Category: English

Source: The Conversation – Africa – By Alan Whitfield, Emeritus Chief Scientist, NRF-SAIAB, National Research Foundation

The origins and migrations of modern humans around the world are a hot topic of debate. Genetic analyses have pointed to Africa as the continent from which our ancestors dispersed in the Late Pleistocene epoch, which began about 126,000 years ago. Various dispersal routes have been suggested.

As a group of scientists who have been studying human evolution, we propose in a recently published review paper that the coast of southern Africa was likely where Homo sapiens began this worldwide journey. We suggest that some people started leaving this area about 70,000 years ago, took a route along the east coast and left the continent about 50,000 to 40,000 years ago.

We base this hypothesis on various kinds of evidence, including geography, climate and environment, marine food resources, genetics, trace fossils, and the technical and cultural abilities of people in that region at that time. The reasons for migration and the advantages of a coastal route out of Africa, compared to an inland route, are outlined in our review.

This proposed route is counter to the current belief among most scientists that the Out-of-Africa migration began in eastern Africa and not southern Africa.

A southern Cape origin?

In our review we accepted that modern humans arose in Africa during the Middle Stone Age about 200,000 years ago and then replaced populations of hominins outside the continent between 60,000 and 40,000 years ago.

We suggested that their African origin was in the southern Cape region of what’s now South Africa, and that their migration along the eastern African coastline and onto the Arabian Peninsula may have happened over a period of less than 20,000 years.

In reviewing available evidence, we focused on the possibility that our ancestors in coastal South Africa were ideally placed to colonise the world. They had an enabling culture that allowed them to survive almost anywhere.

The Pinnacle Point cave complex and other sites in this area are a UNESCO World Heritage Site because they provide the most varied and best-preserved record known of the development of modern human behaviour, reaching back as far as 162,000 years.

Food from the sea, like shellfish, set southern Cape Homo sapiens on their evolutionary path to becoming advanced modern humans. They had an advantage over those who relied solely on hunting and food gathering inland, especially during cold and dry periods on the African subcontinent. The harnessing of bow and arrow technology was also key for their success when compared to other hominins during the same period.

Climate and culture

Episodes of global cooling, also known as ice ages, resulted in a global lowering of sea levels, and had two main effects in Africa. One was that the width of the Red Sea between the Horn of Africa and the Arabian Peninsula narrowed. The other was that in the southern Cape, a vast coastal plain was exposed, providing extra habitat and plenty of food.

Increased cognitive capacity to interpret lunar cycles would have allowed ancestral humans to undertake timed excursions to the shore over spring tidal periods. The predictable coastal food sources might also, however, have led to inter-group conflict and territoriality, which could have played a role in the exodus of groups of people from the southern Cape.

In other parts of the world, there was a cold, dry period from 190,000 years to 130,000 years ago. And the dark, long “winter” after the Mount Toba (Indonesia) super-eruption 74,000 years ago would have reduced food resources in tropical regions. Hominins in the southern Cape appear to have survived these major global climate change events and continued to advance both culturally and technologically. We know something about these advances from research at cave sites such as Klasies River, Blombos and Pinnacle Point. Forms of ancient art have been found in these caves, indicating cognitively advanced humans.

Technical advances meant that the tools carried by these people on their journey were “state of the art” for 70,000 years ago – more advanced than those possessed by other humans encountered on their migration northwards.

Evidence mounts

In summary, the idea of a coastal migration out of Africa is based on:

• the earliest evidence for humans consuming seafood and developing adaptations for living close to the sea shore about 162,000 years ago

• the first evidence of dedicated coastal foraging for seafood, which may have enhanced our ancestors’ cognitive capacity

• the first “recipes” in early human food preparation around 82,000 years ago

• among the earliest reports of bone tool technology from around 100,000 years ago, which may have been used to make complex clothing and shoes

• the regular use of pigments such as red ochre as early as 162,000 years ago

• palaeoart in the form of engravings in ochre dated 100,000 to 85,000 years ago, and a drawing using an ochre crayon dated to 73,000 years ago

• the earliest evidence for making small stone blades around 71,000 years ago

• the earliest evidence for heat treatment of stone to produce advanced tools and weapons

• use of jewellery for adornment

• survival during a period of climate change following the Mount Toba eruption

• complementary evidence from the trace fossil (ichnology) record from the same region and time period. This includes the oldest reported use of sticks by humans, and the oldest reported evidence of humans jogging or running.

