Texas Tech Wil Play For The Championship -- Having Trounced Top-Seeded Michigan State -- That Is All -- April 7, 2019 -- Oh, Yes, And A Tesla Re-Posting

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This deserves to be re-posted:

Tesla: from SeekingAlpha this morning -- (archived) --

• Tesla is moving from a supply constrained into a demand constrained market for the Model 3.
• The North American backlog for the higher priced variants was exhausted in Q4 of 2018.
• Since then, Tesla has been able to pull other demand levers such as the MR, the EU, and China backlog and the SR variant.
• However, these are creating only short-term pockets of demand, the question of whether there is enough sustained demand for 7,000 or even 5,000/week production remains unanswered.

Tesla: After posting the above, a reader sent me a link to a podcast from the Montana Skeptic re: Tesla. One must absolutely listen to this podcast. The SeekingAlpha link above dovetails perfectly with this podcast at ZeroHedge. 

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The Book Page

One of my favorite books, on my "top shelf": The Mistaken Extinction: Dinosaur Evolution and the Origin of Birds, Lowell Dingus and Timothy Rowe, c. 1998.

With all the current excitement coming out of Bowman, ND, and the Hell Creek Formation this past week, I thought it best to pull it down and review some sections.

In cartoon drawings of evolution, of our ancestors migrating from the ocean to land, we always see a linear progression: fish to amphibians to reptiles to mammals to man.

It was not linear and amphibians are not on the line between fish and reptiles.

There were at least four challenges moving from the sea to land:

• respiration: obvious
• locomotion: on which almost "everyone" seems to focus
• reproduction: the need to keep eggs moist or viable, either internally or externally
• predation: eat or be eaten

The problem of reproduction, how to keep eggs moist or viable, either internally or externally, was "solved" two different ways. Amphibians had one solution; non-amphibians had another solution. Non-amphibians were called amniotes; amniote embryos, whether laid as eggs or carried by the female, are protected and aided by several extensive membranes.

So, that's one "biggie." Solving the "egg" problem two different ways: the amphibians did it one way and the amniotes did it a different way. We did not evolve from amphibians but amphibians and amniotes evolved from a common tetrapod ancestor. 

 The amniotes comprised at least five groups, some extinct, some still living: "reptilia" and mammals. "Reptilia" is sort of a grab-bag grouping of any tetrapod that is not amphibian or mammal. 

I think it's easy for youngsters to "define" and give examples of amphibians and mammals. It is much more difficult to "define" reptiles, though it's easy to come up with examples.

After much difficulty trying to define "reptilia" by what they are, I finally gave up and, instead, defined them by what they are not. "Reptilia" are tetrapods that are neither amphibians nor mammals. And if one doesn't know what a tetrapod is, then "reptiles" are "animals" (in the sense that most five-year-olds define animals) that are not fish, amphibians or mammals. 

Predation: one of the big differences between fish and tetrapods that evolved into reptiles -- "the earliest amniotes have the beginnings of a sophisticated joint between the head and neck, enabling the head to bend and twist form side to side, and to take items from the ground." -- Dingus and Rowe, p. 155. It is interesting to note that frogs, the quintessential (?) amphibian, have no neck, so they cannot turn their head. Only one species of frog has teeth in its lower and upper jaws.

Of the reptilia, we know that birds are warm-blooded. Dinosaurs? Apparently the jury is still out on this one, but the evidence seems to be accumulating that at least some (all?) were warm-blooded. 

If so, the quality of warm-bloodedness is an example of convergent evolution, or saying it another way: warm-bloodedness evolved independently at least twice. (Another example is the eye: the eye in the octopus evolved independently from the eye in tetrapods.)

From Dingus and Rowe, page 156: "Large brains and endothermy are points of resemblance between birds and mammals that evolved convergently within different hierarchies of amniote phylogeny."

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Egg-Laying Mammals

Later, while trying to sort out the last common ancestor before branching off to amphibians and mammals, I pictured that the missing link must be an egg-laying tetrapod. I'm sure there are many scientific articles on this but I'm still looking. One possibility: the egg-laying tetrapod laid eggs on the ground (or in a tree, etc) but those terrestrial eggs were subject to terrestrial predators. Could it be possible that the amphibians were siblings of egg-laying reptile-like mammals but evaded predators on land by returning to the water. 

This is the theory regarding the platypus, the marsupial, and the placental. All three had a common ancestor but the platypus "broke away" long before the marsupial and the placental separated. The last common ancestor lived on land, but the platypus returned to the water to escape land-based predators.