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Our interwoven ancestry

Denisova Cave in Siberia. Photo by Демин Алексей Барнаул

*Homo georgicus*, an archaic descendant of *Homo erectus*.

In 2008 a new group of human ancestors – the Denisovans, were defined on the basis of a single finger knuckle (phalanx) bone discovered in Denisova cave in the Altai mountains of Siberia. A molar tooth, found at Denisova cave earlier (in 2000) was determined to be of the same group. Since then extensive work in the region has identified that at the time (about 40,000 years ago), modern humans (ancestors of all people alive today), Neanderthals (to whom we’re also related) and Denisovans shared this environment. Since then, more fossils have been found at the cave and identified as being Denisovans. Their ancestry has also been extended back for many hundreds of thousands of years. More significant than the number of fossil bones, however, is the contribution to our genetic understanding of our ancestry. The DNA sequenced from the Denisovan fossils has been compared to DNA from archaic and modern humans, as well as Neanderthals, allowing us to build up an understanding of the connections between our own ancestors and others in our lineage. The more we understand of this history written in our cells, the more it becomes apparent that we are the result of a complex, interwoven tapestry played out on an enormous framework across the planet.

About 1.9 million years ago, Homo erectus hominins left Africa and began spreading across the world. Homo erectus, whilst enormously successful and persisting in some areas until quite late in the biological sequence (perhaps as late as 50,000 years ago), also seems to have been the origin of several hominin lineages, including our own. The genetic evidence is crucial as it can reveal patterns and developments over time, without being hampered by gaps in the fossil record. For example, we have not found Denisovan fossils anywhere except at Denisova cave in Siberia, however, we can see their genetic influence in populations in other areas. Most intriguing of all was the discovery at Denisova cave in 2014 (published in August this year) of a long bone fragment of a woman, now known as “Denny”, who had a Neanderthal mother and a Denisovan father.

The current understanding is that about 25 920 generations ago (geneticists work in generations, and assume 30 years per generation, on average) there was a divergence from the Homo erectus population of an archaic species (perhaps the fossils designated Homo heidelbergensis and similar). The ancestors of modern humans were part of this divergence. Perhaps only 300 generations later, Neanderthals and Denisovans formed two lineages out of the remaining archaic population. However, this did not result in 3 perfectly distinct lineages.

Denny’s mother was a Neanderthal from the Altai region, however, genetically she was more closely related to a fossil found in Croatia than to a Neanderthal fossil found in Denisova cave and dated 30,000 years earlier! The Neanderthals found at Altai also contain genetic markers showing links to early modern humans from a later time period than the original divergence. The Denisovan DNA also suggests that there is another (so far unknown) hominin species which had had an earlier separation from the Homo erectus line, which contributed 8% of Denisovan DNA. The Denisovan genome also contains a 17% overlap with the local Altai Neanderthals, suggesting a significant level of exchange of genetic material (interbreeding).

Multicultural Children — Multicultural children

Modern humans who do not have solely African ancestry have between 1 and 4% Neanderthal DNA. Melanesian populations have between 4 and 6% (or possibly even higher) Denisovan DNA. Australian Aboriginals and some groups scattered across South East Asia also have Denisovan genetic markers, suggesting that Denisovan ancestry spread into South East Asia at some point. Small amounts (about 0.2%) of Denisovan DNA are also found in modern Asian and American First Nations people populations. Some modern East Asian populations (including Han Chinese and Japanese) show evidence of two groups of Denisovan DNA – one similar to the South East Asian populations and a second one more similar to the population in the Altai region of Siberia, suggesting two periods of genetic exchange. There is also some suggestion of genetic mixture between Denisovans and people in west Asia.

It would seem that Denisovan DNA may be expressed as dark skin, brown hair and brown eyes, as well as a gene assisting with low oxygen adaptation at high altitudes, found in modern Tibetan populations. This can be compared with the Neanderthals genes which entered the European modern human populations and express as light skin, red hair and freckles. What is abundantly clear is that our ancestry throughout history and prehistory is not so much a tree as a complex, interwoven web. As can be seen in any modern population we all have a wide range of different characteristics that reflect our broad and diverse genetic history. We can also see that all humans, our ancestors and relatives throughout time have always moved widely across the world and formed families together with people in different areas. We are indeed a global species.

This Week in Australian History

Black Wattle flowers — Black wattle flowers – photo, John Tann

The end of August and beginning of September is traditionally linked to the beginning of Spring in Australia, although the change in seasons is experienced in different ways in different parts of the country and was marked in locally appropriate ways by Aboriginal people. As a uniquely Australian celebration of Spring, National Wattle Day, celebrated on 1 September since 1910, celebrates the flowering of these uniquely Australian trees, as well as Australian identity.

