Over the past week I read through the first half dozen chapters. I'm finding the book to be an easy read, very straight forward and not anchored down with argument or speculation. The creation debate so far is not the focus of the book which may be a passive approach, though from the index I see that at some point there is discussion of the creationist critique of the supposed lack of intermediate species.

It takes some getting used to in considering the geologic time scales we are reading about. 3.5 billion too 600 million years ago!.

Visualizing a planet that has no atmosphere, zero recognizable continents, no life save for bacterial mats (cyanobacteria) and eventually algae mats, both in otherwise poisonous water. Yet there was biological things here which does suggest that the components for living things were available in the debris that formed the earth. For billions of years these stromatolites pumped out that necessary oxygen all the while other life was slowly emerging as well. Its interesting to note that these subtle changes over time are not restricted to a single organism but that the entire eco system was changing simultaneously. Contingency and necessity combined and biological organism's responded to shifting opportunity.

To call the early earth a waste land is not an exaggeration, that life forms emerged that laid the foundations for more complex organism's seems incomprehensible but the evidence for this is present in both the living fossils we see today and their Precambrian relatives found in those unencumbered places found through out the modern world.

I credit Prothero with ending most chapters with locations and directions to these very important discovery sites "see it for yourself" brings the reader into that discovery process. Prothero's presentation of the internal variance of opinion between the paleontological society shows that he like the reader is involved in a journey of discovery and not conformation bias. So far he has been straight forward in presenting what is known and what is contested hypothesis within a field of study.

Taylor wrote:. . . To call the early earth a waste land is not an exaggeration, that life forms emerged that laid the foundations for more complex organism's seems incomprehensible but the evidence for this is present in both the living fossils we see today and their Precambrian relatives found in those unencumbered places found through out the modern world..

I agree that Prothero does a nice job presenting the various fossils and the people who discovered them. I'm still amazed at how much we've learned in 150 years, much of it just in the past few decades. And, yet, there's so much we don't know yet about our dim and distant past.

The first reference to Creationists is in chapter 4, I believe, where Prothero discusses the so-called "Cambrian explosion" (in quotes). Not so much an explosion at all, but a gradual blossoming of more complex life forms, built on the foundations laid by earlier primitive life. I'm enjoying this book a lot. It's a great companion to books I've read on evolution.

I was a little surprised to read about the large number of scientists involved in this type of work. When laymen like me read about a new find in an online or magazine article we hear about so-and-so primary researcher, until the next find comes along. The author paints a picture of a large number of folks, looking at many steps in the evolutionary ladder, and in several locations.

djkirk wrote:I was a little surprised to read about the large number of scientists involved in this type of work. When laymen like me read about a new find in an online or magazine article we hear about so-and-so primary researcher, until the next find comes along. The author paints a picture of a large number of folks, looking at many steps in the evolutionary ladder, and in several locations.

Also, we see a lot of overlap between scientific fields. For example, to Darwin's question about the lack of preCambrian fossils, geologists—not paleontologists, not evolutionary scientists—have long known one of the primary reasons. Most preCambrian rockbeds have been transformed by heat and pressure into metamorphic rocks. This largely explains the absence, although there are others too, which have already been mentioned.

Of course one of the unanswered questions of the whole field of evolution is why. But specifically, I've always wondered why the whales (and others as indicated) walked back into the sea. Certainly two general reasons exist. Something on land must have threatened their survival, or something in the water appeared advantageous to draw them there. Any speculations?

Good question, Kirk. I'm inclined to think that the move to water would have been "motivated" primarily by food, though it must have been a gradual transition. As the whale ancestor (perhaps the Pakicetus) spent more and more time in the water, it would have gradually become more aquatic. It's not difficult to imagine if you look at modern day animals that spend a lot of time in the water. I was just looking at the hippo, which is distantly related to cetaceans. It spends much of its time in the water, and is quite at home there, but it likes the water primarily to keep cool. It still is primarily a land animal that grazes on terrestrial grasses.

