How life's forms modify and evolve the Earth (Introduction)

by David Turell @, Friday, September 01, 2023, 19:57 (233 days ago)

Noted early on by Darwin:

https://aeon.co/essays/the-insight-of-darwins-work-on-corals-worms-and-co-evolution?utm...

"if Earth had never come alive, it would be a profoundly different world. Conversely: the planet of today has, to a remarkable extent, been made what it is by the activities of lifeforms. Over the course of the planet’s long history, a history that extends back more than 4.5 billion years, lifeforms have shaped the rocks, the water, the air, even the colour of the sky. A Never-Life Earth would not even have as many different kinds of minerals.

" The central observation...is that, over time, lifeforms have profoundly altered the fabric of this planet, and this, in turn, has altered the circumstances in which lifeforms evolve.

***

"Darwin’s first scientific monograph and his last – the two bookends of his thoughts, so to speak – were both about how animals have, over vast spans of time, transformed the landscape.

"These two works of biogeology – one on coral reefs, the other on earthworms – were, as far as I know, the first detailed studies of the subject ever published. On casual inspection, they appear to be unrelated undertakings, just part of Darwin’s long and eclectic list of interests, along with barnacles, orchids, carnivorous plants,...and other animals, the volcanoes of South America, and so on...The Structure and Distribution of Coral Reefs appeared in 1842, while his book on earthworms, The Formation of Vegetable Mould, Through the Action of Worms, with Observations on Their Habits, came out in 1881, about six months before he died. (Vegetable mould is what you and I would call topsoil.)

***

"Darwin suggested instead that atolls form on the slopes of volcanoes that are slowly sinking. Here’s a brief sketch of the idea. A volcano erupts and builds an island in the middle of the ocean. Coral animals settle on its slopes, luxuriating in the warm, shallow, sunlit waters, and begin building the limestone skeletons that, together, will form a reef. If the seafloor then begins to subside, the volcano will gradually sink back beneath the waves – but the corals will continue to grow upwards, so as to remain in the shallows. As long as the volcano doesn’t sink too fast, the corals can keep pace with its descent.

***

"Eventually, the volcano may vanish far beneath the waves, leaving just the coral as a marker of its existence. Each atoll is a requiem for a volcano. Or, as Darwin wrote – ‘a monument over an island now lost’.

"His argument makes a clear prediction: somewhere beneath each atoll, beneath these immense piles of life-built rock, these mountains of limestone, you will find the remnants of a volcano.

***

"In the 1940s and ’50s, the United States government tested dozens of nuclear weapons in the Marshall Islands, a cluster of atolls that lie in a remote part of the Pacific a little to the north of the equator. This brought a host of scientists – geologists, biologists, oceanographers – to study the area. In 1952, a team of geologists drilled deep into Enewetak Atoll. At 1,283 metres (4,208 feet), they struck basalt. Volcanic rock. Darwin was right.

***

"his book on earthworms, The Formation of Vegetable Mould, Through the Action of Worms, with Observations on Their Habits, came out in 1881, about six months before he died...At the time, the book was wildly popular, selling 3,500 copies within the first month. Today, though, it is little read, and often dismissed as the eccentric afterthought of a great man whose life was drawing to a close.

***

"His uncle speculated that this was due to the activities of earthworms. As they burrowed through the soil, the worms were, his uncle suggested, acting as slow-motion ploughs. Altogether, the observations were so interesting that William Buckland, an eminent geologist of the day, suggested that Darwin had identified ‘a new Geological Power’.

***

"Earthworms burrow through soil by eating it; they also nibble on organic matter such as dead leaves. To defecate, they generally come to the surface, where they eject, as Darwin put it, ‘little intestine-shaped heaps’ known as castings. On the basis of his conversations with his uncle, Darwin suspected the worms of tilling the soil, bringing fine particles from deep in the ground up to the surface.

***

"Taking his results together, Darwin showed that earthworms have several important effects. The animals do not just mix the soil by bringing deeper material up to the surface. By munching on fallen leaves, and by pulling those leaves down into their burrows, they also create new soil and enrich it with a nutritious compost.

***

" Darwin: "The plough is one of the most ancient and most valuable of man’s inventions; but long before he existed the land was in fact regularly ploughed, and still continues to be thus ploughed by earthworms."

"Worms might appear insignificant, but because there are so many of them, little by little, they sculpt the contours of the world.

