The ‘twin’ craters are in the Thaumasia Planum region, a large
plateau that lies immediately to the south of Valles Marineris, the
largest canyon in the Solar System.
The northernmost (right) large
crater in this scene was officially given the name Arima in early 2012,
but the southernmost (left) crater remains unnamed. Both are just over
50 km wide and display intricate interior features.
The southernmost crater is also presented here in a perspective view, revealing its complex characteristics in detail.
Multiple
terraces slump from the crater walls onto a flat floor, but perhaps the
most striking feature is the central pit, a feature it shares with
Arima crater to its north.
Central pit craters are common on Mars, as well as on the icy moons
orbiting the giant planets in our Solar System. But how did they form?
When
an asteroid hits the rocky surface of a planet, both it and the surface
are compressed to high densities. Immediately after the impact, the
compressed regions rapidly depressurise, exploding violently.
Impact craters like these can thus provide windows into the past of a
planet’s surface. In this case, they provide evidence for the Thaumasia
Planum region having once hosted plentiful subsurface water or ice that
was liberated during impact events both small and large.
False-color Cassini
radar mosaic of Titan's north polar region; the blue areas are lakes of
liquid hydrocarbons.
"The existence of lakes of liquid hydrocarbons on Titan opens up the
possibility for solvents and energy sources that are alternatives to
those in our biosphere and that might support novel life forms
altogether different from those on Earth."—NASA Astrobiology Roadmap
2008
20 Afterward
God said, Let the waters bring foorth in abundance euery creeping thing
that hath life: and let the foule flie vpon the earth in the open
firmament of the heauen.
21 Then
God created the great whales, and euery thing liuing and mouing, which
the waters brought foorth in abundance according to their kinde, and
euery fethered foule according to his kinde: and God sawe that it was
good.
22 Then
God blessed them, saying, Bring foorth fruite and multiplie, and fill
the waters in the seas, and let the foule multiplie in the earth.
23 So the euening and the morning were the fift day.
The Amplified Bible God created
the great sea monsters and every living creature that moves, which the
waters brought forth abundantly, according to their kinds, and every
winged bird according to its kind. And God saw that it was good
(suitable, admirable) and He approved it.
American Standard Version And
God created the great sea-monsters, and every living creature that
moveth, wherewith the waters swarmed, after their kind, and every winged
bird after its kind: and God saw that it was good.
Darby's Translation And
God created the great sea monsters, and every living soul that moves
with which the waters swarm, after their kind, and every winged fowl
after its kind. And God saw that it was good.
Bible in Basic English And
God made great sea-beasts, and every sort of living and moving thing
with which the waters were full, and every sort of winged bird: and God
saw that it was good.
The Bishop's Bible (1568) And
God created great whales, and euery lyuyng & mouing creature, which
the waters brought foorth after theyr kynde, & euery fethered foule
after their kynde: and God saw that it was good.
Contemporary English Version So
God made the giant sea monsters and all the living creatures that swim
in the ocean. He also made every kind of bird. God looked at what he had
done, and it was good.
Easy-to-Read Version So
God made the large sea animals. God made every living thing that moves
in the sea. There are many different kinds of sea animals--and God made
them all! God also made every kind of bird that flies in the sky. And
God saw this was good.
English Standard Version So
God created the great sea creatures and every living creature that
moves, with which the waters swarm, according to their kinds, and every
winged bird according to its kind. And God saw that it was good.
George Lamsa Translation of the Peshitta And
God created great sea monsters, and every living creature that moves,
which the waters brought forth abundantly after their kind, and every
winged fowl after its kind; and God saw that it was good.
Brenton Translaton of the Septuagint (LXX) And
God made great whales, and every living reptile, which the waters
brought forth according to their kinds, and every creature that flies
with wings according to its kind, and God saw that they were good.
Sea monsters are beings from folklore believed to dwell in the sea and often imagined to be of immense size. Marine monsters can take many forms, including sea dragons, sea serpents,
or multi-armed beasts. They can be slimy and scaly and are often
pictured threatening ships or spouting jets of water. The definition of a
"monster" is subjective, and some sea monsters may have been based on
scientifically accepted creatures such as whales and types of giant and colossal squid.
