How can communities of organisms thrive on both active and extinct volcanoes?

Organisms, typically microorganisms thrive on the active volcanoes. They utilize the sulfur released from the vents of the volcanoes, for energy production. They are chemosynthesizers. The extinct volcanoes are also a very good source of habitation, as they have plenty of minerals, which came out during the eruption. Their soil is fertile and may forms of life utilize them for thriving. 

Ithink the dna sequences may vary but the amino acid sequences are identical.