Wednesday, September 20

Amazing New Fossil Find Further Solidifies Human Evolution Picture

A new fossil, dated 3.3Mya and likened to "Lucy's baby" was discovered in nearly-perfect condition; this being a rare, once-in-a-lifetime type hominid discovery. It appears that this story just broke a few hours ago, as the findings were published in tomorrow's edition of Nature. For details:
CBS
World Science

How much longer will creationists be able to live in la-la land, I have to wonder?

The full-text of the World Science article is tucked below the fold:

“Lucy’s Baby”: pre-human fossil dazzles scientists
Sept. 20, 2006
Special to World Science

Re­search­ers say they’ve unearthed the pos­sib­ly most com­plete known fos­sil of a fore­bear of hu­mans: a ba­by of the same spe­cies as the famed “Lu­cy” fos­sil found in 1974.

Human-like be­low the waist, ape-like above, the tot is a “once-in-a-lifetime” find, said Ethi­o­pi­an pa­le­oan­thro­po­lo­gist Ze­re­se­nay Al­em­se­ged, who led the sci­en­tif­ic team cre­d­ited with the dis­cov­er­y.

De­scribed as the skull of an Aus­tra­lo­pi­the­cus afa­ren­sis ba­by, this meas­ures about 12 cm (5 inches) from the bot­tom of the chin to the top of the head ver­ti­cal­ly. (Image Cour­te­sy Ze­re­se­nay Al­em­seged; © Au­tho­r­i­ty for Re­search and Con­ser­va­tion of Cul­tur­al He­r­i­ta­ges).
The find re­vived me­m­o­ries of “Lu­cy,” be­lieved to be a fe­male in her mid-20s and hailed, when dis­cov­ered, as the most com­p­lete known ske­l­e­ton of a pre-hu­man ho­m­i­nid. A ho­m­i­nid is a spe­cies on the hu­man branch of the ev­o­lu­tion­a­ry tree.

The new spe­ci­men, dubbed “Lu­cy’s ba­by” by some—though it’s ac­tu­al­ly thought to have lived a bit ear­li­er than Lu­cy—is like­wise caus­ing a stir over its splen­did con­di­tion.

That, sci­en­tists say, makes it a trea­s­ure trove of ad­di­tio­n­al clues to hu­man ori­gins.

Years ago, Lu­cy, in many re­search­ers’ view, over­turned a wide­spread as­sump­tion: that our an­ces­tors evolved in­tel­li­gence first and up­right walk­ing la­ter. She was seen to re­fute that be­cause her bones sug­ges­ted at least some up­right-walk­ing abi­l­i­ty, yet a small, ape-like brain.

This helped re­vive a no­tion pro­posed by Charles Dar­win: that up­right move­ment spurred brain evo­lu­tion by free­ing hands for tool use. Hence­forth, suc­cess in the bat­tle for sur­vi­val would de­pend on ever-bet­ter tool use, and the brains to en­able it.

Like Lucy, the new­found child shows the marks of a spe­cies able to walk up­right, re­search­ers said; it also of­fers more clues to the ev­o­lu­tion of that skill, and of the brain and speech. It’s a “mine of in­for­ma­tion about a cru­cial stage in hu­man ev­o­lu­tion­ary his­to­ry,” wrote pa­le­o­bi­o­lo­gist Ber­nard Wood of George Wash­ing­ton Uni­ver­si­ty in Wash­ing­ton, D.C., in a com­men­tary in the Sept. 21 is­sue of the re­search jour­nal Na­ture.

The sci­en­tists cred­ited with the find de­s­c­ribed it in ano­ther pa­per in the same is­sue. They es­ti­mat­ed that the in­fant died at age three, pos­si­bly in a flood that al­so bur­ied it in peb­bles and sand, help­ing pre­serve it.

Artist's conception of a mo­ther and child Aus­tra­lo­pi­the­cus afaren­sis. Ad­ult fe­males of the spe­cies were some 3½ feet tall, judg­ing from the "Lucy" spe­ci­men.
Lu­cy and the ba­by, which date to slight­ly more than three mil­lion years ago, are far from the old­est known mem­bers of the hu­man fam­i­ly.

That dis­tinc­tion be­longs to the chimp-sized Sa­he­lan­thro­pus tchaden­sis or “Toumai Man,” es­ti­mat­ed as sev­en mil­lion years old and found in Cen­tral Af­ri­ca four years ago.

But Lu­cy and the tot—said to re­p­re­sent a lat­er spe­cies, Aus­tra­lo­pi­the­cus afaren­sis—would be part of a burst of hom­i­nid di­ver­si­ty noted in the fossil re­cord from four to two mil­lion years ago.

