It so happened that I came across Dougal Dixon’s book, ‘When
the Whales Walked’. It is a book for children, with little text but plenty of
illustrations, and it talked about evolution. Again, it is a book for children,
with little text, but plenty of illustrations, but as it usually happens with
Mr. Dixon, the text there could have used some work.
What are the problems of WWW? Firstly, an overly basic
reduction of the terms. What is evolution in child-friendly terms? There is a
population of fuzzy (or fluffy) woobies, where all look the same. Eventually, a
mountain range rises up and splits the wooby population into two. One
population eventually ends up living in a savanna, where it evolves longer legs
to further and faster cool down in the warm climate, and also to better attract
mates with the coloration of their legs. The second population ends up living
in a tundra, where it evolves shorter legs to preserve more of its’ body heat,
and also tusks or claws designed to scratch out worms and other invertebrates
in the harsh and hard tundra soil, upon which it feeds. As enough time passes
the two wooby populations change enough so to become two different species
instead of a single one, the end.
Sounds simple, right? Team Dixon tried to go one further, by
reducing the population by just one. Namely, there is a single new island in
the sea, with a single food source – some sort of shrimp. Some sea birds can
survive on it, but only those that can eat shrimp. Those who cannot leave or
die, with the remnant eventually forming a new species. Straightforward? Yes,
but also unrealistic. In real life, there is never a single food source in a
new place, such as a new volcanic island in the sea. (To those people in
Indonesia who died in the tsunami – our hearts go out to you). There are always
several, (even now, with human overfishing and environment pollution), and
there are always several bird species on any island. To reduce them to a single
one is too much, too absurdedly much.
Secondly, there is the use of the word ‘mutation’. Broadly
speaking, ‘mutation’ means ‘transformation’, ‘change’, but due to various
modern mass media influences, (especially Marvel and DC comics, movies and TV/online
series), these days it is usually associated with a physical change – say, male
birds, such as the fowl, sprouting new features, such as tails and head crests,
or male elephants keeping their tusks, while the females – not so much. (Female
Asian elephants usually lack them). In reality, however, evolutionary changes
can mean not only physical changes, but also behavioral ones – i.e., sea otters
learning how to use rocks to smash shellfish and sea urchins, Galapagos
woodpecker finch using cactus spines to catch grubs, or Homo Erectus, a human
ancestor, learning how to utilize fire.
…Okay, true, at least 90% of the WWW book is dedicated to
the various animals evolving into new species by acquiring new physical traits –
i.e., whales going from the Indohyus, an animal more similar to the modern
mouse deer, to the modern species, such as the blue whale. Fair enough, but
even that has went somewhat wonky, at least once: when the book talked about
crocodile evolution raising a suggestion that once upon a time, (in the
Triassic), crocodiles were very different animals and even warm-blooded – unlike
today, when they are cold-blooded. This is an interesting topic, so let us
elaborate on it.
Firstly, the crocodiles belong to the archosaur family,
which also includes pterosaurs, non-avian dinosaurs, and birds. Kudos to WWW for
uniqueness by pointedly not mentioning non-avian dinosaurs, BTW – you do not
often find this approach in a paleontology book, especially one for the
children.
Secondly, modern crocodiles and their cousins are only
distantly related to the Mesozoic species that are featured in WWW and similar
books. ‘The Complete Guide to Prehistoric Life’, which featured prehistoric animals
that were chosen to appear in the currently defunct ‘Impossible Pictures’, ‘Walking
with…’ series. Among them were four extinct cousins of the modern crocodiles:
Proterosuchus, Postosuchus, Metriorhynchus and Sarcosuchus. All four of them
were different from each other, and while at least one of them – Sarcosuchus,
(which also appeared in WWW), was physically similar to the modern crocodiles, ‘Guide’
made it a point to say that the modern crocodiles, caimans and alligators were
only distantly related to their extinct cousins, which is true – if you put a
modern species, say the saltwater crocodile, next to one of their Triassic
cousins, you’ll get two different animals.
But what does their Triassic cousins look like? Postosuchus,
Saurosuchus, Carnufex and co. looked like a cross between a modern crocodile
and a mammal: they walked on all four legs, and those legs were directly
beneath their bodies, as they are in mammals and archosaurs, (including birds),
not splayed to their sides, as they are in lizards or tortoises, or even modern
crocodiles. That is because they are only distantly related to them, and may be
actually more closely related to the ancestors of the dinosaurs proper instead.
…Dinosaur phylogeny is confusing by itself; there are three
main groups – theropods, sauropodomorphs and ornitishchia – aka the
meat-eaters, the long-necked plant-eaters, and every other species. As a rule,
the carnivores and the long-necked herbivores form one main dinosaur group –
the lizard-hipped dinosaurs while the other dinosaurs form the second – the bird-hipped.
Now, however, there is a suggestion that the carnivorous dinosaurs were more
closely related to the bird-hipped herbivores, while the long-necked herbivores
more closely related to the initial species, such as staurikosaurus,
herrerosaurus, eoraptor and etc. It is a mess, and so far, there is no final
verdict on it – and the same goes regarding whether or not dinosaurs were
warm-blooded. Birds are, of course, while the crocodiles are not. Yes, the
American alligator can handle cold temperatures, including cold snaps, which
allows it to move further north in North America than its’ main rival, the
American crocodile can. (Yes, there are two different species of the
crocodilian reptiles in the modern North America). However, it is still very
much cold-blooded, and it is not really related to birds either. (Aka the
modern dinosaurs). Even the scientists who use alligators and crocodiles for
models for dinosaur behavior do not deny that these reptiles are not real
dinosaurs either, not literally.
In other news, as far as scientists are concerned, that when
it comes to the archosaur family tree, the crocodiles derived first, followed
by the pterosaurs, and finally the avian/non-avian dinosaur split. This means
that the whatever evolutionary factors allowed some dinosaurs, (primarily
birds), to become warm-blooded as the mammals are, (and mammals are a
completely separate branch of the tree of life, BTW), never appeared in
crocodiles, especially the modern species, but ditto for the extinct ones. The
Triassic was marked, in the end, by a mass extinction, but it was not due to an
Ice Age, but to a volcanic eruption instead and a prolonged drought, oxygen
level loss, etc. Unlike the birds (and their ancestors) that appeared during
the Cretaceous, neither crocodiles nor their ancestors had to deal with cold
temperatures when they were evolving per se, and as such, they never did. This is
why in the modern times crocodiles are restricted to the tropics, while the
birds are not. They are warm-blooded, (as were their ancestors, apparently), while
the crocodiles never were. To call the ancestral crocodiles ‘warm-blooded’ is doubly
wrong. However…
However, aside from this gaffe, and the previously mentioned
two mistakes, WWW is a good book for children. It tries to be both entertaining
and educational and it does a good job at succeeding. True, the stories go all
over the place, but so did R. Kipling’s ‘Just-So-Stories’, and they work well
enough to become a classic in their own right, (cough Mowgli cough). Who knows,
maybe one day WWW or one of its book fellows will become a classic in its’ own
right. We will just have to wait and see.
This is it for now; see you all soon.
PS: And to all of you, a Happy Christmas for tomorrow