By: Mohamed Ahmed

According to Amnh.org, to qualify to be a mass extinction, at least half of all species die out in a relatively short period of time. In this article we will be looking at the top 5 largest mass extinctions, the: Ordovician, Devonian, Permian, Triassic-Jurassic, and Cretaceous extinctions. 

The Ordovician-Silurian extinction was the second worst mass extinction, according to Study.com. This extinction wasn’t even that far behind the worst mass extinction, which we will later look at. Jawless fish were the most advanced life forms during this time, and the majority of all beings lived in the ocean. The global temperature cooled and sea levels fell. Most species were adapted to shallow, warm water, and that was the reason why 85 percent of all organisms on earth became extinct. It was one of many extinctions that happened in a short period of time. 

The Devonian extinction happened 375-360 million years ago. According to Britannica.com, the cause of the Devonian extinction was never actually solved definitively. There are many theories about this, varying from global warming, to meteors, or even a lack of oxygen. No matter the cause, the marine animals where the ones that made up the majority of the casualties. 

The Permian extinction happened 252 million years ago. This was the worst mass extinction in the history of the world and is known as “The Great Dying”. Over ninety-six percent of all marine life, and 70 percent of land species. No direct cause was found, but according to an article on MIT.edu, it is speculated that a volcano in Russia was the main cause of the extinction. 

According to ‘History of Life’, the Triassic-Jurassic extinction has a lot of debate about the specific percent of the death. The speculated causes are: large impacts, prolonged volcanic activity, climate change, volcanic gases rising, and rain becoming toxic other theories.

Only 66 million years ago, the most well known extinction happened. Why was it the most well known? Dinosaurs! They went extinct with some plant and marine life.  Around seventy-five percent of the population of earth was wiped out. The main cause is speculated to be an asteroid and a virus. The mixing of two is what made mammals the new dominators of the earth. 

For more information, please visit: 

• https://www.amnh.org/exhibitions/dinosaurs-ancient-fossils/extinction/mass-extinction/
• https://www.amnh.org/exhibitions/dinosaurs-ancient-fossils/extinction/mass-extinction
• https://study.com/academy/lesson/ordovician-silurian-mass-extinction-causes-evidence-species.html
• https://news.mit.edu/2015/siberian-traps-end-permian-extinction-0916

By: Olivia Miller

According to Medicinenet.com, ADD is a mental disorder/condition that is common among children and adolescents. ADD/ADHD causes the person, who is diagnosed, to have difficulty paying attention. It can also affect how much the person is able to sit still (which could get difficult over a long period of time).

ADD is also known for taking a toll on young girls and boys learning ability in school. Getting homework/tests done can be twice as difficult for a kid with ADD. Also, these kids may not be able to sit still and quietly for a long period of time like most students do in school, which causes them to be seen as a kid who acts out, or is disruptive, which compromises their whole experience in school.

ADD also has many other effects that people don’t usually associate with ADD. These effects surprisingly can be very different between boys and girls who have been diagnosed.

Starting off, according to the Center for Disease Control and Prevention, boys are three times as likely to be diagnosed with ADD than girls. Boys and girls can share some symptoms but other times symptoms can be different depending on gender. According to Healthline.com, boys seem to show external symptoms, which is usually the hyperactive side to ADD. This could mean running around, speaking out of turn, not being able to sit still, and any other external effects of ADD. Girls are the opposite, their symptoms are usually internal, this could mean having low self esteem, inattentiveness, and impulsivity.

In both boys and girls, ADD/ADHD can lead to other mental disorders such as depression, anxiety, and various eating disorders. If not treated, ADD can be very difficult for children in school, and even adults when it comes to daily commitments. There are different medications that can be prescribed if someone is diagnosed with ADD. There are also different therapies as well that people try.

Although common, ADD is a disorder that can be hard to live with if you’re a kid. It doesn’t matter if you’re a boy or a girl.

By: Leslie Lopez Ibanez

There are many animals going extinct. Some of them are: tigers, elephants, black rhinos, sloths, and red pandas.

There were, in total, 8 subspecies of tigers. 3 of them are now extinct. Tigers are endangered for a couple of reasons. Their habitat is being destroyed by human activities, by building road networks and clearing forests for agriculture and timber, and by the growth of human population. According to WWF, they have lost 95% of their historical range. Also, in some cultures, they use tiger parts to cure diseases like convulsions, rheumatism, dysentery, and typhoid fever.

There are around 40,000 elephants left in the world. The species is classified as endangered. They are going extinct because they are being killed to use their ivory tusks, which later are traded illegally in the international market. They also go through habitat destruction by building roads, mines, dams, and industrial complexes.