It has been proposed that the early Earth hosted multiple origins of
life, some of which produced chemical variations on life as we know it.[1][2] Steven A. Benner, Alonso Ricardo, and Matthew A. Carrigan, biochemists at the University of Florida, argued that if organisms based on RNA once existed, they might still be alive today, unnoticed because they do not contain ribosomes, which are usually used to detect living microorganisms. They suggest searching for them in environments that are low in sulfur, environments that are spatially constrained (for example, minerals with pores smaller than one micrometre), or environments that cycle between extreme hot and cold
The RNA world is a hypothetical stage in the evolutionary history of life on Earth, in which self-replicatingRNA molecules proliferated before the evolution of DNA and proteins. The term also refers to the hypothesis that posits the existence of this stage.
Alexander Rich first proposed the concept of the RNA world in 1962,[1] and Walter Gilbert coined the term in 1986.[2] Alternative chemical paths to life have been proposed,[3] and RNA-based life may not have been the first life to exist.[2][4] Even so, the evidence for an RNA world is strong enough that the hypothesis has gained wide acceptance.[1][5][6] The concurrent formation of all four RNA building blocks further strengthened the hypothesis.[7]
Like DNA, RNA can store and replicate genetic information; like protein enzymes, RNA enzymes (ribozymes) can catalyze (start or accelerate) chemical reactions that are critical for life.[8] One of the most critical components of cells, the ribosome, is composed primarily of RNA. Ribonucleotide moieties in many coenzymes, such as Acetyl-CoA, NADH, FADH and F420, may be surviving remnants of covalently bound coenzymes in an RNA world.[9]
Although RNA is fragile, some ancient RNAs may have evolved the ability to methylate other RNAs to protect them.[10]
If the RNA world existed, it was probably followed by an age characterized by the evolution of ribonucleoproteins (RNP world),[2]
which in turn ushered in the era of DNA and longer proteins. DNA has
better stability and durability than RNA; this may explain why it became
the predominant storage molecule.[11]
Protein enzymes may have come to replace RNA-based ribozymes as biocatalysts because their greater abundance and diversity of monomers
makes them more versatile. As some co-factors contain both nucleotide
and amino-acid characteristics, it may be that amino acids, peptides and
finally proteins initially were co-factors for ribozymes.
Coleoid
cephalopods, a group encompassing octopuses, squid and cuttlefish, are
the most intelligent invertebrates: Octopuses can open jars, squid communicate with their own Morse code and cuttlefish start learning to identify prey when they’re just embryos.
In fact, coleoids are the only “animal lineage that has really achieved behavioral sophistication” other than vertebrates, said Joshua Rosenthal,
a senior scientist at the Marine Biological Laboratory in Woods Hole,
Mass. This sophistication could be related to a quirk in how their genes
work, according to new research from Dr. Rosenthal and Eli Eisenberg, a biophysicist at Tel Aviv University.
In the journal Cell
on Thursday, the scientists reported that octopuses, squid and
cuttlefish make extensive use of RNA editing, a genetic process thought
to have little functional significance in most other animals, to
diversify proteins in their nervous system. And natural selection seems
to have favored RNA editing in coleoids, even though it potentially
slows the DNA-based evolution that typically helps organisms acquire
beneficial adaptations over time.
Preternia is a term used in the Masters of the Universe brand that broadly refers to prehistoric times on the planet Eternia. Whereas Earth
has a largely uninterrupted record of written history, modern Eternia
usually has information only on events within living memory. Thus, while
"prehistoric Earth" describes events that are at least thousands of
years old, "Preternia" may refer to periods as recent as a hundred years
prior to the lifetime of He-Man.
For storytelling purposes, many forms of Masters of the Universe continuity present characters and artifacts of ancient or mysterious origins, such as the Council of Elders or Castle Grayskull. These story elements are often stated or implied to predate some watershed event, such as the Great Wars,
that divide modern Eternian civilization from the lost secrets and
legends of prehistoric Eternia. "Ancients" and "elders" from these lost
times are spoken of with reverence, suggesting that they possessed far
greater power than is known in the present.
The Masters Of The Universe paintings by the great Earl Norem are
classic depictions of MOTU at it's finest. Timeless art associated with
the history of the brand. Norem brought the characters to life in his
work, vivid and iconic illustrations of He-man, Skeletor, and all of the
great characters in the MOTU mythos!
He-Man And The Meteorbs features the rarely seen Meteorb characters
that were meteors that transformed into animals! This painting is the
most iconic representation of the characters!
