Evolution Definition and 51 Discussions

Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes that are passed on from parent to offspring during reproduction. Different characteristics tend to exist within any given population as a result of mutation, genetic recombination and other sources of genetic variation. Evolution occurs when evolutionary processes such as natural selection (including sexual selection) and genetic drift act on this variation, resulting in certain characteristics becoming more common or rare within a population. It is this process of evolution that has given rise to biodiversity at every level of biological organisation, including the levels of species, individual organisms and molecules.The scientific theory of evolution by natural selection was conceived independently by Charles Darwin and Alfred Russel Wallace in the mid-19th century and was set out in detail in Darwin's book On the Origin of Species. Evolution by natural selection was first demonstrated by the observation that more offspring are often produced than can possibly survive. This is followed by three observable facts about living organisms: (1) traits vary among individuals with respect to their morphology, physiology and behaviour (phenotypic variation), (2) different traits confer different rates of survival and reproduction (differential fitness) and (3) traits can be passed from generation to generation (heritability of fitness). Thus, in successive generations members of a population are more likely to be replaced by the progenies of parents with favourable characteristics that have enabled them to survive and reproduce in their respective environments. In the early 20th century, other competing ideas of evolution such as mutationism and orthogenesis were refuted as the modern synthesis reconciled Darwinian evolution with classical genetics, which established adaptive evolution as being caused by natural selection acting on Mendelian genetic variation.All life on Earth shares a last universal common ancestor (LUCA) that lived approximately 3.5–3.8 billion years ago. The fossil record includes a progression from early biogenic graphite, to microbial mat fossils, to fossilised multicellular organisms. Existing patterns of biodiversity have been shaped by repeated formations of new species (speciation), changes within species (anagenesis) and loss of species (extinction) throughout the evolutionary history of life on Earth. Morphological and biochemical traits are more similar among species that share a more recent common ancestor, and can be used to reconstruct phylogenetic trees.Evolutionary biologists have continued to study various aspects of evolution by forming and testing hypotheses as well as constructing theories based on evidence from the field or laboratory and on data generated by the methods of mathematical and theoretical biology. Their discoveries have influenced not just the development of biology but numerous other scientific and industrial fields, including agriculture, medicine and computer science.

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  1. DennisN

    Evolution of the Alphabet

    One of my friends sent a link to this illustration which I found very, very fascinating: (Image by Matt Baker, UsefulChart.com, image source: link) If I decipher the chart correctly, e.g. the letter "O" developed from an image of an eye. According to the wiki page about "O" an eye indeed...
  2. A

    Why do we consider Neanderthals a different species than humans?

    According to wiki "Neanderthals are an extinct species or subspecies of archaic humans who lived in Eurasia until about 40,000 years ago." But according to wiki again: "A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating...
  3. Lren Zvsm

    Sapient Life Indigenous to a Planet Orbiting a Red Dwarf

    I am considering writing a story that features aliens indigenous to a planet orbiting a red dwarf star. Even so, because of its proximity to the red dwarf, the planet's surface receives much more radiation than Earth's surface does. What is more, the planet has no moon to stabilize its...
  4. S

    I Evolving laws of physics?

    The Canadian physicist, Lee Smolin proposed in the 90's that laws of nature may evolve and change over time. He begun proposing that only the constants of nature would evolve, while the most fundamental laws would remain the same, but recently he has change a little bit his ideas and has...
  5. Nick tringali

    Any evolutionary biologists here? Question about the antagonism of selective pressures on pelvic morphology

    I want to do a project for my class on the obstetrical conundrum. Which is basically the antagonism of selective pressures on pelvic morphology. I need help to find literature. I want to know if over the course of history, if Human baby's fontanelles increased in size in order to compensate for...
  6. J

    Writing: Input Wanted What are the Consequences of a Longer PETM?

    This is for an alternate Earth that I've been building and rebuilding for years. Sometime between the Paleocene and Eocene epochs, there was a mysterious, sudden, dramatic rise in global temperature. This moment in time was known as the "Paleocene-Eocene Thermal Maximum", shortened into...
  7. Amaterasu21

    How are ancestors classified in a cladistic system?

