What are streptococcus species?

Mutans

Most environments do not have sufficient resources to support unlimited populations of all the species present. Different species that have the same requirements for habitats and food will attempt to...

Yes, there is one that i know of. The Cuckoo bird lays its eggs in the nest of a host bird of another species, usually one with similar looking eggs to its own. The host bird then looks after the egg...

Taxonomy

i think yes ; mainly because human plays a major role in our ecosystem ,for example mining areas and even human settlements do change our environment from its original to something else.