Good book to learn about evolution. There are some science terms that you will need to look up if you are at the beginner level when it comes to understanding science, like myself, but overall this book is very readable. No surprise from the title of the book that it is about Bill Nye discussing why evolution is a fact and he doesn't just talk about humans. He talks about the evolution in animals, plants, microbes, and even cancer. He touches a lot from Darwin's work on natural selection also and discusses a lot about DNA.
As I learned more about evolution, I realized that from nature’s point of view, you and I ain’t such a big deal. Humans are just another species on this planet trying to make a go of it, trying to pass our genes into the future, just like chrysanthums, mudkrats, sea jellies, poison ivy... and bumblebees.
Darwin realizes that if humans could turn wolves’ into dogs, then any species could come into existence by the same means naturally. He also saw that populations do not grow and grow indefinitely, because their environment will always have limits on resources available. Darwin connected these ideas by observing that living things produce more offspring than can survive. The individuals compete for resources in their respective ecosystems, and the individuals that are born or sprout with favorable variations have a better shot at survival than their siblings.
Evolution describes all of life on earth. It describes any system in which things compete with each other for resources, whether those things are microbes in your body, trees in a rain forest, or even software programs in a computer. It is also the most reasonable creation story that humans have found.
In common sense, the second law [of thermodynamics] is this: given the chance, balls roll downhill; they never roll uphill on their own. Put another way, energy tends to spread out: heat spreads out, and lakes never spontaneously freeze on a warm summer day.
''The law that entropy always increases - the second law of thermodynamics - holds, I think, the supreme position among laws of nature...." - Arthur Stanley Eddington
There are three main sources of energy for life on earth: the sun, the heat from fissioning atoms deep inside earth, and the primordial spin of earth itself. These sources provide energy throughout the day. The sun provides the most energy. It’s a fusion reactor releasing 10^26 watts every second (10^26 joules). Earth’s core also provides energy in the form of heat. The spinning of our planet keeps shifting the energy inputs and adds acceleration to the wind and the waves.
Evolution is also not random; it’s the opposite of random. One of Darwin’s most important insights is that natural selection is a means by which small changes can add complexity to an organism. With each generation of offspring, the beneficial modifications can be retained. Each mutation that doesn’t work as well in nature either dies off with the organism directly, or gets out-competed by others of its kind in succeeding generations of offspring. It’s by the process of evolution that beneficial changes are added up and up and up.
Today, planes have composite plastic winglets. It’s a form of evolutionary selection pressure. It’s a result of market forces, but it’s still human caused decision making. A company that did not embrace that technology might end up selling fewer planes and going out of business. Winglets are a result of countless hours of research and development. They result from management decisions, engineering analysis, and fabricators skill.
Earth is currently reckoned to be 4.54 billion years old. Based on fossilized mats or layers of bacteria, we figure life got started here at least 3.5 billion years ago.
Atoms are made of protons, neutrons, and electrons. Protons and neutrons are, in turn, made of quarks. Energy can come and go, carried by photons and neutrinos, and so on. By studying certain elements carefully, we have observed that, for example, radioactive rubidium 87, containing 37 protons (and 50 neutrons), can change or decay to strontium, which had 38 protons. These two elements can be thought of as a radiochemical system.
Carbon dating only goes back a few thousand years, because the half-life of this type of carbon is only 5,730 years. Compare that with rubidium-strontium; this radio chemical clock goes back into the past almost a million times further. Carbon dating is important for studying human history, but it’s not well suited to reckoning deep time.
In his writings, Darwin makes it clear that he cannot state whether or not there is a creator in charge. The idea was impossible to prove or disprove then, and it still is today. But what emerged from Darwin’s steady investigations was a new view of the world that can be appreciated and understood on its own terms. Perhaps there is intelligence in charge of the universe but Darwin’s theory shows no sign of it, and has no need of it.
We know now that a giraffe’s neck, like all its physical attributes, is controlled by genes. All organisms - sea anemones, fireflies, giant squid, miniature poodles, and humans have to play the genetic hand there dealt. What Darwin realized, and what Lamarck missed, is that the complexity emerges slowly through a whole population, not quickly within a single person or animal.
When we look at the anatomy of a giraffe, we come across a great many surprising and interesting features. First of all, although a giraffe has what seems to us a pretty long neck, a giraffe has seven vertebrae, just as you and i do. Her and his neck is in a fundamental sense, the same as ours. This is evidence of a common ancestry. Somewhere back in time, there were vertebrate mammals (those with backbones) that give rise to both giraffes and to us.
Along this line, the nerve that extends from your brain to your voice box, your larynx, runs down from your brain and past the larnyx. It goes right by your larnyx lime the pavement of a big city beltway. This same nerve runs around an artery near your heart, and then back up to your neck, where it connects to your larnyx. It really does. The same is true for a fish, where the nerve from the brain to the gills takes a pretty short route. But with generation after generation, certain animal’s necks got longer. Gills changed so that they could take in oxygen from the atmosphere rather than take in oxygen dissolved in water. The same nerve kept running the same route. Down from the brain, around a heart artery, then back up to the larnyx. That’s another consequence of evolution: every generation can only be a direct modification of what came before.
