From Article:
Homo erectus, H. ergaster and archaic H. sapiens, was 55,500 individuals, tops, about 1 million years ago. The population may have been as low as 18,500.

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Question/Opinion:
But does a low population in relative terms really mean a population is near extinction???

What puzzles some in the scientific community is why such a small population was so spread out over earth. Did some major disaster not only reduce the population but cause the survivors to run in different directions for dear life.

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Article over on Scientific American.
http://www.scientificamerican.com/article.cfm?id=humans-might-have-faced...