When the era of global cooling ended about 18,000 years ago and sea levels rose again, almost all of this Pleistocene landscape would have been covered by water. So it’s remarkable that so much evidence still exists.

There is no equivalent evidence of an advanced modern human presence from eastern Africa or anywhere else in the world.

Why migrate?

Why would some people choose to move and migrate? It is likely that increasing pressure from successful, growing, competing bands of humans, combined with climatic and environmental changes and a limited number of suitable cave occupation sites, provided a trigger for an initial eastward and then north-eastward migration.

At the same time, advanced cognition skills would have permitted increasing intra-group co-operation, enabling these humans to make their remarkable journey.

We think a coastal migration up and out of Africa was more likely to succeed than an overland migration. The reasons include the availability of seafood, fresh water, level ground, warm temperatures and fewer big, dangerous animals along the intertidal coastline. It seems there weren’t other people in the way either: for example, there is no evidence of an equivalent culture associated with the sea on the eastern coast of Africa.

The lack of suitable coastal caves to live in north of South Africa may have encouraged human clans to keep moving up the coast.

Out of Africa

The exit from the Horn of Africa into the Arabian Peninsula was distinctly feasible from 60,000 years ago onwards. Records from the Red Sea indicate that sea levels in the region were about 100 metres below present levels 65,000 years ago.

Our examination of the available evidence points to the southern Cape coast as a cradle of modern human development. The people of this region were ideally placed 70,000 years ago to undertake a quick and effective migration out of Africa, and then around the world.

– Where did the first people come from? The case for a coastal migration from southern Africa
– https://theconversation.com/where-did-the-first-people-come-from-the-case-for-a-coastal-migration-from-southern-africa-267299

Source: The Conversation – Africa – By Laura Tensen, Assistant Professor, University of Greifswald

Biologists often form deep bonds with the species they study. For some, that relationship begins early in their careers and shapes decades of research. The connection can be personal, even affectionate, but it can also create tensions when others set their sights on the same species.

In biology, certain plants and animals are considered “charismatic species” by the general public. They capture the public imagination through beauty, uniqueness, or cultural significance. Think giant pandas, tigers, or orchids.

Many scientists are drawn to these charismatic species, but that does not always mean they have the opportunity to study them. Competition can be fierce in some academic fields.

We conducted research on these charismatic species, to understand how this field may exclude some academics and give the monopoly on research to others.

Research monopolisation can have several negative effects. For instance, samples may be less commonly shared between scientists. It may even impede an academic’s progress. This can be in the form of sabotaging a competitor’s work, stealing creative ideas and performing biased peer review of funding proposals and publications.

This behaviour doesn’t just harm individual researchers. It can weaken scientific integrity, stifle creativity and drive talented people out of academia. And while our study focused on biology, the patterns are likely echoed across competitive academic fields where prestige and resources are limited.

Charismatic species are easy to love and they’re also good for science. Research on these species attracts more funding, more media coverage, and more space in prestigious journals. But popularity comes with a cost. Our new study reveals that working on these species often fuels competition and, in some cases, fosters exclusionary behaviour.

Over 18 months, we examined academic exclusion in the biological sciences: where established researchers try to prevent potential competitors from studying their preferred animal or plant. We surveyed 826 academics across 90 countries and analysed 800 scientific papers.

The results were striking. We found a positive correlation between a species’ charisma and the impact and volume of scientific outputs. That highlights the benefits of studying such species for a researcher’s prestige and career prospects. But studying charismatic species also tended to increase the likelihood of negative workplace experiences. Younger colleagues, women and researchers based in the regions where the species actually live were the ones who suffered.

Competition and monopolies

Nearly half (46%) of survey participants said they had encountered some form of research monopolisation. Respondents linked charismatic species to greater difficulty obtaining permits or samples, strained relationships with colleagues, and cliquey work environments.

