One theory of speciation is described below.
When two populations become so genetically different that they can no longer successfully interbreed, speciation occurs. In order
for new species to emerge, selective pressures must favor new traits in a given environment. This can happen when
⚫ an organism is born with new, more favorable traits as a result of a mutation, or
• a population moves to a new environment with new selective pressures.
The emergence of a new species is a gradual process, occurring over many generations as individuals with more favorable traits
survive and reproduce more often than individuals with less favorable traits. Eventually, the population becomes genetically
isolated from other populations of the same species, and speciation occurs.
A group of researchers is studying two different species of beetle. One species is native to northeast Asia, and the other is native to
Central America. They have studied the beetles over several decades and many generations. Genetic tests reveal that the two
species' diverged from one another about 4 million years ago and modern populations have major genetic differences.
The researchers have made many observations regarding these two species. Complete the sentence below so that it describes an
observation that would challenge the theory of speciation described above.
Over many generations, the two species of beetle are observed to