Not strictly speaking within this week, but close enough to be included: it was 22 August, 1770, when James Cook claimed the East Coast of Australia for Britain, planting a flag on the island he called “Possession Island“.
On 29 August, 1862, Andrew Fisher, who became the 5th Prime Minister of Australia after Federation and served 3 terms (1908-1909; 1910-1913 and 1914-1915) was born in Scotland in the UK. Fisher had started working in coal mines at the age of 10 and went on to be the leader of the Australian Labor Party between 1907 and 1915. Fisher came out to Australia and worked on the gold mines at Gympie. The cottage in which he lived is a heritage-listed building and can be visited as part of the Gympie and District Historical Society Mining Museum.
On 30 August, 1835, John Batman, with a party of settlers including John Pascoe Fawkner, landed at the mouth of the Yarra River and established a settlement on the site where the current Melbourne Immigration Museum is situated. This settlement later became the city of Melbourne.
Also on 30 August, 1853, the last convict ship to travel directly from Ireland to Australia, the Phoebe Dunbar, arrived in Fremantle, Perth. England continued to send convicts for another 15 years.
31 August, 1933, the township of Stuart in the Northern Territory was renamed Alice Springs.
1 September, 1874, was the day that the General Post Office opened in Sydney. It was the first building purpose-built as a post office in Sydney and was controversially positioned over the Tank Stream, which had provided early Sydney with its drinking water.
A rather unique incident occurred on 1 September, 1846. John Ainsworth Horrocks was an explorer who founded the village of Penwortham in South Australia. Whilst on an expedition in north-west South Australia, he stopped to reload his shotgun. He was busy with this task when a sudden lurch from Harry, his camel, discharged the gun, fatally injuring Horrocks.

From a celebration of Spring to a man who was shot by his camel, there are plenty items of potential interest to students this week. These can also be aligned to aspects of the Australian curriculum. Why not celebrate wattle day in your classroom? Have the students bring in wattle flowers. Younger students can talk about changing seasons, Australian celebrations and draw the flowers; older students can examine Australian identity, Federation and the creation of a separate identity from Britain in the early 20th century. Students in Victoria and New South Wales can also examine the events of particular significance to their state.

Rising sea levels and our children’s future

Global warming and sea level rise sometimes seems like a lot of hype bandied about by the media and politicians. However, it has a different level of importance for scientists in a range of disciplines around the world. The Australian Curriculum emphasises that students should study sustainability and environment issues in HASS and Science subjects, from lower primary school up. This is not just because its fashionable at the moment, but rather because even casual reading of the science tells us that these are going to be some of the most critical issues faced by our children in years to come. The world has already lost inhabited islands to sea level rise, with communities being moved out of their flooded homes. Eight of these islands are in the Pacific. In the Solomon Islands one inhabited island has already lost 75% of its houses to the sea, since 2011.

Global warming and sea level rise are related because a warmer global environment melts the ice at the poles and causes the sea level to rise. The same thing happened at the end of the last Ice Age, 12,000 years ago. In a paper just published in the respectable journal, Nature, Australian scientists (with some international colleagues) present two alternatives for the future of Antarctica (and thus for the future sea level rises around the world). The two lead authors (from the CSIRO and Monash University) have also published a slightly simpler version of this paper, highlighting the key points. The two scenarios explored are based on the kind of action that we all take now to reduce global warming, greenhouse gas emissions and human impacts on the fragile polar environments. The authors argue that actions need to take place within the next decade.

Scenario 1 has us take sudden, urgent action to reduce global warming and greenhouse gas emissions worldwide, as well as putting policies in place to control and reduce human impacts on the poles, and Antarctica in particular (reducing numbers of people in Antarctica, as well as their impact there). The situation 50 years from now (a time scale chosen to reflect the lifetimes of today’s children) has Antarctica enjoying a similar environment to today. The ozone hole has been repaired and the climate remains similar to that of the 20th century. The rate at which the ice has thinned has remained constant, instead of accelerating, and the acidification of the sea water has been kept low. The sea ice has decreased by “only” 12% and the ice on land by “only” 8%. Marine animals and birds show only small declines in population. Antarctica has been protected from invasive plants and animals through decreased human access and impact and maintenance of the harsh climate. Global air temperature has risen by less than 1 degree Celsius. Overall the sea level will rise by just under 1 metre, of which only 6cm comes from melting ice in West Antarctica.

Sea level rise Ade — Sea level rise in Adelaide.