***

"At the end of his book, he remarks: ‘It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organised creatures.’ In this, however, he profoundly underestimated the scale of the changes wrought by other lifeforms."

See life forms II.

How life's forms modify and evolve the Earth II

by David Turell @, Friday, September 01, 2023, 20:15 (233 days ago) @ David Turell

This is the non-Darwin part:

https://aeon.co/essays/the-insight-of-darwins-work-on-corals-worms-and-co-evolution?utm...

"First off, the tilling processes that Darwin described are not limited to earthworms, with different burrowing animals having effects at different scales. Ants, for example, tend to bring up the finest grains of sand or soil. In Berlin, where I live, you often see small piles of fine sand heaped along the edges of cobblestones, and if you look closely, you will often see ants hard at work. Although the grains are typically brought up a few at a time, in places the ants are so abundant that they will shift many tonnes of soil per hectare per year. In one study that was directly inspired by Darwin’s work on earthworms – Geologic Work of Ants in Tropical America (1910) – the author, John Casper Branner, estimated that ants in Brazil were responsible for moving considerably more soil per hectare each year than earthworms in England. Meanwhile, larger burrowing animals such as badgers excavate huge mounds of earth, creating hillocks that can last for centuries, to say nothing of the earth-shifting activities of bandicoots, beavers, chipmunks, gophers, meerkats, mice and moles, or of burrowing birds and burying beetles.

"And it’s not just on land. As you walk to the sea across that part of a beach or mudflat that’s covered by waves when the tide is high, but exposed when the tide is low, you may see tiny crabs, no bigger than your fingernail, excavating burrows one armful of sand at a time. Don a mask and look beneath the waves, and you’ll find an incredible variety of animals digging burrows.

"Moreover, burrowing animals are not the only lifeforms to have a substantial planetary impact. Far from it. Before the evolution of the first trees, around 400 million years ago, rivers were far less likely to boast meanders and oxbows and other features that allow them to dawdle their way to the sea. Plants have also contributed a great increase in mud. Ancient reefs and banks of shells have not only left a legacy of enormous piles of limestones, they also have altered the shapes of mountains: as rocks go, limestones are relatively malleable, so when ancient reefs and banks of shells are crushed and cooked as mountain chains are upheaved, the presence of limestones will affect the way the mountains fold. The more limestones, the more folds. Limestones so treated will also, often, become crushed and cooked into marble. Many of the world’s greatest sculptures and monuments have been created from rock built by life and then transformed by Earth as it builds mountains. Next time you look at Michelangelo’s David, remember that it was built from marble formed from crushed life-rocks, as were many of the grandest buildings and structures of ancient Rome.

***

"First, certain species of archaea are responsible for the biological generation of methane, a greenhouse gas, which warms the climate. Second, no conversation about the impacts of lifeforms upon the planet would be complete without mention of the cyanobacteria. These lifeforms, formerly known as blue-green algae, are, in my view, the most important lifeforms in the history of the planet. At the time they evolved, more than 2.3 billion years ago, Earth had no oxygen molecules in the air to speak of. Instead, all the oxygen atoms were tied up in the water and the rocks. Cyanobacteria evolved to use the radiant energy of the Sun to split water molecules apart, a process that roughly halfway through the history of Earth would result in an atmosphere that contained oxygen molecules.

"Back then, the atmospheric oxygen would not have been adequate to support you or me. Yet its very appearance had several transformative effects. As oxygen is reactive stuff, its arrival led to a proliferation of new minerals. Indeed, Earth began to rust. At the same time, the advent of oxygen led to the creation of an ozone layer, which protects the planet’s surface from the most harmful rays of the Sun. The presence of this layer fundamentally changed the circumstances in which lifeforms on land subsequently evolved. And since the colour of the sky is a consequence of the composition of the atmosphere, lifeforms have also reached out and painted the heavens above.

***

"..the Never-Life Earth would not be the Earth of today, just without the green. It would be profoundly different: an alien planet. A human, or some other animal, magicked there would be killed in an instant, overcome by suffocating air and lethal levels of radiation.

"It would be a planet not merely lifeless, but deadly."

Comment: in the evolution of this planet a broad diversity of living organisms has played a major role. I view it as God guiding the formation of the Earth to be the perfect planet for life to appear. (See Privileged Planet thread) Then diverse life forms helped transform the Earth into its present state. A very emotional and well-written essay should be read in its entirety.

