why ae dinosaurs extinct?

Question

i mean why because ice ages or not anymore food or humans coming to earth?

Answer 1

The Dinosaurs existed during the Mesozoic Era which was from 65 million to 245 million years ago. The Mesozoic Era is broken down into three periods. The Cretaceous Period (65 - 144 million years ago), the Jurassic Period (144 - 206 million years ago), and the Triassic Period(206 - 245 million years ago).
The end of the Cretaceous Period marked the end of any remains of dinosaurs that we have ever found. So, at essentually about 65 million years ago it appears that something ended the existance of a major population of the world. Dinosaurs were to abundant and many were to large to just assume that they just died out.
As far as an ice age many glacial periods have occurred during the last few million years, initially at 40,000-year frequency but more recently at 100,000-year frequencies. So, Appearantly the dinosaurs survived many ice ages during their possible 180 million year evolution. This makes it hard to imagine that an ice age ended their existance.
The only other thing that we can find that might have something to do with the disappearance of dinosaurs can be found in the Caribbean Sea near the Yucatan Peninsula of Mexico. There is a 65 million year old crater called the "Chicxulub impact crater". The horseshoe shape of the crater and the pattern of debris in sedemantary rocks indicate that an asteroid or comet struck at a low angle from the southeast. The effect would have been a cloud of hot vapor and debris that could have killed most of the plants and animals in North America within minutes. The 65 million year old crater coinsides with the end of the Crestaceous Perion and Mesozoic Era 65 million years ago.
This is all we know. We haven't found anything else that could explain the disappearance of such an abundant species.

Answer 2

Asteroid Impact
Asteroids very seldom pass through the earth's atmosphere, but when they do they cause mass destruction. One of the most common extinction theories is that an asteroid 4-9 miles (10 km) wide struck the earth on the tip of the Yucatan Peninsula, in the Gulf of Mexico dealing the dinosaurs a fatal blow. Upon striking, the comet would have sent dust and steam into the atmosphere and caused huge forest fires, tidal waves, severe storms, and eliminated all sunlight. It would be six months before sunlight would reach the ground after such a blow. The dinosaurs, even in their prime, stood no chance without sunlight and plant life.

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Climate Change
The climate of the Cretaceous period was tropical. Scientists know this because nearly one half of the plants in this time were tropical plants. Many scientists believe that at the end of the Cretaceous period the temperature dropped. If this drop in temperature is correct, many of the plants that the plant eating dinosaurs ate would die and thus many of the plant eaters would die as well. If the plant eaters died there would be nothing for the meat eaters to eat and they would eventually die out also. Plankton also seemed to decrease in number during the Tertiary period which could explain the death of the marine dinosaurs that fed on them. This popular theory just possibly could have caused the dinosaurs demise.

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Volcanic Eruptions
Could numerous volcanic eruptions have caused such mass destruction? Possibly. When volcanos erupt, they send huge clouds of dust, sulfuric acid, and poisonous gases into the air making the air almost impossible to breath. The dust and ash in the atmosphere would also change the climate and sunlight levels. On top of that, the ground would be covered with layers and layers of molten rock. The dinosaurs would never have survived such a hostile, poisoned environment!

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Disease
Disease has also been proposed as the killer of the dinosaurs. As the Cretaceous period went on, more and more land bridges started to appear on the earth. The oceans started to dry up and the dinosaurs were able to walk across the land that was there. As the dinosaurs searched for food they would walk across these new land bridges and find relatives of theirs from when the lands of the world were one. But land bridges brought more than dinosaurs looking for food into the new land. They brought all of the diseases that those dinosaurs had inside of them. The diseases did not hurt those dinosaurs because they were immune to them, but to the other dinosaurs they could be fatal and the other way around. In most cases disease in a species is not fatal and is a positive thing because it will wipe out the weak so only the strong survive to pass their genes on to the next generation, but in the dinosaurs case it might not have been that way.

Answer 3

Evolutionists say the dinosaurs died out about 65-70 million years ago. How? Well, 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 this theory. One, 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 has or 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).

Many Creationists believe Noah's 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. They also believe that is the reason why man’s life-span shortened so much after the Flood.

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. Of course we are talking about species and not Genesis kinds.

Let’s think for a minute—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.

Another thing, is that there have been (even recently) reports of strange animals in the amazon and the congo that sound a lot like dinosaurs. And there are reports of giant flying reptiles in Indonesia, and so forth. There are thousands of square miles of almost impenetrable swamps and thick jungle in the world. Natives in some of these places describe beasts that fit with what just might be dinosaurs. And what about all the sightings of lake monsters? This is a field called cryptozoology—the search for hidden animals. There just might be a few dinosaurs left, teetering on the edge of extinction. We are constantly discovering new species of animals and plants in remote areas. A tree can’t run away and hide and yet the Wollemi pine tree avoided detection until just recently (said to have become extinct millions of years ago). An evolutionist has to say, “No way.” But a creationist has no problem with this and can say, “Maybe.”

