Table of Contents
With the establishment of sturdy foundations by vegetation on land, animals followed suit by crawling out of water. Insects were among the pioneering organisms that invaded land around 400 million years ago. Top 5 animals 400 million years ago began to reach land
488 Million years ago
The initial mass extinction event of the seven events throughout geological history occurred during the Cambrian-Ordovician transition.
The extinction event in question resulted in the eradication of 85% of marine species. The possible causes of this event include climate change, underwater environmental destruction, or a decline in oxygen levels. It is also hypothesized that a gamma ray burst may have been responsible, although given the time span of 400 million years, no definitive conclusion can be drawn.
the Cambrian-Ordovician transition
475 Million years ago
The first rudimentary plants that emerged on land are believed to have evolved from green algae that existed along the edges of lakes. These plants likely developed from a symbiotic relationship with fungi. The phenomenon of mycorrhizal symbiosis, in which fungi live in association with the roots of plants, is exemplified by the Earth’s biosphere. However, some scientists contend that molecular clock evidence suggests terrestrial plants and fungi appeared earlier than previously thought. They propose that fungi existed in the Tonian period of the Proterozoic era approximately 1,000 million years ago and that land plants emerged during the Cryogenian period of the same era approximately 700 million years ago.
450 Million years ago
Animals with jointed legs and an exoskeleton, which helps provide support and prevent water loss, were the first species of animals to migrate onto land. Among the first were the Myriapoda, which include centipedes and millipedes, followed by spiders and scorpions.
In the following ten million years, two significant Ordovician-Silurian extinction events occurred, which are considered as the second major mass extinction events. These events happened concurrently, and shortly after, Placodermi, the first jawed fishes, evolved. Their jaws evolved from the arched gills, and their heads and thoraxes were covered with overlapping armor plates, while the remaining part of their bodies were either finned or naked.
Placodermi
410 Million years ago
The first appearance of the Acanthostega fish with limb-like fins, previously believed to be extinct, was documented in 1938. This particular species is commonly regarded as a living fossil.
Acanthostega fish
Animals 400 Million years ago
During the evolutionary process, the silverfish insect developed without wings and a segmented tail, causing it to no longer be classified as an insect. This marked the appearance of the first sharks in the fossil record.
Animals 400 Million years ago
