Eukaryote Quotes

Some ancient eukaryote swallowed a photosynthesizing bacteria and became a sunlight gathering alga. Millions of years later one of these algae was devoured by a second eukaryote. This new host gutted the alga, casting away its nucleus and its mitochondria, keeping only the chloroplast. That thief of a thief was the ancestor or Plasmodium and Toxoplasma. And this Russian-doll sequence of events explains why you can cure malaria with an antibiotic that kills bacteria: because Plasmodium has a former bacterium inside it doing some vital business.

It seems that all eukaryotic cells either have, or once had (and then lost) mitochondria. In other words, possession of mitochondria is a sine qua non of the eukaryotic condition

Look at life from our perspective, and you eukaryotes will soon cease giving yourselves such airs. You bipedal apes, you stump-tailed tree-shrews, you desiccated lobe-fins, you vertebrated worms, you Hoxed-up sponges, you newcomers on the block, you eukaryotes, you barely distinguishable congregations of a monotonously narrow parish, you are little more than fancy froth on the surface of bacterial life. Why, the very cells that build you are themselves colonies of bacteria, replaying the same old tricks we bacteria discovered a billion years ago. We were here before you arrived, and we shall be here after you are gone.

Throughout 150 years of the science of bacteriology, there is no evidence that one species of bacteria has changed into another... Since there is no evidence for species changes between the simplest forms of unicellular life, it is not surprising that there is no evidence for evolution from prokaryotic [i.e., bacterial] to eukaryotic [i.e., plant and animal] cells, let alone throughout the whole array of higher multicellular organisms.

As Lynn Margulis writes: “All the world’s bacteria essentially have access to a single gene pool and hence to the adaptive mechanisms of the entire bacterial kingdom. The speed of recombination over that of mutation is superior: it could take eukaryotic organisms a million years to adjust to a change on a worldwide scale that bacteria can accommodate in a few years.

This was difficult to prove as most hydrogenosomes have lost their entire genome, but it is now established with some certainty.1 In other words, whatever bacteria entered into a symbiotic relationship in the first eukaryotic cell, its descendents numbered among them both mitochondria and hydrogenosomes.

Even if we have a reliable criterion for detecting design, and even if that criterion tells us that biological systems are designed, it seems that determining a biological system to be designed is akin to shrugging our shoulders and saying God did it. The fear is that admitting design as an explanation will stifle scientific inquiry, that scientists will stop investigating difficult problems because they have a sufficient explanation already. But design is not a science stopper. Indeed, design can foster inquiry where traditional evolutionary approaches obstruct it. Consider the term "junk DNA." Implicit in this term is the view that because the genome of an organism has been cobbled together through a long, undirected evolutionary process, the genome is a patchwork of which only limited portions are essential to the organism. Thus on an evolutionary view we expect a lot of useless DNA. If, on the other hand, organisms are designed, we expect DNA, as much as possible, to exhibit function. And indeed, the most recent findings suggest that designating DNA as "junk" merely cloaks our current lack of knowledge about function. For instance, in a recent issue of the Journal of Theoretical Biology, John Bodnar describes how "non-coding DNA in eukaryotic genomes encodes a language which programs organismal growth and development." Design encourages scientists to look for function where evolution discourages it. Or consider vestigial organs that later are found to have a function after all. Evolutionary biology texts often cite the human coccyx as a "vestigial structure" that hearkens back to vertebrate ancestors with tails. Yet if one looks at a recent edition of Gray’s Anatomy, one finds that the coccyx is a crucial point of contact with muscles that attach to the pelvic floor. The phrase "vestigial structure" often merely cloaks our current lack of knowledge about function. The human appendix, formerly thought to be vestigial, is now known to be a functioning component of the immune system.

