Exploring West Africa: Accra, Ghana (Part 1)

Exploring West Africa with Silversea’s Silver Explorer, starting in Accra, Ghana on 10 April 2013 and ending in Dakkar, Senegal on 26 April 2013.

April 9 – 11^th, 2013

Population of Ghana (2010): 24.2 million

Population of Accra, the capital city (2012): 2,300,000

Currency: 2 GHS (Ghana Cedis)  = US$1

Demonym (people from Ghana are called): Ghanaian 

GDP per capita (2013) = US$ 1,670 (in Kuwait it’s US$ 45,824)

HDI (2013): 0.558, i.e. 135th 

Accra is like this massive party happening all on its own regardless of what’s going on around the world. Just bring yourself and you’ll be a part of it. Hot and sticky, colorful and loud, you will not get a chance to be alone, not even in your head. Reminds me a little bit of India, although not as humble. Accrans are friendly, warm, and welcoming, but what I really like about them is that they’re bold, upfront, and inquisitive. In a bustling marketplace, as my husband and I walked in a single file behind the tour guide, a woman from the crowd got my attention. Putting on an authoritative face she yelled, “Hey! Heeey! Where’s yo’ yello-feeeva?!” I kept on walking with the river of bodies that carried us deeper and deeper into bargaining and trade, but reluctantly turned my head to see the demanding woman’s face. I spotted her way back, she smiled with a wink. I smiled back, acknowledging that she was just poking fun at us tourists. 

This market had stalls specializing in everything imaginable. There was a vendor for belts, another one sold jeans. One for electric fans, another for remote controls. There was one for laundry baskets and hangers, and another for tape. Yes tape! Different shapes and sizes! I bought a few meters of Kente cloth. I was supposed to bargain, but I hate playing that game, and I thought the price was reasonable, so I bought it without arguments. Turned out the exchange rate I calculated in my head was off by an entire decimal, and I ended up paying for it way more than I thought. Lesson learned. Always bargain. And using a currency calculator App won’t hurt either.

The roll of Kente cloth I purchased. What do I do with it?

Woman selling tape

Woman selling jeans

We visited what they call a compound, which is basically a community that lives together sharing water sources, electricity and such. This tour, as well as the earlier tour we took in the city were arranged by Easy Track Ghana. Their office is based in the compounds of Kisseman. Jessie, our tour guide, took us to their office where we met with Steve. They explained the activities of the community and took us around to see how people live. It was an unforgettable experience.  

The office of Easy Track Ghana

Jessie and his son

The butcher

Car repair shop

The hair saloon

Woman frying fish

Vegetable market

If you’re thinking of going to Ghana, Easy Track provides a good list of items that are much appreciated as charitable donations.

Jessie invited us to his home, where we met with his wife and son.

At the entrance to Jessie's home

Jessie's wife prepared us lunch.
We ate while watching Ghanaian TV drama ;-)

Adding flavour to the dish!

I smell something cooking...

We also saw the gym..

I left Accra all pumped up about the rest of our West Africa trip. People in this part of the world know how to have a good time and I was ecstatic about spending the rest of my vacation days getting to know the history and culture.

Back in the city

And so we se sail aboard Silver Explorer on the evening of April 11th 2013.

Out of Africa: The Origin of Our Species (Part 10)

Language and Speech

Note: I started reading Africa: A Biography of the Continent by John Reader. The following posts will basically summarize what I find interesting in the book as I’m reading it. None of the ideas or thoughts are of my own. 

It comes without saying that language and speech were only possible with the development of the brain. Together, they pushed the evolution of homo sapiens to what it is today. Large segments of the neocortex, the most recently evolved portion of the cerebral cortex, is wired with neural circuits that transmit the capacity to comprehend language and develop speech. These are one of the most distinguished specializations within our species.

The process appears to have started around 1.5 million years ago with Homo Erectus (see Part 5), whose fossils show that the voice box was already present and whose brain size was significantly large, making it very capable to develop some kind of linguistic communication. Some language experts have pointed out that the most ancient surviving languages came from Africa. However, this theory is widely debated since no tangible proof can be produced about the root origin of language.

