lpetrich

That's sometimes given as an argument for evolution, but the truth is more complicated than that, and it's worth mentioning that one can sometimes discern family trees in the fossil record.

There are many cases with no clear progression towards greater complexity, like foraminifera, radiolarians, and other such protists.

But there are several cases of clearly increasing complexity.

Fossils of eukaryotic algae go back to the Precambrian, while somewhat mosslike land plants start showing up in the early to mid Paleozoic. Ferns appear by the mid to late Paleozoic, and seed plants by the late Paleozoic. Flowering plants start proliferating in the late Jurassic, though there are some possible flowering-plant fossils from before then.

Fossil cephalopods start out with straight shells, and later developed curled ones -- and ones with elaborately curved shell septa.

The earliest arthropods have relatively little limb specialization compared to many present-day ones.

Among some mammalian lineages, there is evidence of increase in brain size over time.

And there are other examples, but my patience has run out.

As to family trees, the horse one is the best-known; any other good ones?