Origin of the universe, evolution of life, new film


This video from the USA says about itself:

Voyage of Time IMAX® Trailer

30 June 2016

Voyage of Time: The IMAX Experience, a 40-minute, giant-screen adventure narrated by Brad Pitt, which immerses audiences directly into the story of the universe and life itself, will be shown exclusively in IMAX® theatres. For more info, visit here.

From Science News:

‘Voyage of Time’ is Terrence Malick’s ode to life

Film offers an artistic take on science

By Erin Wayman

4:38pm, October 7, 2016

Condensing billions and billions and billions of years into a 45-minute film is a tall order. But director Terrence Malick took on the challenge with Voyage of Time. The film, now playing in IMAX theaters, surveys the 13.8-billion-year history of the universe and even looks eons into the future when we — life on Earth, the planet and the entire solar system — are gone.

Starting with the Big Bang, Voyage of Time progresses through highlights of the past, with a central focus on the evolution of life. Malick, best known for directing visually rich dramas such as The Thin Red Line and The Tree of Life, presents breathtaking cinematography, using locales such as Hawaii’s lava-oozing Kilauea volcano as stand-ins for the past. Stunning visualizations and special effects bring to life the formation of the planets, the origin of the first cells, the demise of the sun and other events that scientists can only imagine.

The film marks Malick’s first attempt at documentary filmmaking. If you can call it that. Viewers hoping for a David Attenborough–style treatment of the subject matter will be disappointed. The film is more evocative, with moody scenes that provide little explication. And what narration (by Brad Pitt) there is tends to be philosophical rather than informative.

Serious science enthusiasts may find some reasons to quibble with the movie. For one, it’s hard to grasp the true immenseness and scale of cosmic time. With so much screen time devoted to the evolution of life, many viewers may not realize just how relatively recent a phenomenon it is. After the Big Bang, more than 9 billion years passed before Earth began to form. It took many hundred thousand more years before the first microbes emerged.

Malick’s treatment of evolution may also rankle some viewers. At times, the narration seems to imply life was destined to happen, with the young, barren Earth just waiting around for the first seeds of life to take root. At other times, the narration imbues evolution with purpose. Pitt notes, for instance, that perfecting a leaf took eons. Yet perfection is something evolution neither achieves nor strives for — it’s a process that lacks intentionality.

These critiques aside, Malick sought to tell an accurate story, enlisting an accomplished group of scientists as advisers, including Lee Smolin of the Perimeter Institute for Theoretical Physics in Waterloo, Canada. Smolin says he was impressed with the end result. “It’s a very unusual film,” he says, likening it to a visual poem or piece of art.

And that’s probably the best mindset to watch Voyage of Time: Just sit back, soak in the dazzling visuals and contemplate the wonders of nature.

Human evolution, fire and smoke


This video says about itself:

Smoking Causes Cancer, Heart Disease, Emphysema

20 jul. 2012

This 3D medical animation created by Nucleus Medical Media shows the health risks of smoking tobacco.

ID#: ANH12071

Transcript:

Every time you smoke a cigarette, toxic gases pass into your lungs, then into your bloodstream, where they spread to every organ in your body. A cigarette is made using the tobacco leaf, which contains nicotine and a variety of other compounds. As the tobacco and compounds burn, they release thousands of dangerous chemicals, including over forty known to cause cancer. Cigarette smoke contains the poisonous gases carbon monoxide and nitrogen oxide, as well as trace amounts of cancer-causing radioactive particles. All forms of tobacco are dangerous, including cigars, pipes, and smokeless tobacco, such as chewing tobacco and snuff.

Nicotine is an addictive chemical in tobacco. Smoking causes death. People who smoke typically die at an earlier age than non-smokers. In fact, 1 of every 5 deaths in the United States is linked to cigarette smoking.

If you smoke, your risk for major health problems increases dramatically, including: heart disease, heart attack, stroke, lung cancer, and death from chronic obstructive pulmonary disease.

Smoking causes cardiovascular disease.

When nicotine flows through your adrenal glands, it stimulates the release of epinephrine, a hormone that raises your blood pressure. In addition, nicotine and carbon monoxide can damage the lining of the inner walls in your arteries. Fatty deposits, called plaque, can build up at these injury sites and become large enough to narrow the arteries and severely reduce blood flow, resulting in a condition called atherosclerosis. In coronary artery disease, atherosclerosis narrows the arteries that supply the heart, which reduces the supply of oxygen to your heart muscle, increasing your risk for a heart attack. Smoking also raises your risk for blood clots because it causes platelets in your blood to clump together. Smoking increases your risk for peripheral vascular disease, in which atherosclerotic plaques block the large arteries in your arms and legs. Smoking can also cause an abdominal aortic aneurysm, which is a swelling or weakening of your aorta where it runs through your abdomen.