Black rhinos are critically endangered. They can be found in South Africa, Namibia, Zimbabwe, and Kenya. They are going extinct because they are a part of an illegal wildlife trade. They kill them and take their horn. According to WWF, some Asian consumers, in Vietnam and China, use them for folk remedies. There are about 5,500 black rhinos left in the world.

There are 6 different species of sloths but only 2 of them are going extinct. The maned sloth is one of them. They are going extinct because of habitat loss. Pygmy sloths are actually one of the most critically endangered mammals in the world. There are less than 100 of them hanging in their island home. They can only be found on a tiny island off the east coast of mainland Panama.

Red pandas are another animal that is endangered. They are only found in the mountainous areas in the forests of Asia. The main threat to their extinction is habitat loss by human growth in the area. Climate change has also affected them by the temperature rising and them having to adapt to that. Climate change has led them to fragmentation, and a loss of land that they can no longer live in anymore. Red pandas eat bamboo but only a specific part of it. But since their habitat is shrinking, it is becoming more difficult for them to find food. Red pandas are also hunted. People like them for their fur and meat. According to the WWF, they have found red panda fur hats for sale in Bhutan.

By: Irene Cohen and Ellie Mulvaney

Since the beginning of the earth, from the first single celled organisms to modern species, evolution has developed life as we know it. We see variance in this evolution all around us in the diverse animals that span our environment (for example, the genus canis includes the species: wolfs, dogs, jackals, and coyotes).

With many examples in nature such as this, a frequent question refers to whether or not modern day humans (genus homo) have separate species. Race, though sometimes believed to be, is not a difference in species. Humans everywhere are Homo sapiens, no matter the slight phenotypical differences between them.

To understand this, we have to go back in time to the earliest humans. According to Britannica, ape-like species, around 16-5.3 million years ago (also known as the Middle and Late Miocene Epoch), lead to the first humans. Based on genetic information, scientists are confident that, more specifically, they existed in the later years (11.6-5.3 million years ago).

These primates from Eurasia and Africa are assumed to have become the first Hominins, or the beginnings of human lineage, in the Pliocene Epoch. Among the species that were developed in that era, Graecopithecus, prevailed as ancestral to the following: Australopithecus, Parenthropus, and Homo of the human lineage, while some additionally believe that great apes such as Pan (chimpanzees and bonobos) and Gorilla also came from the species Graecopithecus.

The catalyst for the aforementioned Hominins, was the climatic changes in the Miocene Epoch, as told by BBC.. Forests were replaced by open plains and prairies, which benefited terrestrial life. This meant walking creatures had advantages over terrestrial, or tree-living, creatures, which was a defining factor in the development of bipedalism (the trait of walking on two feet).

Bipedalism is a defining feature of humankind, and though it is not exclusive to humans, we are the only mammalian bipeds to solely use it, while others combine jumping and waddling. Humans advanced further and further into this bipedalism to survive, being able to run away from predators and quickly find food.

As reported by Nature.com, the species Homo sapien, as we now know it, evolved in Africa 315,000 years ago. At the time, Homo sapiens lived alongside Neanderthals and Denisovans (both of which were branches of humanity that are now extinct), and also occasionally interbred, resulting in Neanderthal DNA in most humans excluding those originating from Africa.

The fossils of this species have been found in Europe and West Asia, while the less common Denisovan fossils have been found in Eastern Asia, just 12 years ago.

Neanderthals were defined by their large noses and prominent brow ridges. In stature, they were short and stocky, and had a long, low skull. Overall, they were more compressed and ape-like than humans today, weighing in at anywhere between 64-82kg. They had large front teeth for tough food, and a weak chin, alongside a wide nose, which is theorized to have helped internally warm and moisten the air in their colder environment.

While there is not enough fossil evidence to recreate the appearance of Denisovans, the genetics that we have received lead many scientists to agree on some key features. They may have had a wider jaw and skull, and are theorized to have large molar teeth. This was concluded from a Denisovan jaw bone that was found sporting a high dental arch that suggested the adaptation.

These species went extinct through a pure example of survival of the fittest. Natural selection ran its course as population increased, and, consequently, so did competition.

As mentioned above, climate conditions changed and food became more scarce, leading to a higher death rate. By chance, the random variation that made homosapiens unique, were well suited to these changes and they survived over their counterparts.

Overall, humans did once have multiple species, but one has reigned successfully to become the sole remaining Homo sapiens.

For more information, please visit:

• https://www.nature.com/articles/d41586-019-02820-0
• http://www.bbc.com/earth/story/20150929-why-are-we-the-only-human-species-still-alive