These dominant genes, as listed above, generally provide Bam with an advantage on Berk. Being fast and agile allows Bam to manoeuvre through dense foliage, a tough skull helps protect it from larger predators (e.g. Spiked Dragon, Bibacs), and UV emitting saliva allows better communication between Bam and Akyle when hunting symbiotically. However, growing to 3m is a disadvantage in these environments, since the organism requires more energy to grow. It would be observed, therefore, that the population of Bam would develop the recessive gene (adults grow to 1.5m) which allows it to be more successful in terms of hunting, hiding, agility and efficient energy use.
Trophic Level: Although Bam would most likely remain as a tertiary / third-order consumer, it may still be vulnerable to larger predatory organisms such as the Spiked Dragon (see food web). Its diet would remain carnivorous, preying on smaller organisms living in trees and on the forest ground.
Relationships: Biodiversity is extremely high on the island of Berk. This leads to extensive competition for food sources between secondary and tertiary consumers, which may result in decreasing numbers of such predators. However, Berk provides as a suitable environment for symbiotic behaviour between Bam and Akyle - this would definitely contribute towards their success and help sustain both populations over future generations.
Speciation: (over generations, Bam would diverge into one specific species, adapted for manoeuvring in a dense forest habitat)