Lecture 13- Human evolution

Question 1

Describe the evolutionary tree leading to humans…

Answer 1

• primates
• Spilt into 4 groups of Prosimians, Neotropic monkeys, Hominoids and old world monkeys
• Hominoids diverges into two groups
• First group is the orangutans and Gibbons from south east Asia
• The second group is the Gorillas, chimpanzees and hominins from Africa
• Humans are in the hominin group

Question 2

When did the division into the SE Asia group and African group occur?

Answer 2

7 million years ago

Question 3

What does diverge mean?

Answer 3

The creatures that became gorillas, chimpanzees and humans once came from the same group (have common ancestor). It does not mean that humans used to be gorillas.

Question 4

What are the features of Ardipithecus Ramidus (Ardi)? How long ago did they live?

Answer 4

• Starting bipedalism
• Smaller canines
• Still long arms (associated with tree climbing)
• Small brain

-Lived 4.5 to 5 million years ago

Question 5

What are the features of Australopithecus afarensis

(Lucy)? How long ago did they live?

Answer 5

• More upright in the hip but the head wasn’t directly above shoulders yet
• Stone tools for butchery
• Brain still small.

-Lived 3 million years ago

Question 6

What are the features of Paranthropus? How long ago did they live?

Answer 6

• Big jaws for chewing tough stuff

- Lived around 2.3 to 2.6 million years ago roughly

Question 7

What are the features of Homo erectus? How long ago did they live?

Answer 7

• Fully upright, with forward facing feet +toes specialized for running and walking on two legs
• Some stone tool use
• Lived across the Old World;
• Brain grown from 750 cc to 1,000 cc (large increase)

Question 8

Across all hominin species what is the most important trend displayed?

Answer 8

Increase in brain size up to 1,250 cc

Question 9

What happened to H. erectus? Are humans in placed other the Africa direct descendants from them?

Answer 9

If H. erectus was spread across the old world you might assume that they evolved into homo sapiens simultaneously across the world
-This is not the case instead they died off and H. Sapiens spread from Africa to replace the older species

Question 10

What happened in regards to the population bottle neck? When did this occur?

Answer 10

• Genetic reduction in diversity as only the species in eastern Africa survived
• Migration from eastern Africa replaced previous peoples.
• Possibly due to Lake Toba Supervolcano

-Happened around 7 million years ago

Question 11

Where and when did the species that invented language exist?

Answer 11

• Sub-saharan Africa (eastern and southern)

- 100K-60K ago

Question 12

How did tools evolve over time to become more complex?

Answer 12

• 2 million years ago= Oldowan tools which were hand held rocks that have been sharpened on one side
• 500 thousand years ago= Achulean tools which were more finely shaped
• 100 thousand years ago= Stone blades, microliths, stone AND wood, points to spears
• 50 thousands years ago= Fish hooks, buttons, bone needles, jewelry, paintings

General trend as go on as get more variety and the tools are suited to a particular purpose/ finely crafted

Question 13

How did hunting evolve over time?

Answer 13

• 2 millions years ago= passive scavenging.
• 800 thousand years ago= power scavenging
• Approx. 200 thousand years ago= hunting

Question 14

What is power scavenging how is this different from hunting?

Answer 14

When you let other animals perform the kill and then come in and use tools to scavenger the meat off before the animal can eat it. Different to hunting where the tools were actually used to directly kill.

Question 15

What was vital for complex hunting and scavenging?

Answer 15

Cooperation, as would work together to:

• Herd animals towards a waiting party or to surround
• Herd animals into mud or over a cliff

These techniques required planning and handing out different roles to people based on their strengths. In hunting also need to be able to predict what the other person will do and imagine possibilities.

Question 16

What is an unusual feature of humans in regards to how they hunt?

Answer 16

They share the food after they have caught it. The goal is to catch a meal for the group not the individual.

Question 17

How do chimpanzees behave when they hunt?

Answer 17

• Don’t have the same level of planning
• Most of the time there is not sharing, the chimp who catches the kill eats it
• Can hunt in group but everyone is acting for themselves so a lot of the time have solo hunts

Question 18

What kinds of things were hominins eating by 400 thousand years ago?

Answer 18

• Nuts
• Fruits
• Mushrooms
• Leafy plants
• Underground roots
• Cooked meat (yes there was the use of fire here)

Question 19

What did cooking allow?

Answer 19

• More nutrition to be gained from food
• Reduction in jaw size as no longer needed heavy jaw for chewing (food became softer)
• Both of these left room for a bigger brain

Question 20

Describe the cycle that occurred between food and brain size?

Answer 20

Better food led to a bigger brain which then meant hunting techniques became more advanced and so gained access to even more food. The cycle repeats.

Question 21

Why does human childhood last forever compared to other species?

Answer 21

-Big brains do not just take energy; they take a lot of
nutrition and time to develop.
-The time is given by a long childhood, education also continues until late in life in order to keep growing and building new skills
-The fact that we are born with immature brains also allows cultural development of the brain to then occur as our brains have the flexibility to adapt in different ways/ directions

Question 22

Do mammals (including humans) operate with the mother doing all the work in raising the child?

Answer 22

No generally the task is spilt amongst a group

Question 23

What are three things that weren’t developed at the time language first emerged?

Answer 23

• Animal domestication (earliest was dog 20-30 thousand years ago
• Plant domestication (farming didn’t emerge to 10 to 15 thousand years ago
• Wheels