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Various Science  22

 
Extreme Evolution
 

My research focuses on two species which are examples of extreme evolution. One is the yeast Nadsonia fulvescens, and the other is the mushroom Morchella esculenta.

yeast and mushroom

The yeast is found nowhere but St. Petersburg, Russia, because that is where the most extreme evolution of fungi is occurring. Apparently, consistently cool and humid air from the Baltic Sea keeps the environment ideal for fungi evolution. Mushrooms in Northwest Russia are more diverse than anyplace else on the planet.

Yeasts evolved from filamentous fungi after modern biology began when the dinosaurs died out.

Evolution In Sugary Solutions

What is not being clarified about the dinosaurs dying out is that all biology transformed drastically into its modern forms. During dinosaur years, biology was highly restricted by nonwoody brush which covered the lowlands. Mountains were small and not yet developed like now days.

Prior to dinosaur years, tectonic plates were thin, because cool-down of the planet is a slow process causing tectonic plates to get thicker. Even a lot of scientists don't seem to realize the consequences. The thin plates would stick together as they collided creating super continents. At the time dinosaurs formed, around 252 million years ago, all land masses were stuck together to form Pangaea. Mountains were just starting to get significantly large. Before then, mountains were not large, because tectonic plates were thin.

The formation of significant mountains during dinosaur years allowed some diverse evolution to occur on the hills. Conifer trees evolved on the hills, and diverse species evolved around the conifers. Flowering plants evolved, but they were so rare that they weren't located in fossil evidence until a few years ago. Flowering plants were not shaping the ecology as they do now days.

When dinosaurs died out 65 million years ago, grass destroyed most of the oppressive brush which was holding back evolution. Modern biology is now shaped by flowering plants, broadleaf trees and grass. The flowering plants allowed yeast to evolve in the resulting sugary solutions. Yeasts fought off bacteria by excreting acetic acid and ethyl alcohol. Yeasts also caused fat production to evolve, because acetic acid production is very similar. Fat is approximately a string of acetic acid molecules linked together. Fat production was then transferred to other species including animals through horizontal gene transfer.

The primary feature of yeasts is that they repress TCA enzymes while glucose is available. This allows them to metabolize glucose rapidly preventing competitors from using it. The acetate resulting from glucose metabolism is channeled in three directions. Some is excreted as acetic acid and some as ethyl alcohol. These substances inhibit growth of bacteria and molds. Production of acetic acid and alcohol are phenotypic variations. Oxygen does not have to be absent to produce alcohol. But unlimited amounts of these substances cannot be produced, so acetate is also channeled into fat production. Fat is created from acetate molecules linked together. Yeasts often store up to 40% of their cell mass as fat.

When glucose gets used up, yeasts induce formation of TCA enzymes and re-metabolize the acetic acid, alcohol and fat which they created earlier. Other species do not have repressible TCA systems. Their TCA systems are in place all of the time.

The central property of filamentous fungi is their ability to resist dehydration. This property allows them to grow on surfaces, where drying occurs between rains. Surface growth caused the filamentous shape, which is a rudimentary type of motion on surfaces.

The ability to tolerate dehydration is an extremely demanding property which yeast gave up in growing in sugary solutions. Yeasts cannot grow on exposed surfaces, because dehydration would destroy them. Yeast spores, however, can tolerate a degree of exposure and dehydration.

cells and sporesYeast spores normally form inside the cells. There is one exception: Nadsonia fulvescens (and a related species) forms spores outside the cell. My research explains why.

Most yeasts love to grow on tree exudate, but they can't adapt to it, because the exudate is too transient. Trees can stop producing exudate, and rain can wash the exudate away, which leaves the yeast exposed to a harsh environment causing dehydration. Nadsonia fulvescens adapted to growing on tree exudate by forming a spore immediately when the exudate is no longer available.

Acetate is used as a repressor of sporulation by Nadsonia fulvescens, which prevents spores from forming while nutrients are available. Maximum growth can then occur before spores are formed. When other nutrients are gone, acetate is metabolized allowing spores to form.

The Nadsonia spore must be outside the cell due to endotrophism. It means nutrition from within. When nutrients are no longer available, internal reserves must be used to form the spore.

Yeasts have hard cell walls which do not shrink in size. When internal nutrients get used up, the total volume reduces, and the cell mass must move into a new structure which is smaller. The need for a smaller structure required the spore to form outside the cell.

Soil mushrooms do something similar. They store up nutrients in the mycelium for several weeks. When conditions get right, the mushroom forms from the stored up mass. This allows the mushroom to form rapidly, so it can get spores out before being damaged by dehydration or insects.

