If secondary consumers are removed from the ecosystem, an ecological imbalance may be created. Secondary consumers are generally feed on other animals (primary consumers) Thus, on removing secondary consumers from food chain, there will be increase in population of primary consumers as a result all the grass and other vegetation will be eaten by the primary consumers. This will leads to desertification and eventually all the top consumers will also eliminated from the ecosystem.
They don't have to undergo mitosis -- condensation of chromosomes, segregation, spindle fibre formation, attachment et al aren't involved in bacterial cell division.
