Evolution Definition and 733 Threads

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. S

    Binnig's fractal evolution applied to multiple universes?

    Gerd Binnig, Nobel laureate in physics in 1986, proposed in his article "The fractal structure of evolution" [1] that everything in the universe, including its laws, had changed and became what we have got today through a process which mixes some concepts from darwinian evolution and fractal...
  2. A

    Math-probability and theroy of evolution

    Why people believe that life become by accident if math say that it is almost imposible ? it is matahmaticly-statistic almost imposible that even simple protein become just by accident! mathematitions calculate that probability to becom simple protein by accident is only 1 : 10 to the 171...
  3. 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...
  4. 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...
  5. Leonardo Machado

    A Boundary conditions in the time evolution of Spectral Method in PDE

    Hi everyone! I am studying spectral methods to solve PDEs having in mind to solve a heat equation in 2D, but now i am struggling with the time evolution with boundary conditions even in 1D. For example, $$ u_t=k u_{xx}, $$ $$ u(t,-1)=\alpha, $$ $$ u(t,1)=\beta, $$ $$ u(0,x)=f(x), $$ $$...
  6. 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...
  7. A

    Quantum physics and the theory of evolution

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  8. G

    Chemistry What causes the release of ammonia in organic compounds?

    I don't really have any idea how to approach this, but the answer says that it is the compounds which are more basic than ammonia liberate it.
  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. Prof Mark R Smith

    Insights The Evolution of the Universe, Cosmic Web and Connections

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  11. D

    How the mass of a planet affects the evolution of life on that planet

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  12. S

    D&D scifi, thoughts on the evolution of tech & animals

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  13. H

    Importance of negentropy in the creation of life

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  14. Buzz Bloom

    How evolution builds genes from scratch

    https://www.nature.com/articles/d41586-019-03061-x?utm_source=pocket-newtab
  15. Garlic

    I How does the expectation value of the spin operator evolve over time?

    Dear PF, As an excercise I am to find out how the expectation value of the spin operator evolves over time. There was a hint, stating that it is enough to show that $$ e^{i \frac{\phi ( \hat{n} \cdot \sigma )}{2}} \sigma_i e^{- i \frac{\phi ( \hat{n} \cdot \sigma )}{2}} = [R_{ \hat{n} }]_{ij}...
  16. J

    A Liouville's theorem and time evolution of ensemble average

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  17. ShayanJ

    Is the 'Randomness' of Evolution Really Random?

    (In order to ask my question, I need to explain a little bit. But I don't have a background in biology, so I may make some mistakes along the way. corrections are welcome.) Recently I've been thinking a lot about evolution. Its really fascinating. The random exploration of the life "phase...
  18. J

    I Time evolution of an expectation value

    Watching Dr. Susskind show how to find the time evolution of the average of an observable K, he writes: I can not for the life of me figure out he derived it, and he also did something which I found terribly annoying throughout which is set hbar to 1, so after steps you lose where the hbar...
  19. A

    I Time evolution of a Jacobian determinant

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  20. A

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

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  21. P

    Is there any evolutionary benefit from magnetoreception?

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  22. R

    Does Evolution Occur in Quantum Jumps? Exploring a New Hypothesis

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  23. LarryS

    I Stationary states vs. the unitary time evolution operator

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  24. Auto-Didact

    A Schrödinger Evolution of Self-Gravitating Disks

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  25. A

    The effect of macroscopic quantum phenomena on human evolution

    In a discussion between Sam Harris and Brian Greene, at this point, Brian stated that even if we return the brain and all the environment to its previous state, we "WON'T MAKE THE SAME NOISES"; I know that for example, indeterminacy in determining the precise time of decay of an atom (and the...
  26. A

    Time evolution of wave function in an infinite square well potential

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  27. A

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  28. M

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  29. KF81

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  30. T

    Does this article support Evolution or Disprove it?

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  31. D

    I How Does the Wavefunction Evolve in Quantum Mechanics?

    Hi . For a system such as an infinite well or a harmonic oscillator if the energy is measured and it returns a value , say E1 corresponding to the ket | 1 > then this evolves according to exp( -iE1t/ħ) | 1 >. So this means that for any time >0 a measurement of the system will always give the...
  32. Cantor080

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

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  33. M

    Evolution of a particle in a well

    Homework Statement I posted a picture of the question https://imgur.com/a/8byywYL Homework Equations P = $$(<\psi_{n}|\psi_{o}>)^2$$ The Attempt at a Solution I am guessing that I compute(denote by ##\psi_{o}## the ground state of the old well and by ##\psi_{n}## the ground state of the new...
  34. AchillesWrathfulLove

    Where do you think humans are going in terms of evolution?

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  35. KF81

    Has a Single Mutation Ever Caused a Big Evolutionary Change?

    Hello all.. This is my first question here, i am looking forward to learning new things ! As far as my understanding goes, evolution happens through small incremental changes to populations over time. Mainly due to genetic mutations.. However, instead of small incremental changes, has...
  36. P

    B Collapse and unitary evolution

    In his book "the black hole war" Susskind writes that in quantum mechanics information cannot be lost because it is unitary. As collapse is not unitary does he say that collapse never occurs?
  37. V

    Why Didn't Dinosaurs Evolve Into Intelligent Beings?

    Hi, I'm not a biologist and I'm not studying biology. But I'm curious so I read and watch some popular papers or videos. I have a question but first of all, I would like to conclude what I think is true: a) The evolution is a process of adapting of living to live in some environment. b) The...
  38. cliffhanley203

    Evolution, the Brittanica.com article: is anyone here...?

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  39. jim mcnamara

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  40. A

    A Exploring the Effects of a Decreasing Higgs Field on Universe Evolution

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  41. Glenn Rowe

    A Evolution operator in QFT - why Schrodinger?

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  42. 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...
  43. binbagsss

    QFT, more a QM Question, Hamiltonian relation time evolution

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  44. Non Euclidean

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

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  45. barcodeIIIII

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  46. G

    Human evolution - From sperm to ape

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  47. M

    QM: Writing time evolution as sum over energy eigenstates

    Suppose I have a 1-D harmonic oscilator with angular velocity ##\omega## and eigenstates ##|j>## and let the state at ##t=0## be given by ##|\Psi(0)>##. We write ##\Psi(t) = \hat{U}(t)\Psi(0)##. Write ##\hat{U}(t)## as sum over energy eigenstates. I've previously shown that ##\hat{H} = \sum_j...
  48. G

    Natural selection, evolution "why are we still sick"

    Now first of all biology is not my strong subject but I am interested in it nevertheless, if my questions come off as arrogant or ignorant then pardon and please explain as I am curious.Last night before going to sleep I suddenly stumbled upon a question, the question goes somewhat like this...
  49. 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...
  50. W

    MATLAB Plotting animations (time-evolution)

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