Now where did you get that shit chart? According to the Smithsonian;
- s
- Extinction Over Time
For years, paleontologists did not know what to make of this fossil from the ancient shark Helicoprion that lived 290 million years ago. It was proposed to be a weapon at the tip of the nose, an unusual dorsal fin, or a defensive tail adornment. Research revealed that it is actually a spiral of teeth (tooth whorl) that was used like a buzzsaw to grab and chop food. Smithsonian photo 2007-15308-helicoprion-shark by Chip Clark.
Extinction of Plants and Animals
Extinction is the death of all members of a species of plants, animals, or other organisms. One of the most dramatic examples of a modern extinction is the passenger pigeon. Until the early 1800s, billions of passenger pigeons darkened the skies of the United States in spectacular migratory flocks. Easy to trap or shoot, passenger pigeons became a popular, cheap food. Commercial hunters killed them in vast numbers, eventually decimating the population. The last
passenger pigeon, named Martha, died in the Cincinnati Zoological Garden in 1914, and was donated to the Smithsonian Institution.
Extinct Species List
The passenger pigeon is one of many hundreds of extinctions that have been caused by human activities in the past few centuries, such as:
Extinction Rates
Recent studies estimate about eight million species on Earth, of which at least 15,000 are threatened with extinction. It’s hard to pinpoint the exact extinction rate because many endangered species have not been identified or studied yet. A number of scientists grapple with improving methods for estimating extinction rates.
Regardless, scientists agree that today’s extinction rate is hundreds, or even thousands, of times higher than the natural baseline rate. Judging from the fossil record, the baseline extinction rate is about one species per every one million species per year. Scientists are racing to catalogue the
biodiversity on Earth, working against the clock as extinctions continue to occur.
Learn about the 5 mass extinctions, and see a list of some extinct species. Explore how we can prevent extinctions, or possibly reverse them.
www.naturalhistory.si.edu