Life has had to deal with environmental change, especially climate change, since the beginning of its existence on Earth. Species adjust or go extinct, and both have happened. For life-forms with our kinds of cells—eukaryotic, the kind with distinct organelles—the average existence of a species is about 1 million years, and, on average, one species goes extinct a year, at least of the species we have named and know, including those we know only from fossil records." -Dan Botkin, excerpt from THE MOON IN THE NAUTILUS SHELL.

Actually, the entire ascent of life can be presented as an adaptive radiation in the time dimension. From the beginning of replicating molecules to the formation of membrane-bounded cells, the formation of chromosomes, the origin of nucleated eukaryotes, the formation of multicellular organisms, the rise of endothermy, and the evolution of a large and highly complex central nervous system, each of these steps permitted the utilization of a different set of environmental resources, that is, the occupation of a different adaptive zone.

eukaryotes,

Microbes dominated the Proterozoic and arguably they still largely determine the course of life today. They are, as the microbiologist John Ingraham puts it, ‘our inventors, progenitors and keepers’. (They are also our disposers: death is not the end, it’s just a case of being metabolically different.) In the big picture – the cycles of life on Earth – microbes are the beginning and end of all. Or, as the palaeontologist Andrew Knoll asserts, ‘eukaryotes are the icing and prokaryotes are the cake’.

There is no theoretical reason to expect evolutionary lineages to increase in complexity with time, and no empirical evidence that they do so. Nevertheless, eukaryotic cells are more complex than prokaryotic ones, animals and plants are more complex than protists, and so on. This increase in complexity may have been achieved as a result of a series of major evolutionary transitions. These involved changes in the way information is stored and transmitted. [The major evolutionary transitions, Nature 374, 227 - 232 (16 March 1994)]

Rather surprisingly, to anyone who is most familiar with textbook mitochondria, many simple single-celled eukaryotes have mitochondria that operate in the absence of oxygen. Instead of using oxygen to burn up food, these ‘anaerobic’ mitochondria use other simple compounds like nitrate or nitrite. In most other respects, they operate in a very similar fashion to our own mitochondria, and are unquestionably related. So the spectrum stretches from aerobic mitochondria like our own, which are dependent on oxygen, through ‘anaerobic’ mitochondria, which prefer to use other molecules like nitrates, to the hydrogenosomes, which work rather differently but are still related.

Dorian Purcell, focused intensely on archaea, the third domain of animal life. The first domain is eukaryotes, which includes human beings and all other higher organisms. The second domain is bacteria. Microscopic archaea, which lack a nucleus, were long thought to be a kind of bacteria. But they have unique properties, not least of which is the ability to effectuate horizontal gene transfer.

richly financed experiments were, at the insistence of Dorian Purcell, focused intensely on archaea, the third domain of animal life. The first domain is eukaryotes, which includes human beings and all other higher organisms. The second domain is bacteria. Microscopic archaea, which lack a nucleus, were long thought to be a kind of bacteria. But they have unique properties, not least of which is the ability to effectuate horizontal gene transfer. Parents pass their genes vertically to their offspring. Archaea pass genetic material horizontally, from one species to another. Their mysterious role in the development of life on Earth is only beginning to be understood, and perhaps it is madness to seek to harness them for the purpose of improving the human genome and extending the human life span.

