Tuesday, July 19, 2016

What I Learned Last Week

1. A single Gypsy moth may not amount to much, but collectively ... [nasa]
The ecological consequences of gypsy moth outbreaks are often cosmetic, but they can become serious. Deciduous trees can normally withstand one or two years of defoliation by caterpillars, but three or more successive years of severe defoliation can result in widespread tree mortality.
2. Orcas are dolphins too! [wnyc]

On the Lennard Lopate show, I learned that killer whales are really dolphins. The label "whale" apparently has no biological meaning - it is an informal term that generally means "big". Thus, we have whale sharks (world's biggest fish), and blue whales (world's biggest mammal).

3. Swordfish and drag reduction [nationalgeographic]
So Videler thinks that the gland is yet another drag-reducing adaptation. Its oil repels water and allows incoming currents to flow smoothly over the surface of the bill. That depends on the oil staying warm, but swordfish have a solution for that, too. They have modified some of their eye muscles into heat-producing organs that warm their blood and sharpen their vision as they hunt. This same heating effect could liquefy the drag-reducing oil, allowing it to ooze out of the glands just as the fish have the greatest need for speed.

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