How life's forms modify and evolve the Earth II

by David Turell @, Friday, February 16, 2024, 19:07 (65 days ago) @ David Turell

Microbiology of arctic seabeds:

https://phys.org/news/2024-02-bacteria-arctic-seabed-year.html

"The Arctic is cold and hostile to life, yet it is home to a large number of microorganisms whose activity has a significant impact on life on our planet. For example, bacteria in the seabed play a central role in processing the biomass of dead organisms, thereby transforming the contained carbon into hard-to-degrade substances that can remain stored for a long time.

"In addition to the cold, the unusual seasonality is a striking feature of polar habitats—day and night do not alternate every twelve hours, but rather the entire year fluctuates between midnight sun and polar night. This has a massive impact on local primary production, which is dependent on sunlight. In summer, tiny algae thrive in the seawater and also life on land flourishes. In winter, primary production largely comes to a standstill. Little research has been carried out into the extent to which the resulting strong fluctuations in the input of organic matter influence the bacteria in the seabed.

***

"Surprisingly, the bacterial community in the seabed does not behave as expected considering the environmental conditions. "Although the input of organic material and its turnover rates fluctuate greatly over the course of the year, the composition of the bacterial community hardly changes at first glance," reports principal investigator Katrin Knittel.

"Bacteria in the seabed thus behave very differently to those in the water, where many of them exhibit a pronounced seasonality. "Benthic bacterial communities—i.e., those in the seabed—are very complex," Knittel adds. "That's what makes them so stable and robust, and it makes it very challenging for us to investigate their dynamics."

***

"In winter, enzymes that break down a-glucans (e.g., glycogen) predominate. The a-glucans are intracellular storage compounds of heterotrophic bacteria, animals and fungi. They are also available throughout the rest of the year, but are then less important. In spring, however, there are more enzymes that break down b-glucans such as the algal component laminarin. Then there are so many b-glucans that some of them may be set aside as a storage for later in the year.

"'These enzymes reflect which algal components—especially algal sugars—are available to the bacteria in the different seasons," explains Knittel. "It's not so different to going to the farmers market here: While there are lots of different fresh fruit and vegetables available during the sunny season, at some point during the winter all that's left are the stored potatoes."

***

"The bacteria in the seabed can hence utilize fresh material that sinks from the water column, particularly in spring and summer, such as the aforementioned laminarin. However, they can also consume material that is already present in the seabed or is produced there. This includes tasty treats such as mucin, but also tough chunks such as chitin. On these, the bacteria nibble all year round. This food source is particularly important in winter, when other input is scarce. Their long-term availability Their long-term availability stabilizes the bacterial community in the seabed.

"'These findings occur on very small scales, but they are important in a larger context: When the bacteria consume the algal sugars, they release carbon dioxide. And carbon dioxide is a very important greenhouse gas," Knittel notes. Thus, the tiny ocean inhabitants can have an influence on global processes."

Comment: we must continue to study microbiomes everywhere, since they are so influential.

How life's forms modify and evolve the Earth: whale poop

by David Turell @, Sunday, September 03, 2023, 15:32 (231 days ago) @ David Turell

Stays near the surface supplying nutrients:

https://www.discovermagazine.com/planet-earth/ocean-gardeners-why-whale-poop-matters-no...

"What makes whale poop special? First, there’s a lot of it, since whales are the largest animals on Earth. Second, whales usually feed in deeper water and then poop when they surface to breathe; this cycles nutrients like nitrogen, phosphorus and iron — which naturally sink.

"Third, their fecal plumes are buoyant, lingering in the sunny, uppermost layer of water. This means whale poop could help spur the growth of phytoplankton, tiny plants at the base of the marine food web.

***

"The recycling of nutrients via cetacean poop is called the “whale pump” and has been studied in other parts of the world, too.

"In the North Atlantic, for example, researchers Joe Roman and James McCarthy found that whales and seals in the Gulf of Maine may be responsible for adding more nitrogen to the surface each year than all of the rivers combined.

"And according to a different study co-authored by Roman, the vertical movement of phosphorus from the deep sea to the surface by marine mammals has been reduced by 77 percent worldwide since whaling drastically reduced cetacean populations.

"In the Southern Ocean, feces from fin, sperm and blue whales replenish iron at the surface — a necessary ingredient for phytoplankton growth. A 2010 study found that the iron content in the fecal matter of baleen whales there was 10 million times higher than in background Antarctic seawater.

