The Cretaceous-Tertiary extinction event, or the K-T event, is the name given to the die-off of the dinosaurs and other species that took place some However, in the s, father-and-son scientists Luis and Walter Alvarez discovered in the geological record a distinct layer of iridium—an element found in abundance only in space—that corresponds to the precise time the dinosaurs died.
This suggests that a comet, asteroid or meteor impact event may have caused the extinction of the dinosaurs. Dinosaurs roamed the earth for million years until their sudden demise some Over the years, paleontologists have proposed several theories for this extensive die-off.
One early theory was that small mammals ate dinosaur eggs, thereby reducing the dinosaur population until it became unsustainable. Some scientists believed a great plague decimated the dinosaur population and then spread to the animals that feasted on their carcasses. Starvation was another possibility: Large dinosaurs required vast amounts of food and could have stripped bare all the vegetation in their habitat.
But many of these theories are easily dismissed. Also, plants do not have brains nor do they suffer from the same diseases as animals, so their simultaneous extinction makes these theories less plausible. But in the late Mesozoic Era that corresponds with the extinction of the dinosaurs, evidence shows that the planet slowly became cooler.
Lower temperatures caused ice to form over the North and South poles and the oceans to become colder. Because the dinosaurs were cold-blooded—meaning they obtained body heat from the sun and the air—they would not have been able to survive in significantly colder climates. Yet some species of cold-blooded animals, such as crocodiles, did manage to survive. Also, climate change would have taken tens of thousands of years, giving the dinosaurs sufficient time to adapt. In , Russian astronomer Joseph Shklovsky became the first scientist to consider the extinction was due to a single catastrophic event when he theorized that a supernova the explosion of a dying star showered the earth in radiation that could have killed the dinosaurs.
Once again, the problem with the theory was explaining why dinosaurs died out and other species did not. Also, scientists said that such an event would have left evidence on the surface of the earth—trace amounts of radiation dating back to the Cretaceous Period.
After all, the world has had a particular history. The chronological march of time gives the world direction, and past events are causally linked to the flourishing and diversification of biological novelty today.
Page is right to avoid instrumentalist language in discussing the value of a creature or of an extinct species. The subsequent history can add a dimension of either glory or tragedy to the meaning of past lives without limiting their value to a merely instrumental role. The most well-known major extinction of creatures is that of the dinosaurs some 65 million years ago. Dinosaurs could not survive the changes and were wiped out. The diversification of mammals eventually ended up in the emergence of Homo sapiens—and that development, we might add, led to the incarnation of God in the person of Jesus Christ.
So how do we interpret the mass extinction of dinosaurs? Certainly we want to acknowledge that their extinction was a tragedy. The loss of a unique way of being in the world is a true loss, just as the loss of an individual is a true loss. Teleology now! The position I will outline involves the belief that God does not control all of creation in every respect. Furthermore, God does not know the whole of the future. God rarely has fixed specific outcomes in mind.
God always acts in perfect love and wisdom and will continually and creatively work to bring about good, even if the path to the good is circuitous due to the freedom exercised by creatures. God cannot be simply using the present as a means to a foreordained end because God does not know which ends will actually occur. God knows only the possibilities of the future. At the same time, creatures have important and lasting effects on future creatures.
The world looks as it does today precisely because creatures in the past lived and died, fought and reproduced, flourished and were made extinct. Their lives and their narratives are linked to ours today. The full meaning and impact of species long since extinct are, in fact, still in development. Our stories continue their stories. This adds a providential twist: in the choices that are made today, the possibilities which God foresaw in the life of a now extinct Tyrannosaurus rex are either realized or closed.
The possibilities that help make the extinction of a species more or less meaningful in retrospect are realized only in the future. God is constantly working toward giving the greatest amount of meaning to the events that have occurred.
God is constantly redeeming the lives of the past by luring creation toward ends that will lead to the greater glory of the individuals of the species now extinct. An analogy is found at the end of Hebrews The saints of the Hebrew Bible recounted in chapter 11 lived and died long before, but the author of Hebrews feels that the current righteous action of believers enriches their legacy. Although they are long since dead, part of the promise of their lives is realized in the present.
In a similar way, consider the role of Abraham. This view can be extended to all living creatures. All living creatures are companioned by God and loved and valued on their own terms.
Yet each life also lives within a divine promise that the legacy of their life will be for the good. It is possible to see the ongoing history of evolution, comprising as it does ever increased complexity and interrelations, as the way that the promise of the past is being fulfilled. Ancient forests seem to have flamed out across much of the planet.
And while some mammals, birds , small reptiles, fish , and amphibians survived, diversity among the remaining life-forms dropped precipitously. In total, this mass extinction event claimed three quarters of life on Earth. For now, two leading ideas are battling it out within the scientific community: Were dinosaurs victims of interplanetary violence, or more Earthly woes? One of the most well-known theories for the death of the dinosaurs is the Alvarez hypothesis, named after the father-and-son duo Luis and Walter Alvarez.
In , these two scientists proposed the notion that a meteor the size of a mountain slammed into Earth 66 million years ago, filling the atmosphere with gas, dust, and debris that drastically altered the climate. Iridium is relatively rare in Earth's crust but is more abundant in stony meteorites, which led the Alvarezs to conclude that the mass extinction was caused by an extraterrestrial object.
At about 93 miles wide, the Chicxulub crater seems to be the right size and age to account for the dino die-off. In , scientists drilled a rock core inside the underwater part of Chicxulub , pulling up a sample stretching deep beneath the seabed. This rare peek inside the guts of the crater showed that the impact would have been powerful enough to send deadly amounts of vaporized rock and gases into the atmosphere, and that the effects would have persisted for years.
And in , paleontologists digging in North Dakota found a treasure trove of fossils extremely close to the K-Pg boundary , essentially capturing the remains of an entire ecosystem that existed shortly before the mass extinction. Tellingly, the fossil-bearing layers contain loads of tiny glass bits called tektites—likely blobs of melted rock kicked up by the impact that solidified in the atmosphere and then rained down over Earth. However, other scientists maintain that the evidence for a massive meteor impact event is inconclusive, and that the more likely culprit may be Earth itself.
Ancient lava flows in India known as the Deccan Traps also seem to match nicely in time with the end of the Cretaceous, with massive outpourings of lava spewing forth between 60 and 65 million years ago. Today, the resulting volcanic rock covers nearly , square miles in layers that are in places more than 6, feet thick.
Proponents of this theory point to multiple clues that suggest volcanism is a better fit. Exactly what caused dinosaurs to go extinct is unknown, but by far the likeliest explanation is that the Earth was struck by a large asteroid. It is traditionally used as an abbreviation for the Cretaceous Period.
You can find out more about when dinosaurs were alive here: Dinosaur Periods. Geology is the scientific study of rocks. Therefore, periods of time identified by rock layers form the geological time scale. Therefore, rocks formed during the Cretaceous Period appear above those formed during the older Triassic Period. The layers of rock in which fossils are found give us an idea as to how old the fossil is.
For example, Tyrannosaurus Rex fossils appear in Upper Cretaceous rock formations, letting us know that it was one of the very last dinosaurs. The rock layers also provide us with many clues as to when dinosaurs went extinct — and also what caused them to go extinct ….
The most likely explanation for the extinction of the dinosaurs is that the Earth was struck by a large asteroid.
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