New answers tagged

-1

Artifical life simulations I have encountered tend to allow for sufficient important aspects of evolution to improve fitness over time, or if you prefer, over iterations. These being reproduction and mutation/variation. Note that search algorythms that test creatures against a survival heuristic (score, fitness function), usually in an intelligent order ...


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Are you thinking of phytoplankton, tiny plant components of plankton? Plankton float at the surface of the sea, which means they don't require roots. In addition, plankton don't tower over each other, like trees. They're further preyed on by a less diverse variety of animals. (There are no truly marine insects, for example.) Yet another thing to consider ...


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The key point is that the first equation is describing frequencies, i.e., $\sum_{i=1}^n x_i = 1$, so there are only $n-1$ degrees of freedom. For instance, if $n=2$ (as in Hawk-Dove), you can totally describe the state of the system with just $x_1$, because $x_2$ is just $x_2=1-x_1$. This constraint is enforced by adjusting $\phi$. To convert the ...


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The straight forward answer is: we don't know. We don't have any direct evidence for what happened at that time nor any completely developed and coherent theories for how it worked. The widely believed hypothesis is the "RNA World" hypothesis. RNA, unlike DNA, is capable of spontaneously folding to form catalytic molecules and thus avoids the needs for ...


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I am not sure exactly what you are after when asking "how did these glands came?". It seems that you wrongly believe that similar glands do not exist in other primates. Here is a short answer that will help you to search for more information about the evolution of these glands. Chimpanzees and Gorilla also have sweat glands. The use of sweat gland in ...


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Tears contain an important hormone that kills bacteria. Closing eyelids during sleep allows a prolonged contact between the cornea and tears killing resistant bacteria in the process. The action of the tears during blinking is not sufficient to completely get rid of the foreign bodies in the eyes. Closing eyelids gives the tears a capacity to accumulate ...


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People who think in creationism or think about species rigidly might have a bit problem with that, so let me describe an example: When are humans "adult"? Legally, at 18 (or your national equivalent). However, everyone understand that people are becoming adult gradually. Sometimes, they "age" very quickly after some harsh experience (16 years old student ...


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Yes, primitive earth was more exposed to radiation as a result of the Earth not having gaseous oxygen during the Hadean eon (which was formed after the oxygen catastrophe as a by-product of cyanobacteria's photosynthesis), which could form ozone and the ozone layer. As a result of the absence of the ozone layer, ultraviolet radiation would not have been ...


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I can think of two factors that would influence this, but there are probably more. 1) How do transposable elements (TE) get into the genome in the first place? The answer is both vertically and horizontally. Vertical transmission needs no explanation. Horizontal transmission of TE has been documented in several cases. In some cases, infectious agents ...


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Actually citric acid is not only available in citrus fruit but also in pretty much any living thing. it is an important intermediate in Krebs cycle, but I guess the main reason that it is available in high concentrations in citrus fruits is because citrate is an inhibitory compound for phosphofructokinase, that means it stops the glycolysis and hence it ...


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As a couple of counterexamples, species in the classes Symphyla (Pseudocentipedes) and Pauropoda within Myriapoda have 8-11 and 12 leg pairs respectively, so between 16 to 24 legs (sometimes with one or two leg pair stronlgy reduced in size). (species in Symphyla, from wikipedia) Another common and species-rich group with 14 walking legs (7 leg pairs) is ...


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There are a few issues your question brings up. First, the idea that species evolve from simple to complex is actually not a prediction or inevitable consequence of evolution by natural selection. The terms "simple" and "complex" themselves are ill-defined. For instance, if you defined "complex" to be size of the genome, the most complex organism found to ...


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You can find a discussion of this topic in the literature: Mitchell, Edward. 1970. Pigmentation pattern evolution in delphinid cetaceans: an essay in adaptive coloration. Canadian journal of Zoology 48(4): 717-740. Perrin, W.F., 1972. Color patterns of spinner porpoises (Stenella cf. S. longirostris) of the eastern Pacific and Hawaii, with comments on ...


2

I could be misreading your question, but it doesn't sound very specific. Rather, it sounds like you're asking "How can I make sense of all the various color schemes employed by venomous species?" So I'll take a stab at it... Animal coloration is a very complex phenomenon, with a number of overlapping physiological traits, evolutionary strategies, etc. ...


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Welcome to Biology.SE Issues with the question It is impossible to correctly answer this question as the phrasing is so fantastically unclear, wrong and misleading (no offense, really). I will give a few points here that may help you but the only thing you can really do to answer your own question is take some time to follow an introductory course to ...


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In my opinion smell could have an impact on why we buried the dead but I also theorize we did this so our family members or friends would not get eaten by a scavanging animal. I would assume being eaten was a constant worry while alive and probably a fear among early man to be eaten after death. That's just my theory though.


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This question is interesting. First of all, I recommend you to look a little bit about the most popular definitions of species and, more importantly, how speciation can occur. I can picture a problem of hybridization when I think of your question. Since speciation takes many (plentiful) generations to happen, and as I can remember, can involve sympatric ...


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Poison dart frogs have aposematic colouration, making them the exact opposite of camoflaged. They are also predators, since they feed on ants, termites and beetles.


