Whale`s wrong turn leads to scientific discovery

Whale's wrong turn leads to
scientific discovery
By Los Angeles Times, adapted by Newsela staff on 03.26.15
Word Count 764
An artist's rendering of an ancient whale. Photo: Wikimedia Commons
A whale that apparently took a wrong turn up an African river about 17 million
years ago may offer clues to the climate-change forces that shaped human
evolution.
Lost for more than 30 years, the fossilized beak and jaw bone of the 22-foot
whale helps to determine that the East African Plateau probably began rising no
earlier than 17 million years ago, according to a study. The report was published
in the journal Proceedings of the National Academy of Sciences.
The Whale Has A Lot To Tell
That geologic upheaval in an area known as the cradle of humankind is
believed to be responsible for the gradual change of dense, humid forests into
grasslands with fewer trees. The change made it advantageous to evolving
human ancestors to walk standing up.
“The whale is telling us all kinds of things,” said study co-author Louis Jacobs, a
paleontologist at Southern Methodist University in Dallas. “It tells us the starting
point for all that uplift that changed the climate that led to humans. It’s amazing.”
Jacobs had been searching for the specimen since 1980, when he was head of
paleontology at the National Museums of Kenya. He had read about the 1964
find by James G. Mead in a 1975 research paper.
Every time Jacobs visited Harvard University, Washington or Nairobi, he would
try to find it.
“It was protected by a plaster jacket, so you couldn’t really see it,” he said. “I
suspect nobody knew what it was. It was just kept in the collections there.”
Finally, just before another trip to Kenya in 2011, a collections official at Harvard
located the fossil there, Jacobs said.
Something Was Missing
Jacobs had the specimen scanned and analyzed. Then he contacted Henry
Wichura, a structural geologist at the University of Potsdam in Germany.
Wichura had been studying the plateau region, trying to determine when it
started rising. He had found evidence that rivers and lava had flowed east from
high points on the plateau at least 13 million years ago.
“What was missing was geological evidence of the onset” of uplift, Wichura
said.
That’s because the area is shaped by multiple forces. A hot spot in Earth’s
mantle has been pushing up a wide area of East Africa. The mantle — the thick,
middle layer of the Earth — surrounds the planet's superhot core. Meanwhile,
moving tectonic plates have been fracturing the crust, on which we live. That
makes for bad conditions for fossils in sedimentary rocks.
Pinpointing The Mammal's Location
The researchers used Mead’s original field notes to pinpoint where the fossil had
been excavated, and at what elevation — more than 2,000 feet above modern
sea level. Then they looked up incidents of whales swimming upriver from the
sea.
The river had to be large and it had to rise gradually, Jacobs said. The whale
would have had to swim a long way up, he said.
No whale had swum to anywhere close to such an elevation. Even the Antarctic
minke whale that took the longest known detour, more than 600 miles up the
Amazon, reached an elevation of little more than 3 feet above the Atlantic
Ocean sea level. A humpback whale, dubbed Humphrey, twice swam a more
modest 82 miles up the Sacramento River in California. Freshwater dolphins
have been found at elevations of more than 300 feet in Peru.
Based on the sea level and shape of the African coast at the time, the whale
would have traveled 372 to 559 miles from the Indian Ocean, bringing it to an
elevation of 78 to 121 feet, according to the study. So the area must have been
pushed up at least 1,935 feet since the whale died to reach its present
elevation, the authors estimate.
"It's An Amazing Thing"
The whale bone was found in a thick layer of debris beneath a lava flow dated to
17 million years old, according to the study. Around it were mammal fossils that
date to a period when Africa and Eurasia were joined.
Fossil and geologic evidence show the uplift happened around the same time
as a long-term drying of the local climate. The drying changed a humid forest
into grasslands with more widely spaced trees. Scientists theorize that this kind
of environmental pressure favored primates that could straighten their backs
and walk longer distances on two feet. This eventually led to modern humans.
The chances that one such modern human, Mead, would find a fossilized bone
from an errant, lost marine mammal, buried under the desert, are astonishingly
slim. “It’s an amazing thing,” Jacobs said. “But there it is.”
Quiz
1
Which paragraph from the section "The Whale Has A Lot To Tell," MOST strongly
supports the idea that important discoveries are not usually made overnight?
2
Which sentence from the section "Pinpointing The Mammal's Location" MOST
strongly supports the idea that the finding of the whale fossil was evidence of a
geologic uplift?
3
(A)
The river had to be large and it had to rise gradually, Jacobs said.
(B)
Even the Antarctic minke whale that took the longest known detour,
more than 600 miles up the Amazon, reached an elevation of little
more than 3 feet above the Atlantic Ocean sea level.
(C)
Freshwater dolphins have been found at elevations of more than
300 feet in Peru.
(D)
So the area must have been pushed up at least 1,935 feet since the
whale died to reach its present elevation, the authors estimate.
Read the paragraph from the section "Pinpointing The Mammal's Location."
The researchers used Mead’s original field notes to pinpoint
where the fossil had been excavated, and at what elevation
— more than 2,000 feet above modern sea level. Then they
looked up incidents of whales swimming upriver from the sea.
Which BEST explains how the two sentences are connected?
(A)
The first sentence describes what caused researchers to take the
actions that are described in the second sentence.
(B)
The first and second sentences make a comparison between the
actions taken by two groups of researchers.
(C)
The first sentence and second sentences contrast two ideas about
whale locations.
(D)
The first sentence describes what happened after the researchers’
actions that are described in the second sentence.
4
Read the paragraph below from the section "The Whale Has A Lot To Tell."
That geologic upheaval in an area known as the cradle of
humankind is believed to be responsible for the gradual
change of dense, humid forests into grasslands with fewer
trees. The change made it advantageous to evolving human
ancestors to walk standing up.
Which BEST explains the role of the second sentence in the paragraph?
(A)
to describe a problem that resulted from the change described in
the first sentence
(B)
to offer an explanation for the change described in the first
sentence
(C)
to describe an effect of the change described in the first sentence
(D)
to offer a solution to a problem that is described in the first
sentence