Answer 4

Extinction theories


The sudden mass extinction of non-avian dinosaurs, an event that occurred approximately 65 million years ago, is one of the most intriguing mysteries in paleontology. Many other groups of animals also became extinct at this time, including ammonites (nautilus-like mollusks), mosasaurs, plesiosaurs, pterosaurs, herbivorous turtles and crocodiles, most birds, and many groups of mammals. The nature of the event that caused this mass extinction has been extensively studied since the 1970s; at present, several related theories are supported by paleontologists. Though the general consensus is that an impact event was the primary cause of dinosaur extinction, some scientists cite other causes, or support the idea that a confluence of several factors was responsible for the sudden disappearance of dinosaurs from the fossil record.


Asteroid collision

The asteroid collision theory, which was first proposed by Walter Alvarez in the late 1970s, links the extinction event at the end of the Cretaceous period to a bolide impact approximately 65.5 million years ago. Alvarez proposed that a sudden increase in iridium levels, recorded around the world in the period's rock stratum, was direct evidence of the impact. The bulk of the evidence now suggests that a 5-15 km wide bolide hit in the vicinity of the Yucatán Peninsula, creating the 170 km-wide Chicxulub Crater and triggering the mass extinction. Scientists are not certain whether dinosaurs were thriving or declining before the impact event. Some scientists propose that the meteorite caused a long and unnatural drop in Earth's atmospheric temperature, while others claim that it would have instead created an unusual heat wave.

Although the speed of extinction cannot be deduced from the fossil record alone, various models suggest that the extinction was extremely rapid. The consensus among scientists who support this theory is that the impact caused extinctions both directly (by heat from the meteorite impact) and also indirectly (via a worldwide cooling brought about when matter ejected from the impact crater reflected thermal radiation from the sun).


Multiple collisions—the Oort cloud

While similar to Alvarez's impact theory (which involved a single asteroid or comet), this theory proposes that a stream of comets was dislodged from the Oort cloud due to the gravitational disruption caused by a passing star. One or more of these objects then collided with the Earth at approximately the same time, causing the worldwide extinction. As with the impact of a single asteroid, the end result of this comet bombardment would have been a sudden drop in global temperatures, followed by a protracted cool period.


Environment changes

At the peak of the dinosaur era, there were no polar ice caps, and sea levels are estimated to have been from 100 to 250 metres (330 to 820 feet) higher than they are today. The planet's temperature was also much more uniform, with only 25 degrees Celsius separating average polar temperatures from those at the equator. On average, atmospheric temperatures were also much warmer; the poles, for example, were 50 °C warmer than today.

The atmosphere's composition during the dinosaur era was vastly different as well. Carbon dioxide levels were up to 12 times higher than today's levels, and oxygen formed 32 to 35% of the atmosphere, as compared to 21% today. However, by the late Cretaceous, the environment was changing dramatically. Volcanic activity was decreasing, which led to a cooling trend as levels of atmospheric carbon dioxide dropped. Oxygen levels in the atmosphere also started to fluctuate and would ultimately fall considerably. Some scientists hypothesize that climate change, combined with lower oxygen levels, might have led directly to the demise of many species. If the dinosaurs had respiratory systems similar to those commonly found in modern birds, it may have been particularly difficult for them to cope with reduced respiratory efficiency, given the enormous oxygen demands of their very large bodies.

Answer 5

Most scientists believe that a meteor hit Earth that day but not all dinosaurs could have been killed. After that meteor a black smoke rose to the air for many days. It was very cold so some dinosaurs could have died from that. More and more volcanes erupted which means dinosaurs could have died from that, too. When the last few dinosaurs roamed the Earth there was nothing to eat. Plants were dead so the herbavores died. Herbavores were dead so the carnovores died. Thus the dinosaurs were gone.

Answer 6

Certainly not because of humans coming to earth. Dinosaurs died out 60 million years before people showed up on the scene.
There are some descendents of dinosaurs still around today -- birds.
{scratching head}: Noah's flood?????

Answer 7

They are extinct because they didn't have enough food and water. It was drying up.

Answer 8

what if i told you that dinosaurs were still here ? they never left they just dont get as big! it has been that way since Noahs flood!

Answer 9

what are all these theories about? simply, they had not enough space on Noach's ark....

Answer 10

comet. then they ecvolved smaller. if they were that big now we'd've killed them all anyway right?