ANT%20151%2005

ANT%20151%2005 - 1 Lecture 5 The Rise of Primates Before...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 Lecture 5 The Rise of Primates Before the Primates To understand the origin of primates we must first understand something about the Earths ancient history. We need to place primates in context with the rest of the world. Earths ancient origin We know that the Universe is ~15 to 20 billion years old, so the Earth itself is a late-comer in being only 4.5 billion years old. Life seems to have taken only a short time to get started- we have many fossils back to 3.5 billion years, so life was probably around well before that date. Larger life forms- such as worms- dont appear until ~600 million years ago during a period called the Cambrian. The Cambrian exploded with life. It began the Paleozoic Era- the old age of animals (600-250 mya). So lets take a closer look at the Paleozoic. During the Cambrian, all major phyla living today appeared and they showed up within a very short period or time, within a span of about 5 million years. This has been called the Cambrian Explosion. Eyes first appeared about 543 mya in trilobites and its been argued that the Cambrian Explosion occurred because vision made it possible for animals to actively pursue their prey. 2 Which also led to the evolution of hard body parts such as teeth and jaws to assist in predation. Anomalocaris may have been the largest predator in the Cambrian seas. It was about 1.5 ft. (half a meter) long. And in response, other hard body parts, such as shells, evolved for protection against predators. This is called the Light Switch theory (see FTS , p. 44-45) If the Light Switch theory is true, then it means that vision has been associated with predators-prey relationships for a very long time. Perhaps a change in the atmosphere allowed more light to penetrate into the oceans. During the first part of the Paleozoic all life seems to have lived in the oceans. The land seems to have been barren and plants did not appear on land until the middle of the Paleozoic around 400- 450 my. The first land animal was a scorpion-like thing at about 375 my. Beginning at about 370 million years ago, some fish developed legs to crawl from water to land. "Another great moment in evolution" 6 April 2006 Nature reports on the missing link between lobe-fined fish and terrestrial tetrapods Tiktaalik intermediate between fish with fins and limbs like tetrapods Late Devonian (375 mya) 2 April 2004 Science reported discovery of early tetrapod Fins became fingers that could walk on land in the late Paleozoic, about 370 to 360 million years ago. 3 During the Paleozoic, the land masses didnt resemble those of today today. As we know, continents drift around so the face of the Earth is in a continual state of change....
View Full Document

This note was uploaded on 12/13/2009 for the course ANT 151 taught by Professor Lynn during the Winter '09 term at UC Davis.

Page1 / 10

ANT%20151%2005 - 1 Lecture 5 The Rise of Primates Before...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online