Theories of the Extinctions of the Dionsaurs:
Dinosaurs became extincted 65 million years ago, at the end of the
Cretaceous period, something so devastating that it altered the course of life on earth. It
seems like it happened so sudden, as geologic time goes, that almost all the dinosaurs
living on earth disappeared. So how did these dominant creatures just die off? Was it a
slow extinction, or did it happen all of the sudden? These questions bring rise to many
different beliefs on how the dinosaur disappeared over 65 million years ago.
Extinction is when the birth rate fails to keep up with the death rate, it is
called extinction. But, the definition does not answer the question about the nature or
causes of extinction. Paleontologists generally divide extinctions into two types, for that
of different causes arose. The first is called background extinctions, isolated extinctions
of species due to a variety of causes. Included is out competition, depletion of resources
in a habitat, changes in climate, the development or destruction of a mountain range, river
channel migration, the eruption of a volcano, the drying of a lake, or the destruction of a
forest, grassland, or wetland habitat. The second type of extinction is called mass
extinctions. Large numbers of species go extinct; many types of species go extinct; the
effects must be global, and the effects must occur in a geologically short period of time.1
The dinosaur could not have lived for ever. No creatures, no plants, no tiny bacteria are
forever, not even Homo sapiens. Extinction is the fate of all species. One theory on how
the dinosaurs became extinct is that of carbon dioxide, and the greenhouse effect.
Volcanoes produced the proposed conditions. A massive volcanic eruption could have
saturated the atmosphere with carbon dioxide so that it caused a sharp rise in
temperatures worldwide. The excessive carbon dioxide would have permitted solar
energy to enter the atmosphere but would have blocked the radiation of most surface heat
back out into space, therefore causing the greenhouse effect. Rising temperatures could
have killed off or reduced the activity of plankton, disrupting food chains and also
messing up the plankton's normal role in converting carbon dioxide to oxygen through
photosynthesis. From there it would not have been long for all the dinosaurs to have been
suffering, and then to become extinct.
My theory of the extinction of the dinosaurs is the theory of the comet
“...99.9 per cent of all [species] that have ever existed are now extinct.” (Benton 1) After one hundred and sixty million years of domination, the reign of the dinosaurs ended in fire and ice. Sixty five million years ago, the largest volcanoes in the history of the Earth erupted across what is now India, effectively annihilating the dinosaurs by spewing out noxious gas and ash, that effectively blocked out the sun killing off most vegetation and breaking the food chain, leaving the dinosaurs to starve. Compared to other groups of animals the dinosaurs were the most vulnerable to such a climatic event and the result was the end of the dinosaurs’ glorious evolutionary history.
So what killed the dinosaurs? Without having any background education in science it is hard for the general public to comprehend such matters and they rely on the knowledge of the scientists in this field. Although there has been much research on the subject nobody has come up with a conclusive answer. And we are left to read the countless articles, all having their own opinions as to the mass extinction. One such theory is that a shift in the solar system could have caused the mass destruction. According to an article published in Nature magazine,
Every so often a discovery is made that attempts to shake up pre-conceived notions of how the dinosaurs actually lived or how they came to be. On June 22, 2000, in Oregon, scientists announced the discovery of the oldest known animal to have feathers. Though no records indicate how the age of the animal was determined, the fossil was dated at 220 million years old. It lived at the time of the very earliest dinosaurs, and about 75 million years before the first known bird.1[1]
[7] Klug, W., Cummings, M., Spencer, C., Palladino M. (2012) Concepts of Genetics: Tenth Edition. Pearson's Education, Inc.
During the Civil Rights Movement, which lasted from 1865 to the late 1960s, three different amendments were composed and ratified in favor of African Americans. Many famous African Americans, from musicians to authors and leaders to entertainers, sprouted from the influence of this period. Two strong leaders from this era were Martin Luther King Jr. and Malcolm X. Martin Luther King Jr. made a bigger impact on the population than Malcolm X because of his speeches, beliefs, direct and peaceful activities, and the effect his death had on the population.
