reptiles – Page 2 – Heraclitean Fire

Next up is the Leatherback Turtle, Dermochelys coriacea.

I’ve wanted to seeone of these since I saw a stuffed specimen at the Natural History Museum as a kid. I couldn’t believe how big it was. They grow to eight feet long and bulky with it. As you can see in this picture of people from the Monterey Bay National Marine Sancturay tagging a leatherback, that’s quite big:

Reptiles evolved as land animals, of course; that’s the point of having waterproof skin and laying leathery eggs. But they’ve returned to the water 16 times over the course of evolutionary history. Remarkably, although the marine turtles evolved from a tortoise-like land animal, modern tortoises are evolved from aquatic ancestors; which means they came out of the sea, went back in, then came out again.

The shells of tortoises and turtles are evolved from their ribs, rather freakily, so they’re all hollow inside:

Leatherbacks mainly eat jellyfish, which is very public-spirited of them, and so they often die after choking on plastic bags. Their distinctive appearance is due to them having lost the bony shell in favour of a thick rubbery skin stiffened with cartilage and small bits of bone (that skeleton above is some other kind of turtle). Leatherback-type turtle fossils have been found as far back as the Eocene, apparently (i.e. over 35 million years ago), but D. coriacea is the only surviving species.

Anyway, I seem to have wandered from ‘why I would like to see a leatherback’ (recap: they’re really big!) to a list of turtle-facts. So before it gets any geekier, assuming that’s even possible – finis.

[EDIT: People keep finding this site by Googling ‘the difference between reptiles and amphibians’ This is the basic answer:

Amphibians are frogs, toads, newts, salamanders and caecilians.

Reptiles are snakes, tortoises, turtles, lizards, crocodiles, alligators and a few other oddities. Dinosaurs were reptiles.

Reptiles are more fully adapted to life on land than amphibians. The biggest difference is that amphibians typically need to return to the water to breed, because their eggs need to be kept wet. Reptile eggs have a tough outer shell that prevents them from drying up.

Amphibians [with a few minor exceptions] have a larval stage (i.e. tadpoles/polliwogs) when they breathe underwater through gills; when they become adult, they develop lungs and need to come to the air to breathe. Reptiles have lungs from the moment they leave the egg.

As a further adaptation to life on land, reptiles have scales. Amphibians have smooth skins, and many species need a fairly damp environment so they don’t lose too much water through their skin, although some are adapted to much dryer conditions.

Mammals and birds are evolved from reptiles. ~~Reptiles are evolved from amphibians.~~ correction: amphibians and reptiles evolved separately from an early tetrapod ancestor. Amphibians are evolved from fish.

I hope that helps, Google-people. END OF EDIT]

The first in an occasional series of things which are ‘Something Every Educated Person Should Know’.

When I was at university, as someone interested in science but doing a degree in English, I was frequently annoyed by the wilful ignorance of both academics and students on scientific topics. And I mean wilful – they took a coy, self-deprecating pride in not knowing about ‘those kind of things’. I just think there’s no excuse for taking pride in your ignorance about anything, whether it’s the Britney Spears back-catalogue, Slovakian dialling codes or the second law of thermodynamics.

Anyway, that’s when I started fantasising about writing a book called What Every Educated Person Should Know, which would just lay down the minimum that anyone ought to know who thinks of themselves as educated. Most of the things I thought of then were scientific; I can’t believe it doesn’t bother people that their understanding of how the universe works is often three hundred years out of date. But it would also cover literature, art, geography, politics and general knowledge of all kinds (I don’t claim to know everything, btw – a musician’s list of SEEPSKs would certainly catch me out – this is just a venue for my irritability).

So, SEEPSK #1. One of the presenters on Today this morning had to correct himself after a flood of emails about his reference to a salamander as a reptile. I think it was Edward Stourton, educated at Ampleforth and Trinity College Cambridge, and the man doesn’t know a reptile from an amphibian. Aargh!