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1

The data used in the graph you posted seems to be from Bambach. 2002. Supporting predators: changes in the global ecosystem inferred from changes in predator diversity (in Kowalewski & Kelley. The Fossil Record of Predation) - see fig 19b - and, if so, is specifically dealing with marine predators. I don't have time to look at that paper closely (it is ...


0

My 2 pennies on this discussion Entropy in general is the total number of states a system can occupy which is also called degrees of freedom (so is with the supply of heat, the molecules vibrate and can occupy more states). Any system tries to avoid confinement and maximize the number of states it can occupy. However if the system is in a stable state and ...


0

I would say A or D are acceptable, but A is probably the better answer: firstly, the entropy of the planet system alone is probably not increasing (indeed, it's probably near to constant) and as noted elsewhere, you need to consider a closed system to apply the Second Law, so you need to think about everything that comes to and leaves the Earth. This is the ...


-2

Evolution increases complexity (entropy) e.g., developing a new citrate path way in E. coli It does this process by of expending energy. i.e., via a lifeforms metabolism So to answer your question: A,B,C are all correct (or part of a correct answer) However D is the most correct answer (It is an all of the above type answer) E is a none of the above ...


1

The Second Law is one of the most misunderstood and misapplied laws of thermodynamics. It has a scope largely confined to physics, nothing more should be read into it. Simply put, it states that "Heat cannot spontaneously flow from a colder location to a hotter location". (Wikipedia) There is nothing about life that violates that, or creates "negative ...


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However, I do not understand. Biological evolution does cause the system (living organisms)'s entropy to decrease. So, by the second law of thermodynamics, the entropy of the universe (in this case Earth), must have overall increased. The universe and the earth are not equatable. Earth is not an isolated system. Life causes entropy of the earth to ...


5

The inner membrane is that of the engulfed bacteria. The bacterium would have been phagocytosed by a larger cell. Hopefully you can see in this image the smaller cell being engulfed in the membrane of the larger cell: [ source ]


1

Eyebrows function to protect the eyes from perspiration and provide shade. Eyelids function to protect the eyes from foreign objects and sunlight. Eyelashes function to protect the eyes from foreign objects, produce sebum (a lubriant that the eyelids) and acts as protection for the eyes from tears [1]. The above seems to be backed up by health ...


1

If I understand your question correctly, you are essentially distinguishing between the timescale on which the variation in the character of interest is generated, and the timescale on which selection prunes the population based upon that variation. The argument is then that "all the evolving happened gradually, long before the selection event" because that ...


1

This is just a guess, but maybe it's cheaper to masturbate than to maintain the additional machinery to quickly re-absorb or otherwise dispose of the unused/old sperm. Assuming that fresher sperm will be more likely to fertilise the egg, selection will favour those with a larger proportion of fresher sperm per ejaculation. So individuals who have recently ...


0

It is my understanding that the dark-adapted eye can perceive single photons. Those have a well-defined range of energies in the visible spectrum. Also, as others have pointed out, light is very directional and localized: if you are not looking at the source, it will not be perceived. Sound comes to the ears from all directions at all times. The waves are so ...


2

From the limited information, I can provide the following but I am not sure if this is what you are looking for. Also, I still don't see the statement where the author concludes we get the Linear regression model $E(q_i) = Aq_i + C$ which is odd notation since it says the expected value is a linear regression. In fact, if it is a linear regression, it should ...


3

This article by Philip Lieberman On the subcortical bases of the evolution of language, page 22, he asserts the neurons associated with language may have developed based on the demands of bipedal posture. While there's no concrete data to support when we see the first languages, here we see evidence of arches (and presumably bipedal posture) in ...


2

You'll see that in many cases, when any sort of cell enters a zone of intolerance or zone of physical stress, the replication machinery gets put on the backburner (and thus replication). Expression of stress-response proteins like heat shock proteins is increased as a result (1). If a cell isn't within acceptable parameter to undergo division at G1 or G2 ...


-2

Death can in fact be advantageous (in the sense of increasing your fitness) in many cases. For example, salmon die after mating and laying fertilised eggs. This is a biological process known as semelparity, where an organism reproduces only once in their lives. Other examples include bamboos, octopodes, mayflies, agave, and so on. This is because the ...


5

The frequency fluctuations will be determined by a standard model of selection as found in any basic population genetics text. In this scenario they take a very basic form: during each long period $i$ the frequency of $A_1$ increases from $f_i$ to $f_i\cdot (1+s_1)^{n_1}$ and during each short period $j$ the frequency of $A_1$ decreases from $f_j$ to ...


