Today I wrote a synthesis of a passage and a lecture as required for the Toefl-test. It's about two different theories of the origin of the homo sapiens. Hope it's not to confusing and you could be so kind to proofread it.
"According to the Out of Africa hypothesis, today's mankind spread from Africa abroad all continents, replacing all less developed groups of humans like Neanderthals.
Researchers found common gene sequences in recent populations from all over the world; therefore, they suggest that all humans are descendants of one little population living 200000 years ago. Due to this common origin, there is a huge similarity among humans compared with other species.
Scientists have moreover reconstructed the pathway, humans took emigrating from Africa. As the researches put it, early hmans took a route through the Middle East, before spreading all over the planet. Since this model has been supported by some founds of fossils, the Out of Africa theorie is widely accepted today.
In the lecture, the professor counters the hypothesis presented in the passage. He introduces an alternative theorie, called the multiregional or continuity hypothesis.
According to this model, humas had been settling all over Eurasia millions of years ago; thus, this theorie determines humans appearance outside Africa long before it would be expected by the hypothesis presented in the passage. Although the multiregional theorie assumes seperated development of local populations in Eurasia, it claims that sometimes single members of different groups got together; therefore, common gene sequences in today's mankind were explained by gene flow, contrary to the Out auf Africa theorie in wich they result from a common origin."