Extinctions- Out with the Old/ In with the New-
Please pay attention, readers, and read this Fact verbatum! For a good several centuries, Early Biologists, thought that all organisms that had ever lived on this Earth was still alive, and no one would have thought that God would be one to let his most precious creations die off. Yet, in the late 18th Century, French Anatomist Baron Georges Cuvier (1769-1823), known by many as the Father of Modern Paleontology, proposed the idea of Extinction.
EXTINCTION?! Why in the history of the World would God kill off His own creations? The answer is known by many today as not the hand of God but Natural Selection, with the great Father taking a backseat to the Universe and intervening as He sees fit. This leads into my next topic of Discussion: "What is it?" and "How does it apply to us today?"
What IS Extinction?!
Extinction, by working scientific definition, is the absence/disappearance of all individuals of one taxa or several populations of several taxa in an ecosystem. That's extinction, in a nutshell, however, this is still a complicated topic to instruct, so please keep reading.
What CAUSES Extinctions?
Now that we know WHAT Extinction is by working definition, we need to understand what it's role in Evolution actually is...more specifically the "Causes." Unfortunately, many scholars know WHAT it is and it's implications, but WHAT truly causes these mysterious disappearances of populations of organisms remains unknown. That's what this Fact is truly about and I've had an ambition to discuss this recently.
However, we do know that Extinctions are multi-factorial and that not ONE factor can cause extinctions as it's like a Dominoe effect, where one change affects the other factors until the group is wiped out, or at least, that's what is believed to happen, yet when it comes to large extinctions like the extinction of the Dinosaurs, the Permian extinction, and the Pleistocene extinction (A few of which I will cover briefly in a little while, if you'll bear with me.) the factors aren't as forgiving as they are with modern extinctions, thanks to the gap in the Fossil Record.
Extinctions On A Large Scale-
Many extinctions continue to occur today and everyday, despite human (H. sapiens) interaction, but the one's that make the headline news are the global "Mass" Extinctions like the ones Humans are causing or are we? (I'll get to that soon enough.) and the infamous K-T Event.
Here are a Few of the Infamous Mass Extinctions, their Time Periods, Evidence and Possible Factors:
- The K-T Boundary- 65 million Years Ago- a.k.a. the Extinction of the Dinosaurs- This is marked by a higher concentrated layer of Irridium (rare on Earth, but abundant in meteors) at the boundary of the Cretaceous ("K") and Tertiary ("T") periods. The "K" for Cretaceous is used as a notation to prevent confusion with the Cambrian and Carboniferous periods. Approximately 68% of all life on Earth was wiped out in this event. The Irridium indicates a definite meteor strike, but was that the finger that fired the loaded gun of Evolution? Possibly, but I have another idea. If one were to go into the Badlands of Alberta, Canada, Outside of Drumheller, you would see some of the best evidence of the end of the Cretaceous. As the Fossil Record shows, the Dinosaurian speciation was down to 12 individual speies of each group around the end of the Cretaceous, yet the the fossils seem to end a few feet below the irridium line, indicating that the meteor strike had not done them in, something else. However, that's not to say that it did NOT wipe them out, but rather, as fossils are extremely rare, some may not have fossilized, so there's really NO way to tell. We KNOW it was an environmental change but the exact combination of the factors is nearly impossible to tell.
As you all can see, Extinction is a VERY complicated topic and I am already exhausted from typing it honestly. lol! ;P The most important thing to remember is when you hear about Extinction theories and hypotheses, keep in mind that it takes MORE than ONE factor to cause extinctions!!! In fact, ALL extinctions share the same basic trait in common with one another is that they share the same factors for the most part, the ENVIRONMENT, yet the combinations of those factors differ with each one! I hope you enjoyed and I encourage you to get in touch with experts and ANY of the Open Access Journals, such as PLos One and continue to read up on it if you have ANY further questions! Take Care, Readers! Talk to you Tomorrow!! :)