Evolution And Catastrophes

“A minority disputes this theory, arguing that other events-such as volcanic eruptions, sea-level changes or a series of impacts-were to blame for the spectacular loss of species that occurred at the transition between the Cretaceous and Tertiary periods…”

Large amounts of iridium – a chemical element that is not a part of the Earth’s crust composition – were originally found in rocks of Europe and United States, and have been found everywhere ever since. Iridium, common in meteorites, is a testable evidence of the disaster hypothesis. Gould continues that the Cretaceous debacle, which is one of five episodes of mass dying, occurred at the same time as the large comet might have smashed into the Earth. The author believes this is not merely a coincidence, rather, it is a proof of the cause-effect relationship. The demise of a wide range of habitats along with the extinction of dinosaurs gives an inestimable advantage to the disaster theory over other claims, the author adds. The comet struck the Earth, and habitats, from terrestrial to marine, died with geological suddenness. Finally, this hypothesis has had an impact on the study of an atomic war and its consequences. A nuclear war, Gould says, may cause a huge drop in temperatures and result in the extinction of humanity. Testable evidence, study, development, contribution – all this makes good science.

Gerta Keller, professor of geosciences at Princeton University, has recently conducted research on the Chicxulub asteroid in which she analyzed new core samples taken from the asteroid site (Botzer 2004). These samples indicate that the impact that occurred at Chicxulub actually predated the mass extinction of the dinosaurs, which occurred at the Cretaceous-Tertiary boundary about sixty-five million years ago. Keller claims that the Chicxulub impact occurred approximately 300,000 years before the extinction (Keller 2004). Although previous researchers estimated that the Chicxulub asteroid was the cause of the extinctions, there had always been doubts about the exact age and size of the crater, and about the origin of the “mega tsunami deposits” that were located within the crater (Keller 2004). The focus of Keller’s recent research was on finding some answers to these questions. To do so she analyzed Cretaceous limestone, dolomite, and anhydrite deposits as the site of the Chicxulub crater (Keller 2004).

Dinosaurs ruled the earth for over 65 million years and thankfully for the human race, they became extinct. Ultimately, only a major catastrophe could completely wipe out an entire species, let alone an entity of dinosaurs and the debacle on the causes of dinosaur extinction have flooded the minds of paleontologists for centuries. Geologist and zoologist Stephen Jay Gould published “Sex, Drugs, Disasters, and the Extinction of Dinosaurs,” to compare scientific and speculative causes of dinosaur decimation. Personally, I found this passage very informational and enjoyed reading it. Gould provides three theories that capture the reader’s curiosity, allowing room for pondering in one’s mind.

The question of what caused the extinction of megafauna during the Late Pleistocene period is one that archaeologists have struggled to answer for decades, but why should it matter? Discovering with certainty the cause of megafaunal extinction would

“The Great Dying” was the largest mass extinction ever recorder in the Earth’s history. It was the death of approximately 90% of all living species, such as, the trilobites, sea scorpions, and coral dating back to 254 million years ago (Randall). It is suspected that the eruption of many volcanoes in the Siberian Traps was the fallout of these species because the eruption killed off almost all plant life, leaving nothing for the animals alive. However, researchers have found new evidence to suggest that acid rain was the cause for this destruction (Randall).

The article discussed the changes in many habitats due to anthropogenic activity. Anthropogenic is an adjective that describes changes in nature due to the people. Next, this article discussed climate change and the impact that it is having on species like clams, and fish due to ocean temperatures rising. The article also addressed carbon dating of fossils to look for cause of extinctions. Human development and agriculture have had a tremendous impact on the population of many species that are terrestrial. Deforestation is a big problem that has caused a decline in the bird species. Commercial fishing in many areas has led to a decline in fish populations. Furthermore this article