Scenario 2 has us take very little to no action to reduce global warming, greenhouse gases and human impacts on Antarctica. Fossil fuel use and deforestation have continued and there has been no regulation of human access to Antarctica. Global air temperatures have risen by more than 3.5 degrees Celsius. The oceans have warmed and become more acidic – at levels that corrode marine shells and the exoskeletons of marine animals. Ice shelves in Antarctica have collapsed, accelerating the melting of ice and icebergs pose a continual risk to fishing, tourist and commercial shipping fleets. Sea ice is reduced by almost half. In this scenario, global sea levels rise at rates similar to that at the end of the Ice Age, gaining 3 metres by the year 2300 and more than half a metre in the first 50 years alone. Fisheries around the world are collapsing, and animals (such as penguins, seals and whales) who depend upon fish are in sharp decline. Antarctica has been colonised by invasive species of plants and animals, further disrupting the ecosystem and preventing ice from reforming in some areas. Antarctica is also being denuded of its original nature by rampant harvesting of resources, including mining, and the arrival of about 1 million tourists per year, who come to try to catch a glimpse of what Antarctica used to be, before it all disappears.

Sea level rise B — Sea level rise in Brisbane.

This sounds like a doom and gloom scenario, but it is one of the most likely scenarios, with the impact on our way of life being severe. Websites are now available to examine what sea level rises mean for our coastal cites. The impact varies in different cities, with Adelaide and Cairns being amongst the worst affected, although Brisbane’s port and airport are also in trouble. None of our coastal cities are exempt. These pictures show a 1.1m sea level rise by the year 2100 – close to the best case scenario mentioned above! They also do not take into account storm surges, erosion and other effects as our weather systems continue to be disrupted by the changing world environment. Now imagine 3 times that amount of impact, as forecast by the worst case scenario!

This is our children’s future. We need to prepare them well for handling these disasters. They need to understand how these have happened and what can be done to mitigate the effects of these changes. It is the job of all parents and educators to guide our children to develop the skills to interpret, understand and act in creative and innovative ways when tackling problem-solving and to start discussing these issues of their future now. Science, and the Scientific Method in particular, is an essential tool and the only hope that we have of both tracking what is happening and monitoring the efficacy of possible solutions.

QWERTY 150 years old

Did you realise that QWERTY and typewriters were from that long ago? I certainly didn’t. I did grow up in the late era of the typewriter (70s/80s), and I first learnt how to type on a mechanical typewriter. It was a model with a dual-coloured ribbon (black/red) which I used to good effect for a variety of things.

I still own a “capture the flag” type card game called the Oasis game which I manufactured myself: I typed up the text for each of the cards (in the two different colours, as appropriate), cut them, and put contact on (no laminator). The game is still in pretty good shape, as it is stored in an also home-made card case. I’ve got proof, I just took a picture of it (below).

Now, back to history… in the 1860s, a politician, printer, newspaper man, and amateur inventor in Milwaukee by the name of Christopher Latham Sholes spent his free time developing various machines to make his businesses more efficient.

One such invention was an early typewriter, which he developed with Samuel W. Soulé, James Densmore, and Carlos Glidden, and first patented in 1868. The grant date of US patent US79265A is 23 June 1868, thus today is exactly the 150 year mark. So, happy birthday QWERTY!

Sholes typewriter, 1873 — Sholes typewriter from 1873, isn’t it a beauty? (in Buffalo NY history museum)

Assessment Time

For many of us, the colder weather has started to arrive and mid-year assessment is in full swing. Teachers are under the pump to produce mid-year reports and grades. The OpenSTEM® Understanding Our World® program aims to take the pressure off teachers by providing for continuous assessment throughout the term. Not only are teachers continually kept appraised of students’ progress towards meeting the learning goals for the term, they can also provide timeous feedback to students, allowing them to reach those goals more effectively. The Understanding Our World® units are also curriculum aligned, and each curriculum strand is matched through each section of the model answer to the assessment guide, which provides a grading schedule and vocabulary to describe each student’s progress through the core curriculum areas. Thus, teachers need only to collate this information for each student in order to populate the reports.

Students in year levels from Foundation (Kindy/Prep) to Year 3 work through curriculum-aligned sections of work throughout the term and are assessed through a variety of interactions, which include students’ verbal and written responses, as well as drawings and craft projects completed as part of the term work. Students in Years 4 to 6 usually have one main project or summative assessment piece for the term. However, the student workbook provided with each unit is structured to step students through the formative process of completing this work over several weeks, allowing teachers to keep track of their progress and provide regular feedback. The assessment guide provided with each unit, guides teachers on how to assess the assessment piece (as well as the rest of the term work, including the student workbook), as well as providing a marking rubric and vocabularies for students’ achievements from A to E.

