Trudy Myers's Blog, page 22
April 24, 2021
Long excerpt - Hank's Widow
“Who are you filling up with chips and cake, Ella?” Wanda asked as Zita hurried away.
“Lyle’s wife,” Ella answered.
Wanda knew a moment of abject fear and looked around nervously. “Lyle’s here?”
“No, he should be at work. Mom stopped by and picked up Gloria and Sammy and brought them here for the party.” The girl paused, took a deep breath and pasted a smile on her face. “Now, this isn’t the time to talk about the failures of some of my relatives. I have succeeded in getting through high school, and that’s a reason to celebrate.”
“Indeed it is. And it’s a lovely party, Ella. The cake is delicious. Did all the graduates’ parents get together to organize the party?”
“No, the only thing the parents have to do is provide a dessert for their child, and a picture for the wall. The party itself is organized by the Belgrade Fire Brigade.”
“The fire brigade?”
“Well, it’s more than a fire brigade, but they worked hard to raise the money to build this station and buy some used fire engines. They raise money every year, and some of it is used to educate members of the volunteer fire department, and some of it is used to have parties for important milestones, like kids who graduate from high school!”
“So it sounds like it started as an organization to get a fire brigade started, and now it does other things too, but it hasn’t changed its name.”
“That’s right. Oh! There’s Shirley. I should go tell her how great her mother’s banana walnut cake is.”
April 17, 2021
Devonian Period
The Devonian Period spanned about 60 million years of the Paleozoic, from 419.2 million years ago to 358.9 million years ago. It is sandwiched between the Silurian Period, which came earlier, and the Carboniferous Period, which is more recent.
The first significant adaptations of life on dry land occurred during this period, for life was well underway in colonizing the land. Moss forests and bacterial/algal mats of earlier were joined early in the period by primitive rooted plants that created the first stable soils and harbored such arthropods as mites and scorpions. By far the largest land organism at the beginning of this period was a poorly-understood plant which was possibly the fruiting body of an enormous fungus, a rolled liverwort mat, or another organism of uncertain affinities. This plant stood more than 8 meters (26 ft) tall, which means it towered over the low, carpet-like vegetation that covered the land. The first fossils of insects appeared around 416 million years ago, in the Early Devonian.
Many Early Devonian plants did not have true roots or leaves like modern plants. These were generally very short, growing hardly more than a few centimeters tall. By the middle of the period, forests of shrub-like plants existed, for plants like horsetails and ferns had evolved. These had true roots and leaves, and many were quite tall. Also, the earliest-known trees appeared in the Middle Devonian, although probably not any that we would recognize. Certainly I didn't recognize them from their descriptions, and they all seemed to have 'extinct' in their description. By the end of the Devonian, the first seed-forming plants had appeared. There was such a rapid appearance of so many plant groups and growth forms that it is called the "Devonian Explosion". Various terrestrial arthropods (which includes insects, spiders, and crustaceans) also became well-established.
Fish reached substantial diversity, so that Devonian is often called the Age of Fishes. Among the marine vertebrates, jawless armored fish declined in diversity, while jawed fish increased in both the sea and fresh water. Early cartilaginous and bony fishes also became diverse in the seas. The first abundant genus of shark appeared during this period. The ancestors of all four-limbed vertebrates began adapting to walking on land, as their pectoral and pelvic fins evolved into legs.
The first ammonites (an extinct specie of mollusc) appeared during the Devonian. Trilobites (which look something like armored roaches), brachiopods (similar to a mollusc) and great coral reefs were common in the seas. The Late Devonian extinction, which started about 375 million years ago, affected marine line severely, killing off—among other things—all trilobites save for a few species.
The Devonian was relatively warm, and probably lacked any glaciers. For this reason, the sea level was high. The temperature gradient from the equator to the poles was not as large as it is today. The weather was also very arid, particularly along the equator. Surface temperature of the tropical seas was probably 86°F in the Early Devonian, but CO2 levels dropped steeply throughout the period, because the newly evolved forests drew carbon out of the atmosphere. By Mid-Devonian, there was a cooling of about 9°F. However, there is evidence that the temperature rose again in the Late Devonian, which may have contributed to the extinction event.
