The green lizards of Florida are one of the best examples of how fast Evolution can happen. When the brown lizards decided to occupy the same habitat the green lizards had no option but to go higher up in the trees. In just 15 years the toe pads grew and got stickier to be able to stay attached to the slimmer, smoother branches. They were studied over roughly 20 generations by the College of Natural Sciences at The University of Texas in Austin.
The cave dwelling Mexican tetra (Astyanax mexicanus) have no need for sight, so Evolution has taken away their eyes. Due to the energy, and brain power required for sight, this became extremely advantageous in other areas, and enhanced other senses required for survival.
The Tawny Owls in Finland were predominantly Grey but due to climate change, and lowering temperatures they have gradually been turning brown. A study over 30 years has seen watched this change, and scientists believe it’s due to the need to survive. They found that during the harsher winters the brown owls were less abundant but as the winters have warmed the grey owls have become less abundant. Climate-driven natural selection has meant that the DNA coding in the gene is now favouring brown over grey.
The Algerian mouse has been studied intensively of late due to its ability to survive the common mouse poison warfarin. Members of two species can’t generally mate, and if they do the offspring either die young or are sterile, but the Algerian mouse, and the common house mouse have been mating, and their offspring have been healthy, and gone on to reproduce, and become super-mice due to immunity to poison.
The peppered moth was light in colour before the industrial revolution, and dark examples were very rare. Due to air pollution the lighter coloured moths were easily visible to predators. Once again Evolution stepped in, and the moths over generations became dark to blend in with their surroundings, meaning that now the lighter coloured moth was hunted by predators more frequently.
And finally, flightless birds. Here’s an interesting article on the subject.
“There is a long history in evolutionary biology of converging traits — the idea that there’s independent evolution toward the same kind of phenotype,” Sackton said. “What we were interested in is how does that happen? These birds all have a similar body plan,” he continued. “They have reduced forelimbs, to different degrees, and they all have this loss of the ‘keel’ in their breastbone that anchors flight muscles. What that amounts to is a suite of convergent morphological changes that led to this similar body plan across all these species.” – Source