1.4: Culture and human uniqueness

Question 1

Uniqueness

Answer 1

What characterises a species

Question 2

Are humans more closely related to chimps than gorillas? Are chimps more closely related to gorillas than humans?

Answer 2

Humans and chimps are more closely related than chimps and gorillas and humans and gorillas

Question 3

List 5 anatomical differences between humans and other apes

Answer 3

Feet 
Hands/grip
Brain structure
Pelvis
Larynx

Question 4

Give 2 ways in which human and chimp feet differ

Answer 4

Human foot and abducted big toes points to walk straight
Human foot has a large heel, strong arch, and ankle adapted to walking long distances

Chimp foot and big toes curves sideways to cling onto branches for climbing
Chimp foot has a small heel, flexible midfoot (midtarsal break), and ankle adapted for climbing

Question 5

How do human and chimp hands/grip differ?

Answer 5

Human thumbs are longer and straighter than chimp thumbs, so humans have a more precise grip – humans are more efficient with tools

Question 6

Give 4 ways in which human and chimp brain structures differ

Answer 6

Chimps brains are 3x smaller than human brains
Chimps have a reduced frontal lobe
Chimps have no Broca’s or Wernicke’s area
Chimps have Brodmann’s area 10 and planum temporale, so they can make and receive calls, but not create speech nor process language

Question 7

How do human and chimp pelvises differ?

Answer 7

Human pelvis is bowl shaped, allowing bipedalism

Chimp pelvis is not as round

Question 8

How do human and chimp larynxes differ?

Answer 8

Human larynx positioning is lower, allowing speech

Question 9

What is the percentage of genetic difference between humans and chimps, and how many genes are unique to humans?

Answer 9

1.2% genetic differences

97 genes are unique to humans

Question 10

Give 3 examples of human specific genes and explain their function and how they might have led to the evolution of human specific adaptations

Answer 10

The ARHGAP11B gene stimulates creation of the folds and fissures on the brain (brain growth)

The FoxP2-2 mutations separate human and chimpanzee variants of the gene, people who have a defect in this gene have speech problems – gene is linked to more complex vocalisation and faster learning

The HCNS1 gene co-ordinates between the brain and hands and limbs, and therefore contributes to human bipedalism and tool making

Question 11

Life history theory

Answer 11

The idea that you have to budget/adjust your time and resources to suit your probable lifespan

Question 12

Give an example of one species with a fast life history and one species with a slow life history. Explain why their life histories differ.

Answer 12

Fast life history: mice; live with high predation rates, thus they grow fast, they reproduce very early and intensely to create a lot of low quality offspring

Slow life history: elephants; large, limited predation, few but high quality offspring, reproduce late

Question 13

Give 4 examples of life history trade-offs

Answer 13

Clutch Size → offspring Quality
Length of reproductive span → Adult body size
Current reproduction → Later reproduction
Reproduction → Survivorship

Question 14

What is the main time constraint of life?

Answer 14

Death

We must reproduce before death

Question 15

Why does evolution not produce eternal life?

Answer 15

The longer you live, the more likely you are to die by accident

Question 16

Give 9 features of human life history that are characteristic of slow life histories (compared to other apes)

Answer 16

Longest life span
Later age of first reproduction
Long term dependent children
Long gestations
Largest new-born size/mother weight ratio, fattest new born babies 
High caloric demanding babies
Low daily investment in infants (cheaper lactation)
Lower infant mortality rates
Highest investment in quality

Question 17

Do humans have slow or fast life history?

Answer 17

Humans have extremely slow life history (exaggerating Primate and Ape trends)

Question 18

Why are human babies so fat?

Answer 18

Humans have the largest brain to body proportion
Babies are born with 30% of the brain ready
Brain doubles in size in first year of life
Baby brains consume 65% of total caloric intake
60-85% of babies basal metabolic rate goes to brain maintenance
Fat on babies is needed for body energy

Question 19

Give 2 reasons why human fertility rates are higher than in other apes?

Answer 19

Shorter IBI (inter-birth interval) and lactation period

We rely on society/other family members to take care of our children

(Allows quantity and quality of offspring)

Question 20

Give 5 features of human life history that are characteristic of fast life histories

Answer 20

Higher fertility (number of infants produced by year) 
Shorter lactation period 
Earlier weaning
Shorter inter-birth Intervals (IBI) 
High investment in quantity

Question 21

Why do women hit menopause only half way through their life span/have a shorter reproductive span than post-reproductive span?

Answer 21

To maximise both quality and quantity of produced babies through use of grandmothers

Question 22

Explain the ‘grandmother hypothesis’

Answer 22

Mothers have reduced IBI to create offspring quantity
Healthier grandmothers are selected for, so they can feed the grandchildren while the mother invest in the next reproduction
Whales are the same in terms of menopause – convergence evolution

Question 23

Explain Kaplan’s Model in reference to slow human life history and brain size

Answer 23

Time invested in brain growth is also time invested in learning for both sexes
Learning to obtain high quality food is important to provide for females and offspring

Question 24

In 90% of mammal species, what is the role of fathers and mothers?

Answer 24

Fathers are not present

Mothers invest the most in offspring

Question 25

Explain human father provisioning

Answer 25

Human males provide double the provisions they need, allowing offspring to be produced in large quantity and quality

Question 26

Name the 5 special features of human life history

Answer 26

Women stop reproducing half way through their adult lives
Babies are expensive and have high survival rates
Humans have high natural fertility
Humans have very short IBI
Humans depend on social help for reproducing (cooperative breeding)

Question 27

List and describe the three things that make human behaviour different from other primates

Answer 27

Cognition – language vs. sounds/callings; use of language to convey info and negotiate relationships, ability to empathise and subsequently create ‘mutual knowledge’ with language

Cooperation – not many animals cooperate, but social ones do; affiliative cooperation; hyper cooperation even with unknown people

Culture – cumulative culture by innovation, together with collective mutual knowledge, is an exclusively human trait