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

Question

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

Answer 1

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.