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What is a predator? As discussed in the comments by @MarchHo and @AMR, there is discrepancy between the definition of predation in the biology literature and in the every day use. Population definition From the Oxford dictionary predation- The preying of one animal on others; the behaviour of a predator (predator n. 2); (also occas.) an instance of ...


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Here is how I would explain what a genetic signature is: A genetic signature of a certain type of evolutionary history (type of selection or demography) refers to the effect that this specific type evolutionary history has on genomic properties of populations.* We are interested in understanding such signatures because knowing the asociation between a ...


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Although not a biologist, Steven Pinker notes that bilateral symmetry evolved in organisms to allow them to move in a straight line. For a bilaterally symmetrical animal to move, they simply alternate movements between one half of their body and the other. This is true for fish, snakes, insects, mammals, etc. There are exceptions, for instance, flying and ...


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One of the comment to David's answer (which covers the history and reasons for spiderwebs in its two links) mentions a comparison between web patterns and molecular phylogeny. Not precisely that, but I found this article which opens up some interesting possibilities (I can delete this or turn it into a comment if you consider it too unrelated, please let me ...


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There is an interesting theory coming from a slightly different, yet related, field. It was developed by Paul Vasey and Doug VanderLaan of the University of Lethbridge, they are both evolutionary psychologists: An Adaptive Cognitive Dissociation Between Willingness to Help Kin and Nonkin in Samoan Fa’afafine (or direct link) They called their theory the ...


2

It is, of course, not just mammals, but nearly all animal life is symmetric. Even plants are usually symmetric in some degree. There are exceptions here and there. For example, one interesting exception is that of the fiddler crab which has one claw larger than another. In general, when a single appendage is present on an animal it is nearly always on the ...


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There's really two answers to the question. The first is overall symmetry: mammals, like all tetrapods, are bilaterally symmetric. This comes from a distant common origin with other bilaterally symmetric organisms. Organisms which evolved from this common ancestor often have organs in pairs, probably evolving as a re-use of regulatory genes. The other ...


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Why organisms reproduce If they didn't reproduce, they would die out. More concretely, suppose an animal is born with a mutation that removes the desire to reproduce. That animal will not have any offspring, so its genes will not be passed on to the next generation. When that animal dies, that mutation will die with it. Why some organisms reproduce a ...


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Here are a few metrics you can calculate to get you started. You can use R to perform these calculations. Net Diversification Rate (r) Net diversification rate is (rate of speciation - rate of extinction). You can calculate it using the bd.ms or bd.km functions in the geiger package for R. r = 1: r = 2: Tree Imbalance: Colless index (I) Colless's ...


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https://youtu.be/hOfRN0KihOU Sorry, this video is not short, but perfect. From Kurzgesagt chanel youtube


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It is not really a video but it is a real life simulation in the browser about vehicles that evolve to master a race track. I project it onto the screen while I introduce genetic algorithms in my data science classes. I then ask people to identify key features of the evolutionary process and we talk about it while the "cars" are still evolving: ...


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I saw this HHMI video today. It is called The Animated Life of A.R. Wallace, and it discusses the contributions that Alfred R. Wallace made to evolutionary theory. It is a little long for your stated time of 3-minutes. but it talks about how in fits of malaria he came up with his ideas on evolution. HHMI also has a whole series of videos and modules on ...


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In principle open-ended evolution can occur with condition one violated. Because evolution is simply a change from one generation to the next (see answers here, here, and here), the is no requisite for a "non-trivial minimal criterion". Such a minimal criterion (e.g. survival to sexual maturuity) would imply that evolution is occurring by drift or selection, ...


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Species are generally defined in terms of populations (see e.g. the wikipedia page), and it is therefore relatively meaningless to talk about individuals as species. That species is defined in terms of populations is true for many species concepts, e.g. as groups that can produce fertile offspring (biological species concept) or as a evolutionary distinct ...


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I found a paper which gives four conditions that have to be met: Condition 1: A rule should be enforced that individuals must meet some minimal criterion (MC) before they can reproduce, and that criterion must be nontrivial Condition 2: The evolution of new individuals should create novel opportunities for satisfying the MC Condition 3: Decisions about how ...


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"This would be like trying to write a computer program where each line of code must be advantageous to the program. An intelligent design just cannot be done like this." On the contrary, this is precisely how most successful programs are developed nowadays: using incremental test-driven design. You start off with a blank program and a test ...


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Linguistic An Ostrich egg. A chicken egg. A quail egg...whether you call an egg based on who laid it or who is inside of it is not a question of science but a question of linguistic. Non-fertilized chicken eggs do not contain any chicken. We still call these eggs chicken eggs. Following the same logic, I would call an egg based on who laid it. But really ...


4

Wow, interesting theoretical question. If scientists compared the parent's genes to the hatchling's genes and decided they're sufficiently different to merit their designation as distinct species, then I imagine they would give the young its own scientific name. But it's hard to imagine such an event happening. New species generally evolve gradually over ...


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To start I will repost some of an answer I have previously posted, which will explain what evolution is: Evolution is simply a process of change. It is a change in trait values of populations over time. It results from four mechanisms: mutation, migration, drift, and selection. "Evolution means change, change in the form and behaviour of organisms ...



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