We also found a striking imbalance in participation. Researchers from universities in North America and Europe frequently studied species in Africa, South America and Asia – but the reverse was rarely true. For instance, the eastern barred bandicoot (Perameles gunnii) occurs and was only studied in Australia. The striped skunk (Mephitis mephitis) occurs in the US, where it was studied. But the Malayan culogo (Galeopterus variegatus) was commonly studied by institutions outside Malaysia, as was the aye aye (Paradoxurus hermaphroditus) from Madagascar. This pattern was less pronounced for non-charismatic species.

The result is a skewed scientific landscape. Non-charismatic species, despite their ecological importance, are often underfunded and overlooked.

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Read more: Africa’s freshwater ecosystems depend on little creatures like insects and snails: study maps overlooked species

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Career advantages and disadvantages

For those who secure access to charismatic species, the career payoffs can be enormous. Working on them tends to result in more publications, higher citation rates and more opportunities for international collaboration.

The largest collaborative effort we found was for the charismatic cheetah (Acinonyx jubatus), with a total of 50 authors, 37 institutions and 21 countries on one paper. This effort was rewarded with a journal impact factor of 11.1 and 193 citations, showing the benefit to be gained from collaborating. These advantages feed into the academic reward system, where prestige and productivity often dictate career progression.

A journal with an impact factor of 2-3 is considered solid in most fields, 5-10 is highly regarded, and 15+ is exceptional, usually limited to big multidisciplinary journals like Nature or Science. Only a small fraction of academics (perhaps the top 5%-10%) regularly publish in those very high impact journals. Citations vary hugely by discipline and career stage. A typical early-career researcher might have 20-100 citations total, whereas established mid-career academics often have a few hundred to a few thousand.

Our study also highlights the darker side of this system. Early-career scientists and women reported higher rates of exclusion, including refusals to collaborate, appropriation of research ideas and even harassment.

Gender inequities are particularly stark, despite the biological sciences having a much more even gender balance than most other science fields. Women were less likely to participate in international collaborations, which are strongly linked to career advancement. And when women did lead studies, their papers received fewer citations than those with male first or last authors.

The first author is usually the person who did most of the hands-on work – designing the study, collecting and analysing data, and writing the first draft. The last author is typically the senior researcher or group leader who supervised the project, secured funding and guided the work conceptually. In total, of all first authors, 69% were men, and of all last authors, 81% were men. Male dominance differed depending on the study species, where charismatic mammal species scored relatively high.

Productivity in academia manifests itself in publication rates, publication visibility and citation patterns. These can have a cumulative advantage and lead to substantial inequality among researchers. In our survey, 51% of female respondents reported gender-based discrimination.

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Read more: We think there’s a better way to assess the research of African academics: here’s how

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Editorial boards also play a role. Many biodiversity conservation journals have male-dominated boards and a bias towards publishing studies on charismatic species. Species preference intertwines with gender inequity. For instance, studies on large carnivores are known to be historically male-dominated, and this association may give men a head start in their careers.

Rethinking incentives

What can be done? One solution is to broaden how scientific success is measured. Instead of focusing so heavily on academic output – publications, citations and journal impact factors – institutions and funders could also value contributions such as community engagement, public communication and policy impact.

This may reduce cumulative advantage in science and increase a sense of fairness, hopefully reversing the subtle ways in which organisational logistics serve to perpetuate disparities in academic institutions.

Such measures are becoming increasingly important in biodiversity conservation, where connecting science with society is essential. By shifting incentives, we may reduce the negative side-effects that arise from competition.

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Read more: University ranking systems are being rejected. African institutions should take note

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Scientists themselves also have a role to play. Instead of racing to publish first, research groups could coordinate their work, share data and agree on joint publication strategies. Collaboration over competition could benefit everyone, not least the species that need protecting.

Charisma may help a species capture attention, but it shouldn’t determine who gets to study it, or who gets to succeed in science.

– Some animals are more equal than others: the dark side of researching popular species
– https://theconversation.com/some-animals-are-more-equal-than-others-the-dark-side-of-researching-popular-species-266306