Barnacles’ information about whales


This video from California in the USA says about itself:

Rare Blue Whale with Many Barnacles

9 July 2015

Just very close and shallow to the shore of the Torrey Pines Cliffs, with the depth of between 150 and 200 feet, the blue whale had so many black specks all over its body! It also had a dorsal fin that had been torn off and shaped like a sickle! It is very unusual for a blue whale to have very many barnacles.

From Science News:

Barnacles track whale migration

Chemical composition of hitchhikers’ shells might reveal ancient baleen travel routes

By Thomas Sumner

12:01pm, September 27, 2016

DENVER — Barnacles can tell a whale of a tale. Chemical clues inside barnacles that hitched rides on baleen whales millions of years ago could divulge ancient whale migration routes, new research suggests.

Modern baleen whales migrate thousands of kilometers annually between breeding and feeding grounds, but almost nothing is known about how these epic journeys have changed over time. Scientists can glean where an aquatic animal has lived based on its teeth. The mix of oxygen isotopes embedded inside newly formed tooth material depends on the region and local temperature, with more oxygen-18 used near the poles than near the equator. That oxygen provides a timeline of the animal’s travels. Baleen whales don’t have teeth, though. So paleobiologists Larry Taylor and Seth Finnegan, both of the University of California, Berkeley, looked at something else growing on whales: barnacles. Like teeth, barnacle shells take in oxygen as they grow.

Patterns of oxygen isotopes in layers of barnacle shells collected from modern beached whales matched known whale migration routes, Taylor said September 25 at the Geological Society of America’s annual meeting. Five-million-year-old barnacle fossils have analogous oxygen isotope changes, preliminary results suggest. Converting those changes into migration maps, however, will require reconstructing how oxygen isotopes were distributed long ago, Taylor said.

Record number of migrating spoonbills


This video from Belgium says about itself:

Migration: spoonbills – Fonteintjes, Zeebrugge, 29/03/14

Group of spoonbills migrating over land, hesitating to land on the pools next to the counting station.

According to Dutch site Trektellen.nl, on 27 December 2016 844 spoonbills, migrating to the south, passed the Digue de Malo near Dunkirk in France.

This is a record number.

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.

Coral reefs, parrotfish poop and sand


This video says about itself:

Parrotfish Poop! | JONATHAN BIRD’S BLUE WORLD Extra

23 September 2016

In this short Jonathan Bird’s Blue World Extra, Jonathan discusses where sand comes from and you may be surprised to learn that a lot of sand is actually fish poop!

Jonathan Bird’s Blue World is an Emmy Award-winning underwater science/adventure program that airs on public television in the United States.

‘Ancient humans left Africa once’


Human migration out of Africa, picture by P.D. deMenocal and C. Stringer/Nature 2016

From Science News:

Going global

Previous studies have used fossil, archaeological and genetic data to time humans’ colonization of the world (times shown above). New genetic studies may change that map; they suggest small numbers of people left Africa 120,000 years ago, but left little trace in the DNA of present-day people. Most non-Africans inherited their DNA from people who left Africa between about 70,000 and 50,000 years ago, new studies suggest. But a climate study indicates that was the worst possible time for an out-of-Africa migration and suggests people may have left earlier, between 80,000 and 100,000 years ago.

This video says about itself:

Predicted spread of humans around the world | Science News

21 September 2016

Earth wobbles on its axis, causing major climate shifts. Some of those shifts turned the Arabian Peninsula into lush grassland that ancient humans could have traversed as they migrated out of Africa. Researchers at the University of Hawaii at Manoa simulated climate conditions over the last 125,000 years and predicted how those changes would have allowed humans to spread around the globe (increasing intensity of red shows greater predicted migration).

Credit: Tobias Friedrich

The Science News article continues:

Single exodus from Africa gave rise to today’s non-Africans

Genetic data point to a date less than 72,000 years ago but climate scientists disagree

By Tina Hesman Saey

3:28pm, September 21, 2016

One wave of ancient human migrants out of Africa gave rise to all non-Africans alive today, three separate genetic studies conclude.