The hard part, evolutionarily, was getting from prokaryotic cells to eukaryotic ones, then getting from single-celled organisms to multicellular ones. Earth is around 4.5 billion years old, a timescale I simply cannot get my head around. Instead let’s imagine’s Earth’s history as a calendar year, with the formation of Earth being January 1 and today being December 31 at 11:59pm. The first life on Earth emerges around February 25. Photosynthetic organisms first appear in late March. Multicellular life doesn’t appear until August or September. The first dinosaurs like eoraptor show up about 230 million years ago, or December 13 in our calendar year. The meteor impact that heralds the end of the dinosaurs happens around December 26. Homo sapiens aren’t part of the story until December 31 at 11:48 pm. Agriculture and large human communities and the building of monolithic structures all occur within the last minute of this calendar year. The Industrial Revolution, two world wars, the invention of basketball, recorded music, the electric dishwasher, and vehicles that travel faster than horses all happen in the last couple of seconds. Put another way: It took Earth about three billion years to go from single-celled life to multicellular life. It took less than seventy million years to go from Tyrannosaurus rex to humans who can read and write and dig up fossils and approximate the timeline of life and worry about its ending. Unless we somehow manage to eliminate all multicellular life from the planet, Earth won’t have to start all over and it will be okay--- at least until the oceans evaporate and the planet gets consumed by the sun. But we`ll be gone by then, as will our collective and collected memory. I think part of what scares me about the end of humanity is the end of those memories. I believe that if a tree falls in the woods and no one is there to hear it, it does make a sound. But if no one is around to play Billie Holiday records, those songs won’t make a sound anymore. We’ve caused a lot of suffering, but we’ve also caused much else. I know the world will survive us – and in some ways it will be more alive. More birdsong. More creatures roaming around. More plants cracking through our pavement, rewilding the planet we terraformed. I imagine coyotes sleeping in the ruins of the homes we built. I imagine our plastic still washing up on beaches hundreds of years after the last of us is gone. I imagine moths, having no artificial lights toward which to fly, turning back to the moon.

i'm looking for the face i had before the world was made. I was the primordial flaring forth, the gravitational waves, the whirling galaxies, and the exploding supernovas that would become stars and planets. I was the steaming planet Earth, the bacteria awash in the sea, and the early eukaryotes and multicellular animals. I exploded in the Cambrian explosion, stumbled onto land, walked with dinosaurs, saw trees and flowers appear, walked upright in Africa, and walked on the moon. I felt the embrace of gravity. I was one with all that had been and all that was to be. I experienced subjective mystical communion with the evolutionary, emergent universe. I was the universe. We know not where the journey leads, nor whether a final destination is even a meaningful concept. The attraction is the inherent thrill of participating in a grand creative endeavor for which participation is its own reward

The hard part, evolutionarily, was getting from prokaryotic cells to eukaryotic ones, then getting from single-celled organisms to multi cellar ones. Earth is around 4.5 billion years old, a timescale I simply cannot get my head around. Instead let’s imagine’s Earth’s history as a calendar year, with the formation of Earth being January 1 and today being December 31 at 11:59pm. The first life on Earth emerges around February 25. Photosynthetic organisms first appear in late March. Multicellular life doesn’t appear until August or September. The first dinosaurs like eoraptor show up about 230 million years ago, or December 13 in our calendar year. The meteor impact that heralds the end of the dinosaurs happens around December 26. Homo sapiens aren’t part of the story until December 31 at 11:48 pm. Agriculture and large human communities and the building of monolithic structures all occur within the last minute of this calendar year. The Industrial Revolution, two world wars, the invention of basketball, recorded music, the electric dishwasher, and vehicles that travel faster than horses all happen in the last couple of seconds. Put another way: It took Earth about three billion years to go from single-celled life to multicellular life. It took less than seventy million years to go from Tyrannosaurus rex to humans who can read and write and dig up fossils and approximate the timeline of life and worry about its ending. Unless we somehow manage to eliminate all multicellular life from the planet, Earth won’t have to start all over and it will be okay--- at least until the oceans evaporate and the planet gets consumed by the sun. I know the world will survive us – and in some ways it will be more alive. More birdsong. More creatures roaming around. More plants cracking through our pavement, rewilding the planet we terraformed. I imagine coyotes sleeping in the ruins of the homes we built. I imagine our plastic still washing up on beaches hundreds of years after the last of us is gone. I imagine moths, having no artificial lights toward which to fly, turning back to the moon.