    Hi all, When I first learned about cladistics, it seemed like an elegant and objective way of classifying life - forget about subjective physical similarities, classify purely based on scientifically testable ancestry, and have all taxa be monophyletic clades, so everything in one taxon is more...
  8. A

    Are these “flaws of evolution”?

    There are several facts one wonders why evolution evolved some traits that look disadvantageous. The typical example that comes to mind is the appendix that has no function in our digestive system, and it can easily become infected. But several other aspects can be cited. Wisdom teeth in humans...
  9. A

    Von Neumann Entropy time derivative(evolution)

    I'm not sure about my proof. So please check my step. I used log as a natural log(ln). Specially, I'm not sure about "d/dt=dρ/dt d/dρ=i/ħ [ρ, H] d/dρ" in the second line. and matrix can differentiate the other matrix? (d/dρ (dρ lnρ))
  10. H

    Importance of negentropy in the creation of life

    Summary: A supply of negentropy into a system is necessary to create states of higher order and complexity. Since the origin and evolution of life involves the creation of ever more complex molecular arrangements of atoms, life could not start without a sufficient supply of negentropy. So when...
  11. A

    Did I find an error in the logic of Evolution with just 2 questions?

    1. If we descended from an unknown common ancestor that was a step up from chimpanzees and bonobo's, then by biological definition, shouldn't chimpanzees and bonobos be much more wise and more intelligent than humans as they are the ones who came first through evolution before our unknown common...
  12. P

    Is there any evolutionary benefit from magnetoreception?

    Some organisms still have magnetoreceptors, what would be the evolutionary benefits of these receptors?
  13. T

    Does this article support Evolution or Disprove it?

    Link: https://www.techtimes.com/articles/228798/20180530/massive-genetic-study-reveals-90-percent-of-earth-s-animals-appeared-at-the-same-time.htm Question: Does this article support Evolution or Disprove it? I've seen Pastors Link: https://www.youtube.com/watch?v=5dkwg4fKElw using this article...
  14. Cantor080

    I Was there any need or utility or aim, for Cantor's theory?

    Was there any need or utility or aim, for which Cantor created his theory? Did Cantor's theory clear any of the problems which existed before? (Though my user name is Cantor, I don't know lot about him or his theory :biggrin:) Reddit...
  15. Ygggdrasil

    What type of bacteria evolved into mitochondria?

    An important step in the evolution of plants, animals, and other complex, multicellular forms of life was eukaryogenesis, the evolution of eukaryotes. Eukaryotes are one of the three major classifications of life (alongside single-celled bacteria and archaea) and are characterized by cellular...
  16. Non Euclidean

    Other Can a physicist study evolutionary biology? How can I do?

    Hello, I’m an undergraduate physics student. Recently, I recognize that I am interested in evolution and I want to study life’s origin. When I preferred physics, because I want to learn how nature works. Now, I am not only interested in how nature works, also I’m passionate for neuroscience and...
  17. V

    Where does the gene for green color come from?

    I was studying evolution and speciation and an example was given in my textbook. It said that there is a species of red beetles and through variation a green beetle is formed and then is naturally selected as red beetles are easily seen by crows and green are not. My question is where does the...
  18. W

    MATLAB Plotting animations (time-evolution)

    Hi all, I have a spatial probability density function that is dependent on ##x##, space and ##t##, time. I am able to make a plot for spatial probability density for each point in time by specifying ##t## values by using the fplot function. However, I want an animation that allows me to see...
  19. N

    Benefits of variation?

    Homework Statement Variation during reproduction is beneficial to the species but not necessarily for the individual? Homework Equations Not any The Attempt at a Solution I only know about variation during reproduction is beneficial to the species but I don't know anything about how it is not...
  20. F

    Life on other planets, are we looking at the wrong planets?

