Final answer:
"Y-chromosome Adam" refers to the most recent common paternal ancestor from whom all living men are descended, estimated to have lived between 200,000 to 300,000 years ago.
Step-by-step explanation:
"Y-chromosome Adam," also whimsically referred to as "Steve" for the sake of rhyme, is the name given to the most recent common paternal ancestor from whom all currently living men are descended Patri lineally. He is not a single individual who was the first human male but rather the most recent person whose Y-chromosome is reflected in the Y-chromosomes of all existing men. Genetic studies estimate that Y-chromosome Adam lived between 200,000 and 300,000 years ago, though this is subject to ongoing research and refinement. It's important to understand that while Y-chromosome Adam is the most recent common ancestor through male lines, this does not mean he was the only male alive during his time, nor does it mean that he interacted with "Mitochondrial Eve," the matrilineal equivalent who lived at a different time.