Quick Write p 102: What are hominids and how do they relate to humans? ¿Cuáles son los homínidos y cómo se relacionan con los seres humanos?

What is a hominid?  Any human-like species, including us.  Bipedal ( walks on two legs ).  Intelligent ( large brain, uses tools ).

 Honor time limits  Actively participate (Have S.W.A.G.)  Listen respectfully to your colleagues  Place cell phones on vibrate or silent mode  Participants may write burning questions on a sticky note and place on the parking lot  BE PRESENT (Developing H.O.T.S. for Science)

Burning Issues Questions Comments Ideas to Share

Hominid Evolution

Humans share a common ancestor with other primates.  Primates are mammals with flexible hands and feet, forward-looking eyes and enlarged brains.

 Primates evolved into prosimians and anthropoids. –Prosimians are the oldest living primates. –They are mostly small and nocturnal.

 They are subdivided into the New World monkeys, Old World monkeys, and hominoids. – Anthropoids are humanlike primates. –Hominoids are divided into hominids, great apes, and lesser apes. –Hominids include living and extinct humans.

Hominids are not the same as modern apes.  Modern apes like chimpanzees, gorillas, orangutans are not bipedal.  Modern apes do not have a large brain case compared to ours.  Modern apes do not make tools.  However, chimpanzees are our closest relative - our DNA is 98% similar to theirs!

 Bipedal means walking on two legs. –foraging –carrying infants and food –using tools Walking upright has important adaptive advantages.

There are many fossils of extinct hominids.  Most hominids are either the genus Australopithecus or Homo.  Australopithecines were a successful genus.  The Homo genus first evolved 2.4 million years ago.

We are still not exactly sure when the first bipedal hominids evolved, but an amazing discovery in 1974 proved that hominids were bipedal a lot earlier than previously believed. Her name was Lucy.

“Lucy In The Sky With Diamonds.”  Discovered in Ethiopia in 1974 (Dr. Donald Johanson)  Dated at 3.2 million years old!  40% of her skeleton was found.  Only four feet tall.  Bipedal for certain. She walked upright.  Her scientific name is Australopithecus afarensis, a distant ancestor to us, Homo sapiens.

An even more impressive fossil was found in 1978, but there were no bones to it at all. Huh? This discovery proved that there were bipedal hominids even earlier than Lucy.

The Laetoli Footprints  3.6 million years old.  Even older than Lucy.  Clearly bipedal.  Also showed that these early hominids walked together.  (Dr. Mary Leakey – discovered.)

Modern humans arose about 200,000 years ago.  Homo sapiens fossils date to 200,000 years ago.  Human evolution is influenced by a tool-based culture.  There is a trend toward increased brain size in hominids. Australopithecus afarensis Homo habilisHomo neanderthalensis Homo sapiens