Those human explorers left Africa about 50,000 to 72,000 years ago, mixed with Neandertals and spread across the world, researchers report online September 21 in Nature. The studies present data from genetically diverse and previously unrepresented populations. Together they offer a detailed picture of deep human history and may settle some long-standing debates, but there is still room to quibble. All non-Africans stem from one major founding population, the studies agree, but earlier human migrations are also recorded in present-day people’s DNA, one study finds. And a fourth study in the same issue of Nature, this one focusing on ancient climate, also makes the case for an earlier exodus.

Scientists have long debated when anatomically modern humans first trekked out of Africa and how many waves of migration there were. Archaeological evidence indicates there were modern humans in Asia by at least 80,000 years ago. Human DNA in a Neandertal woman from Siberia indicates humans interbred with Neandertals outside Africa as long as 110,000 years ago (SN: 3/19/16, p. 6). But those people died out and didn’t contribute DNA to later generations, says Swapan Mallick, an evolutionary geneticist at Harvard Medical School and coauthor of a paper that traced the genetic history of 300 people from 142 populations around the world. The ancestors of today’s non-Africans probably left Africa about 50,000 years ago, Mallick and colleagues calculate.

Data in another study reveal remnants of a much earlier exodus from Africa that persist in the genomes of present-day Papuans, biological anthropologist Luca Pagani of the Estonian Biocentre in Tartu and colleagues report. About 2 percent of the genome of Papuans can be traced back to small bands of humans who left Africa 120,000 years ago. “This expansion was successful in leaving descendants today,” Pagani says. But a massive wave of migrants who left Africa after about 75,000 years ago probably overwhelmed that small trickle, swamping out their genetic signature.

A third study focusing on the genetic history of aboriginal Australians and Papuans from the New Guinea highlands didn’t find traces of a 120,000-year-old migration, but didn’t rule it out either, says study coauthor Eske Willerslev, an evolutionary geneticist at the University of Copenhagen.

Some previous studies have suggested that ancestors of Australians and Papuans came from an earlier wave of migration than other non-Africans did. “Australians and Papuans are descendants of some of the earliest modern human explorers,” Willerslev says. His group’s evidence suggests a single wave of migrants left Africa about 72,000 years ago and settled initially in the Middle East. Ancestors of Europeans and Asians stayed put for thousands of years before splitting into different groups. But Australian and Papuan ancestors kept going. “These guys were heading off on this marvelous journey across Asia,” ending up in Australia and Papua New Guinea about 50,000 years ago, Willerslev says.

Mallick and colleagues also found evidence of a main wave of migration into the Middle East that split into two groups after breeding with Neandertals. Those groups took different routes. One ended up in Europe, the other populated Asia. Instead of Australians and Papuans sprinting ahead of everyone else as an independent group, the researchers say they moved with the ancestors of East Asians and continued to the islands only later.

Pagani and colleagues used a method for analyzing their data that helped them pick out older chunks of DNA, says Mattias Jakobsson, an evolutionary geneticist at Uppsala University in Sweden. That method enabled them to see evidence of the older migration where the other studies couldn’t. But genetic dating methods are far from perfect; they can differ because of inaccurate mutation rates, skewed sampling, biased analyses or other reasons. Future genetic studies of present-day people added to new work on ancient DNA and archaeological evidence may help resolve some of the remaining discrepancies.

Even though results from Pagani’s study seem to disagree with the other two, “it’s a superficial disagreement,” says evolutionary geneticist Joshua Akey of the University of Washington in Seattle who was not involved in any of the studies. “One group is saying 98 percent” of DNA came from the main wave of migration, “while the other groups say it’s 100 percent. … The main conclusion is that the vast majority of ancestry in non-Africans can be traced to a single out-of-Africa dispersal.”