Different media present differing interpretations of his
character. The original toyline presents him as a blue-skinned robot
replica of He-Man built to serve Skeletor, the toy was packaged as "Evil
robot of Skeletor" (or "Evil robot impostor"), and this is the way he
is generally viewed by fans, but other media showcase him as a magical
creation rather than a robot, or as an exact physical replica of He-Man
intended to fool the people of Eternia.
"The ancient inhabitants of Kazakhstan had a highly developed culture -
they had their own writing and mythology. The most vivid element of
their heritage, a reflection of the artistic originality and richness of
spiritual content is the "art of animal style". The use of images of
animals in everyday life was a symbol of the relationship between man
and nature, pointed to the spiritual guidelines of inhabitants of
steppe", – said the Head of state in his article "Seven facets of the
Great steppe".
Zilant (Russian: Зилант) is a legendary creature, something between a dragon and a wyvern. Since 1730, it has been the official symbol of Kazan. This winged snake is mentioned in legends about the foundation of Kazan.
A Zilant is a legendary creature with the head of a dragon, the
body of a bird, the legs of a chicken, the tail of a snake, the ears of a
canine, red wings, sharp teeth, dark-gray feathers and scaly dark-gray
skin.
Some Tatar flags
Zilant's conventionalized image was the official tamğa (sign) of Kazan's Millennium. قازان is a Tatar name of the city written in İske imlâ.
A visitor walks near the "Amazon" (L) and "Garuda" cast bronze
sculptures by Russian artist Dashi Namdakov at his personal exhibition
"The Bronze Asia" at the Surikov Art Museum during the 4th Krasnoyarsk
International Music Festival of the Asian-Pacific region, in central
Krasnoyarsk, Siberia July 1, 2014. Dashi Namdakov is a representative of
Buryats, the native people of Siberia, who lives and works in Britain
and Italy, casting bronze, silver and gold sculptures based on symbiosis
of national traditions of nomad Buddhists, West European myths and
classical art school, according to organizers. More than 600 artists,
dancers and actors representing 29 countries from all over the world
will take part in more than 100 concerts and exhibitions during a
one-week-long festival in the centre of Siberia, according to
organizers.
And the Lord God said to the serpent, Because you have done this, you
are cursed above all [domestic] animals and above every [wild] living
thing of the field; upon your belly you shall go, and you shall eat dust
[and what it contains] all the days of your life.
https://www.nytimes.com/2019/11/20/science/snakes-legs-fossil.html That’s why recently excavated snake fossils from Argentina, described in a study published Wednesday
in Science Advances, are such a big deal for serpent fans. The
intricate fossils, mostly skulls, are nearly 100 million years old and
belong to the extinct snake group Najash, which still retained hind
legs. The fossils suggest that snakes lost their front legs much earlier
than had previously been believed but also held onto their hind legs
for millions of years. The find will also help to resolve mysteries over
when snakes began their transition to their modern form.
And God said, See, I have given you every plant yielding seed that is on
the face of all the land and every tree with seed in its fruit; you
shall have them for food.
And to all the animals on the earth and to every bird of the air and to
everything that creeps on the ground--to everything in which there is
the breath of life--I have given every green plant for food. And it was
so
Just like a seat-belt buzzer, the call is designed to get attention, and fast. During the winter, birds often sing fewer notes, or just one note, to each other. These notes are simply a way to alert the flock of their whereabouts and to announce whether there's any food nearby, Buhl said.
They imitate many things, from spoken words to creaking doors to barking dogs. Most parrots are simply mimicking their owners. They don't really know what they're saying. But some professionally-trained parrots have learned to understand what they're saying.
Flamingos and doves are more closely related than they look, a new
genetic analysis of birds shows. That's not all: chickens are close
relations of dinosaurs, and genetic patterns in the brains of birds that
learn new calls show remarkable similarities to humans.
These findings stem from a project that sequenced genes from 48 bird
species and then used several months of supercomputing time to analyze
relationships. This week, eight papers appear in Science from the effort, which included more than 200 people from 80 labs. More than 20 papers will also be published in separate journals.
Another study compared birds to crocodiles, alligators, and gharials
— so-called crocodilians, descendants of a lineage of dinosaurs that
lived through the mass extinction period. The three types of animals,
birds, crocodillians, and dinosaurs, are considered to be archosaurs, a
scientific grouping called a clade that arose at least 200 million years
ago. So far, scientists have found that crocodilians are evolving more
slowly than birds, which in turn are evolving more slowly than mammals.