Smoking damages two main parts of your lungs: your airways, also called bronchial tubes, and small air sacs called alveoli. Cigarette smoke irritates the lining of your bronchial tubes, causing them to swell and make mucus. Cigarette smoke also slows the movement of your cilia, causing some of the smoke and mucus to stay in your lungs. While you are sleeping, some of the cilia recover and start pushing more pollutants and mucus out of your lungs. When you wake up, your body attempts to expel this material by coughing repeatedly, a condition known as smoker’s cough. Over time, chronic bronchitis develops as your cilia stop working, your airways become clogged with scars and mucus, and breathing becomes difficult.

Your lungs are now more vulnerable to further disease. Cigarette smoke also damages your alveoli, making it harder for oxygen and carbon dioxide to exchange with your blood. Over time, so little oxygen can reach your blood that you may develop emphysema, a condition in which you must gasp for every breath and wear an oxygen tube under your nose in order to breathe.

Chronic bronchitis and emphysema are collectively called chronic obstructive pulmonary disease, or COPD. COPD is a gradual loss of the ability to breathe for which there is no cure.

Cigarette smoke contains at least 40 cancer-causing substances, called carcinogens, including cyanide, formaldehyde, benzene, and ammonia. In your body, healthy cells grow, make new cells, then die. Genetic material inside each cell, called DNA, directs this process. If you smoke, toxic chemicals can damage the DNA in your healthy cells. As a result, your damaged cells create new unhealthy cells, which grow out of control and may spread to other parts of your body. Cigarettes can cause cancer in other parts of your body, such as: in the blood and bone marrow, mouth, larynx, throat, esophagus, stomach, pancreas, kidney, bladder, uterus, and cervix.

Smoking can cause infertility in both men and women. If a woman is pregnant and smokes during pregnancy, she exposes her baby to the cigarette’s poisonous chemicals, causing a greater risk of: low birth weight, miscarriage, preterm delivery, stillbirth, infant death, and sudden infant death syndrome. Smoking is also dangerous if a mother is breastfeeding. Nicotine passes to the baby through breast milk, and can cause restlessness, rapid heartbeat, vomiting, interrupted sleep, or diarrhea.

Other health effects of smoking include: low bone density and increased risk for hip fracture among women; gum disease, often leading to tooth loss and surgery; immune system dysfunction and delayed wound healing; and sexual impotence in men.

From Leiden University in the Netherlands:

Are modern humans simply bad at smoking?

Published on 21 September 2016

Scientists looked for the genetic footprint of fire use in our genes, but found that our prehistoric cousins – the Neanderthals – and even the great apes seem better at dealing with the toxins in smoke than modern humans.

Mixed blessing

The art of making and using fire was one of the greatest discoveries ‘ever made by man’, wrote Charles Darwin. Besides providing protection against cold temperatures, the use of fire in food preparation and the introduction of energy-rich cooked foods in our prehistoric diet had a major impact in the development of humankind. However, fire use comes at a cost. Exposure to the toxic compounds in smoke carries major risks for developing pneumonia, adverse pregnancy outcomes in women and reduced sperm quality in males, as well as cataracts, tuberculosis, heart disease, and chronic lung disease. In short, the use of fire is a mixed blessing.

Debate

This mixed blessing, however, put researchers at Leiden University and Wageningen University on the trail of finding genetic markers for the use of fire in prehistoric and recent humans. The use of fire is notoriously difficult to ‘see’ for archaeologists, and this has led to strong disagreement over the history of its usage. A very early start is advocated by Harvard primatologist Richard Wrangham, who argues that our Homo erectus ancestors were already using fire around two million years ago. However, numerous excavations and intensive research carried out by archaeologists in Europe and the Near East suggest that control of fire occurred much later, around 350,000 years ago.

Genetic markers for fire use

In order to bring fresh data into this ‘hot’ debate, the Leiden/Wageningen team studied the biological adaptations of prehistoric and recent humans to the toxic compounds of smoke: fire usage implies frequent exposure to hazardous compounds from smoke and heated food, which is expected to result in the selection of gene variants conferring an improved defence against these toxic compounds. To study whether such genetic selection indeed occurred, the team investigated the gene variants occurring in Neanderthals, in Denisovans (contemporaries of the Neanderthals, more related to them than to modern humans), and in prehistoric modern humans.

