Biology – Page 2 – The Progressive Democrat

24,000-Year-Old Body Shows Kinship to Europeans and American Indians

Scientists studied the genome of a boy buried near Lake Baikal in Siberia and were amazed to find partly European ancestry.

The genome of a young boy buried at Mal’ta near Lake Baikal in eastern Siberia some 24,000 years ago has turned out to hold two surprises for anthropologists.

The first is that the boy’s DNA matches that of Western Europeans, showing that during the last Ice Age people from Europe had reached farther east across Eurasia than previously supposed. Though none of the Mal’ta boy’s skin or hair survives, his genes suggest he would have had brown hair, brown eyes and freckled skin.

The second surprise is that his DNA also matches a large proportion — about 25 percent — of the DNA of living Native Americans. The first people to arrive in the Americas have long been assumed to have descended from Siberian populations related to East Asians. It now seems that they may be a mixture between the Western Europeans who had reached Siberia and an East Asian population.

A Simple Prairie Garden

Opuntia humifusa, rescued from a vacant lot in downtown Oklahoma City.

View photo gallery here.

Hummingbirds: hovering on the brink of extinction

I have been fascinated by hummingbirds ever since I was given a pack of wild animal cards in hospital while my tonsils were removed and fell in love with Heliothrix aurita, a speck of fire and jade. And also wine-red Topaza pella, perched in a jungle whisking a crimson tail.

I still have those cards. Their pictures seem crude now, but when I was eight I was enraptured. The Aztecs said the Earth’s first flower was fathered by the god of poetry in the shape of a hummingbird; and everything about hummingbirds seems tailor-made for a poet.

Birds see ultraviolet light, and female hummingbirds have a taste for iridescence, so males have turned themselves into flying jewels. Their metallic sheens, glancing as soap bubbles, are reflected in equally iridescent names for which taxonomists have plundered all the shimmer in the lexicon.

There are more than 300 species: words such as emerald, copper, bronze, gold, fire, sapphire, lazuline, emerald and sunbeam spill like Aladdin’s treasure through the list: amethyst woodstar, blue-headed sapphire, Brazilian ruby, buff-winged starfrontlet – you marvel not only at nature’s capacity for spangly variation but the human urge to match it in language.

Hummingbird nests – the size of a nutshell, spun out of plant down, covered with lichen, bound by spider’s silk – are works of art straight out of A Midsummer Night’s Dream. Hummingbird tongues, almost transparent, are liquid-trapping miracles of bioengineering that change shape as they flick in and out of the nectar. Their tips are forked: the V’s inside edges have feathery tufts that draw in nectar by capillary action. When hummingbirds sleep they fall into hibernation-like torpor. Metabolism drops, temperature zooms to near-hypothermic levels and breathing slows so drastically that if you find a sleeping hummingbird you think it’s dead. Which, in the Peruvian Andes, makes it a symbol of resurrection.

Monarch butterfly numbers drop to new lows

Few monarchs in eastern Canada this year

The number of monarch butterflies now on their migration to Mexico appear to to be at record lows. A monarch feeds on silky red milkweed, in a monarch way station as part of Monarch Watch, a continental effort to create backyard habitats for the butterflies along their migratory routes. (Steve Smedley/The Pantagraph/Associated Press)

Monarch butterflies appear headed for a perhaps unprecedented population crash, according to scientists and monarch watchers who have been keeping tabs on the species in their main summer home in Eastern and Central North America.

There had been hope that on their journey north from their overwintering zone in Mexico, the insects’ numbers would build through the generations, but there’s no indication that happened.

Only a small number of monarchs did make it to Canada this summer to propagate the generation that has now begun its southern migration to Mexico, and early indications are that the past year’s record lows will be followed by even lower numbers this fall.

Elizabeth Howard, the director and founder of Journey North, a citizen-scientist effort that tracks the migrations of monarchs and other species, says one indicator for the robustness of the monarchs is the number of roosts they form in late August and September, something Journey North monitors throughout the migration periods.