We are not alone. Humans’ vast inner and outer spaces teem with a menagerie of microbes that stand poised to alter conceptions of what and who we are.True, this understanding is not new but grasping it in a meaningful and productive way will not be possible if the neo-Darwinist model continues to dominate biological thinking. One must not forget that it was neo-Darwinists who fought the hardest to block the progress of a line of new and almost crazy thinking that resulted in what is now called "evo devo" ( evolutionary developmental biology). They refused and refused to consider anything but an adaptationist view of animal anatomy. They were caught completely by surprise when it was finally proved that genes are indeed highly conserved among animals with radically different appearances. Life really is repetition (deep) and difference (surface). The foundation of a "new biology" (to borrow from the late and great Carl Woese) will not be established by zoologists, ornithologist, or entomologists. Only those who understand that this is a planet of cells will lead the way.
Traditionally, microbes have been viewed as insidious invaders that make people sick or as freeloaders in the human gut. That view is beginning to change. In 2013, scientists amassed substantial evidence that people and other animals form a unit with their resident bacteria, archaea, fungi and viruses — the collection of microbes known as the microbiome. In fact, only about 10 percent of a person’s cells are human; microbes make up the other 90 percent.
Many researchers point out that ultimately, every species is out for itself. Nevertheless several new studies argue in favor of considering animals as superorganisms composed of host and microbes. Some scientists even advocate lumping a host organism’s genes with those of its microbes into one “hologenome.”