A study of ancient climates may create another discrepancy. It suggests the departure window geneticists propose was the absolute worst time to leave Africa. “Every 20,000 years or so, Earth’s axis wobbles caused massive shifts in climate and vegetation,” says Axel Timmermann, a climate scientist at the University of Hawaii at Manoa. Those fluctuations opened green corridors across northern Africa and the Arabian Peninsula, then turned those same areas to parched deserts.

Timmermann and University of Hawaii colleague Tobias Friedrich did computer simulations of climate and sea level changes over the last 125,000 years to predict when and where humans might have easily moved. By the scientists’ calculations, the timing of a mass human migration out of Africa 60,000 to 70,000 years ago “is the most unlikely scenario from a climate point of view, because … northeastern Africa was completely dry. It was one of the worst drought periods in the entire history, so the corridor was closed,” Timmermann says.

The researchers predict conditions were favorable for migration between 107,000 and 95,000 years ago and again 90,000 to 75,000 years ago. Another window didn’t open until 59,000 years ago, after humans were probably well on their way to Australia. “People could have chased antelope across and they wouldn’t even know they were on a different continent,” Timmermann says. That seamless landscape transition would have been mirrored in people’s mating habits, with populations moving in and out of Africa and mixing freely, he speculates.

Most genetic analyses don’t take that back-to-Africa movement into account, Timmermann says. Back-and-forth mating would make the Africans and non-Africans genetically indistinguishable from each other and obscure the real date at which people left Africa.  Allowing for cross-continent mingling puts people’s exodus from Africa at about 80,000 to 100,000 years ago. Climate shifts that turned Arabia to desert 70,000 years ago would have cut off the connection, making people already outside Africa genetically distinct from Africans. That would show up in the genetic studies as the point at which people left Africa instead of the point-of-no-return.

Some previous genetic research has found evidence of back-to-Africa migrations starting about 45,000 years ago (SN: 6/25/16, p.14).

The climate study reinforces the idea that people had spread out of Africa much sooner than the new genetic evidence indicates, says archaeologist Michael Petraglia of the Max Planck Institute for the Science of Human History in Jena, Germany. He is a coauthor of the Pagani study, but says genetics alone won’t solve all the mysteries of early human history.

Debate over when people left Africa, where they came from inside Africa and who they interbred with as they spread around the globe are far from over, says Petraglia. “I expect some fireworks in the next few years.”

Iridescent hummingbird’s feathers


This video says about itself:

Brilliant Iridescent Throat Plumes of the Bumblebee Hummingbird

3 July 2016

The feathers on this hummingbird’s throat are surprising. One minute they’re bright red, the next, black. This is known as iridescence, a common, showy feature of many birds’ plumages, from hummingbirds to starlings to jays to ducks.

Iridescence doesn’t exist as a pigment—it is a structural color created by light striking the feathers. In each iridescent feather, keratin, melanin, and air are arranged in such a way that the appearance of the feather changes at different viewing angles.

Bumblebee hummingbirds live in Mexico. They are the smallest birds in the world.

Hummingbird migration: here.

Strange mammoth discovered in California, USA


This video from the USA says about itself:

Strange Mammoth Skull Discovered In California Baffles Scientists

18 September 2016

A unique fossil discovery has baffled scientists as they dig through a California Island looking for clues about human migration and mammoth extinction.

Deep within centuries of dirt, the team uncovered a well-preserved complete mammoth skull on Santa Rosa Island that they say exhibits features unlike any of its kind.

The skull is not large enough to be identified as a Columbian mammoth, yet not small enough to qualify as a pygmy – experts hope the creature’s fossilized teeth will reveal its true identity.

‘This mammoth find is extremely rare and of high scientific importance,’ Just Wilkins, a paleontologist at The Mammoth Site in South Dakota, said in a statement.

‘It appears to have been on the Channel Islands at the nearly same time as humans.’

