Most critics of evolution contend that there is no direct evidence that today's animals were descended from earlier life forms. There is no link to previous earlier animals.
But that is not true.
As early as 1861, with the discovery of the Archaeopteryx, part bird and part lizard, there is a connection from one early species to another. Here are some more recent findings.
Other new specimens of birds have been found in Spain and China, which are some 30 or 40 million years younger than Archaeopteryx, and they are more bird-like, exactly as an evolutionist predicts. Their characteristics include short bony tails, and their hand claws are reduced, which indicates that they are becoming more bird-like. The Chinese localities have not only produced amazing new birds, but also new dinosaur specimens with feathers!
These new specimens really complete the argument. Archaeopteryx is no longer alone and unique. No, below it, on the evolutionary tree, are countless of theropod dinosaurs that become ever more birdlike through time, and above it stretch numerous bird species that bridge every step of the way from Archaeopteryx to fully-fledged birds. Also, a long series of fossils through the Jurassic and Cretaceous periods, which is a span of 140 million years, document the evolutionary transition from reptile to bird.