2020-04-02_Science_Illustrated

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scienceillustrated.com.au | 13


ANSWERS TO TEST YOURSELF P82: NO PEEKING!


A 3.8-million-year-old skull from an Australopithecus indicates that the evolution
towards the Homo genus did not happen directly, but took place in isolated groups.

EVOLUTION (^) A skull recently
discovered in Ethiopia belonged to
one of our early ancestors, according to
scientists from the Cleveland Museum of
Natural History in the US. After analysing
the skull, they determined that it belongs
to the Australopithecus anamensis
species, an ancestor of the
Homo genus.
The 3.8-million-year-old
skull reveals features that
differ from those which
scientists know from the
Australopithecus afarensis, the species
which became famous when an almost
complete skeleton known as ‘Lucy’
was discovered in 1974. The two species
differ particularly in the lower part of
the face of anamensis being more
protruding than that of afarensis.
The differences are important, because
scientists can now identify other finds of
skull bones such as 3.9-million-year-old
finds made in 1981. According to the new
knowledge, they must be from an afarensis.
From the discoveries made of the two
so far, we now know that Homo
anamensis lived 4.2-3.8 million years
ago, while Homo afarensis existed from
3.9 to 3.0 million years ago,
so that they co-existed for
at least 100,000 years.
The discovery changes
the history of our early
ancestors. So far, most
scientists believed that the early
anamensis evolved directly into afarensis,
but now we know that it happened in
a different way. Perhaps a group of
anamensis was isolated in a region
where it evolved into the new species,
while in other places, anamensis survived
in their original form for much longer
than previously believed.
AUSTRALOPITHECUS
is a common designation for
several members of the genus
that included the precursors
of the Homo genus.
Ancestors with new faces
Several times, our planet has been
a Snowball Earth, with huge ice masses
covering the entire world. One of these
times was 2.4 billion years ago, and
scientists now believe that an asteroid
strike in Australia defrosted it again.
Australia has
the world’s
oldest crater
The Yarrabubba Crater is located
in a region of Australia that
consists of 3-billion-year-old
crust. The crater has now been
dated to be 2.229 billion years
old – the world’s oldest known
asteroid crater. The dating is
consistent with the impact
being a cause of the global
ice age easing its grip on Earth.
AUSTRALIA
YarrabubbaCrater
Region with 3-billion-year-old crust
From 2029 to 2031, each 107. PROBLEM 4:
brother will add 2 years: 99 + (4 x 2) = 107
In row after row, the same S. PROBLEM 5:
figure moves one step to the left.
The completed letter ST. PROBLEM 6:
sequences are names of famous scientists:
EURST EIN & PAST EAU, EINST COU
In all figures, the number in the 8. PROBLEM 3:
black circle is the average of the other numbers.
Boeing X-48 was an experimental plane
developed by Boeing and NASA. The X-
tested the blended wing body (BWB),
in which body and wings are merged.
The red 4. PROBLEM 2:
diagonals in the rectangle
show that each of the
rhombus sides is as long
as the circle's radius.


. NGand EI, , BO PROBLEM 1:


Boeing 48
ORD CODE W

Editor: Jens E. Matthiesen
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