What is the Universe expanding into..

Do you think there was anything before the big bang?

  • I don't think there was anything before the Big Bang

    Votes: 56 12.5%

  • I think something existed before the Big Bang

    Votes: 200 44.7%

  • I don't think the big bang happened

    Votes: 54 12.1%

  • I think the universe is part of a mutiverse

    Votes: 201 45.0%
  • Total voters
    447
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#10,901

Some transitions among reptiles
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  • Scutosaurus and other pareiasaurs (mid-Permian) -- Large bulky herbivorous reptiles with turtle-like skull features. Several genera had bony plates in the skin, possibly the first signs of a turtle shell.
  • Deltavjatia vjatkensis (Permian) -- A recently discovered pareiasaur with numerous turtle-like skull features (e.g., a very high palate), limbs, and girdles, and lateral projections flaring out some of the vertebrae in a very shell-like way. (Lee, 1993)
  • Proganochelys (late Triassic) -- a primitive turtle, with a fully turtle-like skull, beak, and shell, but with some primitive traits such as rows of little palatal teeth, a still-recognizable clavicle, a simple captorhinid-type jaw musculature, a primitive captorhinid- type ear, a non-retractable neck, etc..
  • Recently discovered turtles from the early Jurassic, not yet described.
 
#10,905
Fast Eddie D said:
Ask and you shall receive.

Transition from from primitive jawless fish to bony fish​

​

  • Cladoselache (late Devonian) -- Magnificent early shark fossils, found in Cleveland roadcuts during the construction of the U.S. interstate highways. Probably not directly ancestral to sharks, but gives a remarkable picture of general early shark anatomy, down to the muscle fibers!
  • Tristychius & similar hybodonts (early Mississippian) -- Primitive proto-sharks with broad-based but otherwise shark-like fins.
  • Ctenacanthus & similar ctenacanthids (late Devonian) -- Primitive, slow sharks with broad-based shark-like fins & fin spines. Probably ancestral to all modern sharks, skates, and rays. Fragmentary fin spines (Triassic) -- from more advanced sharks.
  • Paleospinax (early Jurassic) -- More advanced features such as detached upper jaw, but retains primitive ctenacanthid features such as two dorsal spines, primitive teeth, etc.
  • Spathobatis (late Jurassic) -- First proto-ray.
  • Protospinax (late Jurassic) -- A very early shark/skate. After this, first heterodonts, hexanchids, & nurse sharks appear (late Jurassic). Other shark groups date from the Cretaceous or Eocene. First true skates known from Upper Cretaceous.
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Fast Eddie D said:

Transition from primitive bony fish to amphibians​

​

  • Paleoniscoids again (e.g. Cheirolepis) -- These ancient bony fish probably gave rise both to modern ray-finned fish (mentioned above), and also to the lobe-finned fish.
  • Osteolepis (mid-Devonian) -- One of the earliest crossopterygian lobe-finned fishes, still sharing some characters with the lungfish (the other lobe-finned fishes). Had paired fins with a leg-like arrangement of major limb bones, capable of flexing at the "elbow", and had an early-amphibian-like skull and teeth.
  • Eusthenopteron, Sterropterygion (mid-late Devonian) -- Early rhipidistian lobe-finned fish roughly intermediate between early crossopterygian fish and the earliest amphibians. Eusthenopteron is best known, from an unusually complete fossil first found in 1881. Skull very amphibian-like. Strong amphibian- like backbone. Fins very like early amphibian feet in the overall layout of the major bones, muscle attachments, and bone processes, with tetrapod-like tetrahedral humerus, and tetrapod-like elbow and knee joints. But there are no perceptible "toes", just a set of identical fin rays. Body & skull proportions rather fishlike.
  • Panderichthys, Elpistostege (mid-late Devonian, about 370 Ma) -- These "panderichthyids" are very tetrapod-like lobe-finned fish. Unlike Eusthenopteron, these fish actually look like tetrapods in overall proportions (flattened bodies, dorsally placed orbits, frontal bones! in the skull, straight tails, etc.) and have remarkably foot-like fins.
  • Fragmented limbs and teeth from the middle Late Devonian (about 370 Ma), possibly belonging to Obruchevichthys -- Discovered in 1991 in Scotland, these are the earliest known tetrapod remains. The humerus is mostly tetrapod-like but retains some fish features. The discoverer, Ahlberg (1991), said: "It [the humerus] is more tetrapod-like than any fish humerus, but lacks the characteristic early tetrapod 'L-shape'...this seems to be a primitive, fish-like character....although the tibia clearly belongs to a leg, the humerus differs enough from the early tetrapod pattern to make it uncertain whether the appendage carried digits or a fin. At first sight the combination of two such extremities in the same animal seems highly unlikely on functional grounds. If, however, tetrapod limbs evolved for aquatic rather than terrestrial locomotion, as recently suggested, such a morphology might be perfectly workable."
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Fast Eddie D said:

Transition from amphibians to amniotes (first reptiles)​

​

  • Proterogyrinus or another early anthracosaur (late Mississippian) -- Classic labyrinthodont-amphibian skull and teeth, but with reptilian vertebrae, pelvis, humerus, and digits. Still has fish skull hinge. Amphibian ankle. 5-toed hand and a 2-3-4-5-3 (almost reptilian) phalangeal count.
  • Limnoscelis, Tseajaia (late Carboniferous) -- Amphibians apparently derived from the early anthracosaurs, but with additional reptilian features: structure of braincase, reptilian jaw muscle, expanded neural arches.
  • Solenodonsaurus (mid-Pennsylvanian) -- An incomplete fossil, apparently between the anthracosaurs and the cotylosaurs. Loss of palatal fangs, loss of lateral line on head, etc. Still just a single sacral vertebra, though.
  • Hylonomus, Paleothyris (early Pennsylvanian) -- These are protorothyrids, very early cotylosaurs (primitive reptiles). They were quite little, lizard-sized animals with amphibian-like skulls (amphibian pineal opening, dermal bone, etc.), shoulder, pelvis, & limbs, and intermediate teeth and vertebrae. Rest of skeleton reptilian, with reptilian jaw muscle, no palatal fangs, and spool-shaped vertebral centra. Probably no eardrum yet. Many of these new "reptilian" features are also seen in little amphibians (which also sometimes have direct-developing eggs laid on land), so perhaps these features just came along with the small body size of the first reptiles.
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Fast Eddie D said:

Some transitions among reptiles​

​

  • Scutosaurus and other pareiasaurs (mid-Permian) -- Large bulky herbivorous reptiles with turtle-like skull features. Several genera had bony plates in the skin, possibly the first signs of a turtle shell.
  • Deltavjatia vjatkensis (Permian) -- A recently discovered pareiasaur with numerous turtle-like skull features (e.g., a very high palate), limbs, and girdles, and lateral projections flaring out some of the vertebrae in a very shell-like way. (Lee, 1993)
  • Proganochelys (late Triassic) -- a primitive turtle, with a fully turtle-like skull, beak, and shell, but with some primitive traits such as rows of little palatal teeth, a still-recognizable clavicle, a simple captorhinid-type jaw musculature, a primitive captorhinid- type ear, a non-retractable neck, etc..
  • Recently discovered turtles from the early Jurassic, not yet described.
Click to expand...
Wow! Right off the top of your head?
Now that's typing championship material.
Verification by none other than Spike, aka TNT himself!
 
#10,906
#10,908

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#10,915
Fast Eddie D said:
Change in allele frequency of heritable traits.
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I did a two-term 'History of Science & Technology" course in 1st year at University and submitted an essay which included mention of Mendel's work on flower colour in pea plants.

Because of allele gene variations, his pea plants had either white or purple flowers.

Although the white variety was the least common it could be the one that attracts more pollinators and therefore determine which plant will be more successful at reproducing.

In humans, alleles determine eye colour and hair colour. In Scotland, red hair is a survival trait! 🧑‍🦰

https://www.bbc.co.uk/bitesize/guides/zvb7hyc/revision/3

That kind of knowledge is 'beginner's level' when it comes to understanding the complexity of life, and it is at 'beginner's level' where I remain!
 
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#10,916
As an experimental botanist, well aware of the difference between white Pinguicula Alpina and purple Pinguicula Vulgaris...

https://en.wikipedia.org/wiki/Pinguicula_alpina

https://en.wikipedia.org/wiki/Pinguicula_vulgaris

I was explaining to my gardening friends that pre-historic plants, Ferns, which replicate by spores, still dwell in my garden:

Ferns.JPG


These Jurassic things co-existed with Dinosaurs about 200,000,000 years ago. One of the dimmer students in our house attempted to correct me. He thought it must be no more than 6,000 years old.

Not a true scientist, in my opinion. Denying the fossil record and Darwin. Another CRANK! 🙄
 
#10,918
Unfortunately, our well intentioned but woefully misinformed friend provides us with a look into the mindset of a typical American. Their minds have been poisoned by the Religious Right propaganda. I keep saying they're winning. They're highly organized and well funded. They infest local school boards across the country and push their agenda. They run "alternative" schools which teach the most ridiculous nonsense to impressionable children. They have constructed an elaborate alternative reality.

We need scientists. I live in a bubble where many of my neighbors are university professors or engineers. But most of the country has deep anti-science sentiment.
 
#10,919
@ cumbb - Why so many inverted commas?

Does mass 'bend' spacetime or does mass 'fall into' spacetime?

There, that's much more like Standard English! 😎

Edit: I had to do some quick editing there to get it just right!
 
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