How Did Animals Survive The Ice Age

Thu, January 23, 2020 at 12:30PM

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By James "Zach" Zacharias, Senior Curator of Education and History

What is an extinction upshot? Most people do not realize that paleontologists and scientists have created sure criteria for extinction events. These events are characterized by a abrupt alter in the abundance of multi-cellular organisms and a widespread decrease in the Earth's biodiversity. Well-nigh of the variety and biomass on Globe is microbial and hard to measure so these events are limited to easily appreciable biologically complex components of the biosphere.

Scientists have established three criteria for a major extinction event. The first is that the event must be worldwide. Animals must be affected over the entire globe non but regionally. Second, an extinction event must happen very quickly in a short geologic fourth dimension calibration. Finally, one-third of all existing species must disappear. What is remarkable is that afterwards these catastrophic events new life, new species, and new ecosystems sally to fill the void very speedily.

There have been 5 major such extinction events referred to as the "Big V." The kickoff extinction event goes back 444 million years agone to the Paleozoic era. The 2nd was the Ordovician where 86% of all life on World was eliminated. This was followed by the Devonian extinction outcome 375 million years ago were 75% of life went extinct. The biggest extinction event was the devastating End-Permian extinction event 251 million years ago where 96% of all species disappeared. The fifth, and most famous, extinction event is the catastrophe that wiped out the dinosaurs called the Stop-Cretaceous event. Over the years it has gained a lot of notoriety and publicity due to what scientists have chosen "the smoking gun." A large asteroid hit the Earth 65 million years agone almost the Yucatan Peninsula in Mexico. This created a global meltdown of plant life and ecosystems which ended the long 250-million-year reign of the dinosaurs. This began the "Historic period of Mammals" with many new mammalian life forms filling the major ecosystems and quickly diversifying into many new types.

A diorama representing the habitat of a prehistoric Eremotherium laurillardi (Giant Ground Sloth).

Fast frontward to 13,000 years ago and what are the theories that explicate why the water ice age animals went extinct? What was different during the Pleistocene Epoch when giant sloths, giant armadillos, and huge cavern bears dominated places like Florida? Most of the animals that perished at the terminate of the last ice historic period were chosen the megafauna or animals over 100 pounds. Huge multi-ton animals like mastodons and mammoths disappeared along with apex predators like saber-toothed tigers and dire wolves. About of these ice age animals had endured at least 12 previous ice ages and did non go extinct. Why was this one unlike? Scientists take grappled with this question for over 150 years. Scientists have developed iv scientific theories to accost this conundrum.

The start theory, championed by Geoscientist Dr. Paul Martin at the University of Arizona, is called the Blitzkrieg or overkill theory. Dr. Martin posits this disappearance of the megafauna was due to a new devastating apex predator that could problem solve, throw objects like spears, and make weapons. Obviously, he is referring to humans. Wherever humans came into new lands, corresponding extinction of big country animals occurred shortly afterward. In North America, a group of humans chosen the Clovis people arrived about 12,000 years ago. These prehistoric people received their name later the big spear points they fabricated which were beginning discovered in New Mexico. They used these big blades in conjunction with a unique tool chosen the atlatl. This tool enabled them to catapult a spear at loftier velocity and over a long distance to bring down tiresome-moving mammoths and other megafauna. In a short fourth dimension span, these animals were hunted to extinction. This created a domino consequence equally the other carnivores that hunted them roughshod by the wayside. Eventually, a new equilibrium was established in the ecosystem.

The atlatl is a paleo carved wooden tool used to launch a spear at a loftier velocity to
bring down large mammals such as mammoths. (Replica) ca. x,000 before nowadays.

In a short ane,000-yr span, the Clovis people spread from Alaska to the tip of South America. For unknown reasons, they disappeared, and scientists theorize they became the major aboriginal tribes of North and South America. The Museum has show of these Clovis People at piece of work. In a example within the Prehistory of Florida Gallery at MOAS sits the skull of a Florida bison. If you look closely, you can find what appears to be a small stone sticking out from the meridian of the skull. This is no rock, but a broken piece of the spear point that delivered the deathblow to the animal. The skull was found in the muck of the Aucilla River in North Florida. It is carbon dated at 12,000 years quondam – the right time for the Clovis people in Florida. This proves that these ancient people were hunting big megafauna.

