How do scientists know there was a particular plant/animal species that existed by now it’s extinct?


I just want to understand how scientists conclude that animal/ plant species existed but has but became extinct a long time ago when we didn’t even exist at that time?

In: Biology

I’m not a scientist, but I feel like they have journals, illustrations, fossils, and bodies to confirm this. Of course, not everyone is 100% sure.

We do find evidence of plants and animals in the ground. Usually as some sort of fosil. We are then able to date this evidence. There are various ways of dating things like this and we usually use more then one technique in order to verify the age of something. When we collect these evidence from multiple sites around the world we can tell when a species existed. And you are technically correct that we can not truely know when it became extinct. The only evidence we have of a species going extinct is often the lack of evidence. But given how many archeological sites we have with fosils from all different ages we would expect at least some evidence of the species if it had been around. So we theorize that the reason we do not find any evidence is because they have gone extinct. Sometimes we can also provide an explanation as to why they would go extinct although hard evidence for this can be impossible to find.

Fossils were the first widely recognised evidence for extinction; it’s fairly obvious that nothing like a t-rex is alive today. Once the theory of evolution became established, people began to hypothesise now extinct missing links between similar looking species. Nowadays there are a host of other ways of inferring the existence of now extinct species; unoccupied ecological niches, survival adaptations for absent predators, seed dispersal mechanisms that rely on missing hosts, etc.

Because we have fossils preserving those animals remains.

Someone didn’t just come up with a Velociraptor one day, they found bones from one buried in the ground.