The most recent Bioko land bridge and the Recent-out-of-Africa event both began about 70,000 years ago
Jun 11 #245
From sea depths in the Gulf of Guinea (easily available on Google Earth) we see that a land bridge between Bioko and mainland Africa would emerge whenever sea levels drop to about 60 meters below the present level. During the ice ages, sea levels were often between 60 and 120 meters lower than today. The most recent land bridge must have begun about 70,000 years ago (for example, see this chart). From genetics it is thought that the ancestors of living humans appeared about that same time. That is the Recent-out-of-Africa theory.
If there was a stable population of 1,000 paleohumans on Bioko, about 20 would die and 20 be born each year. Another 20 might have left across the land bridge each year, and migrated along the coastal areas (which are now submerged by our relatively high sea level) to the Mediterranean Sea. If 20 newcomers arrived each year between 70,000 and 50,000 years ago, this would be an influx of 400,000 new people. It would help explain the genetic evidence, where it seems that a "wave" of paleohumans appeared from Africa.