Richard Wrangham, a professor of biological anthropology at Harvard University and a co-director of the Kibale Chimpanzee Project, found that within groups of the Gombe chimpanzees social groupings and individual behavior were highly dependent on the availability of food. When all members of the group are well fed and satisfied they tend to have playful interactions and overall peaceful existence. However, when food is scarce, the behavior of the individual becomes to maximize selfish satisfaction, which makes the chimpanzees behave in a less altruistic manner.

Wrangham also studied the ecology and behavior of the Mbuti people of the Ituri rainforest in the Democratic Republic of Congo. He found that language gives the advantage of keeping a level of understanding instead of resorting to physical conflict; when otherwise in a case of chimpanzees violence would’ve inevitably erupted, people extend the line of verbal communication. This observation came about when a group of hunters of the Mbuti pygmies had killed an elephant (a rare event in the community) and brought the caracas to the village. Soon others from nearby communities joined, excitement erupted, and the atmosphere got tense. While the hunters worked on cutting up the parts of the animal, tight groups of people were pushing, shoving, and shouting about who gets what. Eventually the hunters were told by the people of the village to honor the obligations of kinship and give meat to their relatives. Old debts and favors were exchanged for meat, and new deals were made. Talking reduced the fighting. 

Language was only made possible after the evolutionary stages that hominids went through in the African savannas. Teeth and jaws evolved such that the species would be able to eat a varied diet of vegetable and animal foods (see Part 4), the naked skin and upright stance allowed the species to roam around during the hottest hour of the day (see Part 7), and the whole body system allowed for the development of a large cognitive brain (see Part 8) in which reason was put before immediate instinct. These adaptations were all beneficial in their own right, each evolving as a consequence of the environment and whatever the pre-existing circumstance was at the time; none was "designed" to facilitate future evolutionary development. Together they created the circumstance from which speech and language evolved. 

Thanking a group of Ewe kids for letting me have my picture taken with them (Togo, 2013).

Robin Dunbar, a professor of Evolutionary Psychology at the University of Oxford, concluded that language is a response to social imperatives primarily, and related to hunting and gathering only secondarily. He also noted that there is a strong correlation between the size of the neocortex among primates and the size and social complexity of the group in which they lived: the larger the neocortex the larger the social group. Lemurs for example, with a small neocortex in proportion to the rest of their brain, live in groups of less than five. Chimpanzees, with four times the ratio of the neocortex to the rest of the brain, live in groups of fifty five. So in evolutionary terms, the correlation between larger neocortex and group size suggests that the benefit of living in larger groups had been the selective advantage which favored the evolution of the primate’s brain. What size of a group does this trend predict for the ratio of human neocortex to brain? 148 individuals in a group (see Dunbar’s Number).

Individuals are not consciously aware of this number, so what does hold them together in groups of just the right number?

Among primates in general, and apes in particular, individuals live in a web of interactive relationships that are formed and enforced by the act of grooming. The practical purpose is to remove insects and debris from the pelt, but grooming also provides the means to express pleasure and reconciliation between members of the group. Wrangham predicts that was the elephant incident to occur with a group of chimpanzees like it did with the Mbuti people, the chimpanzees would’ve spent hours grooming each other after the event in an attempt to mend the harm done. 

The problem with grooming as a process of communication and bonding within a social group is time consuming. And the amount of time devoted to grooming is proportional to the number of individuals in the group. If a group of chimpanzees consists of about 55 chimps, and they spend 20% of their time grooming, social primates in human-size groups of 150 would have to devote 35% to 45% of their time to grooming. This would take a significant amount of time from any group of species. It would’ve been impossible for human ancestors to keep up with roaming the planes of Africa in search of food resources, in high heat conditions, with that much attention given to grooming. Dunbar suggests that language took human evolution through the grooming constraint on group size, and the size of the neocortex was large enough to handle this change. 

As a result, people talk, and unlike with grooming, they have the ability to do so while engaging in other activities, and they can address several individuals at the same time. Dunbar also points out that since talking replaced grooming for the sake of making communication more efficient, and as grooming can only happen 1:1, the talker should be able to communicate at a ratio higher than that, i.e. to be able to communicate at the same time to more than one person. This ratio is calculated (148 ÷ 55), the ratio of human group of 148 to a chimpanzee group of 55 gives 1:2.7 (one speaker and 2.7 listeners, making a group of 3.7 individuals). He found that the conversation groups he monitored indeed consisted of 3.4 individuals on average. A group larger then four members had the tendency to fragment into two or more smaller conversation groups. As for the topic of conversation, Dunbar observed that social relationships and personal experiences accounted for about 70% for conversation time, half of which was about people not present. As it turns out, it is pretty important to exchange information about people who are not present because it allows humans to coordinate social relationships effectively among dispersed groups.

One more picture from Togo!

Out of Africa: The Origin of Our Species (Part 9)

Early Human Migration

Note: I started reading Africa: A Biography of the Continent by John Reader. The following posts will basically summarize what I find interesting in the book as I’m reading it. None of the ideas or thoughts are of my own.

The African fossils found so far are up to 100,000 years old, while the non-African counterparts have all been significantly younger. This tells us that anatomically modern humans from Africa were ancestral to all non-African populations and their modern descendants. Gunter Brauer, a German anthropologist, published his "Afro-European sapiens hypothesis" in 1984, in which he concluded that anatomically modern humans had evolved in East Africa from the pre-existing hominid stock not less than 150,000 years ago. From there the early human species, homo sapien sapien, spread rapidly throughout the African continent to the Nile valley reaching the Delta, the Mediterranean, the Middle East, and from there to the continents of Europe, Asia, Australia, and the Far East.

Map showing early human migration (Wiki). Numbers accompanied by arrows indicate how many million years ago the migration of homo sapiens happened.
Red: Homo Sapiens Yellow: Neanderthals Green: Earlier hominid

The fossil record shows that modern humans were in the Middle East by 100,000 years ago. Populations that migrated north from that point on were established in Europe 40,000 years ago. And those that turned east reached Australia by 35,000 - 50,000 years ago at the latest, and those who reached China did so before 30,000 years ago. From Asia, when the sea levels were low, groups of modern humans crossed the Bering Straits into North America between 30,000 and 15,000 years ago and from there to the tip of South America by 12,000 years ago.

In addition to fossil records, the past history of human populations can be constructed from genes. A group of geneticists at the University of California at Berkley analyzed the mitochondrial DNA of different groups of people around the world, and found that more mutations had occurred among Africans than among or between any other groups. The mitochondrial DNA molecules are identical in every cell of an individual. Mitochondria reproduces by cloning; asexually, by division. But the mitochondria are only inherited from the female parent because in the sperm cells they disintegrate at fertilization. Clonal reproduction and female inheritance leave mtDNA unaffected by the combination of genes that occurs in the reproduction of nuclear DNA.

Mitochondria in a cell

The Berkley geneticists found the greatest degree of variation in mtDNA among indigenous people in Africa, and significantly less variations among non-Africans. In fact, the mtDNA of an individual born in England and another born in New Guinea was more alike than the mtDNA of two individuals from Nigeria. This shows that a greater time-depth of mutation was preserved among people in Africa, while everyone else shared a predominance of mutations which had accumulated in the relatively recent past. From this, the geneticists concluded that the entire population of the modern world was descended from a relatively small group of people that left Africa about 100,000 years ago.

In addition to that, the geneticists found that every human being alive today carries the mtDNA of just one African woman who lived more than 10,000 generations ago. She wasn't the only woman alive at the time (i.e. she wasn't the Biblical Eve). It just happened that her particular mtDNA steadily became dominant as some maternal lineages disappeared with each succeeding generation. Not every woman produces daughters who would go on carrying the mtDNA. The geneticists referred to this ancestor as "our common mother," but later she became known as "The African Eve."

