Final answer:
Vertebrates adaptable to dry conditions would likely dominate an island with little water. Lizards without predators would not need defensive adaptations, while birds with genetic diversity, like Genus B, are more likely to survive environmental changes such as a volcanic eruption.
Step-by-step explanation:
If you were to introduce a group of vertebrates to a newly formed island with little surface water, the species that are most adaptable to dry conditions would likely become dominant. When considering two populations of lizards separated by a tsunami with only one group exposed to predators, we can predict that the population without predators might not develop strong defensive adaptations like camouflaged coloration, sharp spines, or toxins. These traits would likely be unnecessary in the absence of predation pressure. In contrast, the lizards on the island with predators would potentially develop or strengthen such characteristics as a means of survival.
Similarly, between two genera of birds on an island post-volcanic eruption, Genus B with a wider variety of genetic traits would stand a higher chance of survival. A diverse genetic makeup provides a better chance for at least some species to adapt to new conditions, demonstrating the importance of genetic diversity in the face of environmental changes. The concept of island dwarfism may also come into play, where small animal species on islands may evolve larger bodies in the absence of predators, or larger species may become smaller due to limited resources.