The chicken or the egg
causality dilemma is commonly stated as "which came first, the chicken or the egg?" To ancient philosophers, the question about the first chicken or egg also evoked the questions of how life and the universe in general began.In yet another absolutely amazing display of nature's prowess, the contents of the egg are wrapped in a perfect, seamless, incredibly strong shell as though by magic! Eggs are objects of art. It turns out the chicken has little to do with the formation of an egg's shell -- the egg actually grows the shell around itself!
It does this using processes that are also seen in bones and seashells.Why do eggs become hard when you boil them?
Renowned paleontologist Jack Horner has spent his career trying to reconstruct a dinosaur. He's found fossils with extraordinarily well-preserved blood vessels and soft tissues, but never intact DNA. So, in a new approach, he's taking living descendants of the dinosaur (chickens) and genetically engineering them to reactivate ancestral traits — including teeth, tails, and even hands — to make a "Chickenosaurus".
To look at the evolution of modern bird feathers, we must start a long time ago, with the dinosaurs from whence they came. We see early incarnations of feathers on dinosaur fossils, and remnants of dinosaurs in a bird’s wish bone. Carl Zimmer explores the stages of evolution and how even the reasons for feathers have evolved over millions of years.
How can a “thumbs up” sign help us remember five processes that impact evolution? The story of the Five Fingers of Evolution gives us a clever way of understanding change in gene pools over time.
How does evolution really work? Actually, not how some of our common evolutionary metaphors would have us believe. For instance, it's species, not individual organisms, that adapt to produce evolution, and genes don't "want" to be passed on -- a gene can't want anything at all! Alex Gendler sets the record straight on the finer points of evolution.