Facts for kids: Why do animals become extinct?

Why do animals become extinct

The Western Black Rhinoceros was hunted to extinction for its horns.

Since the dawn of life on Earth, at least 99.9 percent of all species have become extinct. The causes vary but the result is the same. Looking back into history, there have been five major events that have caused mass extinction. These were caused by meteorites, massive volcanic eruptions, a possible comet strike on the planet, and perhaps even a gamma ray burst.

If this sounds outlandish, consider the fact that scientists believe the dinosaurs were wiped out 65 million years ago by a meteorite that hit Mexico’s Yucatan Peninsula.

But species generally become extinct as a result of less dramatic events. Researchers have found that species disappeared due to natural climate change, competition from other species, invasive species (such as cats eating native wildlife), and disease.

More worrying, however, are the causes of extinction that have become predominant in the last couple of hundred years. With a growing global population and consequent demand for food, fuel and resources, humans have played an ever increasing role in extinction. Loss of habitat and human predation have been disastrous for some species. Logging, industrialised fishing and farming, cities expanding into the countryside, poaching, pollution, and greedy hunting practices have all contributed to species either being wiped out or pushed to the brink of extinction.

Short answer: While nature has played a role in making species extinct, the greatest threat posed to animals and the environment in the twenty first century is humankind. A rapidly growing global population, combined with an appetite for the earth’s resources, is causing irreversible damage to nature.

Facts for kids: What was the first animal?

fossil otavia

Humans will never last as long as this critter.

No one knows what the first animal was but scientists have been able to travel back in time to a time when the Earth was a snowball of ice.

Fossil records reveal the oldest known species as that of a small, tube-like, multi-cellular, primitive sponge known as Otavia antiqua. The oldest known specimen lived 760 million years ago in Namibia, filtering mud and feeding on algae and bacteria. With a size somewhere comparable to a grain of sand, it isn’t much to look at.

Still, it was one tough species. It survived at least two epic global freezes, and hung around an estimated 200 million years before disappearing during the Cambrian Explosion.

Short answer: It’s likely the first animal was a sponge of some sort several hundred million years ago. And, yes, you ultimately evolved from it.

Facts for kids: Why do cats purr?

Why do cats purr?

Do I own Dexter or does he own me?

Most people believe cats purr because they are happy, but there is a lot more to it than that. Cats sometimes purr when they are sick or stressed, or want to signal to other cats they are friendly. There is also the theory that purring is how a kitten communicates with its mother while the kitten is feeding. Ever seen a kitten feed and meow at the same time?

Research at the University of Sussex in England suggests cats adapt their purrs to trigger a nurturing response in people as a means of getting what they want, usually food and attention. This is interesting, given that humans and cats are believed to have been hanging out together for around 10,000 years.

The sound of purring is created when the brain sends signals to the laryngeal muscles, which then twitch somewhere between 25 to 150 per second. This twitch results in the vocal cords separating when the cat inhales and exhales, and thus the sound of the purr is produced.

Short answer: Generally, a purring cat is a happy cat but the behaviour may mean something more, depending on the situation the cat finds itself in. Interestingly, studies have suggested a purring cat may reduce its owners stress levels and blood pressure.