This is a miracle of coevolution—the bacteria that coexist with us in our bodies enable us to exist. Microbiologist Michael Wilson notes that “each exposed surface of a human being is colonized by microbes exquisitely adapted to that particular environment.”21 Yet the dynamics of these microbial populations, and how they interact with our bodies, are still largely unknown. A 2008 comparative genomics analysis of lactic acid bacteria acknowledges that research is “just now beginning to scratch the surface of the complex relationship between humans and their microbiota.”22 Bacteria are such effective coevolutionary partners because they are highly adaptable and mutable. “Bacteria continually monitor their external and internal environments and compute functional outputs based on information provided by their sensory apparatus,” explains bacterial geneticist James Shapiro, who reports “multiple widespread bacterial systems for mobilizing and engineering DNA molecules.”23 In contrast with our eukaryotic cells, with fixed genetic material, prokaryotic bacteria have free-floating genes, which they frequently exchange. For this reason, some microbiologists consider it inappropriate to view bacteria as distinct species. “There are no species in prokaryotes,” state Sorin Sonea and Léo G. Mathieu.24 “Bacteria are much more of a continuum,” explains Lynn Margulis. “They just pick up genes, they throw away genes, and they are very flexible about that.”25 Mathieu and Sonea describe a bacterial “genetic free market,” in which “each bacterium can be compared to a two-way broadcasting station, using genes as information molecules.” Genes “are carried by a bacterium only when needed . . . as a human may carry sophisticated tools.”26

Suppose you entered a boat race. One hundred rowers, each in a separate rowboat, set out on a ten-mile race along a wide and slow-moving river. The first to cross the finish line will win $10,000. Halfway into the race, you’re in the lead. But then, from out of nowhere, you’re passed by a boat with two rowers, each pulling just one oar. No fair! Two rowers joined together into one boat! And then, stranger still, you watch as that rowboat is overtaken by a train of three such rowboats, all tied together to form a single long boat. The rowers are identical septuplets. Six of them row in perfect synchrony while the seventh is the coxswain, steering the boat and calling out the beat for the rowers. But those cheaters are deprived of victory just before they cross the finish line, for they in turn are passed by an enterprising group of twenty-four sisters who rented a motorboat. It turns out that there are no rules in this race about what kinds of vehicles are allowed. That was a metaphorical history of life on Earth. For the first billion years or so of life, the only organisms were prokaryotic cells (such as bacteria). Each was a solo operation, competing with others and reproducing copies of itself. But then, around 2 billion years ago, two bacteria somehow joined together inside a single membrane, which explains why mitochondria have their own DNA, unrelated to the DNA in the nucleus.35 These are the two-person rowboats in my example. Cells that had internal organelles could reap the benefits of cooperation and the division of labor (see Adam Smith). There was no longer any competition between these organelles, for they could reproduce only when the entire cell reproduced, so it was “one for all, all for one.” Life on Earth underwent what biologists call a “major transition.”36 Natural selection went on as it always had, but now there was a radically new kind of creature to be selected. There was a new kind of vehicle by which selfish genes could replicate themselves. Single-celled eukaryotes were wildly successful and spread throughout the oceans.

The hard part, evolutionarily, was getting from prokaryotic cells to eukaryotic ones, then getting from single-celled organisms to multicellular ones. Earth is around 4.5 billion years old, a timescale I simply cannot get my head around. Instead let’s imagine’s Earth’s history as a calendar year, with the formation of Earth being January 1 and today being December 31 at 11:59pm. The first life on Earth emerges around February 25. Photosynthetic organisms first appear in late March. Multicellular life doesn’t appear until August or September. The first dinosaurs like eoraptor show up about 230 million years ago, or December 13 in our calendar year. The meteor impact that heralds the end of the dinosaurs happens around December 26. Homo sapiens aren’t part of the story until December 31 at 11:48 pm. Agriculture and large human communities and the building of monolithic structures all occur within the last minute of this calendar year. The Industrial Revolution, two world wars, the invention of basketball, recorded music, the electric dishwasher, and vehicles that travel faster than horses all happen in the last couple of seconds. Put another way: It took Earth about three billion years to go from single-celled life to multicellular life. It took less than seventy million years to go from Tyrannosaurus rex to humans who can read and write and dig up fossils and approximate the timeline of life and worry about its ending. Unless we somehow manage to eliminate all multicellular life from the planet, Earth won’t have to start all over and it will be okay--- at least until the oceans evaporate and the planet gets consumed by the sun. I know the world will survive us – and in some ways it will be more alive. More birdsong. More creatures roaming around. More plants cracking through our pavement, rewilding the planet we terraformed. I imagine coyotes sleeping in the ruins of the homes we built. I imagine our plastic still washing up on beaches hundreds of years after the last of us is gone. I imagine moths, having no artificial lights toward which to fly, turning back to the moon.

