26 April 2021

Book review -- evolution and geography

Here Be Dragons by Dennis McCarthy (2009)

Biogeography is the study of the global distribution of living things and the interaction of geological change, especially plate tectonics, with biological evolution.  It's not really a new field -- biogeographical concepts played a role in Darwin's discovery of natural selection -- but its implications and contributions aren't widely recognized by laymen.  This book (buying info here) gives a good overview of its explanatory power -- why certain kinds of animals are almost never indigenous to islands, why the life forms of the southern continents are so different from those of the north, the dramatic and sometimes catastrophic effects of continental drift, and why invasive species and the ecological disruption they cause have been a part of the story of life since long before modern times or even the appearance of humans.

The book is somewhat reminiscent of Jared Diamond's Guns, Germs, and Steel, which it cites several times -- the impact of geography on biological evolution somewhat parallels its impact on human cultural development, though obviously over a far longer time frame.

Most people are familiar with the separation of South America from Africa in the late dinosaur period, but actually the most important biogeographical event in Earth's history was the break-up of the ancient southern super-continent of Gondwana into the land-masses which eventually became Africa, South America, India, Australia, and Antarctica.  This caused the native Gondwanan species to diversify in often-surprising ways, though much of the animal and plant life of those lands remains noticeably similar (and somewhat bizarre-looking to northern-hemisphere humans).  It also led to the freezing-over of Antarctica, reducing a once green and teeming continent to the icy wasteland we see today.

Quality of writing can be as important to readers as the information being presented, and Here Be Dragons tells its story in a gripping way.  It's at its best in the chapters "The Volcanic Ring that Changed the World" and "The Bloody Fall of South America", illuminating the icy death of the Antarctic biosphere and the effects of the invasion of North American predators into formerly-isolated South America after the formation of the isthmus of Panama just a few million years ago.  These episodes of mass death and extinction, among the worst in the planet's history, get the dramatic treatment they deserve.

There's also a particularly interesting digression on the orca, a highly-intelligent sea mammal which seems to be divided into at least three subgroups which operate more like human cultural or ethnic groups than biological subspecies.

Toward the end, the book touches on a more controversial topic -- the diversification of humans as they spread around the globe.  In fact, humans are a remarkably homogenous species considering the vast range of lands we inhabit -- less genetically diverse than chimpanzees, despite the latter being confined to a narrow belt of habitat across Africa.  But genetic differences between human populations do exist.

Even if you already have a good general understanding of evolution, you'll pick up some new insights from this.  Thanks to Carol Seidl for bringing the book to my attention.


Blogger F. Andy Seidl said...

I read Here Be Dragons the first day I could get my hands on a copy (after all, Dennis is my brother-in-law ) and I second everything you say about it. I had been reading about evolution for many years at the time I read Dennis's book and I, too, found it to be both a hugely entertaining and informative read--a double win.

26 April, 2021 10:36  
Blogger Debra She Who Seeks said...

Sounds interesting, in a heavy-duty kind of way. One thing it does show is that the Earth's history long preceded OUR arrival and will long exist after we're gone.

26 April, 2021 11:21  
Blogger Mike said...

"the diversification of humans as they spread around the globe.
Could we be Earth's COVID infection?

26 April, 2021 12:02  
Blogger Mary Kirkland said...

That sounds like a very informative book.

26 April, 2021 14:13  
Blogger Sixpence Notthewiser said...

This is soooo cool!
I've been watching Eons, the PBS webseries and they talk about the formation of the continents. Love it (well, I'm motivated by the eye candy, but hey!).
It's really great when people can write about science (or math, or physics) in a way that it's easy for people who are not versed in the subject (me) to understand.


26 April, 2021 15:36  
Blogger Lady M said...

Sounds like a good one - I enjoyed Gun, Germs, and Steel and The Greatest Show on Earth so I would probably enjoy this. I will look for it at the library.

26 April, 2021 16:16  
Blogger Infidel753 said...

Thanks for the comments. I do recommend it. It's certainly written in a way that's easy for the non-specialist to understand.

27 April, 2021 11:00  
Anonymous Annie said...

Sounds fascinating. I knew of Dennis McCarthy’s work because Carol had sent me a link to a Boston Globe article by the author of a new book about him—in a vastly different field. He seems to have immersed himself in a search for the inspirations behind Shakespeare’s plays and made a discovery that may be a valuable insight unknown to Shakespeare scholars. Quite a guy!

29 April, 2021 19:17  
Blogger yellowdoggranny said...

i'm at the point right now the only thing I want to learn is how to keep alive.

02 May, 2021 13:04  

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