Continuous assessment is widely recognised internationally as promoting “inclusive and equitable quality education”. A UNESCO report from August 2017 describes the advantages of continuous assessment for teachers, students, parents and other “education actors”. It includes statistics on how it has improved student engagement, confidence and performance, whilst improving the teaching-learning process. The impact of the shift to continuous assessment is particularly marked when applied to lower performing schools and students, where performance increases significantly once continuous assessment is used. Studies from countries in Africa, including Zambia, have shown that students’ performance and engagement were greatly increased after continuous assessment was introduced. On a global scale, continuous assessment has been shown to improve outcomes for students, parents, teachers and education systems as a whole, especially in the vital area of fostering critical 21st Century competencies. Continuous assessment has been shown to “improve overall quality and equity in education delivery and outcomes”. Feedback – from teachers to students, from students to each other, from teachers to parents and also within the education system itself, is a critical component of this success.

The authors of the UNESCO report warn that “high-stakes, large-scale, annual and multi-annual instruments” of assessment “threatens education” and “continues to favour information over knowledge, and mechanical skill over practical application”. Continuous assessment is also in line with the suggestions in the Gonski 2.0 report. It is perhaps apposite to mention that the Queensland government is currently undertaking a review of NAPLAN and is looking for survey responses. Click on the link provided to take part.

This Week in Australian History

Today we introduce a new category for OpenSTEM® Blog articles: “This Week in Australian History”. So many important dates in Australian history seem to become forgotten over time that there seems to be a need to highlight some of these from time to time. For teachers of students from Foundation/Prep/Kindy to Year 6 looking for material to engage students around Australian history we recommend the OpenSTEM® Understanding Our World® HASS + Science program, which is filled with curriculum-aligned topics specifically designed to capture the interest of students. Whether you use our program or not, one can still connect with students by finding content applicable to their current lives which aligns with curriculum requirements. Here are some suggestions for this week:

6th June: This year Wednesday 6 June was marked by the opening match of the annual State of Origin rugby league series between the NSW Blues and the Qld Maroons. Whilst rugby league has its own fascinating history, closely allied to Australia’s colonial history, and the first match between Qld and NSW was played on 11 July, 1908, the date of 6th June has another significant historical association for both states. It was on 6th June, 1859, that Queensland became a colony of Britain, separate from New South Wales. Officially referred to as “Queensland Day”, this date was celebrated with parades and festivals all over the state at its centenary in 1959. I’m sure many Queenslanders would like there to be more widespread recognition of their state’s “birthday”. Students in Years 5 and 6, in particular, with their focus on colonial and Federation history, might enjoy looking into the birthday of their own state, and the OpenSTEM resources on the history of each state can be used to good effect, see here for links: New South Wales, Victoria, Western Australia, South Australia and Tasmania.

10th June: A more tragic event in Australian history is the Myall Creek Massacre, which took place on 10 June 1838 in central New South Wales. About 30 unarmed indigenous Australians were killed by a group of 12 convicts and former convicts, working as stockmen in the area. No reason was given for the massacre apart from the expansion of European settlers into the area. The incident was notable in that it actually came to trial (a rare event at the time). After the jury refused to convict “a white man for killing a black” (letter to the editor of The Australian newspaper, 1838), the Attorney-General convened a second trial for 7 of the 11 men held in custody. All 7 were found guilty and hanged. The remaining 4 men were remanded to the next court session, but after the sudden disappearance of the chief Aboriginal witness against them (who was never seen again), they were released. One of them later committed suicide. The event and trial were extremely controversial, further polarising the colonial population. Today a memorial stands on the site and an annual commemoration is held. The curriculum offers the opportunity for students in Year 5 to study massacres in Australian history in the context of colonial history.

11th June: On this day in 1770, Captain James Cook encountered the Great Barrier Reef off the coast of Australia. Unfortunately, Cook’s ship, The Endeavour, ran aground on the reef now named for Cook’s ship, near Cape Tribulation (which was named by Cook for this unfortunate event) at 11pm at night. This incident led to Cook and his crew spending 7 weeks ashore, near modern Cooktown, repairing their ship. As a result of this time, the word “kangaroo” entered the English language and the stage was set for Australia to later become a British colony. In 1969, 6 cannons, ballast and an anchor, tossed overboard in an attempt to get the ship off the reef, were discovered and one of the cannons is on display at the Australian National Maritime Museum in Darling Harbour, Sydney. Today, with the Great Barrier Reef under extreme threat from warming, coral bleaching, pollution and increased carbon dioxide, we would do well to remember its part in our history.

Some events in history are pleasant and can be embraced with excitement, whilst others are more sombre. However, all contain lessons for our modern lives. Students love to discuss wide ranging topics, especially if these can be made relevant to their own lives. The OpenSTEM® Understanding Our World® HASS + Science program offers a vast range of engaging ways to help teachers gain interest in these topics from their students and to stimulate enquiry and problem-solving, as well as introducing basic research skills which will stand them in good stead for life. Why not make your classroom a vibrant hub for curious young minds by implementing our programs next term?