LONDON — Humans will grow to an average of 6 feet 6 inches, live to the age of 120, and all have brown skin by the year 3000, an evolutionary expert suggested yesterday.

Dr. Oliver Curry, of the Darwin@LSE research center at the London School of Economics, said our species will evolve to be taller and live longer, and that racial differences will become less and less pronounced, thanks to trends in nutrition, medicine, and migration.

Further into the future, Dr. Curry predicted, humans will decline physically and lose key social and interactive skills thanks to an overdependence on technology and medical interventions. By the year 102000,mankind will have split into two distinct subspecies — the “genetic haves” and the “genetic have-nots.”

The analysis of technological, biological, and environmental trends suggests H.G.Wells may not have been too far off the mark in his novel “The Time Machine,” in which mankind splits into a frail, wealthy genetic upper class and a downtrodden, ape-like worker class.

Dr. Curry, who was commissioned to carry out the study of how man would evolve over the next 1,000, 10,000, and 100,000 years by the TV channel Bravo, said: “The future of man will be a story of the good, the bad, and the ugly.While science and technology have the potential to create an ideal habitat for humanity over the next millennium, there is a possibility of a monumental genetic hangover over the subsequent millennia due to an over-reliance on technology — reducing our natural capacity to resist disease and our ability to get along with each other.After that, things could get ugly, with the possible emergence of genetic ‘haves’ and ‘havenots.'”

Dr. Curry believes humans will reach physical peak around the year 3000, with improved nutrition and understanding of the human body. Men will reach average heights of between 6 feet and 7 feet. Physical features will evolve to emphasize features valued in the opposite sex by men and women looking for potential mates, such as health, youth, and fertility.

Men will therefore have more symmetrical facial features, squarer jaws, and deeper voices. Women will have lighter skin, large, clear eyes, pert breasts, glossy hair, more symmetrical features, and smooth, hairless skin. Variations in skin coloring are expected to be smoothed out, with most humans moving toward a brown tone.

Further into the future, the outlook is less rosy, Dr. Curry argued, with humans declining physically thanks to excessive reliance on technology and medical interventions.By around the year 12000,he believes communication skills and emotional abilities such as love, sympathy, trust, and respect to have diminished, eroding the abilities of humans to care for others or perform in teams.

Dr. Curry predicts that 100,000 years from now, mankind will be divided into two distinct subspecies, with a genetic elite moving in ever more exclusive circles.The genetic upper class will, he argues, be increasingly tall, thin, symmetrical, clean, healthy, and creative, while the genetic underclass will be short, stocky, asymmetrical, grubby, unhealthy, and less intelligent.