According to the principle of parsimony, the evolution of the 4-chambered heart should placed birds and mammals in the same clade. Why does the most accepted evolutionary tree show them as separate branches from the reptilian line?
Explain the reason behind the statement " Evolution is not goal or oriented?
The first appearance of free oxygen in the atmosphere triggered a massive wave of extinctions among prokaryotes of the time. Why?

The ecological tree is formed after the different beings are well arranged on the basis of there basic characteristics and taxonomic level inside the region or environment giving rise to a more unique branch of the enormous structure of the taxonomic order.As, the different organisms have there own unique structural, mental and morphological characteristics on basis of which the different branches and kinds of the species are either placed inside the same category or either they are placed inside a more different groups of organisms.However, the different organisms when generalized and evaluated inside the different taxonomic order can be termed to be less of a issues these days because we know more of these animals then we did in the past.  Evolution as we say occurs more spontaneously then ever, as the different beings experience the requirement for the resources and the shelter to live in a more proper way inside a given region.While, we can never term the idea of evolution to be more objectified by any company or individuals, as it can not occur on our will as the process takes generations to happen and more spontaneous then ever. The amount of Oxygen inside the atmosphere is more crucial for the different beings and play the most pivotal role in the development of the cell structure, as the prokaryotic cellular structures did not end or faced extinction but it was then when after the symbiotic association between the different organelles resulted in the formation of much bigger and more complicated form of cellular structures, which are called as the eukaryotes.