Evolving this physiology in a yeast is so demanding that it only occurred in St. Petersburg Russia, and the yeast cannot survive anyplace else because of its narrowly defined requirements. Presumably, conditions are too hot and dry too often everywhere else. A related species in the same genus, Nadsonia elongata, is found in many coastal areas, because it evolved the ability to grow under loose tree bark which provides greater protection.

The mushroom which I studied, the morel, has extremely unusual characteristics. It does not have a cap with gills producing spores. Instead, it forms spores within the tissue, like yeasts do. This method of producing spores is extremely problematic preventing spores from being disseminated easily. As a result, morels acquire highly localized characteristics with recognizable genetic differences every few hundred miles of ground space.

Morels follow sandy river basins and will not grow on clay type soils. The reason is because the mycelium will not tolerate dehydration. Sand does not dehydrate due to its lack of capillary action. Clay has strong capillary action due to its fine texture. This property cause moisture to move to the surface and evaporate away resulting in rapid drying of clay type soils between rains, unless a lot of organic matter or cultivation breaks up the motion of water upward.

The extreme limitations caused by spores inside of cells was not an evolved property of morel mushrooms, as there is no advantage. Instead, the property is a disadvantageous carry-over from its ancestor—a yeast. The morel has yeast-like properties in all of its characteristics except morphology (shape).

The morel shows that morphology can evolve easily, while physiology is difficult to change. Morphology can change simply by counting a different number of cells in any direction, but physiology cannot change so easily, because enzymes must be fixed in an exact location much like an assembly line. Moving anything around is highly disruptive.

The morel re-evolves during each ice age cycle, as indicated by spore surfaces for two cup fungi which also form spores inside the cells. Ice ages have been cycling at 100 thousand years, which is an extremely short amount of time for such drastic changes. It means the morel evolved from a yeast less than 100 thousand years ago. Most of that evolving would have occurred at the base of trees, where yeast filaments would have reached down into the soil and fed upon bacteria by excreting acid.

The morel evolves in front of the ice sheet of each ice age cycle. That's because a filamentous yeast growing at the base of trees needed cool and humid conditions, because yeasts do not tolerate dehydration. Cold fog sweeping down the ice sheet and following the ground topology allowed the yeast to survive on tree trunks and extend into the ground, while up higher, the leaves of the tree would get sunlight.

Innumerable properties of the morel mushroom show how dramatic evolution occurs in the transition of a single-celled organism into a multi-celled organism in a few short years. The morel still maintains numerous disadvantageous properties. An example is autolysis, which means self-breakdown. All bacteria and yeast break down as they die off for the purpose of recycling nutrients. Large molecules are broken down enzymatically into subunits which provide ideal nutrients, not only for the same species but for plants also. Residual autolysis in the morel results in tissue break-down as morels age. Bacteria grow on the deteriorating tissue, which can cause sickness when eating old morels.

To survive through an ice age cycle, the morel must evolve into a cup fungus. Cup fungi are better adapted to getting spores out of the tissue, because there is a gradient of drying rates from rim to bottom of the cup. Drying rate is important, because it must be delayed enough to allow spores to form and then dry enough to shrink the tissue and create a propelling force for the spores.

The morel will never evolve into a cup fungus fast enough to survive beyond the present ice age. But there is a related species, Helvela crispa, which already has a good start and will probably evolve into a cup fungus. The morel sometimes has an indent on the side, which starts the evolution into the cup shape and shows the need for that morphology. But the morel shape prevails where there are rich nutrients, because there is much more surface area with that shape. Helvela grows later in the year when nutrients are more scarce causing it to adapt to extreme conditions.

Yeast evolution was quite dramatic, as filamentous fungi adapted to sugary solutions. Such drastic change in morphology and physiology preconditioned a yeast for the dramatic evolution from a single-celled organism into a multicellular mushroom.

Prairie Wildflowers

Wildflowers on the northern plains produce extreme evolution due to harsh conditions including hot, dry summers, hard clay and whipping grass. With limited moisture, flower heads are small. The smallest flowers will sometimes produce scent, while larger flowers do not. To prevent whipping grass from stripping leaves two mechanisms are used: Leaves might be small and hard and tucked close to the stem. Or they might be close to the ground to get below whipping grass. cone flowersFlower heads are often hard, which prevents damage from whipping grass.

Cone flowers are the most adapted to the conditions. There are two types: yellows and purples. The flower heads are hard with petals that can be sacrificed, and the leaves are close to the ground.