The geography was dominated by the supercontinent Gondwana to the south, Siberia to the north, and the early formation of Euramerica in between. It was a time of great tectonic activity, as Euramerica and Gondwana drew closer together. In the early Devonian, Laurentia and Baltica collided, forming Euramerica, which rotated into the natural dry zone along the Tropic of Capricorn (appromately 23.3° South of the equator). Then the plate of Euramerica and Gondwana started to meet, beginning to form the supercontinent Pangaea. This raised the northern Appalachian Mountains and formed the Caledonian Mountains in Great Britain and Scandinavia. The west coast of Euramerica was low lying, with deep silty embayments, river deltas and estuaries (found today in Idaho and Nevada). However, a volcanic island arc approached the west coast in the Late Devonian, and began to uplift that coast in a prelude to mountain-building that happened later.
Hey, we're getting somewhere! If trees and tall bushes could grow during this time period, then the soil must be decent, right? So maybe we could grow crops, so long as we bring our own seeds. And maybe we could set up a farm with some barnyard animals, too, like chicken, ducks, cows and goats. There's insects for the fowl to eat. Do you think cows and goats would eat horsetails and liverworts? Because the article didn't say anything about grasses. And as long as we don't go swimming in shark-filled waters, I think we'd be relatively safe.
April 9, 2021
Silurian Period
After the Ordovician Period came the Silurian Period, lasting 24.6 million years, from 443.8 million years ago to 419.8 million years ago. It began approximately the same time as the major series of extinction events mentioned at the end of the Ordovician Period, when a large number of marine fauna were wiped out.
The Silurian saw wide-spread diversification of jawed fish as well as bony fish. Multi-cellular life also appeared on land as small plants similar to liverworts, hornworts, and mosses, which grew besides lakes, streams and coastlines. Invertebrate animals with an exoskeleton also found land during this time period. This includes insects, spiders and crustaceans. However, terrestrial life would not greatly diversify until later.
With the supercontinent Gondwana still covering much of the southern hemisphere, a large ocean occupied most of the northern half of the globe. High sea levels and relatively flat land (there were few significant mountain belts) produced a number of island chains, meaning there was a rich diversity of environmental settings.
What was left of Gondwana remained intact and continued to drift south, but there is evidence that the icecaps were less extensive than those of the late-Ordovician time period. The smaller continents of Avalonia, Baltica, and Laurentia drift together near the equator, starting the formation of a second supercontinent known as Euramerica.
When proto-Europe (Baltica) collided with proto-North America (Laurentia), the collision folded coastal areas from modern New York State through Europe and Greenland to Norway. At the end of the Silurian Period, sea levels dropped again, and the new mountain ranges were rapidly eroded.
The Silurian period enjoyed relatively stable and warm temperatures, in contrast with the extreme glaciations of the period before it, and the extreme heat that would follow it. Sea levels rose during the first half of this period, and fell during the second half.
Climate was warm because high CO2 levels and warm shallow seas produced a greenhouse phase. Glaciers at the South Pole nearly disappeared entirely. There is strong evidence of a climate dominated by violent storms generated by warm sea surfaces.
The Silurian was the first period to have megafossils in the form of moss-like miniature forests along lakes and streams. The first fossil records of vascular plants (land plants with tissues that carry water and food) appeared in the second half of the Silurian period.
Fish reached considerable diversity. A diverse fauna of sea scorpions (some of them several meters in length) prowled the shallow Silurian seas of North America. Leeches made their appearance.
About the middle of the Silurian, the earliest-known animals fully adapted to terrestrial conditions appeared, including a millipede. There is also some evidence of predatory spiders and millipedes and centipedes. Predatory invertebrates indicate that simple food webs were in place that included prey animals. These may have included those who grazed on micro-organisms.
Yes, we are getting closer and closer modern Earth. That is what happens when you start at the beginning and work your way towards today. I'm still not seeing any fauna that would be worth hunting. Although a millipede several meters in length might have enough meat to make a stew. Is the ground fertile enough to grow carrots and potatoes to put in that stew? And just how bad did those storms get? Maybe I'll keep going before I try to colonize.
March 10, 2021
Big Sale
March 5, 2021
Ordovician Period
When I first started reading the article on the Ordovician Period, I got to the mention of Gondwana, which made me stop and wonder, "Wait, haven't we been through this breakup before?" And the answer is yes, we have, in the blog I wrote about the Paleozoic Era, which the Ordovician Period is part of. I had to remind myself that this is not really déjà vue, that the Paleozoic Era has 6 periods to it, and my blog on the Era would have been like an overview, while the blogs on the periods would have more details. So, some of the big events, like the breakup of Gondwana, will be mentioned in both posts.
