What were the 3 theories of dinosaur extinction?

Question

I think the comet hitting Earth is pretty much determined to be the cause of dinosaur extinction, but I remember as a kid that there were 3 theories. What were they? I can't remember them!! :(

Answer 1

Problem with separating the impact theory and the volcanic theory is that they both definitely happened, therefore we have an extra theory:

1. effects of meteor impact.
2. effects of volcano.
3. effects of meteor impact and volcano combined.

If we're looking for a "smoking gun" culprit then the only meteor victims we can be certain about were the ones who happened to be at the Chixulub crater site at the time. Likewise with the volcanic events and any species that may or may not have been standing at the opening when it blew.

The best explanation I heard of the extinction event was Horner when he did his lecture series at the Natural History Museum (sorry don't have the reference but the NHM may have recorded archives of their speakers) - he said the combined events at that time knocked all life for six, affecting all species and bringing them all down to a critically endangered state. From there it was pure luck which ones would be wiped out and which ones would flourish to fill all the empty niches.

This nicely explained away Bakker's "frog problem" and just about any "if this died out, why didn't that" style of questioning. The larger dinosaurs were just unlucky, but the smaller ones diversified, just like mammals did.

Answer 2

Well, there are (of course) more than three theories, but the three main theories go like this -

1) Meteorite hits the ocean at Chixulub, off the Yucatan Penninsula in Mexico. We do have proof that the meteorite did impact here at the end of the Cretaceous, but the question is whether or not it caused the mass extinctions. The impact would have supposedly thrown up massive clouds of dust that would have blocked out the sun for months, resulting in global darkness and cold, causing plants to die, and dinosaurs along with them.
The problem with this theory is that small, ectothermic ("cold-blooded") creatures, such as frogs, would have definately been devastated if this were the case, but the fossil record shows virtually no changes whatsoever in the populations of these organisms.

2) Massive volcanic eruptions in the Deccan Traps, a series of huge volcanoe in what is now India. This event would have spewed enormous quantities of toxic vapors into the atmosphere, and perhaps would also have blacked out sunlight as in the meteorite impact theory. The volcanic theory also encounters some of the problems of the impact theory.

3) I'd say that the third biggest theory is that of disease. Towards the end of the Cretaceous Period, the landmasses known today as Asia and North America had just been joined as a result of continental drift and the oceans receding from record high levels. This would have allowed dinosaurs to travel from these different continents, and bring with them new diseases and sicknesses, which would have spread rapidly throughout the dinosaur populations like wildfire.
The problem with this theory is trying to explain other extincions, besides those of the dinosaurs, that occured at the end of the Cretaceous, such as those of marine reptiles.
(However, these can perhaps be accredited to climatic change as a result of the world's continents changing.)

Answer 3

1) A catastrophic impact by comet, meteorite, or asteroid.

2) Climate change.

3) Competition from evolving mammals.

It turns out, all three of these factors were involved, as the result of the imapct off of the coast of Yucatan, 65 million years ago.

Answer 4

There are over 50 different theories. Let me just list a few:
-Mammals eating dinosaur eggs.
-New narcotic plants evolving.
-Global cooling/global warming.
-Loss of plants causing herbivores to starve which in turn caused the carnivores to starve.
-A supernova exploded nearby, spraying the earth with radiation.
-A passing comet poisoned the earth with chemicals.
-One of the current favorites is the “deep impact” theory proposed by the geologist Walter Alvarez in about 1980. This theory states that a meteor strike caused dramatic climate changes much like a “nuclear winter” which supposedly caused the extinction of the dinosaurs and many other animals. His evidence was his discovery of an alleged world-wide layer of clay with a high iridium content, which is found in meteorites.

Well, there are plenty of papers that talk about the problems with the "deep impact" theory. One problem, is that the earth’s core also has iridium in it that can be brought up by volcanos. Many Creationists believe Noah's Flood would have caused the greatest volcanoes that there have ever been, and some believe God pelted the earth with meteors during the Flood as well.

Many evolutionists though, don’t think dinosaurs are extinct anyway. The entrance to the bird exhibit at the Cincinnati zoo in Ohio had a sign that said: “Dinosaurs went extinct millions of years ago—or did they? No, birds are essentially modern short-tailed feathered dinosaurs.”

