Mutualism, association between organisms of two different species in which each benefits.
Amensalism, association between organisms of two different species in which one is inhibited or destroyed and the other is unaffected.
Chemicals that function as signals between organisms of the same or different species are often referred to as semiochemicals.
DNA acquisition/exchanges in bacteria can occur between organisms of the same or different species via one of three mechanisms: conjugative transfer, phage transduction, or natural transformation.
Hence, the impossibility of referring to common mental states in different physical systems manifests itself not only between different species but also between organisms of the same species.
We conclude that the intrinsic likeliness of differential gene loss and the unlikeliness of HGT between organisms as different and distant as Archaea and Bacteria or even between many phyla within the same Domain (requiring several events without any obvious selection in most cases) bring in doubt the rampant character attributed to HGT by many authors.
Different studies have focused on the process of symbiont acquisition and characterization of genes differentially regulated between organisms at different symbiotic states [ 4- 10].
This is problematic because it precludes comparisons of the biomarker responses between organisms from different areas and does not provide significant information on the impacted area.
It is possible that some of the enzymes in groups 1 3 could have evolved relatively recently and subsequently been horizontally transferred to the other domains of life but the evidence of horizontal gene transfer between organisms belonging to different domains of life is not abundant.
