second coming of dinosaurs

[cambrian_exp]

humans will leave the earth or become extinct within 50 million years from now. current rates suggests that major mass extinction does really occurs every 100 million years. last one occured 65 million years ago so next may occur within 35 million years from now. just imagine only creatures less than 15 kg survive i.e very small lizards and insects and some mammals too and evolutionary arms race begins during post extinction period . so these small house lizards can again become large permian type reptiles like archeosaurs and dinosaurs like creature again come into existance like history repeats itself type phenomena? what do you think?

[MattC]

Mass extinction can occur for many reasons. I suspect that, if we survive a million more years (not so long a time, really), we will be able to prevent objects from space from impacting earth. That's one less mass extinction.

 

If there is a supervolcanic eruption or two, and the earth is dusted over, that may be a different story. Or perhaps by then humans will be able to survive under the earth?

 

Let's see... what are some other plausable causes of mass extinction?

 

Anyway, while it's a nice idea, it's a bit of a stretch to assume that, should another mass extinction come, huge reptiles would end up dominating the Earth. There are many other possibilities.

[cambrian_exp]

but generally most mass extinction have been occuring at rate of 1 per 100 million years and small extinctions at rate of 1 per 30 million years i think

[cambrian_exp]

whenever i look at house lizard i think of second coming of dinosaurs , well but is

it scientifically possible? because there is not much difference between common lizard and first reptiles which gave rise to dinosaurs. and yea we may not develop technology to prevent objects from impacting earth because we will soon or later end up ourselves. most of advanced civilizations end up themselves i think so. because as civilization advances many new different ideologies emrge within it self which is cause of war . so we may soon end up and when mass extinction occurs we may not be able to protect our self and new dinosaurs may rise again . it is possible that invertebrates like octupus eventually colonize land and produce some intelligent species ( as shown in future is wild ) because octupus have tencticules which can be used for handling tools!

[Mokele]

Actually, iirc, the periodicity is around 26 million years, not 100, with a steady rate of background extinction. Interestingly, Raup (where the above comes from) also noted that "mass extinction" seems to be a rather arbitrary designation, since the 'big ones' are merely the large end of a range of intensities.

 

As for the re-emergence of large reptiles as dominant land fauna, it's possible, but so are a wide varity of other things, such as new mammal forms, terrestrial birds, or maybe something totally new. It all depends on the circumstances at the time.

 

Mokele

[RoyLennigan]

give humans a few hundred years and it will be almost impossible to wipe them out. we will have colonized the moon and mars, and would be working on sending manned missions to other planets. give humans a few thousand years and we will have reached planets in other systems.

[Ophiolite]

As for the re-emergence of large reptiles as dominant land fauna' date=' it's possible, but so are a wide varity of other things, such as new mammal forms, terrestrial birds, or maybe something totally new. [b']It all depends on the circumstances at the time[/b].

And on a large element of chance. If, for example, Australia were to survive say a bolide impact, relatively unscathed, we might see a resurgence of marsupials.........., or perhaps giant rabbits. They do spend a lot of time underground.

[The Peon]

I think mammals got "lucky." Reptiles are truely masters of survival IMO.

[Tigerbeam]

if we get wiped out, my money is on the squids,either that or dolphins cause they have a head start.

[JonM]

In no more than 10,000 years from now we will have the power to stop any disaster or mass extinction that threatens our species.

[T-Nemesis]

But dinosaurs weren't even reptiles/lizards, were they?

[Mokele]

Yes and no. Way back when, sometime around 370 mya, give or take, the amniotic egg evolved, which allowed life to reproduce on land, unlike amphibians, who needed to lay eggs in water. These first amniotes had simple, box-like skulls with only openings where they were needed for eyes, nostrils, etc, and were called anapsids. (There's a raging debate about whether turtles are surviving anapsids or not, but I'll not bother with that. However, if turtles are not anapsids, the anapsids are now extinct.)

 

Eventually, the anapsids produced two new lineages, each of which had extra holes in their skulls, which served to lighten them and to provide additonal sites for muscle attachment. One group had a single hole, th synapsids, and they evenually became mammals. The other group, diapsids, had two holes, and these have a more interesting history.

 

The Diapsids split again into two groups. One, the lepidosaurs, are modern snakes and lizards. The other is called the Archosaurs, or "ruling reptiles", and for good reason. This group has evolved into some of the most successful and frightening predators ever, including the rauisuchids, ornithosuchids, popsaurids (all 3 of which would best be imagined as giant, fast-running land crocodiles, often over 20 feet long), crocodiles, phytosaurs (similar to crocs, but with a nostril near their eyes rather than at the tip of the snout), pterosaurs, dinosaurs, and birds.

 

So, technically, dinosaurs weren't lizards, but they *were* reptiles, close cousins of the crocodile and ancestors of the bird.

 

Mokele

[T-Nemesis]

^Cool, thanks for the info. Very interesting