A few hundred million years later, some of these eukaryotes developed a novel adaptation: they stayed together after cell division to form multicellular organisms in which every cell had exactly the same genes. These are the three-boat septuplets in my example. Once again, competition is suppressed (because each cell can only reproduce if the organism reproduces, via its sperm or egg cells). A group of cells becomes an individual, able to divide labor among the cells (which specialize into limbs and organs). A powerful new kind of vehicle appears, and in a short span of time the world is covered with plants, animals, and fungi.37 It’s another major transition. Major transitions are rare. The biologists John Maynard Smith and Eörs Szathmáry count just eight clear examples over the last 4 billion years (the last of which is human societies).38 But these transitions are among the most important events in biological history, and they are examples of multilevel selection at work. It’s the same story over and over again: Whenever a way is found to suppress free riding so that individual units can cooperate, work as a team, and divide labor, selection at the lower level becomes less important, selection at the higher level becomes more powerful, and that higher-level selection favors the most cohesive superorganisms.39 (A superorganism is an organism made out of smaller organisms.) As these superorganisms proliferate, they begin to compete with each other, and to evolve for greater success in that competition. This competition among superorganisms is one form of group selection.40 There is variation among the groups, and the fittest groups pass on their traits to future generations of groups. Major transitions may be rare, but when they happen, the Earth often changes.41 Just look at what happened more than 100 million years ago when some wasps developed the trick of dividing labor between a queen (who lays all the eggs) and several kinds of workers who maintain the nest and bring back food to share. This trick was discovered by the early hymenoptera (members of the order that includes wasps, which gave rise to bees and ants) and it was discovered independently several dozen other times (by the ancestors of termites, naked mole rats, and some species of shrimp, aphids, beetles, and spiders).42 In each case, the free rider problem was surmounted and selfish genes began to craft relatively selfless group members who together constituted a supremely selfish group.

The Greek word for kernel is karys, so the word used to describe creatures without a nucleus is prokaryotic—the name, originally procariotique, was coined in the 1930s by Edouard Chatton, a French marine biologist—while creatures with nuclei are eukaryotic. Bacteria are prokaryotes. Pretty much everything else, from yeast to elephants, are eukaryotes. This realization resulted in the creation of a fifth Kingdom, dividing one-celled eukaryotes, who retained the Protist name, from prokaryotes. Thus, by the time the dust had settled, in the 1970s, the hierarchical tree of life had two domains—Prokarya and Eucarya—and five kingdoms: Plantae, Animalae, Fungi, Protista, and Bacteria.*

In Plato's thinking, our desire for immortality is what drives us to reproduce (hence to heterosexual expression). The great philosopher would not have clearly understood that any particular eukaryotic legacy declines exponentially toward the vanishing point in subsequent generations....