Tobacco

Single nucleotide variants in 19 genes were tested that are known from modern tobacco-smoking studies to increase the risk of fertility and reproduction problems when exposed to smoke and hazardous compounds formed in heated food.

These genes were compared with variants observed in Neanderthals and their Denisovan cousins, and were also studied in chimpanzees and gorillas, two closely related species that are obviously not using fire, and are therefore not exposed to smoke on a regular basis.

Neanderthal more efficient in handling smoke?

In a study now published in PLOS ONE, the team shows that Neanderthals and the Denisovan predominantly possessed gene variants that were more efficient in handling the toxic compounds in smoke than modern humans. Surprisingly, these efficient variants were also observed in chimpanzees and gorillas, and therefore appeared to be evolutionary very old (ancestral) variants.

Plant toxins

The less efficient variants are observable from the first modern human hunter-gatherers for which we have genetic information onward, i.e. from about 40,000 years ago. The efficient defence against toxic compounds in chimpanzees and gorillas may be related to the toxins in their plant food. Smoke defence capacities in humans apparently hitchhike on those adaptations, developed deep in our primate past. Our prehistoric ancestors were probably already good at dealing with the toxic compounds of smoke, long before they started producing it through their campfires. What allowed for the emergence of less efficient hazardous chemical defence genes in modern humans is a question for future research.

Traces of long-lost human cousins may be hiding in modern people’s DNA, a new computer analysis suggests. People from Melanesia, a region in the South Pacific encompassing Papua New Guinea and surrounding islands, may carry genetic evidence of a previously unknown extinct hominid species, Ryan Bohlender reported October 20 at the annual meeting of the American Society of Human Genetics. That species is probably not Neandertal or Denisovan, but a different, related hominid group, said Bohlender, a statistical geneticist at the University of Texas MD Anderson Cancer Center in Houston. “We’re missing a population or we’re misunderstanding something about the relationships,” he said: here.

Seabird evolution, new study


This 2014 video from Britain is called BBC Natural World – Saving Our Seabirds – Full Documentary.

From the Journal of Ornithology:

31 May 2015

Speciation in seabirds: why are there so many species…and why aren’t there more?

Vicki L. Friesen

Abstract

Speciation—the multiplication of species through the evolution of barriers to reproduction between populations—plays a central role in evolution since it enables two or more populations to adapt and evolve independently. However, mechanisms of speciation are notoriously difficult to study and poorly understood.

Seabirds provide useful models to investigate factors that may promote or inhibit speciation because their ecology and evolutionary genetics are relatively well understood. Here I review population genetic studies of seabirds to test the importance of six factors with the potential to disrupt gene flow enough to result in speciation.

Over 200 studies, including over 100 species, have been published to date. Most show evidence of restrictions in gene flow. Physical (geographic) barriers to dispersal are clearly important: conspecific populations that are separated by large expanses of land or ice show evidence of restricted gene flow, and sister species often are separated by physical barriers to gene flow. However, many species of seabirds show evidence of restrictions in gene flow in the absence of physical barriers to dispersal.

Study results indicate that differences in ocean regimes, nonbreeding distributions, foraging distributions during the breeding season, and breeding phenology also can disrupt gene flow enough to lead to speciation. Of these, physical isolation and differences in ocean regime appear to be the most important. Philopatry alone may be sufficient to result in reproductive isolation, but usually it acts in combination with other barriers to gene flow.

The effects of many other potential influences on gene flow need to be investigated more thoroughly, including colony distribution/location, wind, interspecific interactions, environmental stability/variability, variation in phenotypic traits associated with mate choice (morphology, behaviour, vocalisations) and intrinsic (genomic) incompatabilities. Recent advances in genome sequencing, especially if used in combination with ecological tools such as geolocators and new methods for data interpretation, are opening exiting new avenues to test the importance of various behavioural, ecological, demographic and genomic factors in reducing or promoting gene flow and so affecting speciation.

Evolution biology on trial in Tennessee, USA


This video from the USA is called The Scopes Monkey Trial Explained in 5 Minutes: US History Review.

By Peter Frost in Britain:

Primate witness: the monkey trials go on

Thursday 7th May 2017

PETER FROST is amazed that, 90 years after the famous Tennessee trial, the evolution versus creationism argument still rages

ON MAY 5 1925, 90 years ago this week, a group of thinkers in the small town of Dayton, Tennessee, are discussing a newspaper announcement.

