Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture Money Videos
Pikaia gracilens
Directory
References
Discover
The Colosseum, Rome, Italy. Giant amphitheatre built in Rome under the Flavian emperors. (ancient architecture; architectural ruins)
New Seven Wonders of the World
Snowshoe hare (Lepus americanus) with its Summer coat on the left side and its winter coat on the right.
7 Animals That Turn White in Winter
cloning. First cloned cat. First cloned companion animal. CC (copy cat) female domestic shorthair cat (b. Dec. 22, 2001) photo Jan. 18, 2002. Cloned at Texas A&M Univ. College of Vet. Med. & Biomedical Sciences. Reproductive cloning genetics DNA cc cat
CC, The First Cloned Cat
Andrew Jackson delivering a speech while on his way to Washington, D.C., for his inauguration in 1829. From Harper's Weekly, 1881.
5 Remarkably Close U.S. Presidential Elections
New York NY/ USA- November 23, 2018 Hordes of shoppers throng the Macy's Herald Square flagship store in New York looking for bargains on the day after Thanksgiving, Black Friday.
Why Is It Called Black Friday?
Ahura Mazda - relief of the Zoroastrian god Ahura Mazda at the ancient ruins of Persepolis in Iran. Also known as Ormazd Zoroastrianism,
Which Religion Is the Oldest?
Set of emoticon. Smile icon set.
What’s the Difference Between Emoji and Emoticons?

Pikaia gracilens

paleontology

Learn about this topic in these articles:

chordates

  • Chordate
    In chordate: Evolution and paleontology

    …oldest known fossil chordate is Pikaia gracilens, a primitive cephalochordate dated to approximately 505 million years ago. There is disagreement over whether older animals—such as Yunnanozoon lividum and Haikouella (both of which date to 530 million years ago and possess several chordate features)—should be considered chordates. An extensive vertebrate fossil…

    Read More