The harshness of conditions is shown by contrast with Asclepias incarnata—the incarnate milkweed. Asclepias incarnataIt has very large flowers with marvelous scent and luxurious leaves. That's because the roots are always in water along streams and lakes. There is no grass beating on the leaves.

A short distance away, growing on the bank in clay can be the closest relative of Asclepias incarnata. It is small with a flower head of only 15 mm, with a few thin threads out the top for petals. The leaves are small and close to the stem.

One of the things this contrast shows is how easily macro-morphology changes, as also shown by the morel mushroom. But also shown by the morel is that micro-morphology is highly resistant to change, as is physiology.

The Elm Tree

Another example of extreme evolution is the elm tree. It acquired a very long tap root that seeks underground water. If the elm does not find such water, it does not grow well. But with the unlimited water that it finds, it acquires vastly different characteristics from other trees.

The elm stores so much sap during the winter that it forms a soft seed early in the spring. The seed must germinate early before conditions get hot and dry. So it forms flowers and seeds before leaves in early spring. A late freeze often destroys the earliest blossoms. But nearby will be an elm tree which forms flowers and seeds later. Various elm trees flower from early April to late May.

These differences look preposterous based on normal science. There can't be that much difference in genetics or environments. But as clarified by the morel mushrooms, all species produce phenotypic variation as a method of coping with rapid changes in environments such as seasonal differences.

Scientists encounter phenotypic variation constantly and are usually confused by it. With the morel, scientists assume the different phenotypes are different species, and they have various species names for them. Other scientists, usually horticulturalists, have a pretty good understanding of phenotypic variation, as they must cope with it, usually by grafting instead of using seeds to get a uniform result.

The elm produces a lot of exudate, usually where insect damage occurs. When cutting a green elm at the trunk, sap will gush from both sides of the cut.

When burning elm, it burns unlike other types of wood. Usually, wood requires a flame to keep it burning. That's why wood stoves are made of heavy cast iron. The wood must burn fast and store the heat in the metal. When the wood burns up, the metal slowly releases heat. But the room temperature is always too hot or too cold with than scheme.

Barrel StoveBy contrast, the elm burns like coal. Once it is started, it burns down to a grey ash. Therefore, a barrel stove with thin metal can be used, and the burn rate can be controlled by the flow of air. The result is continuous and uniform heat.

The problem with burning elm is that dry wood will not split. When the sap dries, it is like glue. There is a lot of dead elm due to Dutch Elm Disease, but it can't be split. However, there is a fix in northern areas. When the temperature gets around -20°F (-29°C), the glue becomes nonfunctional, and the wood shatters when hit with a wedge.

Puffballs and Boletes

Puffball and BoletePuffball and bolete mushrooms evolved at about the same time around 300 million years ago. Conifer forests formed on the hills creating a break from the overwhelming nonwoody brush which was suppressing the evolution of other species and forcing dinosaurs to get large.

Over time, the puffball and bolete evolved the same type of tissue, at least when young. It's a white tissue which removes all flavor causing animals to avoid eating it. chew marksAnimals will bite into it and walk away leaving bite marks in it. Extreme evolution is required to produce such tissue, as no other mushrooms accomplish it. If more recent mushrooms need to keep animals from eating the tissue, they have to produce a toxin or repulsive chemicals.

The reason why there is a bulge at the base of the bolete is so rodents can stand on the bulge and eat spores under the cap. The spores have a lot of flavor even when the mushroom is young. Sometimes chefs will use the spore area only, since that is where the flavor is. The bulge at the base disappears as the mushroom gets large, which indicates the purpose is for small animals early on.

After the bolete gets large, the tissue acquires a lot of flavor, which causes animals, mostly squirrels, to chew around the sides where they eat spores and carry the spores around as a method of dissemination.

Usually, boletes are picked while small, because insect lava invade over time. Then the white tissue does not have flavor, only the spore area does. But if the young boletes are dried in a slow manner, the tissue develops flavor while drying.
 
While all species use phenotypic variation to cope with environmental complexities, the puffball is unique in its method of producing phenotypes. Usually, phenotypes are varied during reproduction or when a spore forms. The puffball forms four phenotypes in sequence from the same mycelium. Apparently, the mycelium sectors forming different phenotypes in different locations on the mycelium.

four puffballs

Puffball mycelium grows under the ground, continually expanding, for several decades. Puffballs emerge about once every ten years. By keeping the mycelium covered, predators and diseases do not develop against it as easily.

A lot of variants have formed for the puffball and bolete in recent times in response to variations in environmental conditions. As with all ancient species, a mainline type does not change much but continually becomes more sophisticated, while a wide variety of alternatives evolve continually from the main stem.