‘I have seen a lot of mammoth skulls and this is one of the best preserved I have ever seen.’

Mammoths roamed North America some two million years ago, with Columbian mammoths appearing a million years later.

It is believed that the Columbian mammoths migrated to the Channel Islands during the past two ice ages when sea levels were lower and the island land mass was closer to the mainland coast.

Over time, descendants of the migrants downsized from approximately 14 feet to a six feet tall pygmy form, becoming an endemic species known as Mammuthus exilis.

The scientific team is particularly curious about the newly-discovered mammoth’s tusks.

The right tusk protrudes 1.4 meters in a coil characteristic of an older mammal, while the shorter, sloped left tusk is more typical of a juvenile.

From Science Alert:

Palaeontologists can’t explain the strange mammoth skull found in a California park

Its tusks don’t make sense.

BEC CREW

19 SEP 2016

An exceptionally well preserved fossil of a complete mammoth skull has been unearthed on a tiny island off the coast of California, and it’s got palaeontologists rethinking how these massive animals might have lived alongside humans.

Dated to 13,000 years ago, the skull was uncovered near a stream on Santa Rosa Island – part of California’s Channel Islands National Park. That date is important, because it happens to coincide with the age of the Arlington Springs Man – the oldest human skeletal remains found in North America.

“This mammoth find is extremely rare and of high scientific importance,” said one of the team, Justin Wilkins, a palaeontologist from the Mammoth Site museum in South Dakota.

“It appears to have been on the Channel Islands at the nearly same time as humans,” he adds. “I have seen a lot of mammoth skulls and this is one of the best preserved I have ever seen.”

Based on an analysis of the skull, the team suggests that new type of mammoth could have been roaming the Channel Islands with some of its earliest human inhabitants.

The remains of the Arlington Springs Man were also discovered on Santa Rosa Island – about 42 km (26 miles) off the coast of Santa Barbara, California.

Archaeologists have placed his life at the end of the Pleistocene, when the four northern Channel Islands formed one mega-island called Santarosae.

We know from previous evidence that mammoths roamed the continent of North America approximately 2 million years ago, and a species called the Columbian mammoth (Mammuthus columbi) managed to swim to Santarosae between 20,000 and 40,000 years ago.

But this skull doesn’t look like a Columbian mammoth’s.

Over several thousand years, these Columbian mammoths rapidly evolved to suit their new island lifestyle, and shrunk from 4.2 metres tall to 1.8 metres, and their features became so different, a new species arose – the more diminutive pygmy mammoth (Mammuthus exilis), the smallest mammoth in the world.

But this skull doesn’t look like a pygmy mammoth’s either.

The team explains that the skull is not large enough to be a Columbian mammoth’s, but it’s not small enough to be a pygmy mammoth’s. So the two most likely explanations is that this is a juvenile Columbian mammoth, or it could represent a transitional species that was partway through evolving from Columbian to pygmy.

Of course, the juvenile scenario would be a whole lot easier to explain, except for the fact that its tusks are all weird.

“The right tusk protrudes 1.4 metres (4.5 feet) in a coil characteristic of an older mammal, while the shorter, sloped left tusk is more typical of a juvenile,” they explain.

Instead, this could be the first evidence that there were two sets of Columbian mammoth migrations to Santarosae.

“The discovery of this mammoth skull increases the probability that there were at least two migrations of Columbian mammoths to the island – during the most recent ice age 10 to 30,000 years ago, as well as the previous glacial period that occurred about 150,000 years ago,” says one of the team, Dan Muhs, from the US Geological Survey.

It’s important to note that this is pure speculation right now – the team has only done preliminary measurements and analyses on the skull, and will need to prepare their findings for peer-review in the coming months.

But this strange skull could be our first glimpse into how these incredible extinct creatures used their trunks as snorkels not once, but twice, to get a taste of that sweet, sweet island life.