The Ordovician Period spans 41.6 million years, from the end on the Cambrian Period some 485.4 million years ago to 443.6 million years ago.
Life continued to flourish during the Ordovician Period, although there was an extinction event at the end of the period. The Ordovician Period is known for its biodiversification event, which considerably increased the diversity of life. Invertebrates, namely molluscs and arthropods, dominated the oceans, although fish, the world's first true vertebrates, continued to evolve, and fish with jaws may have first appeared late in the period. Life on land had yet to diversify.
However many meteorites strike the Earth in a year today, there were 100 times that many hitting the Earth per year during this period.
The southern continents were collected into Gondwana, which started the period in equatorial latitudes but then drifted toward the South Pole. Meanwhile, other continents, Laurentia (part of North American), Siberia, and Baltica (northern Europe), were drifting north, and Baltica started moving towards Laurentia later in the period. Another small continent, Avalonia, separated from Gondwana and began moving north towards Baltica and Laurentia.
Temperatures were mild in the early and middle Ordovician Period, but from 460-450 million years ago, volcanoes along one of the oceans spewed massive amounts of carbon dioxide (a greenhouse gas) into the atmosphere, turning the planet into a hothouse. These volcanic island arcs eventually collided with proto-North America and formed the Appalachian Mountains. [At last! I've been waiting for billions of years for the Appalachians to appear!]
Initially, sea levels were high, but as Gondwana moved south, ice accumulated into glaciers and the sea levels dropped. At first, low-lying sea beds increased diversity, but later glaciation led to mass extinctions as the seas drained and continental shelves became dry land. By the end of the period, the volcanic emissions had stopped. By then, Gondwana had neared the South Pole and was largely glaciated.
Reef-forming corals first appeared early in this period. Land plants probably evolved from green algae, first appearing in a form resembling liverworts. Fungi was also an early adopter of living on land, and facilitated the colonization of land by making mineral nutrients available to plant cells.
This period closed with a series of extinction events that are generally regarded as one major event, in which 49% of all fauna died. It is generally agreed that this event or series of events were caused by an ice age. That ice age had several pulses of increasing/decreasing glaciation. Each time the glaciation increased, the sea level dropped, killing many of the fauna that inhabited the shallow seas. When the sea levels rose during the next decrease of glaciation, there were entire families of fauna that had not survived to re-establish themselves in the shallow seas. This may have happened several times, producing a series of extinction events.
Well, now we're starting to get some place. Plants (of sorts) on land, starting to make the soil arable. Not sure about the carbon dioxide level in the atmosphere, but the meteor showers would be beautiful, as long as they didn't land too close. Hunting probably wouldn't do much good yet, but, hey, there's fish! Too bad I can't stand fish.
Maybe the next period will be even more amenable?
February 26, 2021
Cambrian Period
The Cambrian Period was the first geological period of the Paleozoic Era. It lasted 55.6 million years, from 541 million years ago to 485.4 million years ago. The Cambrian is known for sites of exceptional preservation where even 'soft' parts of organisms are preserved, so our understanding of the Cambrian biology surpasses that of some later periods.
A profound change in life on Earth happened during the Cambrian Period, in that mineralized multicellular organisms became common. The rapid diversification of life-forms in this period—known as the Cambrian Explosion—produced the first representatives of all modern animals, probably from a single common ancestor.
Although life prospered in the oceans, the land is thought to have been comparatively barren. Shallow seas flanked several continents and were relatively warm. Polar ice was absent for much of the period.
Large, high-velocity rotational movement of Gondwana appears to have occurred in the early Cambrian, and may have resulted in Laurentia (North America), Baltica and Siberia being 'tossed away' and forming isolated land masses. Most continental land was clustered in the Southern Hemisphere, but was drifting north.
With a lack of sea ice, the sea level was high, which led to large areas of the continents being flooded in warm shallow seas, which were ideal for sea life. The sea levels fluctuated, suggesting there were pulses of expansion and contraction of a south polar ice cap.
The article stated that the Earth was generally cold during the early Cambrian, and then said the average temperatures were 7 degrees Celsius higher than today. That doesn't seem very cold to me.
The Cambrian flora was little different from what had existed in the previous period. Primarily, there were marine macroalgae in the seas, and that was pretty much it. There were no land plants known from the Cambrian, although biofilms and microbial mats were well developed on tidal flats and beaches 500 million years ago. There were also microbes forming microbial Earth ecosystems, comparable with modern soil crust of desserts, which contributed to soil formation.
