Carvalho et al., 2012 (chimpanzee carrying)

Question 1

Compelling evidence shows that the shift to habitual bipedality in our ancestors occurred with … changes that reduced … areas, forcing early hominids to range in more open settings.

Answer 1

climatic, forested

Question 2

This study reports results showing that wild chimpanzees walk bipedal more often and carry more items when transporting …, … resources to less … places.

Answer 2

valuable, unpredictable, competitive

Question 3

Most chimpanzee bipedality is …, rather then …, and takes place during … … in short trees (not while carrying items)

Answer 3

postural, locomotory, fruit foraging

Question 4

Used two types of locally available nut:
… nut (rare resource of unpredictable availability)
… … nut (naturally available and familiar)

Along with stones suitable for nut-cracking

Answer 4

Coula, oil palm

• in 11 individuals

Question 5

Three conditions:

• only oil palm nuts present
• coula nuts present at low availability (high …)
• and coula nuts present as majority resource (low …)

Answer 5

competition, competition

Question 6

… rates were three times higher in the … … than the other two conditions.

Answer 6

transport, high competition

Question 7

When coula nuts were highly available the chimps stopped transporting and cracking the oil palm nuts, suggesting…

Answer 7

they valued coula nuts more highly

Question 8

Most transport overall was ….

Answer 8

quadrupedal

Question 9

However, the frequency of bipedal transport increased by a factor of … in the … … and … … conditions compared to the … … … ….

Answer 9

four, high competition, low competition, oil palm nut only

Question 10

Chimpanzees also carried more than … as many items (including stones to open nuts) when walking bipedally, suggesting bipedality was being practiced more frequently in order to carry more items

Answer 10

twice

Question 11

Carrying nuts and tools to another location may have … advantages - may help an individual to establish temporary “personal space boundaries”, allowing them to … more and … less, especially at higher levels of group competition.

Answer 11

energetic, consume, share

Question 12

Foods may be worth carrying if they are … in availability. It is uncertain whether these foods will remain where they are for long (especially if competition is high), so it is best for individuals to take them and carry them away to somewhere they can be safely consumed (first come, first served). Bipedalism allows more to be carried to this spot. It is all about reducing competition and maximising energy efficiency.

Answer 12

unpredictability

Question 13

Selection for effective food …, which may have been enhanced by … …, may have led to evolution of bipedality as we see it today.

Answer 13

carrying, environmental constraints

Question 14

My thoughts:

perhaps ancient hominins set up bases where certain individuals (women and children) stayed and went further afield. It was beneficial to be able to carry as much food as possible, to maximise the energetic rewards. Therefore bipedality was selected for (also bipedalism in humans 75% more efficient than in chimps - minimise energetic costs as well as maximising energetic rewards by carrying).

Answer 14

nice one mate

Question 15

Chimp data also revealed that … carried more items more often than …, especially under more intense competition.

Answer 15

males, females