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0:00
This is Vagheesh Narasimhan.
I'm an assistant professor at
the University of Texas, Austin.
I'm going to talk to you
today about human evolution.
0:10
I'd like to begin by
saying that the study of
human evolution is something
that has fascinated
generations of scientists.
Charles Darwin, of course,
famously wrote a book
about human origins,
where he got many
basic things right,
including our relationship
with the great apes,
as well as the origin of
modern humans being in Africa.
0:30
One of the most obvious
ways to understand
human origins is to
compare ourselves
to our closest relatives,
the great apes.
Prior to molecular methods
looking at genomes,
this was carried out
primarily by examining
anatomical differences between
the great apes and us.
For example, we are
the only great apes
to have longer legs than arms
and we have additional
anatomical changes
in the pelvis and spine which
allow us to walk upright.
0:57
Fortunately, we're able to
look at these
differences in anatomy,
not just by comparing
ourselves to the great apes,
but over time by looking
at evidence from fossils.
Over the past 100 years
or so, large numbers
of hominin fossils
have been uncovered.
Hominids, as in
fossils that possess
particular characteristics
that differentiate
ourselves from the great apes,
however primitive these
characteristics might be.
These fossils provide
a way to look at
our evolutionary history
in steps of time.
Of course, this process
of drawing relationships
between fossils is not exact,
but it provides a record
of change over time
that we can use to understand
the evolutionary process.
1:36
One amazing thing that these
fossils allow us to do
is to look at skeletal
and anatomical changes
in structure that have evolved
over the past few million years.
In particular, it allows
us to look at changes
that allow for bipedalism,
the ability to walk
upright on two legs.
In this figure are a sequence
that we're observing in
the anatomy of the
hominid lineage
leading to ourselves.
As you can see,
the stability of these
hominids being able to
walk upright drastically
improves over time.