"Whale poop likely plays an important role in fertilizing the cold waters of the North Pacific, too. An estimated 1,500 humpbacks migrate to Southeast Alaska every summer to feed, along with gray whales, orcas and other marine mammals.

***

"In addition to boosting nutrients, whale poop may also play a role in sequestering carbon. “There’s this idea that phytoplankton are helping draw carbon out of the atmosphere and sink it into the deep ocean where it won't return to the surface for thousands of years,” says Pearson.

"Some scientists are even attempting to use artificial whale poo to boost both fish populations and phytoplankton growth, in hopes the marine plants absorb more carbon dioxide from the atmosphere.

"Pearson co-authored a recent paper that estimates the amount of carbon sequestered by the whale pump. But she cautions that “to fully realize these benefits, we need to be talking about stringent conservation actions that allow whale populations to recover.”

***

"One way to inspire more conservation is to help people “look at whales in a different light,” says Pearson. This includes putting numbers on how much they contribute to ecosystem health through nutrient cycling or carbon sequestration. (my bold)

"Which brings us back to Bloch in her small boat, scooping up bottles full of whale poop. She also hopes the findings will tell us more about how these gentle giants affect the food web, and give us even more reasons to protect whales. (my bold)

Comment: everything an animal does has some effect on its ecosystem. Every ecosystem has effects on other ecosystems in an enormous interconnected web over the Earth.

How life's forms modify and evolve the Earth: cyanobacteria

by David Turell @, Sunday, October 15, 2023, 18:15 (189 days ago) @ David Turell

Group together in webs:

https://phys.org/news/2023-10-scientists-unique-formation-ancient-algae.html

"A team at Nottingham Trent University and Loughborough University has revealed the physical mechanism behind the geometric patterns formed of cyanobacteria, one of the oldest and most abundant forms of life on Earth, and which has played a pivotal role in the evolution of our planet.

***

"Ancient cyanobacteria were the first life form to develop photosynthesis and are responsible for injecting oxygen into the Earth's environment, thereby laying the foundation for the emergence of the complex life forms we are familiar with today.

"Today's cyanobacteria continue to play a key role in maintaining the composition of today's atmosphere and oceans. To help it survive, many species also grow into long chains of cells that crawl across surfaces and weave together into large networks of closely-bundled filaments over hours or days.

"However, until now, the origin of these reticulate or web-like patterns has puzzled scientists.

***

"They found that when cyanobacteria are present at a high enough density, they begin to organize into their reticulate pattern, as a result of only a few simple rules.

"As the bacteria move, they bump into each other. In most instances, filaments pass over or under each other, but occasionally one deflects and turns to travel alongside another. These two filaments follow each other for a while, before one splits away.

"These interactions lead to the formation of bundles of aligned filaments which organize denser colonies into sprawling networks.

***

"The team says the findings pave the way to inspiring future investigation of how different types of bacteria self-organize to form structures.

"This could improve our understanding of how bacterial biofilms—collections of bacteria that have attached to a surface and each other—are formed. This knowledge is critical given their central role in various processes, such as human infections, environmental degradation, and bioengineering."

Comment: I view these bacterial actions as programmed into their DNA. They are so important for oxygen supply they must have strong methods of survival.

life's forms modify, evolve the Earth: cyanobacteria origin

by David Turell @, Sunday, October 29, 2023, 00:28 (175 days ago) @ David Turell

So important for oxygen:

https://www.sciencedaily.com/releases/2023/10/231027110716.htm

"Cyanobacteria are a key species in Earth's history, as they introduced atmospheric oxygen for the first time. The analysis of their evolution therefore provides important insights into the formation of modern aerobic ecosystems. For a long time, a certain type of fossil lipid, so-called 2-methylhopanes, was considered to be an important biomarker for Cyanobacteria in sediments, some of which are hundreds of millions of years old. However, this came into doubt when it turned out that not only Cyanobacteria but also Alphaproteobacteria are genetically capable of producing these lipids.

***

"Center for Marine Environmental Sciences at the University of Bremen has now studied the phylogenetic diversification and distribution of the genes -- including HpnP -- that are responsible for the synthesis of the parent lipids for 2-methylhopanes: The researchers have deciphered when these genes were acquired by certain groups of organisms. They were able to show that HpnP was probably already present in the last common ancestor of Cyanobacteria more than two billion years ago, while the gene only appeared in Alphaproteobacteria about 750 million years ago. For the times before that, 2-methylhopanes can therefore serve as a clear biomarker for oxygen-producing Cyanobacteria.

