They are soon replaced by new species more adapted to the new conditions. Mass extinctions happen because of climate change, asteroid impacts, massive volcanic eruptions or a combination of these causes. One famous mass extinction event is the one that lead to the extinction of dinosaurs, 65 million years ago.

There are have been many periods of extinction, from when the first organism emerged on Earth until today. However, according to fossil records, only five eras have drastically reduced the population of living beings on earth to warrant the label of mass extinction.

The role of mass extinction in evolution. At the most basic level, mass extinctions reduce diversity by killing off specific lineages, and with them, any descendent species they might have given rise to. But mass extinction can also play a creative role in evolution, stimulating the growth of other branches.

Many species have gone extinct throughout history and all that marks their presence on Earth are fossils, such as this one of a dinogorgon. When a species disappears, biologists say that the species has become extinct. By making room for new species, extinction helps drive the evolution of life.

In psychology, extinction refers to the gradual weakening of a conditioned response that results in the behavior decreasing or disappearing. In other words, the conditioned behavior eventually stops. For example, imagine that you taught your dog to shake hands.

Several factors can cause a species to become extinct….Extinction

• new diseases.
• new predators.
• new, more successful competitors.
• changes to the environment over geological time, such as climate change.
• a single catastrophic event, such as a massive volcanic eruption or a collision between an asteroid and the Earth.

So far, humanity has only eradicated one human infectious disease comparable to COVID-19 in its broad geographic distribution: smallpox. Previous efforts to eradicate malaria, yellow fever and yaws failed, while current efforts to eradicate poliomyelitis and Guinea worm disease still hang in the balance.

The last recorded case of smallpox occurred in 1977 in Somalia. The disease was officially declared eradicated by the World Health Organization in 1980….

5 Diseases That May Be Cured Within Our Lifetime

• HIV/AIDS. The Human Immunodeficiency Virus, or HIV, was only discovered mere decades ago.
• Alzheimer’s Disease. Alzheimer’s affects nearly 5.7 million Americans who struggle with varying stages of dementia.
• Cancer.
• Cystic Fibrosis.
• Heart Disease.