Darwin's theory addresses the evolution of possible bodies into which mental continuums can take rebirth over several periods in the history of the earth. It does not describe the evolution of bodies that an individual mental continuum will take in subsequent lives. There is a great difference between the actual physical life forms on this planet and the continuity of the mental continuums that are reborn in them.
Some explanations about evolution in the Buddhist texts may seem a bit strange to us. They speak about beings that were in a better situation than us in the past and then deteriorated. Whether or not this is true needs investigation. Not everything Buddha and his followers taught can be corroborated by science, and those that cannot, His Holiness the Dalai Lama is willing to leave aside. The masters may have given seemingly odd explanations for specific reasons and did not intend for them to be taken literally. They may indicate various social or psychological truths.
Nevertheless, within the context of evolution itself, there once were dinosaurs and now they are extinct. For karmic forces and potentials to ripen, there need to be appropriate circumstances available; and the circumstances are no longer present for beings to take rebirth as a dinosaur on this planet now. There are different physical bases that are available for mental continuums to take as a body now. It is not contradictory with Buddhist explanations for the physical bases available for rebirth to change over time.
During a discussion that His Holiness Dalai Lama had with scientists, he was asked whether computers could become sentient beings: Could computers one day have minds? He answered in an interesting way, saying that if a computer or a robot reaches the point at which it was sophisticated enough to serve as the basis for a mental continuum, there is no reason why a mental continuum could not connect with a purely inorganic machine as the physical basis for one of its lives. This is even more far-out than Darwin!
This is not saying that a computer is a mind. It is not saying that we can create a mind artificially in a computer. However, if a computer is sophisticated enough, a mental continuum could connect with it and take it as its physical basis.
Such far-reaching thought makes modern-age people excited and interested in Buddhism. Buddhists are brave and willing to enter into these discussions with scientists and to face the various popular issues in the modern world. Not only does Buddhism have the ancient wisdom from unbroken lineages going back to Buddha, Buddhism is alive and vibrant in this way.