3

This just in addition to @anongoodnurse's excellent answer. It was mentioned in the OP that asexual organisms do not undergo recombination; this is not true. Recombination is used for integration of foreign DNA into prokaryotic chromosomes and for repair. Also, don't underestimate the power of mutational change in rapidly reproducing organisms. While ...


3

When you say, why don't we see more sexually reproducing species than asexual, I presume you are referring to bacteria, protists, archaea, some fungi, etc. Most multicellular organisims do reproduce sexually, which makes sense since an organism would need to be multicellular to have cells specialized for gametes. As you stated, the advantage is that sexual ...


1

Great question I think evolution and its derivatives are among the most misconceived and abused terms in Biology. Evolution is often seen as the driving force that pushes life to perfection. For example, what I often encounter are things along the line: "Organism A has trait X, A has been evolving for Y years, thus X is evolved into a useful and optimal ...


3

A couple of comments, but maybe not an answer; I think misuse is the wrong word - alternative meaning is better. 'Evolve' as a word is much older than the theory of evolution, and has its origin in the Latin evolvere: evolve (v.) 1640s, "to unfold, open out, expand," from Latin evolvere "to unroll, roll out, roll forth, unfold," especially of ...


0

I think Dawkins answers this in the book as well. The point was that most strategies are not stable because the "random" introduction/mutation/evolution of some alternate strategies will disrupt a population of the first strategy. The example was a group of doves being invaded by a single hawk (the conspiracy of doves). Because the hawk does relatively ...


2

That's an interesting model, because mosquitoes are vectors for serious illnesses, so are pretty well studied. One team of scientists are working on genetically altering mosquitoes in Africa to make them unable to transmit the parasite that causes malaria. As the mosquitoes breed, it spreads through the population. In an interview, the lead researcher ...


1

I don't enjoy the idea of comparing people to dogs, but this is a bit akin (please note the bit) to asking if people who are genetically short (or "little people", both proportionate and disproportionate dwarfism), pygmies, short people, normal sized people, tall people, very tall people, and people with acromegaly (gigantism) can be called different ...


2

There's some. The basic idea is that entropy, as rigorously defined in statistical physics, can be equated to complexity. This is an idea that has been around since at least the 1957 paper by Jaynes. In a fairly hand-wavey way, one can then say that a system that is being fed a large quantity of free energy (as the earth is by the sun) tends to become more ...


0

There was never a human that was not bipedal - so we never became bipedal we've always been that way because it was our who ancestors became bipedal. And there are many hypotheses for what bipedalism arose in the primate line. The evolution of bipedalism in hominids and reduced group size in chimpanzees: alternative responses to decreasing resource ...


0

The largest area of temperate rain forest in the world is on the west coast of North America, which has a summer dry season. In other words, at precisely what would be the best time for plants to grow (based on temperature), there's a shortage of water. (Summer vacation visitors to the rain forests on the Olympic Peninsula are often wondering "where's the ...


-2

I would wager a guess that time had something to do with it: a non-bipedal ape could evolve to become bipedal faster than it could evolve to be simply larger in all aspects to be taller. Another possible reason would be food consumption: changing ones stance doesn't require an increase in body mass, therefore it doesn't require an increase in food ...


0

The real mutation rate of any organism depends by too many factors both external, like the environment, and internal, like the error rate of the DNA polymerases and DNA-repair enzymes and even from different region in the same genome (the mutation rate of non-coding DNA tend to be higher than the one of actively used DNA). In general however it is possible ...


7

Abiogenesis, the development of living things from non living matter, is not something we know much about, since it happened about 4 billion of years before we were around and haven't reproduced it in the lab. My guess is that it's not easy. However, the Miller-Urey experiment and others have told us something about abiogenic production of organic compounds. ...


-1

Abiogenisis, where imperfect micelles (spheres) of hydrophobic carbon chain formatiions leads to potentials for capturing and mixing elements and molecules forming peptides, polypeptides and protiens that can then catalyze enzymes to patterns to the micelle to a cell of sorts. Was it inside a terrestrial micelle that life formed or Did amazing spiraling ...


2

There are two questions here: Why does life only generate life? Why doesn't life continue to be generated on Earth? The first one is easy. We don't only generate life. If that were true, it might be illegal to flush toilets. Life forms of some kind would occupy all the space in our atmosphere. Babies - or some living things - would rise up from our ...


2

Actually the derivation is pretty straightforward. It's easier to use the fact that $Cov(X,Y) = E(XY) - E(X)E(Y)$ to derive this result. Suppose $x_{j} = \sum_{i} s_{ij}$. \begin{align*} Cov (x_j, q_{j}) &= E (x_{j}q_{j}) - E (x_{j}) E (q_{j}) \\ &= \frac{1}{n}\sum x_{j} q_{j} - \frac{1}{n}\sum x_{j} q \\ ...