It was once thought that trilobites were the dominant life form of the time period. But it turns out that these had a heavy armor which fossilized far more easily than the bodies of other animals, so there were plenty of trilobite fossils, even though trilobites were only a minor part of the animal diversity.
Earth suffered a mass extinction at the start of the Cambrian Period. It is thought that animals that burrowed into the sea bed, destroyed the microbial mats covering the seabed, and many organisms dependent on the mats became extinct, while other species adapted to the changed environment.
Despite the 'Explosion' at the start of this period, the later half saw a sharp drop in biodiversity. 500 million years ago, oxygen levels in the oceans dropped dramatically, while the level of poisonous hydrogen sulfide increased, producing more extinction events, making the latter half of the period surprisingly barren.
However, some organisms did venture onto land, producing trace fossils of their movements. Some of these fossil trackways suggest a large, slug-like mollusc.
Just when you thought Earth pre-history was going to get interesting, it takes one step forward and two steps back. Dry land is still pretty barren, except for an occasional slug-mollusc looking for some tasty soil microbes.
Well, we're pretty sure humans arrive on the scene eventually, so we're just going to keep slogging forward until we find us.
February 18, 2021
Paleozoic Era
The Paleozoic Era is the earliest era of the Phanerozoic Eon. It is the longest of the Pahnerozoic eras, lasting from 541 to 251.902 million years ago. (I am left wondering why such an odd date for an ending? Why not 252 million years ago? I hope they offer an explanation.)
The Paleozoic was a dramatic time, incorporating geological, climatic and evolutionary changes. There was an explosion of variety in lifeforms, in which almost all modern families appeared. This began in the ocean, but eventually transitioned onto land. Great forests of primitive plants covered the continents, and towards the end of the Paleozoic, the first modern plants (conifers) appeared.
The Paleozoic Era also saw the largest extinction event in the history of Earth. This catastrophe was so devastating that it took life on land 30 million years into the next era to recover. Life in the sea may have recovered much faster.
During the early part of this era, the climate was probably moderate, becoming warmer as the second-greatest sea level rise of the era occurred, where the sea level was 200 meters above today's levels. Gondwana moved south until West Gondwana (Africa and South America) lay directly over the South Pole, while most of the parts that now reside in the northern hemisphere remained in the tropical zone, and China and Australia lay in a temperate zone. This warm period ended rather abruptly with a short but severe ice age that caused the second-greatest mass extinction of the Phanerozoic time. This ice age was only 30 million years long, and occurred 445 million years ago.
Sea levels dropped, of course, during the ice age, but slowly recovered over the middle of the Paleozoic. Bits and pieces of Gondwana moved northward, which created numerous new regions of warm, shallow sea floor. As plants took hold on the continental edges, oxygen level increased and carbon dioxide dropped. The far southern parts of Antarctica and West Gondwana became less barren.
Then a spike in atmospheric oxygen (while carbon dioxide plummeted) destabilized the climate and led to one or perhaps two ice ages. These were even more severe than the brief one already mentioned, but the effects on the world biota were mostly inconsequential. The oxygen and carbon dioxide level returned to more normal levels, but the assembly of Pangaea created huge inland areas that were subject to temperature extremes. The end of the era saw a huge mass extinction event.
While macroscopic plant life possibly appeared before this era began, plants mostly remained aquatic until about 420 million years ago, when they began to explore dry land. They reached a point where towering lycopsid (a type of plant that includes clubmosses, firmosses and quillworts) rainforests dominated the tropical belt of Euramerica. Climate change caused this rainforest to collapse, fragmenting this habitat and diminishing the diversity of plant life.
Nearly all of the invertebrate animal phyla appeared in great abundance at the beginning of this era. The first vertebrates were primitive fish, which lost no time in diversifying. Some fish had lung and powerful bony fins that allowed them to crawl onto land about 367.5 million years ago. Their fins evolved into legs about 390 million years ago. Amphibians were dominant for a time, until the climate change that reduced the rainforests also greatly reduced the amphibian diversity. Then reptiles prospered and increased in number and variety by the end of the era.
I'm sure we'll get even more details when we study each period of this era.