***

"Cyanobacteria played a crucial role in transforming the Earth from its initial oxygen-free state to a modern, oxygen-rich system in which increasingly complex life is possible. Cyanobacteria were probably the only relevant group of organisms that converted inorganic substances into organic ones (so-called primary producers) and produced oxygen for long stretches of the Precambrian (the first four billion or so years of Earth's history, from its beginnings to about 540 million years ago). [start of the Cambrian era]

***

"... due to preservational biases and ambiguities in recognizing fossil cyanobacterial cells, geochemists rather use fossilised diagnostic lipids, such as 2-methylhopanes. 2-Methylhopanoids (non-fossilised parent molecules) are produced by the bacteria and -- in contrast to the bacteria themselves- can be fossilised and detected in sedimentary rocks even after hundreds of millions of years in good quality and in quantities corresponding to their original occurrence.

"However, there have recently been doubts about the suitability of 2-methylhopane as a biomarker for Cyanobacteria: the discovery of the lipid biosynthesis gene revealed that Alphaproteobacteria are also capable of producing these lipids. This means that temporally tracing oxygen-producing processes on Earth by 2-methylhopanes is no longer possible.

"...University of Bremen has now systematically investigated which organisms other than Cyanobacteria possess the genes (abbreviated as the SC and HpnP genes) necessary for the production of 2-methylhopanoids, and when they acquired those genes during the course of evolution. In this way, the team was able to show that the fossil lipid 2-methylhopane can still be used as a clear biomarker for the existence of Cyanobacteria for times dating back more than 750 million years.

***

"There are many bacteria that possess both SC and HpnP genes, but they are mainly Cyanobacteria and Alphaproteobacteria. Each group is found to have acquired the two genes independently. This is in contrast to earlier studies that concluded that Cyanobacteria acquired these genes from Alphaproteobacteria at a late stage in their evolution. The new study further revealed that the common ancestor of Cyanobacteria already possessed both genes more than 2.4 billion years ago, when oxygen began to accumulate in the atmosphere during the so-called Great Oxidation Event. (my bold)

"In contrast, Alphaproteobacteria acquired the SC and HpnP genes at the earliest only 750 million years ago. Before that, 2-methylhopanoids were thus only produced by Cyanobacteria. The researchers interpret a slightly delayed increase of sedimentary 2-methylhopanes around 600 million years ago as a sign of the global spread of Alphaproteobacteria, which may have favored the concurrent evolutionary rise of eukaryotic algae."

Comment: Note my bold. I view the appearance of oxygen producing genes 2.4 billion years ago as a purposeful event in designing for life on Earth with preparation for the future appearance of oxygen breathing for land and ocean organisms. Noting purposeful events is the best way to analyze how God evolved us by design. Always planning for the future developments. It explains why speciation often covers the future needs.

life's forms modify the Earth: wolves vs. beavers

by David Turell @, Tuesday, November 14, 2023, 16:29 (159 days ago) @ David Turell

A study in a Minnesota forest:

https://royalsocietypublishing.org/doi/10.1098/rspb.2023.1377

"Abstract
Predators can directly and indirectly alter the foraging behaviour of prey through direct predation and the risk of predation, and in doing so, initiate indirect effects that influence myriad species and ecological processes. We describe how wolves indirectly alter the trajectory of forests by constraining the distance that beavers, a central place forager and prolific ecosystem engineer, forage from water. Specifically, we demonstrate that wolves wait in ambush and kill beavers on longer feeding trails than would be expected based on the spatio-temporal availability of beavers. This pattern is driven by temporal dynamics of beaver foraging: beavers make more foraging trips and spend more time on land per trip on longer feeding trails that extend farther from water. As a result, beavers are more vulnerable on longer feeding trails than shorter ones. Wolf predation appears to be a selective evolutionary pressure propelled by consumptive and non-consumptive mechanisms that constrain the distance from water beavers forage, which in turn limits the area of forest around wetlands, lakes and rivers beavers alter through foraging. Thus, wolves appear intricately linked to boreal forest dynamics by shaping beaver foraging behaviour, a form of natural disturbance that alters the successional and ecological states of forests.