Out of Africa: The Origin of Our Species (Part 8)

The environment we adapted to

Note: I started reading Africa: A Biography of the Continent by John Reader. The following posts will basically summarize what I find interesting in the book as I’m reading it. None of the ideas or thoughts are of my own.

Figure 1 - Upright bipedal gait

Our early ancestors had an advantage: bipedalism. Our body cooling system was an adaptive response to the environmental stresses of tropical Africa; the upright bipedal gait is otherwise inefficient when it comes to moving fast (Figure 1). 

Quadruped animals were able to run much faster than our ancestors of the time. But the upright stance was better at cooling the body, especially at noon, when the sun was directly overhead. Only 7% of the biped’s body surface was exposed to the sun, while the quadruped had 20% of their bodies exposed. Furthermore, the cooling effect of a biped as a result of standing tall from the ground compared to an other animal standing on the same location is that heat is lost 33% faster. The quadruped may sweat just as much, but it’s that much harder to lose the sweat to the wind when the length of the body is close to the ground. The air at ground level is more humid because of the vegetation which makes it hard for the quadruped to ventilate. 

A baboon roaming the fields of Tarangire
(Tanzania, Feb 2012)

Warthogs (Tarangire, Tanzania, Feb 2012)

Hair is another factor. Fur serves savanna quadrupeds as a shield, reflecting and re-radiating heat before it reaches the skin. If quadrupeds lost their fur, melanin would’ve protected them from harmful UV-B radiation, but this would’ve decreased the reflectiveness of the skin, causing a greater energy gain throughout the exposed body to the sun rays. But a biped could get rid of most of the hair and make it easier to sweat. A shield is only needed where sun rays would hit most severely: the head.

Humans have has many hairs has the chimpanzee per square centimeter but they’re shorter and finer. This nakedness, along with well developed sweat glands, enable us to lose heat at a rate of 700 watts per square meter of skin, a rate not even close to any other living mammal.

Figure 2 - Look at the location of the jugula sinus

We wouldn’t be what we are today, Homo sapien sapiens (i.e., bipedal with large brains), as opposed to something more like a chimpanzee, if it wasn’t for the necessary evolution of our cooling system. This is not to say that temperature controlled strategies caused the evolution of a large brain, merely that they removed certain physiological constraints and thus made the enlargement of the brain possible. As functional as the long muzzle and the carotid rete are at keeping a quadruped’s head cooler than its body, it has its physiological limits. The system depends on the amount of blood that the carotid rete can cool to the critical temperature before it flows to the brain. However, large brains need a larger blood supply and therefore a larger carotid rete. Since the rete functions by pumping blood through an ever-finer network of blood vessels, its maximum size is determined by the the pressure and volume that can be accommodated. It was calculated that if the blood supplying the modern human brain was cooled through a carotid rete, the jugular sinus (Figure 2) in which it was situated would fill the entire diameter of the neck! Clearly, the whole body cooling system supported by the upright stance and naked skin was a more feasible strategy.

The ability to develop a large brain doesn’t come without an expense: providing the energy to keep it functional.

Brain is “expensive tissue.” The brain uses energy nine times faster than is average for the human body as a whole. Skeletal muscle, for example, where energy is more obviously expended, consumes less than 15% of the body’s budget even though it makes up 41.5% of average body weight. The brain makes up 2% of an average body weight, but consumes over 16% of the energy. And since the brain has no means of storing energy for future use, it must be continuously supplied with hight levels of fuel and oxygen.

You’d expect with an increase of brain size a corresponding increase in the size of the digestive tract because of the needed fuel, however, that’s not what happened. In fact, the human gut is almost exactly half the size that would be predicted to match the enlarged brain. This is achieved by learning to seek out nutritious foods that only need to be consumed in small amounts, which comes in contrast with other primates that process large quantities of leaves and grass (see Part 3 - Australopithecus (robust vs. gracile)). The guts of our ancestors filled the environmental niche that allowed them to consume high quality foods such as seeds, nuts, eggs, and bone marrow, in addition to meat.

