Which came first, the
plant or the seed?
Adam Sam, Brakpan
The earliest fossils of complex land plants date from
around 470 million years ago. They resembled
liverworts – a kind of simple moss – and reproduced by
releasing spores, which were carried away when it
rained. Spores contain a single cell, whereas a seed
contains a multicellular, fertilised embryo that is
protected from drying out by a tough coat. These extra
features took another 150 million years to evolve,
whereupon the first seed-bearing plants emerged. So
plants came first, by a long way.
- WINGS
The heaviest-ever flying bird was
Argentavis magnificens, which
lived six million years ago. It had
a similar height and weight to an
adult human, with a wingspan of
6m. These wings would have been
too large and hefty for continuous
flapping, so it probably flew more
like a glider, taking off by running
downhill into a headwind. We’d
have to adopt a similar
flying style. - MUSCLES AND BONES
To flap these wings, we would need
pectoral muscles twice the size of a
pro bodybuilder’s. Our bones would
be lighter and therefore weaker, so
we’d need to strengthen our
collarbone by fusing the clavicles
into a wishbone. We’d also need a
‘keel’ bone protruding down the
centre of our chest, to allow the
pectoral muscles to attach further
from the shoulder, increasing
their leverage. - TECHNOLOGY
Even with all of this, we probably
couldn’t fly unaided. Birds have a
more efficient one-way airflow
through their lungs to get more air
with each breath, and their muscles
have extra oxygen-carrying proteins.
Their nervous system runs faster to
give them the reaction times needed
for in-flight manoeuvring. We would
need help from an oxygen cylinder,
and a flight computer with a heads-
up display.
What would happen if... humans grew wings?
A The leaves of the
rhubarb plant – we
eat the stems – are
poisonous.
A There can be more
than 1,000 seeds in a
pomegranate.
Q
&
A
FLASH