The most recent common ancestor for humans and chickens is thought to
have been some kind of primitive reptile that lived more than 310
million years ago. The information from the chicken genome should paint a
clearer picture of this divergence, and provide information about when
mammals lost certain genes, and why.
Analysis of the data is only
just beginning, but several surprising results have already emerged
from the project. For example, it had been thought that chickens lack a
sense of smell, but the large number of olfactory genes in the sequence
suggests otherwise.
The
gene for keratin, the protein that makes up hair and fingernails in
people and beaks and feathers in chickens, also grabbed researchers'
attention. According to Christopher Ponting, a functional geneticist at
the University of Oxford, UK, and a member of the consortium, keratin is
thought to have arisen from a common source in both mammals and birds.
Yet the chicken sequence looks very different from the mammal keratin
genes known so far, raising the possibility that keratin production
might have evolved twice.
In a 2004 paper published in the journal Nature,
the International Chicken Genome Sequencing Consortium found that
although a chicken doesn't have as much DNA as a human, it has about the
same amount of genes. And in those genes, there were
stronger similarities to human genes when it came down to basic cell
structures and how those cells work. When it came to the genes that
program our reproductive and immune systems, the chicken genes were less
similar.
Despite evidence that the earliest examples of creatures such as
mammals and reptiles gave birth to live young, they actually may have
laid eggs, a scientist argues.
"These eggs are probably out there,
but nobody has looked hard enough for them or they have not been
recognized," says University of Bonn, Germany, paleobiologist P. Martin
Sander, who details his analysis in the Aug. 17 issue of the journal
Science.
Both
mammals and reptiles envelop their developing embryos in protective
layers, something that ultimately helped their ancestors conquer the
land and that still helps their offspring survive. Mammals often keep
these membrane-bundled offspring within them, giving birth to live young, while reptiles generally lay their membrane-swaddled progeny in eggs.
The
fact that mammals and reptiles wrap their embryos within these defenses
makes them known as amniotes, which first evolved about 310 million
years ago. The fossil record of amniotic eggs and embryos is paltry,
leaving scientists little knowledge about when, how and why they
evolved.
Comments
http://www.esa.int/Science_Exploration/Space_Science/Mars_Express/Explosive_crater_twins_on_Mars
The ‘twin’ craters are in the Thaumasia Planum region, a large plateau that lies immediately to the south of Valles Marineris, the largest canyon in the Solar System.
The northernmost (right) large crater in this scene was officially given the name Arima in early 2012, but the southernmost (left) crater remains unnamed. Both are just over 50 km wide and display intricate interior features.
The southernmost crater is also presented here in a perspective view, revealing its complex characteristics in detail.
Multiple terraces slump from the crater walls onto a flat floor, but perhaps the most striking feature is the central pit, a feature it shares with Arima crater to its north.
Central pit craters are common on Mars, as well as on the icy moons orbiting the giant planets in our Solar System. But how did they form?
When an asteroid hits the rocky surface of a planet, both it and the surface are compressed to high densities. Immediately after the impact, the compressed regions rapidly depressurise, exploding violently.https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry#/media/File:PIA10008_Seas_and_Lakes_on_Titan.jpg
The Amplified Bible
God created the great sea monsters and every living creature that moves, which the waters brought forth abundantly, according to their kinds, and every winged bird according to its kind. And God saw that it was good (suitable, admirable) and He approved it.
American Standard Version
And God created the great sea-monsters, and every living creature that moveth, wherewith the waters swarmed, after their kind, and every winged bird after its kind: and God saw that it was good.
Darby's Translation
And God created the great sea monsters, and every living soul that moves with which the waters swarm, after their kind, and every winged fowl after its kind. And God saw that it was good.
Bible in Basic English
And God made great sea-beasts, and every sort of living and moving thing with which the waters were full, and every sort of winged bird: and God saw that it was good.
The Bishop's Bible (1568)
And God created great whales, and euery lyuyng & mouing creature, which the waters brought foorth after theyr kynde, & euery fethered foule after their kynde: and God saw that it was good.
Contemporary English Version
So God made the giant sea monsters and all the living creatures that swim in the ocean. He also made every kind of bird. God looked at what he had done, and it was good.
Easy-to-Read Version
So God made the large sea animals. God made every living thing that moves in the sea. There are many different kinds of sea animals--and God made them all! God also made every kind of bird that flies in the sky. And God saw this was good.