Evolution happens as each generation of living things interacts with its environment and reproduces. Those natural designs that survive to reproduce pass on their genes. Those that don’t successfully reproduce disappear; their genes disappear as well.
Sexual selection is the second fundamental idea in Darwin’s theory of evolution, ranking next behind natural selection. Sexual selection is the process by which organisms of the same species select genes to be passed to subsequent generations. It is what drives so much of what so many of the species in earth do all day and all night.
Natural selection in the general sense is the interplay between organisms and their environment. Nowadays, a century after Darwin, we might describe the process as the interplay between organisms and their ecosystems. Slightly better suited organisms out compete the not quite so well suited organisms. This happens when random processes produce genes that happen to fit in well with the environment and ecosystem extant at the time. It was Darwin’s greatest insight, and still forms the cornerstone for the modern understanding of what drives evolutionary change.
Darwin coined the phrase "artificial selection to describe what human gardeners, farmers, and horse and dog breeders had been doing for centuries: creating better or more useful varieties of animals and plants.
Every organism we can find here on earth has DNA or its chemical partner RNA. The acronym RNA is a contraction for ribonucleic acid. (Ribo derives from an old word for sugar, which was made from a sweet compound called gum arabic. The adjectival form would be aribinose. From there we end up with ribo.)
The areas of earth with the most energy input arr also the areas with the most biodiversity. This gradient from more to less as you go north or south from the equator is yet further evidence of evolution. These ecosystems have been there for a long, long time and the longer an ecosystem is running, the more living things can multiply. As they increase in number, they’ll carry more mutations and more variants. With biodiversity in offspring and lots and lots of time, we end up with a bio diverse ecosystem.
You see the impact of humans on earth’s environment every day. We are trashing the place: there is plastic along our highways, the smell of a landfill, the carbonic acid (formed when carbon dioxide is dissolved in water) bleaching of coral reefs, the desertification of enormous areas of china and Africa (readily seen in satellite images), and a huge patch of plastic garbage in the pacific ocean. All of these are direct evidence of our effect on the world. We are killing off species at the rate of about one per day. it is estimated that humans are driving species to extinction at least a thousand times faster than the otherwise natural rate.
For seven eighths of earth’s history - basically most of it - living things were just revying up. Most of life was single celled organisms or relatively soft bodied animals. The last 500 million years, pretty much every creature you have ever heard of, from trilobites to dinosaurs to Neanderthals, appeared during that time.
I hope we will all soon acknowledge that there really is a sixth mass extinction, one that is happening right now.
There is a great lesson to be learned from our neighboring planet Venus. Venus is very much lime earth in size and composition, but its surface temperature is about 460 degrees Celsius (860 F), hotter than your oven when its set to "broil". The difference between temperatures of earth and Venus is not because Venus is slightly closer to the sun. No, Venus is hot primarily because its atmosphere is full of carbon dioxide, a greenhouse gas that keeps the suns heat trapped in the planet’s atmosphere. Venus is the extreme case of climate change: there is no way, as we know it, that life could survive at those beyond boiling temperatures.
We know that mass extinctions are the result of environmental changes on a global scale. We now have strong evidence that the dinosaurs got walloped with a particular extreme kind of change: a long string of noxious volcanic eruptions topped off with a giant flaming rock falling from the sky.
Dobzhansky incorporated the biochemical details and role of the technical description of a gene: the specific sequence of nucleotides (aka the genetic code) that compromise a portion of a chromosome. Described this way, a gene is a construction plan that ultimately determines the order of amino acids needed to create a specific protein. Simple enough? Actually it is fantastically complex and biologists are still learning the details of how it works. However this molecular point of view is absolutely, completely in every way consistent with the observations and conclusions that Darwin made: DNA directs the construction of strings of chemicals; those chemicals influence the configuration of the whole organism; that configuration influences how likely it is that the organism will reproduce and keep spreading more copies of the code.
Evolution does not influence only physical attributes like height, number of knuckles, eye color, and earlobe shape; it also acts on emotions. What we feel is a result of evolution. This is true, no doubt, of your fear of death. It certainly seems to be true about our drive to reproduce.
Humans have been around in their present form for nearly 100,000 years, yet almost everything we know about evolution has emerged in just the past 150 years.
Think about how evolution works, on all scales of space and time. Viruses mutate from day to day. Fish evolved into land animals and eventually begat dinosaurs and blue whales, over hundreds of millions of years.
It's reasonable that others had noticed that when electricity flows through a wire, a magnetic field is created around the wire, which can easily influence a compass needle. But Faraday realized what apparently no one before him realized: the process also works the other way around. If you have a magnet move near a wire, you get electricity in the wire. Faraday observed and carefully described the key idea. It’s not that there’s a magnet; it’s that there is a moving magnet, a moving magnetic field.
