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Death comes to the Amazon

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 Death comes to the Nile Amazon Amazon River Dolphin (modified from Scientific American). Hot temperatures are again hitting the Amazon River and its tributaries. In 2023, temperature spikes in and around Lago Tefé killed hundreds of river dolphins. Tefé is located in the heart of Amazonas, approximately 400 miles up the Amazon River from Manaus, the capital of the region. As a whole, the region is sparsely populated, as Manaus is one of the two cities that have a large population of over 1 million.  Once again, temperatures are rising, and combined with regional droughts, this has created another deadly zone. In November, the lake's waters reached 41 degrees Celsius (105.8 degrees Fahrenheit). David Hannah said, "Drought conditions often coincide with high atmospheric temperatures, and such trends will become more intense and frequent with climate change." Additionally, droughts have lowered the lake levels, leading to new problems. The issue extends beyond just one lak...
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Have a Heart

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  Figure 1. Shark Heart (author's original image) Hearts have been on my mind lately.    We, humans that is, of course, have a four-chambered heart. We have two atria and two ventricles. The right side carries blood low in oxygen, and the left side, having just returned from the lungs, carries blood high in oxygen. We share this heart anatomy with the other mammals, birds, and crocodiles.    Found in most amphibians and some reptiles is a three-chambered heart with two atria and one ventricle, which allows mixing of oxygenated and deoxygenated blood. That is a bit freaky in my view: oxygenated blood and deoxygenated blood mix in the central chamber; whoever thought this was a good design?    Most animals in the kingdom do not have hearts with 3 or 4 chambers. The most speciose vertebrates, scaly fishes, have a two-chambered heart. Suppose we follow the blood flow in 18-spined sculpin (AKA long-horned sculpin),  Myoxocephalus octodecimspinosus...
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Northern Movements

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  Dusky Shark (from Blueplanetarchive.com) A recent science paper noted Dusky Sharks feeding on Gray Seals off Cape Cod.  The Dusky Shark, Carcharhinus obscurus , is a subtropical to temperate species that roams further north during the warm months; it is not known to enter the icy northern waters north of the Gulf of Maine. Expectably, they tend to be rare north of the New England coast. That was then; this is now. We have already entered a new world of warming.  Dusky Sharks can grow to be quite large, reaching lengths of over 3 meters, or more than 10 feet. They are feeders on fish, lots of fish, and will, apparently, also go in for those nice succulent seals. Thisis not something they were thought to feed on much. However, those cheeseburgers dotting the coastline, hauling out on rocks, must be a pleasant sight for a hungry shark.  The abundance of seals makes them a central target for shark species. These marine mammals are abundant in late August all along the ...
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Much maligned Lamarck was one of the greats

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  His full name,  Jean-Baptiste Pierre Antoine de Monet, chevalier de Lamarck (1 August 1744 – 18 December 1829), is not familiar to most people, they, those hoards of biology 101 students, just know him as Lamarck. Lamarck is best known to biology students as the guy who screwed up the mechanism for evolution in 1809. The use or disuse model, with the inheritance of aquired characters. A few points on this: First, this is how science is supposed to proceed. Ideas get proposed, and over time get solidified or thrown out.  As Francis Crick stated, most hypothesis are wrong. However, if they were not proposed than the wrongness would not have been determined. As Neil deGrasse Tyson has said,  The scientific method is doing its best to be wrong—until it's not . Lamarck did understand that organisms changed over time, that is that evolution occurred, long before most of his contempararies. We should remember Lamarck for his accomplishments, including his attempt at the ...
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