In the book, “A Magnificent Catastrophe” by Edwawrd J. Larson, the author views all the aspects of the events that occurred in the 1800’s during America’s first presidential campaign. The presidential election during the 1800’s was the first campaign that shaped the country’s future. The election was full of chaos and confrontations, and there was a rivalry battle between members of different parties. One of the members was Thomas Jefferson from the Republicans, and on the other side, it was John Adams from the Federalists. In 1776, both Jefferson and Adams were sent as delegates to the second-continental congress to declare independence. When they were there, they wrote the Declaration of Independence. After signing the Declaration of Independence,

There was much speculation regarding the K/T boundary being caused by a meteorite. The impact of this event was believed to have led to extended volcanic activity periods that in turn further polluted the atmosphere. The impact of the K-T boundary happened to be attributed to the extinction of dinosaurs that might have been as a result of new diseases. The impact affected all living things including primates. The impact is believed to have drastically slowed primate evolution (Clyde, 2010).

Earth’s environment is affected everyday by pollution. People must make changes in order for global warming to be slowed. People causing pollution are the largest factor in the climate change. Plants and animals are the most affected by the climate change. “The change has mostly consisted of humans emitting dangerous gases into the atmosphere causing global warming.” (Confronting the Realities of Climate Change). With the Earth’s average temperature rising, many animals and plants are being forced to adapt. The forcing of adaptations is also causing different species to slowly die and eventually they will become extinct. The extreme change in climate has happened before to the dinosaurs. When the dinosaurs roamed the Earth, they lived in a widely tropical climate. Once the climate began to rapidly cool, the cold-blooded reptiles did not have enough time to adapt to the change. People have also stated because the dinosaurs became extinct naturally that this is just a cycle but it is not. The

"We call them dumb animals, and so they are, for they cannot tell us how they feel, but they do not suffer less because they have no words” (Anna Sewell). There is undeniable evidence that animals are being affected by climate change. Even though the effects are difficult to measure, there are many different ways animals are being affected. With the loss of predator and prey species it affects the life cycles in the food chain. The earth’s climate change causes habitats such as snow, ice, or forest areas to alter, resulting in loss of habitat and food accessibility as well as causing extinction.

Ever since the history of Earth has been studied using fossil records, extinctions have always been the object of fascination and interest, particularly the mass extinctions that occurred throughout Earth's history. A mass extinction can be caused by disruptive global environmental changes, where large numbers of species have become extinct (Urry et al. 2008). There have been five major extinctions documented based on fossil records over the past 500 million years, but the Cretaceous (KT boundary extinction – a name that meant it began the Tertiary era) extinction caught a lot of

There have been five well known extinctions on this earth. The one most well known is the mass extinction that ended the dinosaurs. Mass extinction is often described as the elimination of a large number of species in a short period of time. Despite what many think, the elimination of species is almost commonplace at this point. The Earth is currently in the middle of a sixth mass extinction, and it’s been caused by the human race.

This final blow would have sent earth into a nuclear winter. According to this theory, dust caused by the asteroid collision disrupted plant growth by blocking out the sunlight needed for photosynthesis for nearly a year. A chain reaction occurred as plants died off, so did the herbivores relying on the plants, and then the carnivores that relied on the herbivores. Around 75% of species became extinct, including dinosaurs, mammals, giant marine lizards, fish, birds, and insects. Meanwhile, seawater flooded around 40% of the world’s continents ("Mass Extinctions").

Rapid climate change also ends up on the suspect list of possible dinosaur extinction events. During the latter part of the Cretaceous Period continents broke up causing volcanoes to erupt and fill the sky with gas and ash resulting in a drastic climate change (“Dinosaurs Climate Change and Biodiversity”). The shifting of continents changed the Earth’s landscape, altering weather patterns and overall climate (“Dinosaur Extinction Theories”). Also, over a long period of time, climate gradually changed. Ocean habits changed, temperatures grew much more extreme causing scorching summers and frigid winters (Norell, Dingus, and Gaffney). Radical temperature changes like these led to a green-house effect, making life for the dinosaurs a lot