First of all, bird evolution is one of the most controversial areas in evolutionary paleontology and evolutionists often disagree and criticize each other. We hear a lot of reports of feathered dinosaurs being found, but what you rarely hear, is that the main candidates are believed by many experts to simply be frayed collagen fibers, or hair like structures that could have supported a frill or crest like those on iguanas, or are on animals that are not dinosaurs, but flightless birds. The drawings are certainly not what we find; they are just the artists’ imagination. Dr. Alan Feduccia, a world authority on birds and an evolutionist, along with his coworkers have presented a substantial body of evidence to support their view that there are, in fact, no known dinosaurs with feathers (they believe birds evolved from different reptiles, but not dinosaurs). And then you have ones like Archaeoraptor that was proven to be a hoax. Who knows how many times that will happen. All these announcements of feathered dinosaurs cause a lot of media fanfare, but when they are refuted, there is scarcely a whimper in the media.

You may be thinking, “But what about Archaeopteryx? That has been used for years and years.” Archaeopteryx was a true perching bird with fully formed wings and flight feathers, as well as a large wishbone for the attachment of muscles used for the downstroke of the wings. So what is all the fuss about; why is Archaeopteryx such an icon of evolution? Well, it had teeth in the bill, claws on the wings, no keel on the breast bone, an unfused backbone, and a long, bony tail, which are all characteristics most people associate with reptiles. But as Dr. Gary Parker said, “...the reptile-like features are not really as reptile-like as you might suppose. The familiar ostrich, for example, has claws on its wings that are even more ‘reptile-like’ than those of Archaeopteryx. Several birds, such as the hoatzin, don’t have much of a keel. The penguin has unfused backbones and a bony tail. No living birds have socketed teeth, but some fossil birds do. Besides, some reptiles have teeth and some don’t, so the presence or absence of teeth is not particularly important in distinguishing the two groups.” Dr. Alan Feduccia (like I said, an evolutionist, and by the way, one who doesn’t like creationists quoting him) said, “Paleontologists have tried to turn Archaeopteryx into an earth-bound, feathered dinosaur. But it’s not. It is a bird, a perching bird. And no amount of ‘paleobabble’ is going to change that.” On top of that, scientists have found fossils of what they would call “true birds” in layers of rock that they date as being older than Archaeopteryx. That presents a problem for them. I believe Archaeopteryx was something of a mosaic like a bat or platypus. Similar structures can simply point to a common designer. What they need to find, is a fossil showing scales turning into feathers, or a leg turning into a wing, or the reptile lung turning into the avian lung. How you can take a “two-way” reptile lung and evolve it into a fully functional “one-way” bird lung without causing extinction of the species is quite a conundrum.

There is no credible evidence that dinosaurs evolved into birds. Dinosaurs have always been dinosaurs and birds have always been birds. So why did they die off? Well, many Creationists believe the Flood would have drastically changed the climate of the earth (cooler temperatures, more radiation, etc.), and that there was a short ice age after the flood. Some Creationists think the dinosaurs that survived the flood where not able to cope so well in the new environment.

Another possibility is that dinosaurs may have become extinct for the same reason that many animals become extinct today. Why do we have endangered species programs? Extinction is the rule. Why? People killing them, lack of food, man destroying the environment, catastrophes, disease, genetic problems, and so on. I’ve read that in the last 350 years, about 400 species have disappeared, and some say the number is much greater. Countries all over the world have stories of dragon slayers. Perhaps man killed them for food, sport, or because they were a nuisance. I think we just didn’t start our endangered species programs early enough.

Answer 5

Gigantic Volcanic Eruption.
Reptile Diseases. Maybe flesh eating bacteria.
Huge Momma Asteroid hitting earth.

Answer 6

I do not recall any specific theories other than the asteroid hitting off Yucatan. But the details of how that did them in is still a matter of dispute.

Answer 7

1 - catastrophic disaster such as a comet or asteroid hitting the earth.
2 - an ice age or other drastic change in climate
3 - disease and subsequent genetic changes

Answer 8

-meteorite/asteride incident
-depletiion of food supply etc etc