Paul Crowley wrote:
Apes did not have to be aquaphobes.
Talking about evolution, literally NOTHING had to happen. In fact,
most species go extinct. The default is "They all die." The exception
is "They adapted, they evolved."
That
was probably quite accidental. The first apes
(gibbon-like IMO) found themselves on an
island surrounded by fast-flowing water. So,
like many flightless bird species on small
oceanic islands, there was selection against
a near-universal ability which was likely to
get them into trouble.
I tend to think that it happened in stages. That, going back to
monkeys, one or more population adapted to an aquatic
diet and then eventually moved away from it/adapted to an
inland environment while retaining some of the aquatic
features (adaptations).
Look at the skeleton of a giant sauropod dinosaur. It so
closely resembles the skeleton of the much smaller,
bipedal dinosaurs that it evolved from that some crazy
people thought it must've reared up on it's hind legs.
"Law of conservation," baby! Unless there's selective
pressure to get rid of a trait, it's just as likely to remain as
get bred out, even if the trait evolved for a different environment/lifestyle...
And I never believed that the "Aquatic Ape" population was
alone on the planet. Groups were getting driven inland from
the start -- natural disasters, competition, climate change --
and adapting. In fact, I see this and the true engine of human
evolution. That, thanks to the glacial/interglacial cycle, these
separate population were cut off from each other during
interglacials, adapting, evolving, and then during glacial periods
their genes were getting exchanged... the best shared and
retained by all.
The aquatic/coastal population was the key. It was the link. It
was the conduit through which DNA flowed between the
continents.
But the point is, this model has DIFFERENT and DISTINCT
populations!
Apes could well have evolved in another
location, retaining the standard mammalian
ability to swim and never acquired a fear of
water.
But they were an inland group. They were the ones who left the
water, adapted to inland environments.
What difference would that have made for
ape and hominin evolution?
I don't understand the question.
But would hominins have ever evolved?
They split from chimps when there was a
small rise in sea-levels, or a change in the
course of a major river, creating an off-
shore island. If the mainland chimps could
have swum across, that population might
never have achieved the genetic isolation
necessary for a new species.
The chimps split off from us. So we would still have
evolved but they would not have.
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