Question

what happens to the number of individuals and number of shared characters as we go up the taxonomical hierarchy

Answer 1

Taxonomic hierarchy is the arrangement of taxonomic categories one above the another, to indicate the various levels of relationship. Kingdom is at the top of this hierarchy, and species is at the bottom when arranged in increasing order of specificity. It means that kingdoms are formed on the basis of most general characters, while species are based on most specific characters.
Individuals in the species category have the highest number of shared characters, while those included in a kingdom category have the least number of shared characters. Thus, the number of shared characters decreases from species to kingdom.
Species is the smallest taxon, thus the number of individuals is lowest in it. Kingdom is the highest taxon which includes all other taxa, thus the number of individuals is highest in it. Thus, number of individuals increases from species to kingdom.