Bigger brains seek more nutritious foods, and more nutritious foods make bigger brains.

A few more pictures from our trip to Tanzania in February 2012:

Where there's water there is life

Cooling off

Amazing colors

Impalas in the shade

Male impala

Baboons

Out of Africa: The Origin of Our Species (Part 7)

Water & Sweat

Note: I started reading Africa: A Biography of the Continent by John Reader. The following posts will basically summarize what I find interesting in the book as I’m reading it. None of the ideas or thoughts are of my own.

People, like our planet, contain more than 70% liquid. Much of the human body consists of “plumbing” parts, such as blood vessels, lymph and urinary tracts. These parts are vital for transporting nutrients and eliminating waste. The water content of a 65kg human is nearly 50 liters. An average human, in average temperature conditions needs to take in and eliminate 2.5 liters of liquid each day, and no matter how much the intake varies the body’s total water weight remains relatively consistent, deviating less than 1% from what is normal. A minimum of about half a liter of urine output is essential to get rid of toxic wastes. Water is so important for human bodies that about 5% loss impairs many functions such as brain’s ability to process information, and death will result from a loss of anything more than 5%, which amounts to about one day’s liquid intake: 2.5 liters.

Walking with a bush guide in Tarangire, Tanzania.
How our ancestors lived in this environment
without weapons, gadgets, clothing or bottles of
water, I don't know. (Feb, 2012) 

In tropical conditions, humans need more water than normal to keep up with the rate of sweating, which keeps the body at lower temperatures compared to the environment. Our nervous system is sensitive to changes in temperature. Normal functioning of the brain becomes progressively impaired at temperatures above 37^oC, and even a temperature of 40.5^oC can be fatal. Every drop of sweat has to be replaced. Failure to do so within a 24-hour cycle produces serious dehydration. Death is inevitable if a second day of high heat load is experienced. 

The temperatures of the East African savannas 200,000 years ago, in which human ancestors lived, neared 30^oC during the early hours of the day, and peaked at 45^oC. At such temperatures humans would’ve had to have a continuous supply of water within a 24-hour walking vicinity. 

Landscape of Serengeti National Park, Tanzania. (Feb, 2012)

Humans are not the only animals that depended on water so greatly in their daily lives. Grazing animals spend their days exposed to the full impact of the sun. Their muzzles however are effective in keeping their heads’ temperatures lower than their body temperatures. The length of the muzzle loses heat by evaporating water from moist linings of the nasal chambers. The evaporation removes heat from blood flowing beneath the nasal membrane, and the cool blood travels to the base of the cranium. The brain is supplied by the carotid arteries, which pass through the sinus, where they branch into a net of fine blood vessels called the carotid rete. As arterial blood flows through the carotid rete, excess heat is transferred to the cooler venous blood in the sinus, and the brain receives the blood at the critical temperature. 

Impalas (Tarangire, Tanzania. Feb, 2012)

Humans don’t have this natural “radiator”, and the closest living primate to us today, chimpanzees, don’t have it either. During the course of primate evolution the face broadened, and the jaw shrank as a result of dietary changes. Chimpanzees, for example, are very poorly equipped to adapt to high temperatures. Anything above 40^oC causes considerable distress. They sweat and breath heavily, yet the only relief they get is once evening comes.

So if our early ancestors, the Australopithecus Afarensis (Part 2), lived in the East African savannahs, and had to hunt for food during the day (to avoid other predators that hunt during the night), how did they manage? 

To be continued...

A few more pictures from our trip to Tanzania:

Impalas cooling off in the shade (Tarangire, Tanzania. Feb 2012)

Dik dik (Tarangire, Tanzania. Feb 2012)

Impalas in the morning mist (Tarangire, Tanzania. Feb 2012)

Landscape (Tarangire, Tanzania. Feb 2012)

Great migration (Serengeti National Park, Tanzania. Feb 2012)

Landscape (Serengeti National Park, Tanzania. Feb 2012)

Landscape (North of Serengeti National Park, Tanzania. Feb 2012)