Human Evolution

Ch 17.6 “wolf book”

• Human evolution is NOT controversial amongst most scientists BUT disagreements on:

• how many species. • Interpretations of new finds • diet, habitat, partially or fully upright. • Human evolution should not be seen as a simple

linear progression of improvement toward our own present-day form. You will see differences in evolutionary models.

About 220 million years ago

• The first mammal evolves

65-85 million years ago• The first primates evolve

We belong to the Primate order along with lemurs, monkeys, chimps and apes!

A. Primate Characteristics 1. Forward facing eyes: • binocular vision: 3-D vision = jump/catch with

accuracy2. Flexible shoulder and hip: movement = swing,

bipedal (makes taller/vantage point)3. Bigger brains: complicated behavior, social,

tools4. Opposable thumbs: grasp, tools

The Opposable Thumb; How useful is it?

• Introduction: The opposable thumb was caused by a beneficial mutation, which gave some primates an advantage in their environment.

• This thumb became a successful characteristic that was passed to subsequent generations.

• This activity is designed for you to appreciate the importance and benefit of having an opposable thumb.

• Procedure: Work with a partner, you will need help. • Tape your thumbs to the side of your hands. Do this

so that you are unable to use your thumbs, but allow the blood to circulate!

• Several activities are listed. Try to complete each with your thumbs taped. Have your partner record your response. Then switch and have your partner complete the activities while you record their responses.

• You have 10 minutes for each person…total of 25 minutes

• NOTE: there is HW DO IT AT HOME

5/27-28

• Turn in your opposable thumb HW to the bin

Opposable thumb

• This activity should have given you insight into how influential opposable thumbs have been in our evolution.

• It should have also given you insight into behavioral adaptation! You were still able to complete tasks with some modification.

25 million years ago

• Apes lineage separates from monkeys

15 million years ago• Great apes separate from other

primates• Formation of family hominidae

10 million years ago

• Chimpanzee/Human ancestor separates from gorilla ancestor

6-8 million years ago

• Human lineage separates from chimpanzee/bonobo ancestor Toumi – 7million year old fossil a

possible common ancestor

4.4 million years ago

• Age of fossil Ardi

3.2 million years ago

• Age of fossil Lucy

2.3-2.5 million years ago

• The first members of genus Homo appear

• Significant increase in brain size

Which species do we come from?

• We really don’t know!• Lots of fossils, but

really hard to figure out which one gave rise to which

What We Think

• Many species overlapped, some left Africa earlier than homo sapiens did

What is the evidence?• The oldest primate fossils are 55 million years old – few primate fossils have been found, far older

primates may have existed • The oldest hominin fossils are from Africa –Hominins include humans and extinct humanlike

primates –Comparisons of human DNA with that of apes

suggest that the two diverged between 5 and 8 million years ago

A. boisei

A. africanus

A. robustusH. erectus

Australopithecus afarensisSahelanthropus tchadensis

Ardipithecus ramidus

Orrorin tugenensis A. anamensis

H. habilis

Homo ergaster

H. heidelbergensis

H. sapiens

H. neanderthalensis

A Possible Evolutionary Trees for Humans

NOVA• To further explore human evolution we will watch a 3

part Nova Series• As you watch the movie please answer the questions.

We will review the answers.• You will be quizzed on the material from these movies.

It will benefit you to pay attention and watch them.• You will turn in your answers at the end of class for

credit.• http

://www.pbs.org/wgbh/nova/search/results/?q=becoming+human

• Your HW tonight is Hominin Evolution