According to the State University of New York, a fetal pig has a total of seven lung lobes. The right lung is larger and is divided into four lobes<span>: the apical, cardiac, diaphragmatic and intermediate. The left lung has </span>three lobes<span> because it does not have an intermediate lobe.</span>
Causes of speciation
<span>Geographic isolation
In the fruit fly example, some fruit fly larvae were washed up on an island, and speciation started because populations were prevented from interbreeding by geographic isolation. Scientists think that geographic isolation is a common way for the process of speciation to begin: rivers change course, mountains rise, continents drift, organisms migrate, and what was once a continuous population is divided into two or more smaller populations.
</span>Reduction of gene flow
<span>However, speciation might also happen in a population with no specific extrinsic barrier to gene flow. Imagine a situation in which a population extends over a broad geographic range, and mating throughout the population is not random. Individuals in the far west would have zero chance of mating with individuals in the far eastern end of the range. So we have reduced gene flow, but not total isolation. This may or may not be sufficient to cause speciation. Speciation would probably also require different selective pressures at opposite ends of the range, which would alter gene frequencies in groups at different ends of the range so much that they would not be able to mate if they were reunited.</span>
No water has been discovered on either planet yet.
Yes, classification system is still evolving together with our knowledge.
But, before changing the name (e.g. of a species) it is important to collect and gather a wealth of information in order to support that change. Classification system is still evolving. The reasons for the changes are DNA analyzes. It is the new way for discovering relation between organisms and put them in the right context (classification used to be based on morphological characteristics).
Change in classification can be shown in an example of fungi. In the 90s fungi classification included only phyla Chytridiomycota and Zygomycota. Now theyhave been classified mainly on the basis of characteristics of their sexual reproductive structures. So, there are 7 phyla now: Microsporidia, Chytridiomycota, Blastocladiomycota, Neocallimastigomycota, Glomeromycota, Ascomycota, and Basidiomycota
