Humans and Other Primates EQ: How do fossil records provide the history and changes of life on Earth?

Have you ever heard someone say…. That humans descended from monkeys or apes? Well, scientists would not say that exactly. The scientific theory is that humans, apes, and monkeys share a common ancestor. This common ancestor, which resembled a mouse, lived more than 45 million years ago. Many scientists agree that there is enough evidence to support this theory. Fossil evidence

Primates Humans are classified as primates. Primates are the order of mammals that include monkeys, apes, lemurs and humans. Primates have the following characteristics: Eyes in the front of the head Flexible fingers Opposable thumbs

Human Taxonomy Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primate Family: Hominid Genus: Homo Species: Sapiens

The First Primates The ancestors of primates probably co-existed with the dinosaurs. They were not primates. They were nocturnal, mouse-like creatures that lived in trees and ate insects. They did not flourish during the dinosaur age. Best favor the dinosaurs ever did for us was to become extinct!

The First Primates The first primates did not exist until after the extinction of the dinosaur. About 45 million years ago, primates that had larger brains started to appear. These were the first primates that had traits similar to monkeys, apes, and humans

Apes and Chimpanzees Scientists think that the chimpanzee, a type of ape, is the closest living relative of humans. This theory does not mean that humans descended from chimpanzees. What it does mean is that humans and chimpanzees share a common ancestor. Sometime between 6 million and 30 million years ago, the ancestors of humans, chimpanzees, and other apes began to evolve along different lines. The History of The World in Two Hours

Hominids Humans are in a family separate from other primates. This family, called hominids, includes ONLY humans and their human-like ancestors. The main characteristic that separates humans from other primates is bipedalism Means “walking on two feet”

Hominids The earliest hominids, australopithecines, found in Africa, are believed to have existed about 6 million years ago. They had many modern human-like traits: Bipedalism Smaller teeth Flatter faces Larger brains

Hominids Fossil evidence lead scientists to believe that they probably lived in forests and grasslands and had a vegetarian diet.

Hominids About 2.4 million years ago, a new group of hominids appeared. They were similar to the early hominids, but were even more like modern humans. Larger and more complex brains Rounder skulls Flatter faces Tool making abilities Walked upright

Hominids Fossil evidence shows that several groups of these hominids existed at the same time and on several continents They were probably scavengers that ate a variety of foods. They adapted to climate changes by migrating and changing the way they lived.

Hominids One recent hominid, known as the Neanderthal, lived as early as 230,000 years ago in Europe and Western Asia. They hunted large animals, made fires, and wore clothing. They cared for each other as we do. Went extinct about 30,000 years ago, but nobody knows exactly why.

Hominids Modern Humans (Homo sapiens) first appeared in Africa between 100,000 -160,000 years ago. They migrated out of Africa between 40,000-100,000 years ago. Of all known hominids, only Homo sapiens still exists. Organized and complex societies

Vestigial Traits Humans have an amazing knack for clinging to the past. We all have traits or behaviors that suited our ancestors just fine, but no longer make any sense — but we just can't seem to get rid of them. Over time, these traits and behaviors become what are known as "vestigial" — as in, they exist as a vestige of our evolutionary heritage. At their most innocuous, our vestigial features are funny to think about. At their worst, though, they've been known to be detrimental to our health (scientists often refer to this second case as en example of "evolutionary baggage"). So here are some vestigial traits and behaviors that you may still be clinging to:

The Appendix The appendix is probably the most widely known vestigial human organ. Appendices may have once aided our primate ancestors with the digestion of cellulose-rich plants, according to experts. Some scientists believe that the modern human appendix may play a role as a "safe-house" for good, digestion-aiding bacteria, But anyone who's paid for an appendectomy will tell you that its true function is lining the wallets of the surgeons who remove it when it gets infected

Wisdom Teeth Fossil evidence shows that humans used to have longer jaws, with plenty of room for what we call wisdom teeth Evidence that humans are still evolving! Wisdom teeth are like unwanted house guests There usually isn't any room for them to push their way into your personal space, but they do it anyway (even if you ask them not to). When they do, it's very uncomfortable. Discomfort usually escalates to pain as they come in If things get really out of hand they can even become violent, ruining years of orthodontics-work in what amounts to the most protracted punch-to-the-mouth ever.

The Ear No, not the whole ear, but the human ear does have all kinds of strange things going on with it. For one thing, there's an entire group of muscles attached to our ears that, for most monkeys, are used to move the ears like satellite dishes trying to pick up a signal. For us, however, they just sit there — not moving anything — suggesting that they've lost their biological function.

Plica Semilunarius Your plica semilunaris (what many believe to be a vestigial remnant of your third eyelid) is the small fold of tissue located on the inside corner of your eye (not the little bump in the very innermost corner, but the small flap right next to it — check the image). Your plica semilunari are the vestigial remnants of what are referred to as "nictitating membranes," which are most commonly found in birds, reptiles, and amphibians.

Assessment Prompt: Written Explanation On the back of your graphic organizer, explain to someone else why while humans and primates are related, humans did not descend from apes. Share your answer with your table