***

"Herein, we describe and demonstrate how wolf predation is a selective pressure that shapes the foraging behaviour of beavers via consumptive and non-consumptive mechanisms in the Greater Voyageurs Ecosystem (GVE), Minnesota. By altering beaver foraging behaviour, wolves invariably alter the ecological trajectory of forests around wetlands and beaver-occupied water sources (e.g. lakes, rivers).

***

"Beavers are important seasonal prey for wolves in the GVE with beaver constituting up to 42% of wolf pack diets from April to October (the ice-free season) when beavers are vulnerable to predation

***

"Beaver foraging creates ecological heterogeneity and increases biodiversity around wetlands by increasing forest complexity—particularly by creating ‘messy forests’ with substantial dead and standing wood. This in turn affects nutrient deposition and carbon storage, composition of lichen, bryophyte and plant communities, and habitat for, and abundance of, invertebrates, birds and mammals around beaver-altered environments. Consequently, wolves, by reducing the amount of forest beavers can disturb, alter all of these ecological processes as well."

Comment: as usual the forest ecosystem is highly organized as the last paragraph indicates. No organism is an island unto itself. While each human exists in a local ecosystem, viewed as a whole, the human population lives in a whole Earth ecosystem totally under our control. When viewing the process of evolution as a purposeful development, it is obvious God wished to create the current state of affairs. The end point of evolution is humans and the whole of Earth food supply.

life's forms modify the Earth: full human control

by David Turell @, Friday, December 01, 2023, 23:46 (141 days ago) @ David Turell

Some ae trying it:

https://www.quantamagazine.org/the-new-quest-to-control-evolution-20231129/

"Thousands of years ago, humans began to identify plants and animals with preferable traits and selectively breed them, which amplified these traits in their offspring. This approach gave us agriculture, one of the most transformative cultural inventions in human history. Later, artificial selection in animals and plants helped us understand genetics, and how genes evolve in populations. But as effective as it’s been, artificial selection is still fairly limited.

***

"Now biologists hope to dictate how evolution happens at the molecular level, and to exert as much direct control over the reproductive process as we do in crops. Can we orchestrate evolution, mutation by mutation, toward whatever outcome we prefer?


"Remarkably, we’re already partway there. The 2018 Nobel Prize in Chemistry recognized work on a method called directed evolution, which allows scientists to engineer new biomolecules. One of the winners, Frances Arnold, pioneered a way to mutate proteins in the laboratory and then measure their functionality — say, how well an enzyme metabolizes sugar. It’s then possible to isolate the protein candidates of interest, mutate them, and select further, until we have generated a protein with improved function (in this case, an enzyme that metabolizes sugar very efficiently). In this sense, chemists are operating like dog breeders, but without relying on sexual reproduction to generate the protein offspring. Rather, they are generating a diverse population of proteins and measuring their properties in mere hours. And by selecting what they want, they are controlling how evolution happens.

***

"These breakthroughs demonstrate that in some form, evolutionary control is a thing of the present, not the future. But most successful examples have taken place in a small number of settings: microbes, microbial communities and proteins. And even further, existing efforts focus on control over short time periods — no reasonable scientist purports to be able to control molecular evolution acting over decades or centuries (outside of the artificial selection that has taken place over millennia). True control over the evolutionary process remains strictly limited by our current knowledge and tools.

"While the technical challenges of evolutionary control remain substantial, the ethical barriers are also notable. The issues overlap with those around genetically modified organisms. When we engineer a mutation into a strain of corn that confers the ability to grow even in stressful environments, we influence future generations of that strain of corn. Furthermore, embryo selection in humans can resemble artificial selection, giving us the ability to steer the appearance of human traits in future populations. In general, overzealous applications of these technologies can be driven by a kind of genetic determinism — the naïve view that the meaningful differences between organisms within a population can be explained (mostly) by their genetic makeup.

"Should we ever try to naïvely steer evolution in humans and other organisms over a longer timescale, we would fall victim to a sort of evolutionary determinism, which holds that we can and should have full control over how life evolves in the future. Ultimately, these ambitions are misplaced. They underestimate the caprice of biological evolution — the difficulty of considering all the forces that shape how life functions and flourishes. Some may imagine that artificial intelligence can help resolve these uncertainties. But AI is not a panacea for ignorance. It is most effective when we already understand the vagaries of the system that we are attempting to model and predict. Evolutionary biology doesn’t quite meet this standard — at least not yet.

