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 Homo sapiens spread from Africa abroad to 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 group living 200,000 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 the routes taken by the migrating peoples. As the researches put it, early humans took a route through the Middle East, before spreading all over the planet. Since this model has been supported by some founds of fossils,fossil remains, the Out of Africa theory is widely accepted today.
In the his/a lecture, the professor [which professor? Who is he?]counters the hypothesis presented in the passage.above. He introduces an alternative theory, called the multiregional or continuity hypothesis.
According to this model, humans had been settling all over Eurasia millions of years ago; thus, this theory determines humans appearance the evidence of humans outside Africa long before it would be expected by the hypothesis presented in the passage by the Out of Africa theory. Although the multiregional theory assumes separated 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 can be explained by gene flow, contrary to the Out of Africa theory in which it is postulated that they result from a common origin."