The American Civil Liberties Union (ACLU) is looking for someone to challenge the new Butler Act passed by the state to outlaw the teaching of evolution in Tennessee schools. This law bans the teaching of any theory that denies the literal truth of the biblical creation of man.

One of the men, 24-year-old science teacher and football coach John Thomas Scopes, says he will be willing to be indicted to bring the case to trial. Scopes has only taught biology as a substitute teacher and later says he isn’t sure he covered evolution in his classes.

On May 25 John Scopes was brought to trial for teaching evolution. The case, forever known as the Monkey Trial, made world headlines and is still talked about today.

Scopes agreed to purposely incriminate himself so that the case could have a defendant. He knew such a trial would draw intense national publicity to the argument. The world’s press flocked to Dayton. To make room for the many journalists and observers the trial was convened in the open air. This proved a blessing in the stifling Tennessee heat.

Defending Scopes was Clarence Darrow, already a famous lawyer. He would go on to become the best-known and most revered defence lawyer in US jurisprudence.

Darrow had made his reputation as a labour union lawyer and had defended many militant heroes of US working-class strikes and struggles — many of them framed on trumped-up charges. These included many members of the US Communist Party charged with treason. Leading the prosecution of Scopes was William Jennings Bryan, Bible scholar, rabid creationist and three-time Democratic candidate for US president.

Bryan’s argument was simple. He declared the word of God as revealed in the Bible took priority over all other human knowledge. Judge John T Raulston made no pretence at neutrality. He started each day with a hymn and a prayer. The judge ruled that the many scientists who wished to speak in Scopes’s defence could only give their evidence in writing.

British novelist H G Wells was asked if he would join the defence team. Wells replied that he had no legal training in Britain, let alone in the US, and declined the offer. The ACLU opposed the Butler Act on the grounds that it violated the teacher’s individual rights and academic freedom, and was therefore unconstitutional.

Darrow and the judge frequently clashed and there were several threats of action for contempt with Darrow forced to apologise. Darrow attacked the literal interpretation of the Bible as well as Bryan’s limited knowledge of other religions and science. He scoffed at Bryan’s horror that human beings were descended “not even from American monkeys, but from old-world monkeys.”

Darrow took the unorthodox step of calling Bryan, the chief prosecutor, to the stand as a defence witness. Darrow asked him questions such as: “If Eve was actually created from Adam’s rib, where did Cain get his wife?” The confrontation between Bryan and Darrow lasted approximately two hours before Judge Raulston’s announced that he considered the whole examination irrelevant to the case. He ruled that it should be struck from the record. Darrow closed the case for the defence without a final summing up. Under Tennessee law, when the defence waived its right to make a closing speech, the prosecution was also barred from summing up its case.

Scopes was found guilty and ordered to pay a $100 fine. He addressed the court for the first time. “Your honour, I feel that I have been convicted of violating an unjust statute. I will continue in the future, as I have in the past, to oppose this law in any way I can. Any other action would be in violation of my ideal of academic freedom — that is, to teach the truth as guaranteed in our constitution, of personal and religious freedom. I think the fine is unjust.”

The appeal court set aside the conviction because of a tiny legal technicality: the jury should have decided the fine, not the judge, since under the state constitution Tennessee judges could not set fines above $50, and the Butler Act specified a minimum fine of $100. Appeal judge Green added: “We see nothing to be gained by prolonging the life of this bizarre case.”

The Butler Act stayed on the statute books until 1967. In reality this bizarre case and the arguments that caused it are still being debated. Strangely despite logic and scientific proof, the ideas of creationism are still gaining ground on both sides of the Atlantic.

When the Con-Dem coalition established free schools in 2011, three such schools — each teaching creationism — were approved by the then education secretary Michael Gove. Today free schools in Britain are no longer allowed to teach creationism as if it were fact. Now such teaching is confined to religious education classes and not presented as a valid alternative to established scientific theory.

Yet surveys show that, amazingly, one in three US citizens doesn’t believe in evolution. They think humans and other living things have existed in their present form since the beginning of time. White evangelical Protestants, particularly in the Southern Bible belt — states like Tennessee — are most likely to not believe in evolution and ridicule Darwin’s ideas.

Both Tennessee and Louisiana allow the teaching of creationism in school science classes. Currently, less than half of Republican voters, just 43 per cent, believe in human evolution. Only 67 per cent of Democrats think Darwin’s theory credible.