"We can (and should) simultaneously gush at the ambition of modern biology and have the presence of mind to recognize our limits. For example, the eugenics movement suggested that the human race could be improved using the sorts of methods that gave us domesticated animals and crops. We now understand it was both bigoted and based on bad biology. Examples like these are cautionary tales, and they should teach us that careless attempts to control tempestuous forces like evolution are bound to fail."

Comment: my attitude is, guys cool it. We are not Gods or God-like. The article doesn't mention the attempt to sterilize male mosquitos, but that is a small reasonable attempt.

How life's forms modify and evolve the Earth: sea birds

by David Turell @, Thursday, December 07, 2023, 15:50 (136 days ago) @ David Turell

Help grow coral reefs:

https://mail.google.com/mail/u/0/#inbox/FMfcgzGwHxzMBDCqSDDXBdTZSlwWfKlZ

"Seabird colonies have profound effects on the islands and coastlines they inhabit. These animals live on land and hunt at sea, bringing marine nutrients onshore to fertilize habitats. Their nesting behavior can reshape the landscape, and the birds and their eggs feed predators of various sizes. And new research suggests their influence extends beyond the water’s edge, finding that coral reefs around islands populated with birds grow up to twice as quickly as ones lacking feathered friends.

"The reason, it turns out, has to do with their fecal matter. Some seabirds produce so much guano that their colonies can be spotted from space. But not all the nutrients are deposited or stay onshore. The birds also defecate over the water as they come or go, and rain can wash guano into the sea. By examining nitrogen isotopes in corals over three years, researchers found that those next to seabird islands readily use guano-derived nutrients to grow faster.

“'We’ve been able to show a clear link between the presence of seabirds and faster coral growth,” says co-author Cassandra Benkwitt. “This is really exciting and encouraging that a natural solution is available to help boost the resilience of coral reefs in the face of a warming planet.'”

Comment: a very obvious ecosystem. The underlying paper:

https://www.science.org/doi/10.1126/sciadv.adj0390?utm_source=sfmc&utm_medium=email...

How life's forms modify and evolve the Earth: ants & flowers

by David Turell @, Tuesday, March 12, 2024, 16:44 (40 days ago) @ David Turell

How stem ants became modern ants:

https://mail.google.com/mail/u/0/#inbox/FMfcgzGxSHgkzbptQmvlbsKKRccQvqzp

"By analyzing the extensive fossil record alongside a very detailed tree of life for ants, evolutionary biologists have shown how the rise of flowering plants helped ant species thrive. The work, reported this week in the Proceedings of the National Academy of Sciences, validates a nearly two-decade-old idea that angiosperms had been central to the insects’ success but adds a new twist: Without the opportunities provided by these newly evolving plants, ants might have disappeared.

"Today, there are an estimated 2.5 million “modern” ants for each person on the planet, distributed around the world and playing key roles in many ecosystems. Yet for their first 30 to 50 million years, ants were small potatoes, so to speak. And, as flowering plants replaced ferns and conifers, these early “stem” ants began to disappear. (my bold)

"Many scientists assumed modern ants simply outcompeted these earlier evolving species, but this new research suggests otherwise. The authors say it’s more likely these early ants had become so specialized, with adaptations to their mouths and body parts to catch certain foods, that they could not adapt to the changing environment the way their more recently evolved relatives did. In that way, the stem ants may well have been extinction-prone, says Joseph Parker, an evolutionary biologist not involved in the research. “Maybe we wouldn’t have ants today were it not for early angiosperms.'”

From the original article:

https://www.pnas.org/doi/abs/10.1073/pnas.2317795121

"Our results challenge one of the most common hypotheses explaining ant extinction: the competitive exclusion of stem ants by crown ants. Instead, the Angiosperm Terrestrial Revolution acted as a buffer against extinction and a driver of diversification in ants. Our approach clarifies one of the most widely accepted patterns in insect–plant diversification.