They are well-adapted to their aquatic life, with small ears, eyes and nostrils set at the top of the head. These senses are so keen that even submerged in water, the hippo is alert to its surroundings. By closing its ears and nostrils, the adult can stay under water for as long as six minutes.

But as long as it's food sources are on land, the hippo will remain a land animal that merely is comfortable in the water. It still needs strong legs to be able to forage on land.

The manatee, a distant relative of hoofed land animals, is the only living herbivorous marine mammal. It can stay underwater for up to 20 minutes without coming to the surface. But it's found only in shallow, slow-moving rivers, bays, estuaries and coastal water ecosystems.

So its interesting to me that both the manatee and hippo are herbivores. What sets the cetaceans apart is that they are carnivores. Maybe that's what enabled the whale ancestor to thrive as a fully aquatic animal.

Different subject: I never read On the Origin of Species in its entirety. It was always referred to in other texts or in my only anthropology class. I never thought about the fact that human fossils were never mentioned (Chapter 25, Lucy in the Sky with Diamonds). I recall in the movie Gettysburg a scene where the Confederate generals were discussing man being descended from the apes. This must have been an anachronism since the idea was probably not widely considered in 1863. However, it was interesting to note that the character of General Pickett said, that while some men may have descended from apes, who would even consider that General Robert E. Lee was. Whenever the idea was first suggested, it must have made every Victorian cringe.

I read an article recently that Lucy probably died from falling out of a tree.

This past week I've been reading chapter 21 'the origin of Sirenians' Walking Manatees

In southwest Florida manatees are very common even though they are endangered. So I was just the other day standing on a dock at work and here comes a mother and juvenile manatee, there interesting because they like to drink fresh water. So there I was watering these two for about ten minutes(with a garden hose) before they had their fill and ambled on. Quite often these gentle creatures are hit by boats, sometimes they die from prop wounds sometimes they don't and you can clearly see the scar's on their backs.

Imagining the time it took for these things to change from a land mammal to a water bound one, kind of puts them in a whole new light. They have survived for millions of years despite their lack of natural defenses.

I am so far, thoroughly enjoying this book!. Prothero has presented examples of a record for fossil discovery that turns out to be more than I thought existed.

Hi Taylor,

I used to live in Florida and would occasionally see both dolphins and manatees when I was out in my kayak. Both creatures evolved from land mammals, though they are not very closely related. Manatees are more closely related to elephants, and perhaps retain slightly more vestiges of their land ancestry. If you look at the bones of their flippers, you can see the resemblance to mammalian 'toes' and 'fingers'. They still have fingernails. And they have been observed to walk along the sea bottom.

The fact that manatees live in salt water, but still need freshwater to drink is another vestige of their land mammal ancestry. And probably a limiting factor in their survival.





I'm currently on Ch. 17—"Land of the Giants". What continues to amaze me that until the early 1900s, we knew almost nothing about dinosaurs. And we are still piecing together information from a very fractured body of evidence. There is much unknown and much to learn.

geo wrote:What continues to amaze me that until the early 1900s, we knew almost nothing about dinosaurs. And we are still piecing together information from a very fractured body of evidence. There is much unknown and much to learn.

This is the aspect of the book that I thought was a gas to catch, It leaves you wanting more. Each chapter reads so quickly but yet to pact them with more stories may have made it to thick. A documentary film of the book would be an appropriate next venture. I've been watching these guys, Ken Ham, Eric and Kent Hovind and Frank Turek, all young earth creationists/apologists. The arguments they present in countering the ideas of people like Prothero are astonishing, I'd link videos but I'd feel like I was passing on disinformation.

Dinosaurs get all the glory in pop culture. But the idea that giant turtle's (about 11 feet long and 8 feet wide) were considered an apex type predator along side 40 foot crocs and 50 foot snakes is utterly fascinating.