    Scientists are looking for earth like planets/bodies to find life on other planets/bodies, somewhere that is warm enough that liquid water can exist, and somewhere with basic organic molecules. Here's where I have a concern, in the 4 billion years of earths life, to our knowledge life had only...
  21. omnipojack

    Writing: Input Wanted "Natural Born" Androids/Cyborgs

    At the time my story takes place, humans are in an evolutionary transition period. They have been able to modify DNA/genes so that people can have accessories, so to speak (communicator built into your arm, infrared sight, joints that can sustain falls from great heights, etc.), but very few...
  22. A

    B Wave-particle-duality and the evolution of the universe

    If i've understood correct, every particle in the universe exists in a waveform, which i've understood to mean propability where the particle does exist? Then which i've understood is, that the wave transforms into a particle only when observed, is this correct? Then if it is correct, how...
  23. T

    Why arthropod has not evolved to be huge?

    Q: Why arthropods have not evolved to be huge? 1. Homework Statement Arthropods have not been able to achieve great size because (1) the type of organ systems they possess could not support·such a development (2) they would be unable to successfully reproduce (3) chitin is brittle and must...
  24. Cal ben

    How is speciation possible within known confines?

    Please someone help me understand the concept of the actual occurrence of speciation. Cataclysmic Evolution may account for some species but not many, it could only practically apply to asexual species and would undermine genetic diversity. Actually I can save a lot of explanation by clarifying...
  25. Ygggdrasil

    New Findings about the Evolution of Complex Cellular Life

    Humans, other animals, plants, fungi and almost all other forms of complex, multi-cellular life are known as eukaryotes. How eukaryotes evolved from simpler prokaryotic organisms is a major question in evolutionary biology. The current view is that eukaryotes evolved from the fusion between a...
  26. S

    Two or three primary domains?

    I'm wondering if the issue of bacteria and archaea having a single last universal common ancestor (LUCA) with eukarya diverging later, or all three having distinct common ancestors, has been clarified. I've seen a number of texts indicating the eukarya diverged much later, but also some...
  27. L

    Detailed list of all known human ancestors

    Hi everyone, In Carl Sagan's Cosmos there's a short animation video illustrating the shape of all human ancestors, starting from single cell organisms, morphing towards the modern humans. I've searched for a complete list of known human ancestors like that one, but I couldn't find anything like...
  28. Radu Mitroi

    B What percentage of the universe do we know

    Hello. First of all, I must say that I'm new to this forum, so I apologize if I'm posting in the wrong section. I'm a 17 year old with not that much knowledge about physics, so if what I'm talking about makes no sense or is completely stupid, just let me know. A couple of days ago I asked...
  29. S

    Nausea from vertigo: an evolutionary by-product?

    Why do humans (and other mammals) get nauseated from dizziness or vertigo? I can see the evolutionary advantage of nausea from food poisoning, but I can't see the direct "link" between vertigo and vomit. I found something on verywell.com...
  30. H

    I How did egyptian mathematical fractions evolve in antiquity?

    There are certain explanations on how integers might have evolved, like for example "the wings of a bird to symbolize the number two, clover--leaves three, the legs of an animal four, the fingers on his own hand five."1 Seeing all these, and making experience short--abstract, can be said to have...
  31. I

    I Evolution style algorithm to determine EOM

    I had seen a documentary about an algorithm that uses notions of evolution to deduce the equation of motion of a system by sampling a variable connected with the system. For example, they used the double pendulum case where they sampled the position of the free end of the pendulum and arrived...
  32. Aafia

    What is meant by "mode of existence"?

    According Zimmermann in 1953 "evolution is the transformation of the form and mode of existence" so I want want understand what is mode of existence ?
  33. I

    Did tissues arise from other cells or cell differentiation?

    Hi I have a pretty specific question. It is in regards to tissues in multicellular organisms. Is there any information on how different cell grouping arose in multicellular organisms? I have some ideas from what I've so far read and learned: - Would this have happened because two different...
  34. zawy

    Moon reduces Earth's entropy?

    Spontaneous negative entropy reactions can occur when the internal energy decrease is greater than the negative dS*T. dG=dU-dST is spontaneous if dG is negative. The moon is receiving at least 1E8 J/s from the loss of rotational energy from the Earth's water and air. A lot more rotational...
  35. Kitrak

    Why are Darwinian variations considered directional?