***

"we conducted a comprehensive analysis using a large dataset that includes both the ant fossil record (~24,000 individual occurrences) and neontological data (~14,000 occurrences), and tested four hypotheses proposed for ant diversification: co-diversification, competitive extinction, hyper-specialization, and buffered extinction. Taking into account biases in the fossil record, we found three distinct diversification periods (the latest Cretaceous, Eocene, and Oligo-Miocene) and one extinction period (Late Cretaceous). The competitive extinction hypothesis between stem and crown ants is not supported. Instead, we found support for the co-diversification, buffered extinction, and hyper-specialization hypotheses. The environmental changes of the ATR, mediated by the angiosperm radiation, likely played a critical role in buffering ants against extinction and favoring their diversification by providing new ecological niches, such as forest litter and arboreal nesting sites, and additional resources. We also hypothesize that the decline and extinction of stem ants during the Late Cretaceous was due to their hyper-specialized morphology, which limited their ability to expand their dietary niche in changing environments. This study highlights the importance of a holistic approach when studying the interplay between past environments and the evolutionary trajectories of organisms."

Comment: the dynamic interplay of different organisms is clearly shown in this study.

How life's forms modify and evolve the Earth: fire farming

by David Turell @, Tuesday, March 12, 2024, 20:13 (40 days ago) @ David Turell

Early burns to prevent later larger poorly controlled burns:

https://www.nature.com/articles/d41586-024-00693-6?utm_source=Live+Audience&utm_cam...

"Indigenous Australians have been using fire to shape the country’s northern ecosystems for at least 11,000 years, according to charcoal preserved in the sediment of a sinkhole. The study was published on 11 March in Nature Geoscience.

***

"Fire-stick farming involves introducing frequent, low-intensity fires in small areas of the landscape in a patchy, ‘mosaic’ pattern, and is done early in the dry season. The practice is important culturally and environmentally; in particular, it reduces the amount of fuel available for burning and therefore decreases the intensity of wildfires that might spark late in the dry season because of lightning strikes or other triggers.

"Archaeological evidence indicates that humans have continuously occupied the Australian continent for at least 65,000 years2, but little is known about when the practice of fire-stick farming began.

***

"The researchers found that record in the sediment of Girraween Lagoon, a permanent water body formed in a collapsed sinkhole near Darwin in the Northern Territory. The lagoon is an important site for the traditional owners of the land, the Larrakia Nation, and was made famous by the crocodile attack scene in the 1986 film Crocodile Dundee.

"Because the lagoon has remained full, its sediments offer a continuous record of deposition that has not been disturbed by drying out and cracking. Bird and his colleagues were able to extract a core from the bottom of the lagoon that provided a 150,000-year-long record of changes in the type and geochemistry of the deposited charcoal, and in the accumulation of pollen.

"The team notes that, around 11,000 years ago, the changes in the charcoal deposits point to alterations in the intensity of fires in the area.

"Without human influence, fires are less frequent but have enough intensity to burn trees and leave behind charcoal, says Bird.

“'A less-intense fire doesn’t get into the crown — it’s burning what’s on the ground,” he says. The grass, as well as twigs and fallen tree leaves, are more likely to become charcoal than the trees themselves, he adds.

"'Because tree-derived charcoal has higher concentrations of the isotope carbon-13 than does charcoal from grasses, the researchers analysed the composition and geochemistry of the burnt residue in the sample. The authors found a sustained change from low-frequency, high-intensity fires — the ‘natural’ fire regime — to more frequent but less intense ones, which they suggested was the result of Indigenous fire-stick farming.

***

"...Bird notes that European colonization has mostly brought an end to cultural burning practices, and has shifted fire intensity back towards a natural pattern. “Because we’ve had, 10,000 plus years of a particular fire regime, it’s the release from that fire regime that’s actually creating quite significant issues,” he says, suggesting that this shift has contributed to the return of more high-intensity wildfires.

"Joe Fontaine, a fire ecologist at Murdoch University in Perth, Australia, says that the growing understanding of how cultural burning has shaped the Australian landscape, particularly in the northern regions, is crucial for contemporary fire-management practices, which to a large extent have excluded Indigenous people and their expertise. (my bold)

“'The barriers to doing cultural burning, in our arcane system of laws and bureaucracy,” are challenging to overcome, Fontaine says. There are also many more permanent structures in the landscape nowadays than there were before colonization, he says, so the challenge is to work out where and how cultural burning can be restored as a practice.

"The continuing work that “puts cultural burning practices out there and establishes it as something that really existed, is crucial to the evolution of contemporary fire management”, he says."

Comment: my bold is reinforced by Fontaine's comments. The Aborigines are not dumb and have wisdom that we must use. This is an old prejudice among Europeans.

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