Other "impale sites" have been found at Silver and Wakulla Springs, and other sites throughout the continent. Even the Daytona Mastodon excavated in 2011 past museum staff has rib bones with what appear to be butcher marks. These basic were sent to experts at the University of Indiana and Cathay only came dorsum as undetermined.

This bison skull dating back 12,000 years was discovered in the Aucilla River eastward of
Tallahassee by a University of Florida paleontological team in the mid-1990s.

Populations of big animals seemed to radically decrease everywhere when humans first announced in their ecosystem. iii,500 years agone in Cuba, a smaller species of giant ground sloth went extinct. 46,000 years ago, in Commonwealth of australia, big animals like the giant kangaroo became extinct when humans arrived. Information technology is the same story in Europe, Madagascar, and New Guinea. What well-nigh Africa? The large animals there seemed to take survived but fine. Scientists who prescribe to the "overkill" theory suggest this may exist explained past the fact humans and large animals coevolved and existed together for a long fourth dimension. The large megafauna animals on the continent avoided the dangers of these bipedal predators. When humans crossed over country bridges to new continents and islands, existing animals had no clue to exist wary. Many large animals similar elephants and mammoths take irksome reproduction rates making it difficult to keep the birth rate higher than the death rate therefore compounding the problem.

Eremotherium laurillardi (Giant Basis Sloth) skeleton on display at MOAS.

The adjacent theory that some scientists believe is that at the end of the terminal ice age a dramatic climate change wiped out many large animals that could not adapt fast enough. Again, the puzzling piece is the previous ice ages seem to have petty event on megafauna. What was and then different at the end of the terminal water ice historic period to wipe out these magnificent beasts?

When the climate changed at the end of the last water ice age, warmer temperatures raised ocean levels; this especially affected Florida. The coastline was no longer 50 miles farther east from Daytona or 150 miles further west from St. Petersburg than it is today. Many scientists believe that the climate changed apace and the grasses inverse as well. Research from the University of Copenhagen suggested that at the end of the last ice age a change in the grasses resulted in their decline. These grasses changed from what was called C-iii to C-4 grasses, which contain more silica and were far less nutritious. Thus, the animals were not getting the right blazon of food. This ecology change in vegetation led to their downfall.

Another environmental result at the end of the concluding water ice historic period was the retreat of the ice sheet. The large ice canvas that blanketed North America and Europe kept the seasons dampened, merely every bit it retreated, information technology caused sharply defined seasons of winter and summer. This caused the animals to movement to new ecological zones and adapt. New plants and terrain caused by sharp seasons in summertime and wintertime created a new rest in the ecosystem. If yous could not adapt, y'all died off.

The demise of the woolly mammoth could teach us much about our effect on other species. Image Credit: George Teichmann

The next theory is that a hyper affliction spread swept through the megafauna. Perchance, early on homo aboriginals moving into new lands carried a illness. Information technology has happened many times earlier were a illness jumps from ane species to another.  Cases of swine and bird flu are modern examples of this result. What if humans or the wild dogs that followed them carried a virus in their gut which affected large mammal populations. Unfortunately, in that location is non much direct evidence to support the claims of the small number of scientists who are working on this theory.

The final theory, which was just released in the autumn of 2019, suggested a visitor from outer infinite wiped out the large mammals of the world. Researchers take simply published show suggesting that asteroids impacted well-nigh Elgin, South Carolina, and Greenland about xiii,000 years ago. Researchers at the University of Due south Carolina have detected to a higher place-normal amounts of iridium and platinum, which could simply accept come up from such an affect. This could cause a mini ice age, which today is called the Younger Dryas event, which was a temporary return to ice historic period conditions thirteen,000 years to 11,700 years ago. This was an abnormality in the full general warming trends of the period.

Although the concluding ice age was not a major extinction event, roughly 35 different types of large mammals went extinct. Did humans crusade the extinction or perhaps a combination of ecology changes and hunting working together rubbed out the ice historic period mammals? Ane of the problems is that the evidence paleontologist and scientists collect is rarely complete. Any the reason or reasons, large animals were unable to arrange to any changes happened at the end of the Pleistocene Epoch. Scientists just cannot seem to put a "bulls-eye" on whatever unmarried consequence causing this mini extinction result.

Source: https://www.moas.org/Ice-Age-Extinctions--What-Happened--1-5943.html

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