Extreme Differentiation

All biology is on the verge of dying out due to extreme differentiation. Most species could be gone in two to ten million years, even without human influence, due to extreme differentiation.

Differentiation means creation of complexities. Increased interdependence of biological functions is a result of differentiation. As biology evolves toward increased complexities, everything gets more specialized and interdependent and therefore more intolerant of change.

In other words, as highly complex biology, physiology and metabolism become more specialized, total biology becomes less flexible and less able to adapt rapidly to changing conditions. Certainly there are mechanisms for adaptation, which primarily occur through gene exchange; but gene exchange can only go so far in coping with the need to adapt. In fact, phenotypic variation replaces a lot of gene exchange in coping with rapid variations in environmental conditions.

Molds show a lot about this subject. They did a lot of frivolous evolving 200 to 300 million years ago producing a variety of "clamp connections," which are tubes going around cross-walls in the mycelium. Evidence still exists for such things, as evolution will not discard genes without a selective advantage in doing so. Molds evolved a lot of micro-structures back then when frivolous evolution was possible.

The difficulty of higher species evolving now days shows up in zinc metabolism. Vegetarian animals such as monkeys and apes have a shortage of zinc, since there is so little zinc in plants. Carnivores accumulate zinc, being higher on the food chain, just as large ocean fish pick up more mercury.

Human evolution began when the great apes discovered the shore creatures on the south west coast of Africa. At first they would have been drawn to the huge number of bird eggs available, and then they would have noticed the valuable shoreline creatures such as clams and muscles.

These sources of food were high in zinc, which allowed great improvement in metabolism for the great apes. This process would have occurred about 3-5 million years ago. It would have started the evolution into humans, while the increase in protein would have been a more direct cause of human evolution.

One of the most important things zinc does is improve the immune system. Indirect evidence indicates that zinc is used by white blood cells as a catalyst for breaking down foreign substances. This includes the breakdown of metabolic by-products such as the chemicals which create pain. When those chemicals are allowed to increase and linger, pain increases. When taking zinc, the pain diminishes rapidly and dramatically. In fact, only a few minutes are required to notice the effect. Only a catalyst would be so fast.

So the increased availability of zinc when the great apes switched from a vegetarian diet to an omnivorous diet would have greatly improved the immune system. To adapt, the metabolism of zinc apparently hijacked the physiology of copper, because new enzyme systems are very slow at evolving, and survival was greatly improved with increased zinc.

When humans take zinc as a supplement, the result is a copper shortage, because zinc hijacks the copper metabolizing system. It would take several million years for zinc metabolism to evolve its own physiology including separate enzymes. Until then, there is more evolutionary survival in exploiting the copper metabolizing physiology than not.

Copper is an extremely strong oxidizing agent, so much so that it is difficult to take as a supplement. It makes a good sterilizing agent for preventing fence posts from rotting in the ground. It is too toxic for the immune system to use as a catalyst but not too toxic for functioning in a cytochrome which has long-term durability. Zinc is also a strong oxidizing agent but only about half as toxic as copper. So the immune system can use zinc as an oxidizing catalyst, while copper is too toxic for that purpose.

Due to the toxicity of copper, the best way for humans to get copper is in red meat. Plants have very little copper. Taking copper in mineral form will oxidize food creating indigestion. Copper taken without food would get absorbed too fast and damage the liver. So if copper is taken in mineral form, it could be combined with white rice. Oxidation of starch does not produce the degree of toxicity of oxidized nitrogen containing molecules.

Humans have difficulty evolving physiology for the use of zinc because of the highly specialized and rigid complexities of modern differentiation. So copper utilization and zinc utilization are in conflict with each other. Zinc has not evolved its own physiology over the past 3-5 million years of its enhancement of human survival.

What it means is, not only are humans contributing to the loss of species through their disruptive influences over the environment, but all species are very fragile due to the extreme amount of specialization and interdependence that differentiation created. In other words, humans evolved at the most extreme end-point of biological differentiation.

Evolution Physiology

What Scientists Don't Know

Evolution Biology TOP     

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Evolution Biology
 
Cambrian Explosion Of Life
 
Evolution Physiology
 
Human Evolution
 
Evolution Science Errors
 
Phenotypic Variation
 
Physiological Patterns
 
The Biology Of Prairie Wildflowers
 
How Modern Biology Began
 
The Evolution Of Mitochondria
 
P. fluorescens And Mitochondria
 
Zinc And Immunity
 
The Evolution Of E. coli
 
What Scientists Don't Know
 
Morels, The Longer Story
 
Time Scale Of Evolution
 
The Physiology Problem
 
Porphyrins
 

     

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