Final answer:
Kingsley and his team crossed marine and freshwater sticklebacks to test the involvement of the Pitx1 gene in the formation of pelvic spines, contributing to understanding the genetic basis of evolutionary adaptations.The correct option is (b).
Step-by-step explanation:
Kingsley and his team crossed marine and freshwater sticklebacks to test whether Pitx1 was involved in the formation of pelvic spines. This was part of their investigation into the genetic mechanisms underlying the evolutionary changes in the stickleback fish. Due to the divergence of these fish populations into different lakes and development of unique feeding niches, known as micro niches, stickleback populations experienced varying selection pressures which led to different physical characteristics, such as the presence or absence of pelvic spines.
By interbreeding the two types of sticklebacks, the researchers could closely observe the phenotypic outcomes in the hybrid offspring and identify if the variant of the Pitx1 gene from one parent contributed to the presence or absence of the spines. This genetic approach is significant for understanding the gene’s role in development and evolutionary adaptation. Determining the exact involvement of Pitx1 helps to illustrate a broader principle of evolution where specific genes respond to environmental changes, leading to phenotypic diversity within a species.
Their study aligns with the theory of evolution and allows for the exploration of how genetic expression can have far-reaching impacts on not just individual species, but on the ecosystems they inhabit. The evolution of the stickleback population in each lake type likely had substantial effects on the survival of other species within those ecosystems, impacting biodiversity and ecological balance.