Clues are found below puzzle.
| ACROSS | DOWN |
| 1 A geological theory that helps explain the distribution of species and groups of species like marsupials across modern continents (2 words) | 2 Whale fossils in the desert represent sweeping changes in this |
| 4 These represent divergence of one species into two or more descendant species | 3 These basic units of the genetic code demonstrate genetic homology |
| 5 Darwin described evolution as descent with this | 6 Functionless but homologous to useful structures in related species |
| 7 The doctrine that past events not observed today caused geological formations, e.g. Noah's flood | 10 A molecular phenomenon similar to the appendix or 'lost digits' |
| 8 These represent ancestral populations through time | 12 This law states that fossil species in a given area are followed by similar extant species |
| 9 These represent extinct species on a cladogram | 14 Genealogy of a group or species |
| 11 Proteins of different species show genetic homology through this | 15 A trace of an organism that lived in the past |
| 13 A geographic ______ is a geologic history of the earth based on composite relative dating of strata | 16 These species represent a halfway step between a fossil species and a living one |
| 16 A named group of organisms | 18 A phylogenetic tree |
| 17 Homologies consisting of similar composition and arrangement | 19 A tree that does not denote the order in which species diverged, only the divergences |
| 20 The doctrine that past geological processes operated like modern ones | |
| 21 The study of like forms; similarity due to shared developmental pathways | |
| 22 Dating using the decay of unstable isotopes in samples |