Newly found species fills evolutionary gap between fish and land animals

Paleontologists have discovered fossils of a species that provides the missing evolutionary link between fish and the first animals that walked out of water onto land about 375 million years ago. The newly found species, Tiktaalik roseae, has a skull, a neck, ribs and parts of the limbs that are similar to four-legged animals known as tetrapods, as well as fish-like features such as a primitive jaw, fins and scales.

These fossils, found on Ellesmere Island in Arctic Canada, are the most compelling examples yet of an animal that was at the cusp of the fish-tetrapod transition. The new find is described in two related research articles highlighted on the cover of the April 6, 2006, issue of Nature.

"Tiktaalik blurs the boundary between fish and land-living animal both in terms of its anatomy and its way of life," said Neil Shubin, professor and chairman of organismal biology at the University of Chicago and co-leader of the project.

Tiktaalik was a predator with sharp teeth, a crocodile-like head and a flattened body. The well-preserved skeletal material from several specimens, ranging from 4 to 9 feet long, enabled the researchers to study the mosaic pattern of evolutionary change in different parts of the skeleton as fish evolved into land animals.

The high quality of the fossils also allowed the team to examine the joint surfaces on many of the fin bones, concluding that the shoulder, elbow and wrist joints were capable of supporting the body-like limbed animals.

"Human comprehension of the history of life on Earth is taking a major leap forward," said H. Richard Lane, director of sedimentary geology and paleobiology at the National Science Foundation. "These exciting discoveries are providing fossil 'Rosetta Stones' for a deeper understanding of this evolutionary milestone--fish to land-roaming tetrapods."

One of the most important aspects of this discovery is the illumination of the fin-to-limb transition. In a second paper in the journal, the scientists describe in depth how the pectoral fin of the fish serves as the origin of the tetrapod limb.

Embedded in the fin of Tiktaalik are bones that compare to the upper arm, forearm and primitive parts of the hand of land-living animals.

"Most of the major joints of the fin are functional in this fish," Shubin said. "The shoulder, elbow and even parts of the wrist are already there and working in ways similar to the earliest land-living animals."

At the time that Tiktaalik lived, what is now the Canadian Arctic region was part of a landmass that straddled the equator. It had a subtropical climate, much like the Amazon basin today. The species lived in the small streams of this delta system. According to Shubin, the ecological setting in which these animals evolved provided an environment conducive to the transition to life on land.

"We knew that the rocks on Ellesmere Island offered a glimpse into the right time period and the right ancient environments to provide the potential for finding fossils documenting this important evolutionary transition," said Ted Daeschler of the Academy of Natural Sciences in Philadelphia, a co-leader of the project. "Finding the fossils within this remote, rugged terrain, however, required a lot of time and effort."

The nature of the deposits where the fossils were found and the skeletal structure of Tiktaalik suggests the animal lived in shallow water and perhaps even out of the water for short periods.

"The skeleton of Tiktaalik indicates that it could support its body under the force of gravity whether in very shallow water or on land," said Farish Jenkins, professor of organismic and evolutionary biology at Harvard University and co-author of the papers. "This represents a critical early phase in the evolution of all limbed animals, including humans--albeit a very ancient step."

The new fossils were collected during four summers of exploration in Canada's Nunavut Territory, 600 miles from the North Pole, by paleontologists from the Academy of Natural Sciences in Philadelphia, the University of Chicago and Harvard University. Although the team has amassed a diverse assemblage of fossil fish, Shubin said, the discovery of these transitional fossils in 2004 was a vindication of their persistence.

The scientists asked the Nunavut people to propose a formal scientific name for the new species. The Elders Council of Nunavut, the Inuit Qaujimajatuqangit, suggested "Tiktaalik" (tic-TAH-lick)--the word in the Inuktikuk language for "a large, shallow water fish."

The scientists worked through the Department of Culture, Language, Elders and Youth in Nunavut to collaborate with the local Inuit communities. All fossils are the property of the people of Nunavut and will be returned to Canada after they are studied.

The team depended on the maps of the Geological Survey of Canada. The researchers received permits from the Department of Culture, Language, Elders and Youth of the Government of Nunavut, and logistical support in the form of helicopters and bush planes from Polar Continental Shelf Project of Natural Resources Canada. The National Science Foundation and the National Geographic Society, along with an anonymous donor, also helped fund the project.

Most of the New Testament consists of eyewitness accounts and moral arguments.

and LOTS of references to 'scriptures'. (Guess which ones...)

NIV Acts 1:16-17
16. and said, "Brothers, the Scripture had to be fulfilled which the Holy Spirit spoke long ago through the mouth of David concerning Judas, who served as guide for those who arrested Jesus--
17. he was one of our number and shared in this ministry."