For people who study these domains, the difference is clear. Both the Bacteria and the Archaea do not have nuclei. Whereas, you and I do … in our cells. That’s why we are said to be Eukaryotes; it’s from Greek words meaning “having nut” (having nucleus). The Archaea and Bacteria are Prokaryotes, meaning “before nut” (before nucleus). This turns out to be of astonishing significance in the natural history of living things. The

If the genetic properties of bacteria were applied to larger beings, Margulis wrote, we would live in a science-fiction world where people could grow wings by picking up genes from a bat, or a mushroom could turn green and begin to photosynthesize by picking up genes from a nearby plant. This gives me a clearer way to see how Gianoli's theory could work: instead of imagining a foreign set of bacteria hijacking the boquila's ingrained sense of personal shape, perhaps the bacteria that lives within boquila and determines its developmental expression could simply be picking up errant genetic cues from the bacteria doing the same thing inside other plants. "People and other eukaryotes are like solids frozen in a specific genetic mold," Margulis and Sagan write, "whereas the mobile, interchanging suite of bacterial genes is akin to a liquid or gas." One begins to see the world in bacterial terms-a microcosmic sea of shifting identity and form. Under the surface, our bacterial selves are morphing and changing. We are all in flux. Who is to say where any of us begin and end?

life on Earth is basically a giant microbial vat and eukaryotic organisms are merely the bubbles on its surface? Are we – the froth – deluded in valuing ourselves so highly?

cell, for example, has about 2 m of DNA—a length about 250,000 times greater than the cell’s diameter. Yet before the cell can divide to form genetically identical daughter cells, all of this DNA must be copied, or replicated, and then the two copies must be separated so that each daughter cell ends up with a complete genome. The replication and distribution of so much DNA is manageable because the DNA molecules are packaged into structures called chromosomes, so named because they take up certain dyes used in microscopy (from the Greek chroma, color, and soma, body) (Figure 12.3). Each eukaryotic chromosome consists of one very long, linear DNA molecule associated with many proteins (see Figure 6.9). The DNA molecule carries several hundred to a few thousand genes, the units of information that specify an organism’s inherited traits. The associated proteins maintain the structure of the chromosome and help control the activity of the genes. Together, the entire complex of DNA and proteins that is the building material of chromosomes is referred to as chromatin. As you will soon see, the chromatin of a chromosome varies in its degree of condensation during the process of cell division. Every eukaryotic species has a characteristic number of chromosomes in each cell nucleus. For example, the nuclei of human somatic cells (all body cells except the reproductive cells) each contain 46 chromosomes, made up of two sets of 23, one set inherited from each parent. Reproductive cells, or gametes—sperm and eggs—have half as many chromosomes as somatic cells, or one set of 23 chromosomes in humans. The Figure 12.4 A highly condensed, duplicated human chromosome (SEM). Circle one sister chromatid of the chromosome in this micrograph. DRAW IT Sister chromatids Centromere 0.5μm number of chromosomes in somatic cells varies widely among species: 18 in cabbage plants, 48 in chimpanzees, 56 in elephants, 90 in hedgehogs, and 148 in one species of alga. We’ll now consider how these chromosomes behave during cell division. Distribution of Chromosomes During Eukaryotic Cell Division When a cell is not dividing, and even as it replicates its DNA in preparation for cell division, each chromosome is in the form of a long, thin chromatin fiber. After DNA replication, however, the chromosomes condense as a part of cell division: Each chromatin fiber becomes densely coiled and folded, making the chromosomes much shorter and so thick that we can see them with a light microscope. Each duplicated chromosome has two sister chromatids, which are joined copies of the original chromosome (Figure 12.4). The two chromatids, each containing an identical DNA molecule, are initially attached all along their lengths by protein complexes called cohesins; this attachment is known as sister chromatid cohesion. Each sister chromatid has a centromere, a region containing

