Essay On Quaternary Extinction

The Pleistocene faced massive evolutions and changes. The Bering land bridge helped large species such as the mammoth, bison, deer and all their relatives to cross over to the Americas. The ancestors of the human species made its big appearance, but most importantly there was the catastrophic extinction event of many species near the end of the Quaternary period. The event had a great effect on the species roaming on Earth. The Quaternary extinction event was caused by factors such as global climate fluctuations which pushed many to adaptation and others to extinction. It’s also plausible that hunters contributed to the Quaternary extinction by causing local extinctions. After the last ice age, the ecosystem was greatly impacted and a new diversity
of plants appeared.

Experts believe that the increase of global temperature leads many of the large mammals from North America such as the woolly mammoth and the woolly rhinoceros to the extinction.
These cold-adapted large beasts were used to the cold climates of the glacial periods. They could manage to get through the warmth period, but it required some adaptation. “[…], some of them still managed to find places where the climate was just right” Shapiro explained (Voss).
Those who adjusted to a new but comfortable environment were able to thrive through that time period.
Although smaller species such as the reindeer, bison and musk ox survived, larger species like the woolly rhinoceros, the woolly mammoth and the wild horse went extinct. The much larger cold-adapted species had a harder time to adapt to the temperature fluctuations (Voss). Larger organisms produce more heat in their bodies than smaller organisms do, thus the additional heat of the climate was of no help. Even if those large animals did adapt to the new climate, if there was already a decline in number for their population, it would be hard to recover from their loss due to their longer gestation periods compared to smaller animals (Dayton 1819). The increase in global temperatures demanded a great amount of adaptation from these beasts which caused extinctions if the adaptation wasn't done quick
enough.

The rise of man kind’s ancestors is associated with the decline of the megafauna. Humans migrated further out to other parts of the world, from Africa to Europe and Asia and dispersed into the Americas and Australia. For many of these species, it was their first ever encounter with humans. Since these animals were not accustomed to human presence, it makes them easier preys. If humans and animals cohabited in the same time period, it is strongly possible that humans did, in fact, affect the survival or the extinction of those species (Ho 25). The simple presence of humans was something new to most species on Earth. Since they weren't used to it, they wouldn't know how to react if, for example, they’re being hunted. Humans change their environment accordingly to suit their needs. Thus by alternating the environment on their arrival, it makes hunting and travelling easier for the hunters. In return, it has affected habitats of those species and reduce the limited food resources that the large animals need (Dayton 1819). Whilst the vegetation was slowly regenerating, they would begin to starve to death, and eventually all die. And like today’s man, the ancestors of man needed shelter to protect themselves. Humans could have prevented animals from reaching their refuge shelters during warmer climates (Voss). While the large species would migrate during warmer periods, they wouldn't be able to reach their destinations to make it through the season. Although humans may not be the direct cause of the megafaunal extinction, they do play a role in it. It could be something like taking up the shelters of certain animals, causing local extinctions or making it harder to find alternative living spaces.

Given the warm interglacial periods, the climate most likely must have modified the environment. The sudden rise of temperature puts stress on both fauna and flora of the Quaternary period. A major loss of vegetation occurred whilst the animals merely survived (Staff Writers). Altered habitats make the animals spread out to find what is best suited for them (Ho 25). In order to adapt to the new environment, they had to experience greater risks of extinction when travelling greater distances. During the Last Glacial Maximum, when the climate of the planet was at it’s lowest and driest, a great variety of plants was reduced. Experts were able to date and analyse permafrost DNA samples of sediments and fossils of the large animals. Data shows that vegetation of at the peak of late Pleistocene lost considerable diversity (Staff Writers). After the reduction of diversity, a new diversity of vegetation appears, but the past ecosystem that the megafauna was accustomed to did not re-establish itself to the same extent. Although it did become warmer, the protein-rich forbs that animals fed on did not fully recover as abundantly as they were in the past (Staff Writers). The lack of protein-rich food for species such as the mammoth and woolly rhinoceros was fatal and considered to be one of the key points of the ice age megafauna extinction. Thus, climate changes occurred during the interglacial period and the last ice age replaced a considerable variety of protein-rich plants with new ones that did not satisfy the diets of late Pleistocene animals.

The survival of species of the Quaternary period highly depended on their ability to adapt to climate change, but once the population begin to decline, it’s hard to recover from the loss.
The spread of humans especially impacted the wildlife in the areas such as the Americas and Australia, where animals had the least time co-evolving alongside with humans. The smoking gun of the Quaternary extinction lies within the vegetation. The Last Glacial Maximum cut out a lot of the protein-rich forbs and it wasn’t as abundant
anymore.