NIV Acts 8:32-35
32. The eunuch was reading this passage of Scripture : "He was led like a sheep to the slaughter, and as a lamb before the shearer is silent, so he did not open his mouth.
33. In his humiliation he was deprived of justice. Who can speak of his descendants? For his life was taken from the earth."
34. The eunuch asked Philip, "Tell me, please, who is the prophet talking about, himself or someone else?"
35. Then Philip began with that very passage of Scripture and told him the good news about Jesus.

NIV Acts 17:2-4
2. As his custom was, Paul went into the synagogue, and on three Sabbath days he reasoned with them from the Scriptures,
3. explaining and proving that the Christ had to suffer and rise from the dead. "This Jesus I am proclaiming to you is the Christ, " he said.
4. Some of the Jews were persuaded and joined Paul and Silas, as did a large number of God-fearing Greeks and not a few prominent women.

NIV Acts 17:11-12
11. Now the Bereans were of more noble character than the Thessalonians, for they received the message with great eagerness and examined the Scriptures every day to see if what Paul said was true.
12. Many of the Jews believed, as did also a number of prominent Greek women and many Greek men.

NIV Acts 18:24-28
24. Meanwhile a Jew named Apollos, a native of Alexandria, came to Ephesus. He was a learned man, with a thorough knowledge of the Scriptures.
25. He had been instructed in the way of the Lord, and he spoke with great fervor and taught about Jesus accurately, though he knew only the baptism of John.
26. He began to speak boldly in the synagogue. When Priscilla and Aquila heard him, they invited him to their home and explained to him the way of God more adequately.
27. When Apollos wanted to go to Achaia, the brothers encouraged him and wrote to the disciples there to welcome him. On arriving, he was a great help to those who by grace had believed.
28. For he vigorously refuted the Jews in public debate, proving from the Scriptures that Jesus was the Christ.

NIV Romans 1:1-4
1. Paul, a servant of Christ Jesus, called to be an apostle and set apart for the gospel of God--
2. the gospel he promised beforehand through his prophets in the Holy Scriptures
3. regarding his Son, who as to his human nature was a descendant of David,
4. and who through the Spirit of holiness was declared with power to be the Son of God by his resurrection from the dead: Jesus Christ our Lord.

NIV Romans 4:3-8
3. What does the Scripture say? "Abraham believed God, and it was credited to him as righteousness."
4. Now when a man works, his wages are not credited to him as a gift, but as an obligation.
5. However, to the man who does not work but trusts God who justifies the wicked, his faith is credited as righteousness.
6. David says the same thing when he speaks of the blessedness of the man to whom God credits righteousness apart from works:
7. "Blessed are they whose transgressions are forgiven, whose sins are covered.
8. Blessed is the man whose sin the Lord will never count against him."

NIV Romans 10:11-13
11. As the Scripture says, "Anyone who trusts in him will never be put to shame."
12. For there is no difference between Jew and Gentile--the same Lord is Lord of all and richly blesses all who call on him,
13. for, "Everyone who calls on the name of the Lord will be saved."

NIV Romans 15:3-4
3. For even Christ did not please himself but, as it is written: "The insults of those who insult you have fallen on me."
4. For everything that was written in the past was written to teach us, so that through endurance and the encouragement of the Scriptures we might have hope.

NIV 1 Corinthians 15:3-5
3. For what I received I passed on to you as of first importance : that Christ died for our sins according to the Scriptures,
4. that he was buried, that he was raised on the third day according to the Scriptures ,
5. and that he appeared to Peter, and then to the Twelve.

NIV Galatians 3:8
The Scripture foresaw that God would justify the Gentiles by faith, and announced the gospel in advance to Abraham: "All nations will be blessed through you."

NIV Galatians 3:16
The promises were spoken to Abraham and to his seed. The Scripture does not say "and to seeds," meaning many people, but "and to your seed," meaning one person, who is Christ.

NIV Galatians 3:22
But the Scripture declares that the whole world is a prisoner of sin, so that what was promised, being given through faith in Jesus Christ, might be given to those who believe.

NIV 2 Timothy 3:14-15
14. But as for you, continue in what you have learned and have become convinced of, because you know those from whom you learned it,
15. and how from infancy you have known the holy Scriptures, which are able to make you wise for salvation through faith in Christ Jesus.

NIV 1 Peter 2:4-8
4. As you come to him, the living Stone--rejected by men but chosen by God and precious to him--
5. you also, like living stones, are being built into a spiritual house to be a holy priesthood, offering spiritual sacrifices acceptable to God through Jesus Christ.
6. For in Scripture it says: "See, I lay a stone in Zion, a chosen and precious cornerstone, and the one who trusts in him will never be put to shame."
7. Now to you who believe, this stone is precious. But to those who do not believe, "The stone the builders rejected has become the capstone, "
8. and, "A stone that causes men to stumble and a rock that makes them fall." They stumble because they disobey the message--which is also what they were destined for.

NIV 2 Peter 3:16
He writes the same way in all his letters, speaking in them of these matters. His letters contain some things that are hard to understand, which ignorant and unstable people distort, as they do the other Scriptures, to their own destruction.

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.