Oh, talking about old things reminds me a situation of never been able to see my grandparents. I'm just a little bit curious of how do they look those days when I was a young and hardheaded boy. I can't recall their faces. Now, let's talk about animals knowing which of them are the oldest living, breathing until now. The granddaddy of all animal species is the horseshoe crab. A creature that resembles an armored tank, the horseshoe crab has been around for 445 million years or so, more than 200 million years before dinosaurs walked the Earth. Even more amazing, the horseshoe crab looks pretty much the same today as it did back then.
Not true crabs but close relatives to spiders, ticks, and mites, horseshoe crabs are called living fossils. If you were to compare an early fossil of the horseshoe crab to the one of its living members, you wouldn't find much difference. It still has the same hinged carapace or shell, the same tail, which it uses to steer itself, and the same compound eyes, each one is made up of thousands of lenses.
How has the horseshoe crab managed to exist for so many millions of years? Scientists believe it's thanks to the creature's amazing immune system. As soon as bacteria enters the wound of an injured crab, the blood in the surrounding area immediately clots into a jell. This keeps the bacteria from moving forward so the crab won't get sick. This mysterious jell-like substance is called LAL, for short.
Each year thousands of horseshoe crabs are bled to obtain LAL. The substance is then used in medical labs to test drugs that will injected into the human bloodstream. The LAL test can quickly and accurately detect if harmful bacteria is present. Horseshoe crabs are doing their bit to keep humans safe.
- The coelacanth (see-luh-kanth) is the runner-up in terms of the oldest living species. Fossils of this giant fish date back 410 million years.
- The chambered nautilus has lived for the last 400 million years. But today, the mollusk is in danger of dying out. Fisherman hunt the animal for its shell, which is used to make jewelry and decorations.
- Some 350 million years ago, a winged insects almost exactly like today's cockroach scurried around on Earth. These almost indestructible insects stand a good chance of being around millions of years inovations the future.
In the plant world, the ginkgo biloba holds the title of the oldest species. The tree has been around for 270 million years.