February 14, 2021
Hank's Wife
Wanda lost her husband Hank in a terrible Chicago traffic accident caused by a snow storm. She couldn't afford their apartment without getting some kind of a job, and that would play havoc with her writing career, which was just starting to take off. So when she found a deed to a house in Hank's tiny home town in Nebraska, she rather rashly decided to move there, to save on rent. She did get some survivor's benefits from his job, so what could go wrong?
What Hank had never told her was that there were 3 other men living in Belgrade who looked a lot like him. And 2 of them were still bachelors.
Tentatively set for a July release!
February 5, 2021
Phanerozoic Eon
The current geologic eon of Earth is the Phanerozoic Eon. It started 541 million years ago and continues today. It is the only eon during which abundant animal and plant life has existed. It began at about the same time that animals first developed hard shells, as preserved in the fossil record.
During the early stages of the Phanerozoic Eon, a number of animal types came into existence and evolved into diverse forms, and complex plants emerged and developed. In addition, fish, insects and tetrapods (which includes all living and extinct species of amphibians, reptiles, birds and mammals) also emerged and evolved. Plant life appeared on land early in the eon.
Pangaea was the most recent supercontinent during the early days of this eon, but tectonic forces broke it up into the current continental landmasses, and then proceeded to move them around into their current configuration.
The Phanerozoic Eon consists of 3 eras, which are broken up into 12 periods. Now that plants and animals have shown up in earnest, I expect there will be plenty of information about what was going on during each segment.
In fact, the article I found for this eon actually had paragraphs (or more) for each period, but I skipped over them because I didn't want to get ahead of myself. I hope I remember to check back to this article if I have trouble finding information on the eras and periods that comprise this eon.
This is a very short blog, not because I couldn't find much information, but because there was so much information, it needs to be broken into smaller time segments to get that information into manageable bites. But do stay tuned, because we are finally approaching Dinosaur Land!
January 28, 2021
Tonian, Cryogenian, and Ediacaran Periods
Tonian Period
The first section of the Neoproterozoic Era is the Tonian Period. It lasted from 1,000 million years ago to 720 million years ago. The breakup of supercontinent Rodinia began around 900-850 million years ago.
The first large evolutionary radiation of organic microfossils occurred during the Tonian Period. This means a huge increase in diversity caused by a large rate of specialization. None of the examples in this article of evolutionary radiation were from the Tonian period, however, probably since it involved microfossils, which most lay people are not terribly familiar with.
So, Rodinia started breaking up, and microorganisms multiplied and diversified. It still sounds like a pretty barren place to me.
Cryogenian Period
The second geologic period of the Neoproterozoic Era was the Cryogenian Period, lasting from 720 to 635 million years ago. There were 2 ice ages during this period, the Sturtian and Marinoan Glaciations, which are said to be the greatest ice ages known on Earth. There is much debate over whether these glaciations covered the entire planet (Snowball Earth) or a band of open sea survived near the equator (Slushball Earth).
In any case, the Sturtian Glaciation lasted from 720 to 660 million years ago, while the Marinoan Glaciation ended at approximately 635 million years ago, although there was no indication when it began. Whenever it began, it was relatively short-lived when compared to the Sturtian.
Fossils of hard-shelled amoeba first appear during this period, as well as the oldest known fossils of sponges. Debate about how much the glaciation might have impacted biology rages on, with some suggesting that several species began during this period.
Me, I much prefer warmer climes.
Ediacaran Period
The end of the Era is marked by the Ediacaran Period, which lasted from 635 million years ago to 541 million years ago.
Fossils from the Ediacaran are sparse, as not a lot of hard-shelled animals had yet evolved. But there were multicellular organisms with specialized tissues. The most common types resemble segmented worms, fronds, disks, or immobile bags. Although Ediacara biota bear little resemblance to modern lifeforms, more than 100 genera have been described.
During this period, the moon was considerably closer, making the tides stronger and more rapid than they currently are. A day was about 21.9 hours long, meaning there were about 13.1 months per year, and approximately 400 days/year.
Okay, now we're getting somewhere. The place had worms and fronds, or at least lifeforms that looked like them. I was particularly pleased with the information about the days being shorter and the moon being closer. How long do you suppose it would take human colonists to get used to a 22-hour day instead of a 24-hour day?
https://en.wikipedia.org/wiki/Tonian#....
https://en.wikipedia.org/wiki/Evoluti...
https://en.wikipedia.org/wiki/Cryogen....
https://en.wikipedia.org/wiki/Ediacaran
