1. Answer;
They evolved separately as they moved north and became two separate species.
Explanation;
The greenish warblers weren't geographically isolated, but they migrated around the Tibetan Plateau, evolving separately until they were no longer able to interbreed when both species (East and West) contacted 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. Answer;
- Their plumage patterns.
- Genetics and history
Explanation;
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 highly distinct genetically, 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 do not interbreed.
Answer:
Hey. Here's the answer.
The Act was one of the most controversial elements of the 1850 compromise and heightened Northern fears of a "slave power conspiracy." It required that all escaped slaves, upon capture, be returned to their masters and that officials and citizens of free states had to cooperate.
hough the War of 1812 was dubbed “Mr. Madison’s War,” his role in the prosecution of the war was relatively ineffectual. Elected in 1808, President James Madison was intimately familiar with the ongoing diplomatic and trade conflicts with Britain. As Secretary of State under President Jefferson, he was the principal architect of the “restrictive system” of trade embargos designed to force Britain to relax its control of Atlantic trade. Madison’s support of this failed system lasted well into the war itself.
Madison’s attempts to resolve disagreements with Britain peacefully was viewed by some in his own Republican party as a sign of weakness. A group of pro-war Republicans, led by Speaker of the House Henry Clay, argued that military force was the only option left to combat British imperiousness. These “War Hawks” were not a majority of the party, but over time, their influence acted on more skeptical party members.
President Madison eventually did bring a declaration of war to Congress, but his leadership in planning for war was mostly absent. Republican ideology was intensely skeptical of the concept of a national standing army, preferring to rely on state militias, and the Madison administration, following in the footsteps of Jefferson, did much to starve national military forces of men and material support. His influence on Congress was minimal, and in retrospect, it is hard to understand how he, or the War Hawks for that matter, felt that the United States had the necessary military resources to prosecute a war on multiple fronts.
