Evolution’s missing link
'Where we are going as a species is a big question. Human evolution
certainly hasn't stopped. Every time individuals produce a new zygote,
there's a reshuffling and recombination of genes. And we don't know
where all of that is going to take us.' That quote from Donald Carl
Johanson, the American paleoanthropologist who discovered the fossil of
a female hominid australopithecine known as “Lucy” in Hadar, Ethiopia,
reminds us that human evolution is a story that is yet to be finished.
In fact, we do not even know how it started in the first place and how
humans began to dominate our planet.
Humans are easily the most dominant species on the planet today, but
exactly when did they begin their domination? Was it 50,000 years ago?
Was it 10,000 years ago or was it 5,000? Latest research indicates that
we have been really dominating the earth for much less than that.
A new study published in the science journal Nature has indicated
that the human-dominated geological epoch known as the Anthropocene
probably began around the year 1610, which is really much closer to the
present period than most of us thought. The study conducted by
University College London (UCL) showed that previous epochs began and
ended due to factors including meteorite strikes, sustained volcanic
eruptions and the shifting of the continents.
The study authors systematically compared the major environmental
impacts of human activity over the past 50,000 years against these two
formal requirements. Just two dates met the criteria i.e.1610, when the
collision of the New and Old Worlds a century earlier was first felt
globally; and 1964, associated with the fallout from nuclear weapons
tests. The researchers conclude that 1610 is the stronger candidate.
What exactly makes 1610 really special? The scientists say the 1492
arrival of Europeans in the Americas and subsequent global trade moved
species to new continents and oceans, resulting in a global re-ordering
of life on Earth and this rapid, repeated, cross-ocean exchange of
species is without precedent in Earth's history. The Anthropocene
probably began when species jumped continents, starting when the Old
World met the New. Colonisation of the New World led to the deaths of
about 50 million indigenous people, most within a few decades of the
16th century due to smallpox.
The process was accelerated when the Industrial Revolution began in
18th century. It was a clear turning point in human history, and the
rise of atmospheric carbon dioxide from fossil fuel use is a long-term
global environmental change of critical importance. It is a problem that
affects us to this day and although efforts are being made to reduce CO2
emissions and greenhouse gases, it will probably take a couple of
centuries to undo the damage already caused and stop this process
There is a well-known example where the whole history of Planet Earth
is condensed to just one hour and the rise of humans occupies just the
last 30 seconds or less. This shows that mankind’s reign on Planet Earth
is very short, cosmically speaking. However, there are several unsolved
mysteries in terms of human evolution which are being probed only now.
In fact, the recent discovery of a 2.8-million-year-old partial
jawbone in Africa could rewrite the history of human evolution. The
fossil record for humans between two million and three million years ago
is just very poor and has long been known as a gap in human evolution.
An international team of researchers found the lower jawbone, complete
with teeth, at the Ledi-Geraru site in the Ethiopian Rift Valley. This
find could apparently fill a gap in the fossil record that has
The discovery of this yet-to-be named hominid pushes back the
appearance of the Homo genus by some 400,000 years. This fossil strongly
indicates that Homo - the genus to which we belong - first emerged in
East Africa approximately three-million years ago when a select group of
hominids transitioned away from the more ape-like Australopithecus.
Fossils of this nature are exceptionally rare. Specimens from this
particular time period, between 2.5- and 3-million years ago, are few
and far between and those that are found are typically not very well
The teeth found in this perfectly preserved jawbone, now called the
“perfect missing link” suggest a change in diet from the mainly
fruit-eating Australopithecus towards a more meat-based diet that would
also have required the use of tools. What this suggests is that three
million years ago, there would have been a very ape-like creature with
long arms, living in the forest, probably eating fruit. Two million
years ago Homo would have arrived with the tools, a large brain and
There is a debate whether two ‘human-like’ species would have lived
together at the same time during one epoch, but the humanoid with the
bigger brains and the ability to use tools would have won the race to
domination. Over a period of time, man mastered the art (and science) of
agriculture, animal domestication and a sedentary lifestyle, a departure
from the hunter-gatherer lifestyle of the more primitive times.
Human evolution is a fascinating field of study. Some may question
the usefulness of dwelling upon our collective past at considerable
expense (these research efforts are incredibly expensive and time
consuming), mainly because nothing can seemingly be gained by
understanding our past. But this is not true at all.
It is only by studying our past that we can take stock of where we
are - and where we are heading. Understanding how humans have
contributed to change the Earth (via such examples as 1610) will help us
save it from further peril in the future. Reconstructing the
evolutionary patterns through millions of years will also tell us how we
could evolve in the future. In fact, future evolution is a hot subject,
with various studies predicting that Man will essentially have a much
changed body and facial structure just 100,000 years down the line. This
studying our past, our history, is very important in more ways than one
to map our future.