What led 17th century scientists to believe that at one time a super-continent, Pangaea, existed? the observation that the continents fit together like a jigsaw puzzle
the presence of mid-ocean ridges
the discovery of the composition of the asthenosphere
the location of seas at the boundaries of continents

phylogenetic tree is the tree of life or evolution tree. it shows the different branches of evolution. the sequence goes like tissues - coelom - backbone - endoskeleton - segmentation

emerging idea only occurs as a raw idea that could appear out of nowhere. meanwhile, to reach scientific consensus , that idea must be structured and tested over and over again through various experiments. the scientific consensus transforms the raw idea into idea that is more reliable through the process of scientific elimination.