We discovered that cancer evolves. Cancer cells can mutate in the body of a patient, so that malignant cells found new ways to get a supply of blood and become resistant to our anticancer drugs. We can use hormones from other animals - like insulin derived from pigs - to treat people because we came to understand our common ancestry. Medical researchers create new vaccines every summer to anticipate the evolved, mutated flu virus that will make the rounds in the autumn. The connections go on and on.
As any biologist will tell you, living things everywhere on our planet have an astonishing number of things in common. We are made of cells. We have the instructions to build any one of us in almost every one of our cells; we all have DNA. We all produce in the midst of all the worlds other living things. As we do, subtle changes get built into each succeeding generation.
All of these test animals can be used to see what would happen to us if were placed in the same situation for a simple reason: at the cellular level, humans and monkeys and pigs and mice are very much alike in construction and design. We share almost all of our biochemistry. We all have DNA, and its nearly the same. In rhesus monkeys, we are close to 93% the same. In mice it’s closer to 90 percent overall.
In the winter of 1918-1919, the Spanish flu killed about 50 million people - more than all of the combat in World War 1, which had only just ended.
Researchers developed ways to extract genes from one species and insert them into the genetic code of another. The organisms produced in this fashion, which we eat, are called genetically modified organisms.
Dolly the sheep was the first artificially cloned animal. She was produced in 1996 by putting the DNA from a single cell of one sheep into the egg or ovum of another sheep. That artificially fertilized egg was then implanted in the uterus if a ewe who gave birth to dolly. In other words dolly was genetically identical to her mother, or at least she had exactly the same sequence of genes in her DNA as her genetic mother. Her genes were independent and unconnected to the ewe who gave birth to dolly.
There is a way to insert genes into organisms without fertilizing, prodding or poking: genetic engineers turn to viruses to do the work. There are certain viruses known to infect plants, for example. Scientists use viruses like these to introduce genetic traits of their choosing. First they splice a desired gene into a virus. Then they infect the plant with the engineered virus, which inserts the gene into the plants DNA. This technique has been widely applied to corn, soybeans, canola, squash, sugar beets, cotton, and papayas.
A human clone would work the same way that dolly sheep would work. You take a cell from an organism (human) take out the DNA and place it into an egg. After multiple trial and error you can eventually get fertilization. Eventually the human clone would be born and you will have to raise it to adulthood. Would it be exactly like the lerson whom you took the genes from though? No, how are you going to get the baby to go through the same experiences in life as you. We are all shaped not only by our genes, but also by what happens to us.
There are people who object to messing around with human eggs and sperm in any way, based generally on their interpretations of the bible. There is for example the strong belief that life begins at the moment a human egg accepts a human sperm and is thereby fertilized. But that’s not exactly what happens, or more accurately what has to happen. Once the egg has accepted a sperm and its y shaped or x shaped chromosome, it has to attach itself to the wall of the female’s uterus. If it doesn’t do that there will be no baby in the works. After attaching to the uterine wall, the fertilized egg forms a cup shape and three layers. This is gastrulation because if use your imagination, the cup shape reminds you of part of an intestine.
If we did not have a common ancestor, if we did not share DNA sequences, if we had not all descended from ancestral living things, all of life science, all that we see living in nature would be far, far more mysterious and hard to understand.
Humans share 99.9% of the same DNA with other humans and 98.8% with chimpanzees.
In general, the closer people live to the equator, the more ultraviolet exposure they receive and the darker their average skin color. Strong local weather conditions can also attenuate the ultraviolet levels. Take a look at the map of akin color of people native to different regions of earth. Near the equator, people ha e darker skin. Where it’s cloudy a lot, as it is in Britain, people have lighter skin. Where people live closer to outer space, as they do in tibet, they are exposed to more ultraviolet and have darker skin. Skin color is basically a measure of local ultraviolet levels, and it is controlled by relatively minor adaptive changes in the genome.
Where its sunny year round, native people have dark skin. Where it’s only seasonally sunny, natives have much lighter skin. It’s true everywhere.
Since 1995 astronomers have found nearly 2,000 confirmed planets around other stars. Some of these planets are similar to earth in size and mass. About two dozen of them orbit in the habitable zone, the distance where temperatures are potentially suitable to our kind of life. Extrapolating broadly, there may be 50 billion habitable planets in our galaxy.
When I was in school it was generally agreed that in order to live, you had to have sunlight. Everyone still agrees you need a source of energy and sunlight is a great one, but now scientists understand it is not the only possible one. In my lifetime we have discovered hydrothermal vebt ecosystems at the bottom of the sea, were scientists had not considered until they saw it in action. The animals down there rely on certain bacteria that help them metabolize the chemical energy in hydrogen sulfide and water, and the extraordinary amount of heat energy that streams up from the ocean floor. The bacteria in turn produce chemicals for giant tubeworms, bright white crabs, and unusual huge clams as they all make a living.
Amino acids are molecules that hook together to form the proteins that run almost every aspect of biology. They are the building blocks of living things.