Answer:
This is for all 3 questions on edge (100%)
Step-by-step explanation:
1.) They evolved separately as they moved north and became separate species. The greenish warblers were not geographically isolated, but they migrated around the Tibetan Plateau, evolving separately until they could no longer interbreed when both species (East and West) had contact in Siberia. Greenish warblers were thought to have evolved from a single ancestral population that gradually diverged into two new species as it expanded northwards around the Tibetan plateau.
2.) Their plumage patterns, genetics, and history. West Siberian greenish warblers (P. t. viridanus) and east Siberian greenish warblers (P. t. plumbeitarsus) differ subtly in their plumage patterns, most notably in their wing bars, which are used in communication. While viridanus has a single-wing bar, plumbeitarsus has two. Around the southern side of the ring, plumage patterns change gradually. Additionally, the two northern forms, viridanus and plumbeitarsus are genetically distinct, but there is a gradient in genetic characteristics through the southern ring of populations. The greenish warblers were once confined to the southern portion of their range and then expanded northward along two pathways, evolving differences as they moved north. When the two expanding fronts met in central Siberia, they were different enough that they did not interbreed.
3.) Invasive species can bring harm to wildlife. A new species means it will not have predators to control the population within the ecosystem. Feral pigs will eat anything, including native birds competing with wildlife for food, spreading disease to livestock and humans, and spreading e-coli. Water hyacinth forms dense mats in the wild, reducing sunlight for submerged plants and crowding out native aquatic plants.