This is thought to re­flect some of the rich ev­o­lu­tion­a­ry ex­per­i­men­ta­tion that na­ture tossed up on the way to pro­duc­ing our spe­cies, Ho­mo sapi­ens. Ho­minids of that pe­ri­od are col­lec­tive­ly called Aus­tralo­p­iths. Which line­age led to us is un­known, though.

The new­found bun­dle of bones, found like Lu­cy in the Ethi­o­pi­an de­sert, is ar­guably the best fos­sil of its spe­cies ev­er found, its disco­verers said. They judged that it lived 3.3 mil­lion years ago, com­pared to 3.2 mil­lion for Lu­cy, and was al­so fe­male.

“The most im­pres­sive dif­fer­ence be­tween them is that this ba­by has a face,” said team lead­er Ze­re­se­nay (E­thi­o­pi­ans’ first names are their for­mal names.) This face gave away the spe­cies, added Ze­re­se­nay, of the Max Planck In­sti­tute for Ev­o­lu­tion­ary An­thro­pol­o­gy in Leip­zig, German­y.

Al­so un­like Lu­cy—nick­named after a Beat­les song—the ba­by has fin­gers, a foot and a tor­so. Tooth struc­tures clued re­search­ers in to its rough age and its sex, they said, while the se­di­ments that had trapped it re­vealed its time period.

The tot helps ex­p­lain how A. a­fa­ren­sis blurred ape-hu­man bound­aries, Ze­re­se­nay said: her shoul­der blades re­sem­ble a young go­ril­la’s, sug­gest­ing she could climb trees, but her thigh bone is an­gled like hu­mans’, im­ply­ing good up­right walk­ing abil­i­ty. Members of the spe­cies seem to have been for­ag­ing, up­right walk­ers, ca­pa­ble of “climb­ing trees when nec­es­sar­y, es­pe­cial­ly when they were lit­tle,” he said.

Ze­re­se­nay first led a band of fos­sil hunters in­to Ethi­o­pi­a’s Dikika re­gion in 1999, re­search­ers re­counted. Pun­ish­ing heat, flash floods, ma­lar­i­a, wild beasts and oc­ca­sion­al shootouts be­tween ri­val eth­nic groups plague the zone.

On a shade­less De­cem­ber day the next year, the sci­en­tists re­called, they hunt­ed un­der a pound­ing sun for the prize that had elud­ed them—our ape-like fore­bears. Team mem­ber Tilahun Ge­bre­se­lassie then spot­ted the tot’s face, no big­ger than a mon­key’s, peer­ing out from a dusty slope.

Tucked be­neath it in hard sand­stone were more bones, the whole bun­dle of them no big­ger than a can­te­loupe, one fin­ger still curled in a ti­ny grasp, re­search­ers said. Ze­re­se­nay found a rare ex­am­ple of a hy­oid bone, a throat struc­ture lat­er cru­cial to hu­man speech, he said. This of­fers a glimpse of the ev­o­lu­tion of the voice box, which un­der some the­o­ries is in­t­er­wo­ven with that of speech.

Ze­re­se­nay spent the next five years scratch­ing away rock from the skel­e­ton with a den­tist’s drill, ac­cord­ing to mem­bers of his team.

What killed the ba­by is un­clear. But it seems the an­cient Awash Riv­er rap­id­ly bur­ied the body in a flood, the sci­en­tists said, pre­serv­ing rare de­tails such as a full set of both milk teeth and un­e­rupt­ed adult teeth. The brain cast will help reveal “wheth­er our ear­li­est an­ces­tors grew their brains in the uniquely hu­man way,” said a mem­ber of the re­search group, Fred Spoor of Uni­ver­si­ty Col­lege Lon­don.

One of her hu­manlike knees was com­plete with a knee­cap no big­ger than a dried pea, re­search­ers said. But her up­per bod­y, like Lu­cy’s, had many ape­like fea­tures: small brain, nose flat like a chim­p’s, face pro­ject­ing for­ward. Her two com­plete shoul­der blades are the first found from an aus­tralo­p­ith, Ze­re­se­nay said; an­a­lyz­ing their func­tion “will be among the ex­cit­ing chal­lenges that we will face.”
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2 comments:

  1. "How much longer will creationists be able to live in la-la land, I have to wonder?"

    Given the track record of how much evolutionists over-hype fossil discoveries, it shouldn't be any wonder why I, for one, will remain skeptical for now.

    ReplyDelete
  2. But skeptical of what, exactly?

    That whether you accept human evolution or not, the evidence for it is loud and clear? And this is further evidence of it?

    I am responding to nanosplit's haloscan comment, and this one as well, in my next post.

    ReplyDelete