Worse, US opinion is shifting and the numbers doubting evolution and supporting creationism are growing every year. Nearly a dozen states are considering legislation to either outlaw the teaching of Darwinian evolution or to give equal space and time to creationism in school science classes.

In Tennessee the law defines controversial issues including biological evolution, the chemical origins of life, global warming and human cloning and seeks to ensure schools also teach what the Bible has to say on the subjects.

Tennessee law wrongly suggests the scientific community is divided over these issues. It is not, but the law has now made it significantly harder to ensure that science is taught responsibly.

Evolution, Darwin, Wallace and Patrick Matthew


This video says about itself:

Forsdyke Evolution Academy 01-14 Patrick Matthew

12 October 2011

The second of a series of 12 videos on natural selection from a historical perspective.

From King’s College London in England:

April 20, 2015

The overlooked third man

The horticulturist who came up with the concept of ‘evolution by natural selection‘ 27 years before Charles Darwin did should be more widely acknowledged for his contribution, states a new paper by a King’s College London geneticist.

The paper, published in the Biological Journal of the Linnean Society, argues that Patrick Matthew deserves to be considered alongside Charles Darwin and Alfred Russel Wallace as one of the three originators of the idea of large-scale evolution by .

Furthermore, Matthew’s version of evolution by natural section captures a valuable aspect of the theory that isn’t so clear in Darwin‘s version – namely, that natural selection is a deductive certainty more akin to a ‘law’ than a hypothesis or theory to be tested.

Patrick Matthew (1790-1874) was a Scottish landowner with a keen interest in politics and agronomy. He established extensive orchards of apples and pears on his estate at Gourdie Hill, Perthshire, and became adept in horticulture, silviculture and agriculture.

Whilst Darwin and Wallace‘s 1858 paper to the Linnean Society, On the Origin of Species, secured their place in the history books, Matthew had set out similar ideas 27 years earlier in his book On Naval Timber and Arboriculture. The book, published in 1831, addressed best practices for the cultivation of trees for shipbuilding, but also expanded on his concept of natural selection.

“There is a law universal in nature, tending to render every reproductive being the best possibly suited to its condition that its kind, or that organized matter, is susceptible of, which appears intended to model the physical and mental or instinctive powers, to their highest perfection, and to continue them so. This law sustains the lion in his strength, the hare in her swiftness, and the fox in his wiles.” (Matthew, 1831: 364)

In 1860, Matthew wrote to point out the parallels with his prior work, several months after the publication of On the origin of species. Darwin publically wrote in 1860 “I freely acknowledge that Mr. Matthew has anticipated by many years the explanation which I have offered of the origin of species”, while Wallace wrote publically in 1879 of “how fully and clearly Mr. Matthew apprehended the theory of natural selection, as well as the existence of more obscure laws of evolution, many years in advance of Mr. Darwin and myself”, and further declared Matthew to be “one of the most original thinkers of the first half of the 19th century”. However, both asserted their formulations were independent of Matthew’s.

Even if Matthew did not influence Darwin and Wallace, his writings provide a valuable third point of reference on the notion of macroevolution by natural selection, argues the paper’s author, Dr Michael Weale. Dr Weale has created a public website to act as an online repository of the writings by Patrick Matthew, including some of his lesser-known work.

Dr Michael Weale, from the Department of Medical and Molecular Genetics at King’s College London, said: ‘Whilst Darwin and Wallace both deserve recognition for their work, Matthew, the outsider who deduced his idea as part of a grand scheme of a purposeful universe, is the overlooked third man in the story. Matthew’s story is an object lesson in the perils of low-impact publishing. Despite its brevity, and to some extent because of it, Matthew’s work merits our renewed attention.’

Explore further: Darwin’s finches highlight the unity of all life

More information: ‘Patrick Matthew’s Law of Natural Selection’ by Michael Weale is published in the Biological Journal of the Linnean Society and can be accessed here.

From Wikipedia:

Matthew’s idea on society were radical for their times. Although he was a landowner, he was involved with the Chartist movement, and argued that institutions of “hereditary nobility” were detrimental to society. It has been suggested that these views worked against acceptance of his theory of natural selection, being politically incorrect at the time (see Barker, 2001).

Fossils collected by Charles Darwin: here.

Sea snail venom evolution, new research


This video says about itself:

11 January 2012

You’d think a snail wouldn’t be much threat in the sea, but the cone snail proves deadly to unsuspecting fish.

From the University of Michigan in the USA:

Predatory Snails Evolved Diverse Venoms to Subdue a Wide Range of Prey Species

Released: 17-Mar-2015 8:00 AM EDT

ANN ARBOR—A new study by University of Michigan biologists suggests that some predatory marine cone snails evolved a highly diverse set of venoms that enables them to capture and paralyze a broad range of prey species.