    I read that Darwinian mutations are considered as small and directional mutations. Why is that? Regardless of the type of mutation, a mutation (or a variation) is directionless- they are random. From what I understand, the direction is given to these variations through environmental and...
  36. I

    Brain structure terminology consensus?

    I am wondering if there is any consensus on the structure terminology of the brain. 1 - I've heard that the brain has the reptilian, mammalian(limbic) and neocortex parts that overall perform specific functions and evolved in that order. - On that note, would reptiles have had any really...
  37. P

    Human Evolution-Bacteria Conjugation

    So evolution is based on the premise that successive mutations lead to phenotypic changes ultimately resulting in varied species. This despite the fact that many mutations in nature are actually deleterious to that species. The question I have then, is that if mammalian evolution produced...
  38. Ygggdrasil

    A Ring of Life

    Since the time of Darwin, biologists have looked at the history of life as a tree showing how the common ancestor of all life gave rise to all extant species. However, as we have learned more about biology, we've found that organisms do not inherit genetic information from only their direct...
  39. Timelord88

    The first human : male or female

    We humans and chimpanzees had a common ancestor from which we seem to diverge. So that indicates that the common ancestor we had at some point gave birth to an offspring which would have slightly different features or mutations. So at some point in history of the common ancestor of humans and...
  40. A

    Other What's the best highschool biology book?

    What's a good comprehensive book for a highschool student on biology that has never studied the subject before? (Campbell seems to be college/university-level so I can't touch that)
  41. Amine Quentin

    Evolution Is True?

    Hello Guys I'm not an expert in biology and do not know anything about I have some questions about evolution Is evolution fact and scientifically proven? And is there of biologists who say that evolution is wrong? Thank You
  42. AnkurGarg

    Vestigal organs definition clarification please

    Are temporary embryonic structures like gill clefts included under "Vestigeal organs"??
  43. M

    Properties of an evolved universe

    Hello All :) I've heard it proposed that a reason for the fine tuned nature of our universe in a way to allow the existence of complexity and life could be that the universe itself is the product of evolution in a multi-verse. I don't want to debate around the anthropological principle as I am...
  44. AnkurGarg

    Why aren't microspheres and protocells living beings?

    Why aren't microspheres and protocells considered as living beings? What I know is that they do reproduce and exhibit metabolism.. so they fulfill the basic criteria of living systems. I am really confused about it!
  45. Ygggdrasil

    Lokiarchaeota and the Evolution of Complex Cellular Life

    Biologists split life into two broad categories: prokaryotes and eukaryotes. Prokaryotes are relatively simple single-celled organisms and are split into two groups (bacteria and archaea). Eukaryotes, on the other hand, are much more complex cells containing specialized compartments such as...
  46. B

    Making use of Titan

    If a methane-filled planet or moon like Titan was pulled toward a star, as the methane warmed and became gaseous, would it be possible to ignite it, converting the methane oceans to H2O with a CO2 atmosphere, which could in turn cause photosynthesis to naturally occur? If it's possible, it...
  47. Keith Mackie

    Two great fallacies in science

    The first is taught universally (as far as I can make out) at school and university, that Galileo discovered that all bodies (at least in vacuum) fall at the same rate. He didn't. He read it in Lucretius' great work of Roman science "De Rerum Natura" published about 60 BC. Lucretius followed...
  48. Diploria

    Origin/fitness effect of brain coral's grooves?

    Hello, Brain corals, like my avatar's Diploria, get their moniker for visually obvious reasons. I wonder whether there are informed hypotheses how come they look that way. The answer to such a question would probably be partly a morphology/pattern formation story, and partly an adaptive story...
  49. S

    Observational data for evolution of Hubble rate

    Is there any observational data available for evolution of Hubble rate? To give some context, read the dark energy FAQ by Sean Caroll here. He says: "If the universe is decelerating, the Hubble constant is decreasing. If the Hubble constant is increasing, the universe is accelerating. But...
  50. Y

    Why are humans attracted to good looking mates?

    It may not be the general case but this is what it seems from experience. But what's the reason? Do looks indicate health or any other desirable characteristics?