Please, grade my integrated essay.

[Maria1212]

I have some difficulties with this essay. Could you check it and grade.

Reading

The Out of Africa hypothesis, also called the replacement hypothesis, contends that modern humans originated in Africa, probably from a common ancestor. From there, they migrated to other regions, eventually replacing the populations of Neanderthals and other groups of earlier humans that may have survived.
Geneticists who support the replacement hypothesis argue that the similarities shared by all of the modern human populations confirm the existence of a common gene pool, and perhaps even one common female ancestor. They point to the fact that many modern human traits have evolved within the past 200,000 years as evidence of the replacement hypothesis. Furthermore, they cite studies of DNA in cell structures called mitochondria, which codes most of the inherited traits from ancestors. Most of these studies demonstrate that the diversity among human populations is very small as compared with other species. They conclude that there was only one small population from which all other populations descended. From their point of view, the evidence supports the theory that modern humans migrated from a relatively small area in Africa almost 150,000 years ago, moving along a route through the Middle East 100,000 years ago, and slowly populating regions throughout the world by displacing the communities of less developed humanlike species that they encountered.
Paleoanthropologists concede that, to date, the oldest fossil remains of modern Homo sapiens have been found in Africa, with the next oldest dicovered in the Middle East. European fossils are dated at about 50,000 years after the African fossils. Thus, it would appear that the replacement hypothesis is substantiared by archaeological evidence.

Listening

Okay, today I want to talk about a hypothesis that explains where humans might have evolved and how they might have migrated around the world. It's an alternative hypothesis to the replacement hypothesis that you read about earlier. It's called the multiregional hypothesis but I've also heard it referred to as the continuity hypothesis. Now, according to the scientists who support this view, modern humans spread throughout Euroasia about a million year ago and regional populations retained some unique anatomical features for hundreds of thousands of years, but they also exchanged some inherited traits with neighboring populations when they mated with them. And we call this exchange of traits gene flow.
So through this gene flow, certain characteristics that we consider crucial to modern mankind were inherited, as, for example, an increase in brain size with an accompanying change in the skull. And... and this gene flow resulted in the evolution of the early humans whose remains are found throughout Europe and Asia as well as Africa.
Now, scientists who support this theory contend that the populations that migrated were linked by gene flow so that the features that all people have in common spread throughout the world. The relatively slight differences among modern people would have been caused by hundreds of thousands of years of regional evolution. But actually, researchers who support the continuity hypothesis tend to focus on the genetic similarities among human populations world-wide, not the differences. We're really amazingly similar as a spicies. And the fossils of archaic and modern humans in some regions do suggest a continuous evolution in regional traits, like the cheekbone structure, for example, which is further evidence that modern humans may have evolved over a broad area among multiple groups of human ancestors.

Summarize the major points in the reading and explain how the lecture casts doubt on those points.

The reading passage presents the replacement hypothesis, which is also called the Out of Africa hypothesis. It explains the human migration patterns. The lecture, however, casts doubt on several points made in the reading passage.

To begin with, according to the replacement hypothesis, modern humans came from Africa and have one ancestor. Then, they moved to other areas and replaced the less evolved population. However, the lecture casts doubt on this hypothesis and proposes an alternative hypothesis which is called multiregional. According to this hypothesis, modern humans migrated to Europe and Asia and mixed with the regional population that obtained some unique characteristics. As a result, they exchanged some traits with the local population. This exchange of traits is called gene flow and has genetic similarity with modern human beings.

The reading passage also states that the replacement hypothesis is proved by geneticists. DNA research confirms that humans have a large number of genetic traits in common. Moreover, human population does not have such variety as species have. However, the continuity theory asserts that human beings are similar to speices.

Finally, it is said in the reading that according to paleonthropologists, the oldest fossils of human beings are found in Africa. Nevertheless, the lecturer sites that the modern human fossils are found in Europe, Asia and Africa.

TOEFL listening lectures: What aspect of USA Today does the professor mainly discuss?

[Luschen]

Hi, this seems like a very tough subject. Your answer was very good grammatically, but I felt it was a little off on some of the facts. I have added my own sentences to fill in what I thought were some of the gaps.

[Maria1212]

I'm agree with you.Thank you!