The RAG [(Recombination-Activating Gene)] genes [which assist in the facilitation of V(D)J recombination] lack the introns that characterize eukaryotic genes. In this unusual feature they resemble the transposase gene of a transposon, a type of genetic element that can make and move copies of itself to different chromosomal locations. The essential components of a transposon are a transposase—an enzyme that cuts double-stranded DNA—and regions of repetitive DNA, called the terminal repeat sequences, that are recognized by the transposase. These two features allow the transposon to be excised from one location and inserted into another. The similarity of the RAG recombinase to a transposase has led to the hypothesis that the mechanism now used to rearrange immunoglobulin and T-cell receptor gene segments originated in a vertebrate ancestor with the insertion of a transposon into a gene encoding a receptor of innate immunity. The inserted transposase genes evolved to encode RAG proteins, and the terminal repeat sequences evolved to become the recombination signal sequences for the first rearranging gene segments. During this evolution, the transposase gene and the long terminal repeats of the transposon were separated and became components of different genes, both expressed specifically in lymphocytes. Today, the human RAG genes are on chromosome 11[,] and on four other chromosomes are the much-expanded sets of rearranging antigen-receptor genes.

Thus, from the wild speculation of 1967, Margulis’s idea is now accepted as the best possible explanation of the origin of eukaryotes and organelles. Lynn Margulis has even received the National Medal of Science for her groundbreaking and daringly original ideas.

similar to bacteria in size and simplicity of structure but radically different in molecular organization. They are now believed to constitute an ancient intermediate group between the bacteria and eukaryotes.

microorganisms that are similar to bacteria in size and simplicity of structure but radically different in molecular organization. They are now believed to constitute an ancient intermediate group between the bacteria and eukaryotes. Also called ARCHAEA.

organization. They are now believed to constitute an ancient intermediate group between the bacteria and eukaryotes. Also called ARCHAEA.

microorganisms that are similar to bacteria in size and simplicity of structure but radically different in molecular organization. They are now believed to constitute an ancient intermediate group between the bacteria and eukaryotes.

Protozoans were endangered by fast-moving cousins, the carnivores of their world. Some single-celled eukaryotic hunters were equipped with poison launchers (toxicysts)18 on their exterior along with the flagella and cilia needed for brisk movement. These protozoans on the prowl needed to coordinate a host of spirochetic whips and propulsive whiskers (cilia) to produce precision movement. Their potential prey, provided with similar propulsion devices, had to be equally exact in mobilizing their organs for evasion.

One may code for wrinkles, while the other holds the blueprint for smooth. As long as they stay together, only the stronger of each pair rules. Eukaryotes took advantage of this disagreement between twins. Prokaryotes had xeroxed chromosomes in their entirety. But eukaryotes unzipped their chromosomal ribbons lengthwise, ever-so gently separating each genetic pair. This yielded two skinny juliennes,‡ each with slightly different properties.

Eukaryotes thus launched a great leap forward in data mix-and-matching, one which roils and churns within us to this day. We latter-age eukaryotes call the resulting DNA cut-and-shuffle sexuality.

True to Dr. Sauer’s words, 1.4 billion years33 after the new eukaryotic refinements had begun, the first really exotic multicellular beings made their debut beneath the sun.34 One recently discovered fossil clam dates to over 720 million B.C.

According to biologist Lynn Margulis, it was this collaborative approach which allowed life to survive the first toxic pollutant holocaust—the spread in the atmosphere of a gas lethal to earth’s horde of early inhabitants. The killer gas was oxygen. But mitochondria living in the new eukaryotic cells saved the day, gulping oxygen before it could do its harm and turning the murderous vapor into food for their protectress and for the other members of her cellular commune.

Eukaryotes topped that trick with yet another innovation—an elaborately orchestrated breakthrough in cell-division called meiosis.

The dividing eukaryote could not aggressively seek food. Nor could it avoid predatory one-celled creatures whipping through the water in search of someone to eat. The solution: to concentrate spirochetic propellers on the outside of one cell, then to generate an attached cell whose spirochetes could stay inside directing the dance of twining and dividing chromosomes. This, according to Margulis, would start the run-up to another massive leap in the evolution of networks: multicellularity.

