The evolution of animals depends only on the environmental conditions of the Earth. When we delve into Earth's history, we can see a number of animal species that thrived over different geological time periods. Here is a list of the 10 oldest animals on Earth that are still in existence.
10. Martialis huereka, 120 million years old
Martialis is the oldest species of ant discovered in the Amazon rainforest. The name "Martialis huereka" means 'Mars ant', as this species behaves differently from other ant species recorded on earth. It is estimated that this particular type of ant appeared on Earth 120 million years ago. Martialis Huereka is pale in color, 3 mm long, and has no eyes. They live underground. The discovery of Martialis Huereka helps the biologist understand more about other species of ants.
9. The shark with the gill shark, 150 million years old
The shark was discovered in Tokyo, Japan in 2007. They are considered a living fossil, appearing on Earth 150 million years ago. The gill shark is 1.5 m long, has 300 trident-shaped teeth divided into 25 rows. Their strange mouth looks much larger than other sharks. The hydrocarbon-rich liver and oily body help the shark to thrive in the deep waters of the ocean. They also make surprise attacks on their prey. Today, the number of sharks is very small. Excessive pollution and changes in ocean temperature are the main reasons for their decline in numbers.
8. Horseshoe shrimp, 200 million years old
Horseshoe shrimp evolved on Earth at the same time as Dinosaurs, about 200 million years ago. Horseshoe shrimp are extremely small, 2 to 4 mm long. However, they are able to withstand extreme weather conditions and geological changes. Even if the lakes where the horseshoe shrimp live are completely drained, their eggs can survive for years. Scientists discovered this extraordinary sea creature in 1955. They also studied the development of horseshoe shrimp by wetting eggs several years old.
7. Sturgeon, 200 million years old
Sturgeon is the oldest member of the bony fish family. They evolved 200 million years ago. Sturgeon lives in Eurasia and North America, and is the largest freshwater fish in North America. During the winter, they migrate to distant places. Sturgeon is up to 1.5 m long and weighs from 600 kg to 200 kg. Sadly, sturgeon is on the critically endangered species list. They lay large numbers of eggs per litter but humans harvest caviar very quickly and this is the main threat.
6. Coelacanath, 360 million years old
Coelacanath is one of the critically endangered fish that evolved about 360 million years ago. There are two types of Coelacanath, which mainly live on the coasts of Africa and Indonesia. They are 2m long and weigh up to 90 kg. Coelacanath lives at a depth of 700m and has a lifespan of 60 years. They move like trotting horses. The lobe fins are shaped like legs, helping them to perform such a unique movement. Electrical sense organs help Coelacanath easily detect prey. They also have the ability to open their mouths wider than usual to catch large prey.
5. Horseshoe crab, 445 million years old
Horseshoe crabs appeared more than 445 million years ago. They live in shallow seas around the world. Horseshoe crabs have a hard skeleton, a long tail, and spines. They have a total of nine eyes scattered throughout their body. Among them, two large eyes are used more and others are responsible for sensing light to control movements. They can also sense ultraviolet light.
4. Anh Vu snail, 500 million years old
The slug is a mollusk that originated 500 million years ago, long before Dinosaurs ruled the Earth. It is estimated that the Anh Vu snail is the only surviving member of the shellfish group. Snails are found in tropical waters in the Andaman, Fiji and the Great Barrier Reef. Anh Vu snail is also considered a living fossil, found only at a depth of more than 670m The body of Anh Vu snail has many shells. These shells make them look like octopus. Its mouth is surrounded by 100 tentacles and has a muscular hood over its shell. It will help nautilus fight against predators.
3. Jellyfish, 550 million years old
Jellyfish appear in every ocean. They are the oldest multi-organ animal in the world, dating from 550 million years ago. Jellyfish have no brain or nervous system. Jellyfish come in many different shapes and colors. 90 percent of their body is water Box jellyfish are the deadliest venom on Earth. Their tentacles have more than 5000 spiny cells.
2. Sponges, 580 million years old
A sponge is a special type of sea creature that looks like a tree. They appeared in the oceans 580 million years ago. There are 5000 different species of sponges in the world, living in diverse shallow waters. Sponges do not have any internal organs, nor do they have limbs or heads. They have the ability to restore the lost body part and a new sponge will grow from the old part. The body of the sponge contains many grooves, which provide shelter for many small aquatic animals.
1. Cyanobacteria, 2.8 billion years old
Cyanobacteria are the oldest known organisms in the world. They originated 2.8 billion years ago and were the first bacteria to produce oxygen through photosynthesis. Thus, they contribute to the conversion of the Earth's atmosphere into an oxidizing atmosphere. Cyanobacteria are also known as green focal bacteria. Single-celled cyanobacteria reproduce through microfiltration.