When cone snails sink their harpoon-like teeth into their prey, they inject paralyzing venoms made from a potent mix of more than 100 different neurotoxins known as conotoxins.

The genes that provide the recipes for conotoxin cocktails are among the fastest-evolving genes in the animal kingdom, enabling these snails to constantly refine their venoms to more precisely target the neuromuscular systems of their prey.

U-M researchers showed that the mix of neurotoxins in cone-snail venom varies from place to place and is more diverse at locations where the snails have a broad range of prey species. In addition, they concluded that the observed patterns of local conotoxin variation are likely due to natural selection.

That’s a significant finding because it is often difficult for biologists to determine whether place-to-place variations in an organism’s observable traits—the wide range of beak sizes and shapes in the Galapagos Islands finches studied by Charles Darwin, for example—are the result of evolution by natural selection or some other factor, such as the reproductive isolation of a population of animals or plants.

In addition, the U-M researchers were able to directly target the genes responsible for the observed conotoxin patterns. A paper summarizing the work is scheduled for online publication in the journal Proceedings of the Royal Society B on March 18.

“The differences in venom composition that we observed correspond to differences in prey, and a higher diversity of venom is used to capture more prey species,” said first author Dan Chang, formerly a doctoral student in the U-M Department of Ecology and Evolutionary Biology and now a postdoctoral researcher at the University of California, Santa Cruz.

“Our results suggest that prey diversity affects the evolution of predation genes and imply that these predators develop a more diverse venom repertoire in order to effectively subdue a broader range of prey species,” Chang said.

The study involved a common species of tropical, worm-eating cone snail, Conus ebraeus, collected at locations in Hawaii, Guam and American Samoa. These snails are about an inch long and are commonly known as Hebrew cone snails. Their shells are white with black rectangular markings that form a distinctive checkerboard pattern.

The researchers characterized the patterns of genetic variation in five toxin genes in C. ebraeus snails from the three locations. They also collected fecal samples from the snails to determine the types of worms they ate.

“We demonstrated that venom genes used for predation are highly affected by local variation in prey diversity and geographic heterogeneity in prey compositions,” Chang said. “Not all conotoxin genes are affected in the same way though, which implies that these genes may have distinct functional roles and evolutionary pathways.”

The other U-M authors are Thomas Duda and Amy Olenzek. The study was funded by a National Science Foundation grant to Duda, who is an associate professor in the Department of Ecology and Evolutionary Biology and an associate curator at the U-M Museum of Zoology.

Dan Chang
Thomas Duda

‘Conus geographus, the Life and Death Cone Snail’ by Andreia Salvador: here.

The plant family Corsiaceae, new research


This video is called Liliaceae plant family, description, examples, info.

From the Journal of Biogeography:

Ancient Gondwana break-up explains the distribution of the mycoheterotrophic family Corsiaceae (Liliales)

19 FEB 2015

Abstract

Aim

Many plant families have a disjunct distribution across the southern Pacific Ocean, including the mycoheterotrophic family Corsiaceae, which provides a prime example of this biogeographical pattern. A better grasp of the family’s evolutionary relationships is needed to understand its historical biogeography. We therefore aimed to (1) test the uncertain monophyly of Corsiaceae, (2) define its phylogenetic position, and (3) estimate divergence times for the family, allowing us to assess whether the distribution of the family is the result of vicariance.

Location

Southern South America and Australasia.

Methods

We analysed various combinations of mitochondrial and nuclear data to address the monophyly, phylogenetic position and age of Corsiaceae. To test its monophyly, we used a three-locus data set including most monocot orders, and to infer its exact phylogenetic position, we used a five-locus extended data set. We corroborated these findings using an independent plastome dataset. We then used a two-locus dataset with taxa from all monocot orders, and a three-locus dataset containing only taxa of Liliales, to estimate divergence times using a fossil-calibrated uncorrelated lognormal relaxed-clock approach.

Results

Corsiaceae is a monophyletic family and the sister group of Campynemataceae. This clade is the sister group of all other Liliales. The crown age of Corsiaceae is estimated to be 53 Ma (95% confidence interval 30–76 Ma).

Main conclusions

Corsiaceae is an ancient family of mycoheterotrophic plants, whose crown age overlaps with the plate-tectonic split of Gondwana, consistent with a vicariance-based explanation for its current distribution.

See also here.