn by needle from the uterus of a pregnant woman.
A technique in which sperm and egg are removed from the body, combined in the laboratory, then implanted as a fertilized egg in the woman's uterus.
The release of an egg from the ovary.
www.sexology.org /glossary.htm   (8946 words)

 egg - Search Results - MSN Encarta   (Site not responding. Last check: )
Egg, ovum or female reproductive body of multicellular animals, particularly the complex structure produced by birds, reptiles, and certain mammals...
An egg (or ovum) is a female reproductive cell, or gamete.
It has the ability to develop into a new organism after fertilization by a sperm, which is...
uk.encarta.msn.com /egg.html   (154 words)

 Stephen E. Jones: Projects: Problems of Evolution (Outline): Animals
The problem of the origin of the amniotic system is even more enigmatic considering that the basic problem it solves, in freeing reproduction from dependency on a pool of water, has been solved in the amphibia by much less radical means, by merely exploiting the basic amphibian egg.
Nonetheless, the amniotic egg is a derived character that distinguishes the two major groups of tetrapods amniotes and nonamniotes.
The amniotic egg, as we know it, is characteristic of turtles, squamates, crocodilians, birds, monotremes, and in modified form, of therian mammals as well.
members.iinet.net.au /~sejones/PoE/pe13anml.html   (10442 words)

 Lecture Notes, Nat. Hist. Vert., Emporia State Univ.
The selective advantage of the amniotic egg was probably its ability to nourish a larger fetus on land.
It is also possible, though not likely, that the three membranes evolved in a live-bearing ancestor to increase the efficiency of nutrient exchange between mother and fetus and that a descendent of this ancestor returned to egg-laying mode giving rise to the amniotic egg.
The eggs are covered by a leathery membrane, which would prevent sperm from reaching the egg.
academic.emporia.edu /mooredwi/nathist/chap10.htm   (2188 words)

 Avian Embryo
Eggs do not hatch for reasons which may or may not be the fault of the person caring for the eggs.
By breaking a fresh egg and an egg incubated for one day into dishes and then making windows in eggs incubated for 2, 3, 4, 5 and more days, the sequence of growth and development of the chick embryo can be followed easily.
Crack the shell of the egg at the broad end with a sharp knife or scalpel, and pick away the pieces until an opening about one-inch in diameter is made.
www.msstate.edu /dept/poultry/avianemb.htm   (6024 words)

 Amniote Egg
Inside the egg are a series of fluid-filled membranes which permit the embryo to survive: the amnion, allantois, yolk sac, and chorion.
Surrounding all the other membranes is the chorion, providing an overall enclosure for the young.  Around the chorion is the albumin, or "white" of the egg, and an outer shell protects the whole egg, preventing drying while still permitting air to reach the embryo.
The embryo is still surrounded by an amnion filled with amniotic fluid; because it is next to and surrounds the embryo, doctors will sometimes examine the fluid to determine the health of the unborn child.
www.biologycorner.com /worksheets/amniote-egg.html   (487 words)

 What does anapsid mean?
Their eggs, fertilized cells covered by a moist, gelatinous mass, had to be kept wet or damp in order to not dry out before they hatched.
As with today's amphibians, egg masses are laid in water, in very damp burrows or the natural rain-filled cups formed by some plants, or encased in a frothy mass that hardens to a shell-like consistency on the outside, maintaining the necessary humidity inside.
In the late Devonian period, a new egg appeared on the scene: the amniotic egg.
www.anapsid.org /anapsid.html   (359 words)

 Stages of Development: Pregnancy: Merck Manual Home Edition
The egg is swept into the funnel-shaped end of one of the fallopian tubes.
The amniotic sac fills with a clear liquid (amniotic fluid) and expands to envelop the developing embryo, which floats within it.
The fertilized egg (zygote) divides repeatedly as it moves down the fallopian tube to the uterus.
www.merck.com /mmhe/sec22/ch257/ch257c.html   (1083 words)

 Boston IVF - Glossary
DONOR EGGSEggs from a fertile woman that are donated to an infertile woman for use in an ART procedure.
EGG RETRIEVAL – A procedure used to collect eggs from a woman’s follicles for use in IVF, usually performed with ultrasound-directed needle aspiration during IVF.
OVULATION – The release of a mature egg from a follicle.
www.bostonivf.com /info/glossary.cfm   (3379 words)

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