Ego-death is the loss of all anchoring to self,” May said, and as she took another hit of the bowl, she looked as though she were coming to some impossible realization. She spoke as if on autopilot while the rest of her seemed to contemplate the fringes of some great madness that had just clicked in her mind. “During ego-death, there is no more separation between the atoms composing the countless eukaryotic and prokaryotic cells of your body or the atoms composing the air exhausted by the eukaryotic bundles we call plants. There is just the field – the system itself. There is no more you. It’s...it’s not really possible to relate through language because it’s beyond language,” she said with a hint of sorrow, and as she turned to Matt, he noted that her eyes looked distant and afraid suddenly. “I’m sorry if this isn’t making sense,” she finished.

The cyanobacteria, a group of photosynthetic bacteria tinted blue-green by chlorophyll and other pigments, harvest sunlight and fix CO2 much like eukaryotic algae and land plants. However, when hydrogen sulfide (H2S, well known for its “rotten egg” smell) is present, many cyanobacteria use this gas rather than water to supply the electrons needed for photosynthesis. Sulfur and sulfate are formed as by-products, but oxygen is not.

The Prokaryote-Eukaryote Transition is Rare

Eukaryotes evolve morphological responses to environmental challenges—in other words, they develop new body shapes and body parts—which leads to a variety and freshness that is absent in the prokaryotes.

The amount of DNA not coding for RNA, sometimes called junk DNA (a dangerous term for something one does not understand), is also much greater in eukaryotes.

The average human comprises forty trillion eukaryotic cells and an accompanying microbiome of a hundred trillion bacteria, mostly in the gut, and one quadrillion viruses. We are, in raw cell numbers, more microbe than mammal.

Bacteria simply divide themselves in two when the time seems right, as can many single-celled eukaryotes. Many plants and animals have the ability to reproduce themselves on their own quite comfortably. Even among the species that do reproduce sexually, many can switch over to cloning. If you walk through a stand of hundreds of quaking aspen trees on a Colorado mountainside, you may be walking through a forest of clones, produced not by seeds but by the roots of a single tree that come back up out of the ground to form new saplings. Hermaphrodites, such as sea slugs and earthworms, are equipped with male and female sex organs and can fertilize themselves or mate with another. Some species of lizards are all mothers: in a process called parthenogenesis, they somehow trigger their unfertilized eggs to start developing. Compared with these other ways to reproduce, sex is slow and costly. A hundred parthenogenetic female lizards can produce far more offspring than fifty males and fifty females. In only fifty generations, a single cloning lizard could swamp the descendants of a million sexual ones.

Endrocrine cells have neither dendrites nor axons, but many are like neurons in other ways. Some are electrically exitable: when pancreatic beta cells see an increase in extracellular glucose concentration they fire in bursts of spikes that are like the phasic bursts of vasopressin neurons; these bursts lead to calcium entry and trigger insulin secretion. In both neurons and endocrine cells, peptides are packages in vesicles just as neurotransmitters are. Typically, peptide secretion is the result of the same process as that by which neurotransmitters are released: exocytosis is triggered in both cases by an increase in intracellular calcium. In neurons, this happens when spikes depolarize the neuron, opening voltage-sensitive calcium channels, and the same occurs in spiking endocrine cells. However, endocrine cells have another trick. Th cell bodies of all eukaryotic cells contain rough endoplasmic reticulum, which sequesters free calcium, and activation of receptors for some neurotransmitters or hormones can release calcium from these stores. In many endocrine cells, this 'calcium mobilization' can trigger exocytosis of vesicles without any involvement of spikes. There is no rough endoplasmic reticulum in axon terminals, so spikes are necessarily involved in the release of synaptic vesicles.

There is no hierarchy in the cells of our body, for instance in a eukaryotic cell the most basic and common type there is no hierarchy. Everything is in a mutually dependent relationship. However, if that cell mutates, the mutation of that cell spreads to further mutate other cells and then a power-over system begins in the body, a hierarchy is created. These mutated cells are called cancerous cells. A power-over system in biology creates a mono-culture of sickness and disease that destroys diversity and leads to death. And a power-over system in society and in our culture, does the same.