Reading comprehension.
A recent study of ancient and modern elephant has come up with the unexpected conclusion that the
African elephant is divided into two distinct (不同的) species.
The discovery was made by researchers at York and Harvard University when they were examing the
genetic relationship between the ancient woolly mammoth and mastodon modern elephants-the Asian
elepphant, African forest elephant, and African savanna elephant.
Once they obastain DNA sequences (序列) from two fossils (化石), mammoths and mastodons, the
team comparted them with DNA from modern elephants. They found their amazement that mordern forest
and savanna elephants are as distinct from each other as Asian elephants and mammoths.
The scientists used detailed genetic analysis to prove that the African savanna elephant and the African
forest elephant have been distinct species for several million years. The divergence of the two species took
place around the time of the divergence of Asian elephants and woolly mammoths. This result amazed all
the scientists.
There has long been debate in the scientific community that the two might be separate species, but this
is the most convincing scientific evidence so far that they are indeed different species.
Previously, many naturalists believed that African savanna elephants and African forest elephants were
two populationgs of the same species, despite the elephants' significant size differences. The savanna elephant
has an average shoulder height of 3.5 metres while the forest elephant has an averate shoulder double the
weight of the forest elephant. But the fact that they look so differrent does not neccssarily mean they are
different species. However, the proof lay in the analysis of the DNA.
Alfried Roca, assitant professor in the Department of Animal Sciences at t he University of Illinois, said,
"We now have to treat the forest and savanna elephants as two difficult units for conservation purpose.
Since 1950, all Afican elephants have been conserved as one species. Now that we know the forest and
savanna elephants have been distinct animals, the forest elephant should become a bigger priority (优先) for
conservation purposes."
1. One of the fossiles studied by the researchers is that of _____.
A. the Asian elephant
B. the forest elephant
C. the savanna elephant
D. the maslodon elephant
2. The underlined word "divergence" in Paragraph 4 means "_____".
A. evolution
B. exhibition
C. separation
D. examination
3. The researchers' conclusion was based on a study of the African elephant's _____.
A. DNA
B. height
C. weight
D. population
4. What are Alfred Roca's words mainly about?
A. The conservation of Afican elephant
B. The purpose of studying Afican elephant
C. The way to divide Afican elephants into two units
D. The renson for the distinction of African elephants
5. Which of the following can be the best tille for the passage?
A. Naturalist' Beliefs about Elephants
B. Amazing Experiments about Elephants
C. An Unexpected Finding ahout Elephants
D. A Long Scientifif Debate about Elephants