We use dinosaurs to represent the changes in nature that have occurred throughout time. Studies found that although the “oldest rock did not show evidence of life, the progression of plant and animal life that changed in recognizable intervals, from ancient life, age of reptiles to the age of mammals” (Dino Nature Metaphor, slide 6), measured the age of the earth. When we think of dinosaurs in relation to nature, we think of that very powerful force that controls the cycle of life. Nature was able to yield such magnificent ferocious creatures that walked the earth and then take them back when they served nature’s purpose. Dinosaurs fit perfectly in nature’s constant
3 Leicht B. G., McAllister B.F. 2014. Foundations of Biology 1411, 2nd edition. Southlake, TX: Fountainhead Press. Pp 137, 163-168, 177-180,
Have you ever had those moments where you are feeling unmotivated or zero energy to workout? I will be the first to tell you I have had these moments. Being involved in the fitness world, I love every aspect of fitness. For the past 5 years, I was working out 5 days a week and had my ups and downs with results. I am guilty of it, I would pick up a workout magazine and try out this crazy workout and just destroy my body. Sure, I saw some results but I was becoming more and more tired throughout the day. On top of that, I was only getting 5 hours of sleep and not eating appropriately to refuel my body. I know stupid right? I am human and I am not perfect!
The most significant event of the Cretaceous era came at its end. Nearly 65 million years ago, the second most severe mass extinction in earth’s history occurred. This resulted in the loss of around 80% of species living at the time. Though nowhere near as severe as the end-Permian mass extinction, the end-Cretaceous extinction is the most well known mass extinction event. This is due to the violent event that caused it the extinction, as well as the chapter of earth’s history that it closed: the Dinosaurs. The Cretaceous Event ( often shortened to K-T event) Of the animals that were killed off were the flying reptiles (pterosaurs) and the last few mosasaurs and plesiosaurs, both early marine reptiles. Many mollusks and species of microscopic plankton were killed. Terrestrial plants suffered mass extinction as well. Almost 60% of terrestrial plants were lost. This led to high extinction rates among insect populations, especially insects that were highly specialized to feed on just a few types of plants had it the worst. It took approximately 9 million years for the global insect populations to recover from the Cretaceous extinction. Immediately after the extinction, the earth saw an explosion of short term species who respond well to fire, or other external disturbance. Evidence of the catastrophe comes from a thin rock layer deposited worldwide just after the impact. It is dominated by fossil plants whose descendants recover quickly after fires of other disturbances, such as Fire Weed in Alaska. The causes of the Cretaceous extinction are still being debated by paleontologists. Scientists agree that the main cause of the extinction was a...
Almost 23% of all families, 48% of all genera (20% of marine families and 55% of marine genera) and 70% to 75% of all species went extinct (Beaz). Although the cause of this mass extinction is debatable, many speculate that global warming was the killer. Because Pangea was breaking up into Laurasia and Gondwanaland, there was widespread volcanic activity caused by the rifting, increasing atmospheric carbon dioxide. The massive release of this greenhouse gas increased global air temperatures and resulted in acidified oceans along with rising sea levels. If this is the case, the life in the ocean would have died at a significant rate. Many families of brachiopods, gastropods, bivalves, and marine reptiles became extinct (Rafferty). An important trace fossil known as the phylloceratid ammonoid was able to survive, and they gave rise to the explosive radiation of cephalopods later in the Jurassic Period, as well as evolved into many different forms during the later Cretaceous (End Triassic Extinction). This extinction event ranks fourth in severity of the five major extinction events over geologic history
were many other species that were killed off. During what is known as the K-T
Several mass extinctions have occurred during the Earth’s history. The Cretaceous – Tertiary Boundary (K-T) Extinction caused the loss of at least three-quarters of all species known at that time including the dinosaurs. The cause of this mass extinction is a controversial subject among scientists but the fossil evidence of it’s occurrence is abundant.
Many different theories exist as to why the dinosaurs went extinct. We know for sure most dinosaurs died out around 65 million years ago. The majority of scientists agree on a number of theories as to what brought the end of the dinosaurs. The most popular theory is that an asteroid ended the reign of the dinosaurs. Another theory, massive climate change in the pre-historic atmosphere, caused all the dinosaurs to die. Some scientists believe that mammals out competed dinosaurs for food and other resources. The last theory that dinosaurs died due to a large amount of volcanism comes up in scientists list of theories as well. Many different theories of why dinosaurs went extinct include extinction by asteroid, mammals outcompeting dinosaurs, climate change and volcanism.
could go extinct with the way the climate is going (Roach, 2004). When many different kinds
... present rate of human population growth, we might well be heading for the sixth mass extinction crisis.