Evolutionary Trends

name Shulamit
status student
grade 9-12
location IL

Question - I understand that evolution takes millions of
years. It has been a long time since there were dinosaurs. Many
of the life forms that predated dinosaurs are still around. Is it
possible for a new age of dinosaurs? Couldn't evolution repeat
itself? And why limit it to dinosaurs, why not any extinct (or
non-extinct) life form?
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Life doesn't evolve from scratch-it builds from existing life forms.
So since there are no dinosaurs anymore that would be difficult.  That
doesn't mean impossible-there would need to be some selective pressure
for very large, reptile-like creatures to evolve again.  There are
examples of similar features to evolve more than once, such as wings.

kvanhoeck
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Given the random character of mutations that drive evolution, it is
conceivable that forms could be more or less repeated. But any changes or
adaptations that arise must be able to survive and reproduce in their
environment, and that environment is also changing, so the odds against the
same forms arising again would be astronomically large. There are existing
examples of "convergent evolution" in which similar structures and forms
have evolved in very different groups to fit similar conditions, so it is
possible creatures somewhat analagous to dinosaurs, or others, could
eventually evolve. It is highly unlikely anything resembling present human
beings would be around to talk about it.

J. Elliott
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