A reader draws our attention to an interesting article on egg-laying vs. other strategies for getting them out there. It’s based on studies of a lizard that can alternate between egg-laying and live bearing.
But as animals became more complex, vertebrate species — including many amphibians, reptiles and even some fish, like sharks — turned to a less chancy strategy: internal fertilization. Females could then ensure that a higher percentage of their eggs would be fertilized, and they could get more selective about which males they would breed with. The embryo could develop safely inside its mother until she eventually released it inside a protective shell…
The major difference between oviparity and viviparity therefore centers on a strategic evolutionary decision about when the mother should deposit her embryos. If she deposits them early, she’s an egg layer, and if she deposits them late, she’s a live bearer. Most reptiles, for instance, deposit their embryos just a third of the way through their development.
Dana Najjar, “Egg Laying or Live Birth: How Evolution Chooses” at Quanta
“Turned to a less chancy strategy”? “Centers on a strategic evolutionary decision”?
You’d think these reptiles were corporate CEOs strategizing a marketing plan in challenging times.
And then we read,
“Evolution is a random process rather than being directed,” Whittington said. “With environmental changes, it could change the direction of selection and push it back the other way.”
Dana Najjar, “Egg Laying or Live Birth: How Evolution Chooses” at Quanta
Hey, if we are going to knock design out of nature, we can’t go and lay the entire burden of higher end thinking on the lizard. Either nobody is thinking or somebody is, and that somebody had better be able to.
When people have been taught Darwinism from an early age in school, they often don’t appreciate the difficulty. As long as stuff sounds sufficiently Darwinian, it needn’t make any sense. Better if it doesn’t. That reduces the temptation to doubt—a temptation that is ever-present when an incorrect proposition actually makes sense.
Skinks can give birth without eggs: