The “moment” of fertilization?


What moment? Fertilization is a complex process, with a series of steps.

  • First, the sperm cell binds to the pellucid zone surrounding the egg. This is specific; sperm and egg have to recognize each other and bind appropriately. You don’t want the sperm to bind to every epithelial cell of the reproductive tract, after all, and you don’t want the egg cell to be receptive to every passing white blood cell.

  • This binding triggers the acrosome reaction. The tip of the sperm cell ruptures releasing enzymes that break down the glycoproteins surrounding the egg and exposing the sperm cell membrane and the egg cell membrane locally.

  • Those two membranes then fuse, and the sperm cell nucleus is drawn into the cortex of the egg. This is called docking and invagination.

  • Docking triggers a wave of electrical activity in the egg cell membrane; from the point of entry, a ring of depolarization sweeps rapidly across the egg, causing vesicles to fuse and dump their contents into the space surrounding the egg, creating a barrier to additional sperm trying to enter. This can be visualized using chromophores that change color in response to membrane voltage, or that react to the binding of calcium, the important ion that crosses the membrane at this step.

  • The germinal vesicles, or nuclei, of sperm and egg then move via cytoskeletal transport towards each other and fuse to create a single diploid nucleus.

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Creationists and pterosaurs


Of course they don’t understand the science, and they don’t understand the history, either. The Institute for Creation Research makes an utter botch of the history of our knowledge of pterosaurs, arguing that because scientists have a different view of flying reptiles now than we did when they were first discovered, evolutionists have been getting it wrong all along.

Dave Hone explains why they’re wrong. For one thing, the first pterosaur fossils were found in the 18th century, before Darwin, so it’s kind of silly to pin the errors of interpretation on evolutionists — there weren’t any around. I’d also say it’s rather typical that it takes time and much research to establish an accurate interpretation, so basically this is a case where the creationist is complaining because scientific knowledge progresses.

But another thing leapt out at me in the ICR article.

The evolutionary timeline fails to match the most obvious pterosaur fossil data, but Genesis history readily explains them. First, pterosaur structure was flight-ready from the get-go because God created it to be. Second, a terrible, watery cataclysm like Noah’s Flood buried these winged creatures—often in the same layer as dinosaurs, fish, lizards, small mammals, and birds—leaving behind elegant, fully formed pterosaur fossils with no evidence that intermediary “also-ran” versions ever existed.

Oh, really? Pterosaurs are in the Bible? I don’t think so.

I also note the dishonest elision at the end, that pterosaurs are found in the same “layer” as small mammals. This is true. But these are not the small mammals we are familiar with — no squirrels, no mice, no voles or moles.

It’s all just wall-to-wall lies.

Carrie Poppy reads Of Pandas and People, so you don’t have to


Really, you don’t want to ever have to bother reading Of Pandas and People: The Central Question of Biological Origins, the terrible textbook from the Discovery Institute that was at the heart of the Dover trial. It’s badly written sludge, warmed over creationism (remember “cdesign proponentsists”, the typo that was the result of a botched copy/replace of “design proponents” for “creationists”? That was from this book), and it’s basically an error-filled bad textbook.

Carrie Poppy read it for the Center for Inquiry. I don’t know why. Maybe the editors were playing a cruel trick, like saying “here’s a flashlight and a shovel; I need you to do an important investigative piece exploring my cesspool”, but she survived and has written a brief summary of a few things that leapt out at a lay person reading a pseudoscientific text. It’s entertaining.

But come to think of it, my bathroom sink is clogged. I’m sure there’s a story in it. I wonder if Carrie would like to stop by and venture into the world of old toothpaste, hair, and drainage?

By the way, I also talked about Pandas and the Dover trial in my intro class on Monday. It’s important to remember the ugly bits of history so we don’t repeat them.

“Australia’s biggest ever environmental disaster”

The Great Barrier Reef is dying. We’re killing it.

The corals are bleaching. When stressed, They lose their symbiotic algae, and then they starve and die. What’s stressing them? Rising ocean temperatures. What’s making the ocean temperatures rise? Fossil fuel consumption.

So this was a bit ironic.

As news of the bleaching spread around the globe, the Australian government granted more approvals for what could be Australia’s largest ever coalmine in Queensland’s Galilee basin.

This isn’t just Australia’s fault or Australia’s disaster, though. We could point to the exploitation of oil shales by Canada, or the US’s eagerness to suck in more oil pipelines and blow out more CO2, or China’s enthusiastic conversion of coal into smog. It’s a world-wide catastrophe.

We seem bound and determined to destroy ourselves, do we really need to take out every ecosystem on the planet on our way out?