English Standard Version
So God created the great sea creatures and every living creature that moves, with which the waters swarm, according to their kinds, and every winged bird according to its kind. And God saw that it was good.
George Lamsa Translation of the Peshitta
And God created great sea monsters, and every living creature that moves, which the waters brought forth abundantly after their kind, and every winged fowl after its kind; and God saw that it was good.
Brenton Translaton of the Septuagint (LXX)
And God made great whales, and every living reptile, which the waters brought forth according to their kinds, and every creature that flies with wings according to its kind, and God saw that they were good.
Part of Speech: Noun Masculine
Transliteration: tannin
Phonetic Spelling: (tan-neen')
Definition: serpent, dragon, sea monster
https://en.wikipedia.org/wiki/Shadow_biosphere
The RNA world is a hypothetical stage in the evolutionary history of life on Earth, in which self-replicating RNA molecules proliferated before the evolution of DNA and proteins. The term also refers to the hypothesis that posits the existence of this stage.
Alexander Rich first proposed the concept of the RNA world in 1962,[1] and Walter Gilbert coined the term in 1986.[2] Alternative chemical paths to life have been proposed,[3] and RNA-based life may not have been the first life to exist.[2][4] Even so, the evidence for an RNA world is strong enough that the hypothesis has gained wide acceptance.[1][5][6] The concurrent formation of all four RNA building blocks further strengthened the hypothesis.[7]
Like DNA, RNA can store and replicate genetic information; like protein enzymes, RNA enzymes (ribozymes) can catalyze (start or accelerate) chemical reactions that are critical for life.[8] One of the most critical components of cells, the ribosome, is composed primarily of RNA. Ribonucleotide moieties in many coenzymes, such as Acetyl-CoA, NADH, FADH and F420, may be surviving remnants of covalently bound coenzymes in an RNA world.[9]
Although RNA is fragile, some ancient RNAs may have evolved the ability to methylate other RNAs to protect them.[10]
If the RNA world existed, it was probably followed by an age characterized by the evolution of ribonucleoproteins (RNP world),[2] which in turn ushered in the era of DNA and longer proteins. DNA has better stability and durability than RNA; this may explain why it became the predominant storage molecule.[11] Protein enzymes may have come to replace RNA-based ribozymes as biocatalysts because their greater abundance and diversity of monomers makes them more versatile. As some co-factors contain both nucleotide and amino-acid characteristics, it may be that amino acids, peptides and finally proteins initially were co-factors for ribozymes.Coleoid cephalopods, a group encompassing octopuses, squid and cuttlefish, are the most intelligent invertebrates: Octopuses can open jars, squid communicate with their own Morse code and cuttlefish start learning to identify prey when they’re just embryos.
In fact, coleoids are the only “animal lineage that has really achieved behavioral sophistication” other than vertebrates, said Joshua Rosenthal, a senior scientist at the Marine Biological Laboratory in Woods Hole, Mass. This sophistication could be related to a quirk in how their genes work, according to new research from Dr. Rosenthal and Eli Eisenberg, a biophysicist at Tel Aviv University.
In the journal Cell on Thursday, the scientists reported that octopuses, squid and cuttlefish make extensive use of RNA editing, a genetic process thought to have little functional significance in most other animals, to diversify proteins in their nervous system. And natural selection seems to have favored RNA editing in coleoids, even though it potentially slows the DNA-based evolution that typically helps organisms acquire beneficial adaptations over time.
Preternia
Preternia is a term used in the Masters of the Universe brand that broadly refers to prehistoric times on the planet Eternia. Whereas Earth has a largely uninterrupted record of written history, modern Eternia usually has information only on events within living memory. Thus, while "prehistoric Earth" describes events that are at least thousands of years old, "Preternia" may refer to periods as recent as a hundred years prior to the lifetime of He-Man.
For storytelling purposes, many forms of Masters of the Universe continuity present characters and artifacts of ancient or mysterious origins, such as the Council of Elders or Castle Grayskull. These story elements are often stated or implied to predate some watershed event, such as the Great Wars, that divide modern Eternian civilization from the lost secrets and legends of prehistoric Eternia. "Ancients" and "elders" from these lost times are spoken of with reverence, suggesting that they possessed far greater power than is known in the present.
The term "Preternia" was originally developed as the setting for Mattel's canceled The Powers of Grayskull toyline, with He-Ro defending the ancients from the Snake Men in Preternia just as He-Man battles Skeletor in Eternia. The Masters of the Universe Classics toy line has expanded upon this premise, linking the backstories of Zodac, the Goddess, Hordak, and King Grayskull with this period.
The Masters Of The Universe paintings by the great Earl Norem are classic depictions of MOTU at it's finest. Timeless art associated with the history of the brand. Norem brought the characters to life in his work, vivid and iconic illustrations of He-man, Skeletor, and all of the great characters in the MOTU mythos!
He-Man And The Meteorbs features the rarely seen Meteorb characters that were meteors that transformed into animals! This painting is the most iconic representation of the characters!
Faker is a fictional character in the popular toyline Masters of the Universe and the accompanying animated series He-Man and the Masters of the Universe. He is an evil duplicate of the lead character, He-Man, in service to the villain Skeletor.
Genghis Khan by Dashi Namdakov Marble Arch, London
http://presidentlibrary.kz/en/news/legends-great-steppe-live-sculpture
Zilant (Russian: Зилант) is a legendary creature, something between a dragon and a wyvern. Since 1730, it has been the official symbol of Kazan. This winged snake is mentioned in legends about the foundation of Kazan.
A Zilant is a legendary creature with the head of a dragon, the body of a bird, the legs of a chicken, the tail of a snake, the ears of a canine, red wings, sharp teeth, dark-gray feathers and scaly dark-gray skin.
Genesis 3:14
That’s why recently excavated snake fossils from Argentina, described in a study published Wednesday in Science Advances, are such a big deal for serpent fans. The intricate fossils, mostly skulls, are nearly 100 million years old and belong to the extinct snake group Najash, which still retained hind legs. The fossils suggest that snakes lost their front legs much earlier than had previously been believed but also held onto their hind legs for millions of years. The find will also help to resolve mysteries over when snakes began their transition to their modern form.
Genesis 1:29
And God said, See, I have given you every plant yielding seed that is on the face of all the land and every tree with seed in its fruit; you shall have them for food.Flamingos and doves are more closely related than they look, a new genetic analysis of birds shows. That's not all: chickens are close relations of dinosaurs, and genetic patterns in the brains of birds that learn new calls show remarkable similarities to humans.
These findings stem from a project that sequenced genes from 48 bird species and then used several months of supercomputing time to analyze relationships. This week, eight papers appear in Science from the effort, which included more than 200 people from 80 labs. More than 20 papers will also be published in separate journals.
Chickens and turkeys appear to be closer to dinosaurs than other birds are, having experienced fewer genomic changes, according to a paper published in BMC Genomics.Another study compared birds to crocodiles, alligators, and gharials — so-called crocodilians, descendants of a lineage of dinosaurs that lived through the mass extinction period. The three types of animals, birds, crocodillians, and dinosaurs, are considered to be archosaurs, a scientific grouping called a clade that arose at least 200 million years ago. So far, scientists have found that crocodilians are evolving more slowly than birds, which in turn are evolving more slowly than mammals.
Analysis of the data is only just beginning, but several surprising results have already emerged from the project. For example, it had been thought that chickens lack a sense of smell, but the large number of olfactory genes in the sequence suggests otherwise.
The gene for keratin, the protein that makes up hair and fingernails in people and beaks and feathers in chickens, also grabbed researchers' attention. According to Christopher Ponting, a functional geneticist at the University of Oxford, UK, and a member of the consortium, keratin is thought to have arisen from a common source in both mammals and birds. Yet the chicken sequence looks very different from the mammal keratin genes known so far, raising the possibility that keratin production might have evolved twice.
Genesis 3:16
Despite evidence that the earliest examples of creatures such as mammals and reptiles gave birth to live young, they actually may have laid eggs, a scientist argues.
"These eggs are probably out there, but nobody has looked hard enough for them or they have not been recognized," says University of Bonn, Germany, paleobiologist P. Martin Sander, who details his analysis in the Aug. 17 issue of the journal Science.
Both mammals and reptiles envelop their developing embryos in protective layers, something that ultimately helped their ancestors conquer the land and that still helps their offspring survive. Mammals often keep these membrane-bundled offspring within them, giving birth to live young, while reptiles generally lay their membrane-swaddled progeny in eggs.
The fact that mammals and reptiles wrap their embryos within these defenses makes them known as amniotes, which first evolved about 310 million years ago. The fossil record of amniotic eggs and embryos is paltry, leaving scientists little knowledge about when, how and why they evolved.