0

Regarding the equivalence of MLS and kin selection, here is how I see the equivalence between these two approaches to selection. MLS says that cooperation is favored when the response to between-group selection outweighs within-group selection. Price's equation tells us that this happens when the genetic variance between-groups is higher than the genetic ...


0

A strategy is an ESS against a certain strategy. That is, a strategy is not an ESS in itself. In principle, any pure strategy can be destabilized depending on the other strategies in the game. Retaliators are an ESS against Hawks. The reason is that the payoff of Retaliators against other Retaliators is higher than the payoff of a rare Hawk in a population ...


2

I'd like to add a few books to to the above suggestions. The book by Sean Rice "Evolutionary Theory: Mathematical and Conceptual Foundations" covers a lot of ground, including allele-based models, quantitative genetics, Price's formalism, and MLS. If you're interested in social evolutionary models, I found R. McElreath and R. Boyd "Mathematical Models for ...


1

After considering this question some more, I think a key feature for this hypothesis to work is that the original function must be so integrated and vital for the biology of the organism that it must be mimicked/echoed to some extent. In terms of your RNA-example, it was not enought to evolve the ability to synthesize any complex molecule that could function ...


2

See this more as a comment than an answer, since it became too long for a comment. However, I think some of the examples should be relevant to refine your question. One thing that I find vague in this question is what exactly constitutes a "process"/"function"? To me, this can be almost anything. You seem to be focusing on molecular biology and biological ...


2

Infant mortality was high during the paleolithic, so the fecundity of females had to be quite a bit higher than 2 to sustain viable populations. A recent paper by White (2014) that explores how the ratio of young and old individuals in a population relates to demographic rates compiles data on hunter-gatherer societies from previous studies that you will ...


1

If one looks at the sequence map in detail, at the fusion point we find both telomere and pre-telomere sequences. And what is particularly compelling, is that these main groups occur in the correct order. That is, first you see a pre-telomere sequence, then a telomere sequence. Then we see the telomeres inverted and the inverted pre-telomeres after that. ...


0

This is a great question and one we should all be asking. Given that our closest relatives the great apes are all quadrupedal, our ancestors at one point must have also been quadrupedal. In fact we as humans are mainly quadrupedal between our first nine to fifteen months of postnatal life. As adults we still engage in quadrupedal behaviors from time to time. ...


0

This is a brief expansion on DrAlchemist's response; one that I intended to make myself, but saw that s/he had already covered the basics. To see that black is a better emitter of heat we have to leave biology and go to physics, specifically quantum mechanics, even more specifically black body radiation. Like most things, absorption and radiation are ...


0

I think an important point hasn't been mentioned yet. Why then didn't they evolve a black color The changes introduced by evolution initially are random. Only the persistence of those changes over generations can be thought of in a "smart" way. Technically, evolution can lead to some things getting worse! For example, if mutations improve a ...


1

Why then didn't they evolve a black color to absorb more heat? This assumes that evolution is an active process, working by organisms' will or need. Do not forget that the theory of evolution works from generation to generation, by random (imperfect and chaotic) mutations, most of which are unfavorable. The polar bears did not evolve a black color ...


2

The E. coli long term evolution experiment showed that E. coli had evolved a function (the metabolism of citrate) which was not required in the ancestral environment, but which evolved naturally and was selected for in this new artificial environment. AFAIK, this is the only example of a function that has been observed naturally evolving under controlled ...


4

It was getting long for a comment: A species that was originally parasitic, but then evolved to survive independently of its host by independently evolving the same metabolic functions A predator that originally relied on its prey to synthesise some vital metabolite, but later evolved the ability to produce the missing metabolite for ...


0

Although black is a better absorber of (heat) radiation, it is also a better emitter too. As Polar bears live in a cold environment, having black hair would cause them to radiate their body heat away more quickly. Their colour helps them to retain heat better - dark objects equilibrate to the temperature of their surrounding faster, lighter objects more ...


0

Well, Polar bears do have black skin; But, living in the harsh arctic conditions they've adapted several traits such as thick layer of blubber, wide paws etc. But their most peculiar trait is having a white fur coat; unlike other bears, polar bears have evolved to have white fur with hollow hairs which easily allows their black skin to absorb the radiations ...


1

In addition to camouflage, consider that during the colder parts of the year, when they need the heat the most, the nights are longer than the day. Darker fur would radiate more heat away from the body than the lighter fur. So it's possible that they did evolve the white fur for heat - but in their environment, the coldest part of the year heat retention ...


5

How much energy could an Arctic-dwelling creature be expected to capture from sunlight? I think not very much. How much can it gain from having coloration that allows it to capture prey more easily? Quite a bit. Also, given the size of the polar bear, they will probably be generating more than enough waste heat from metabolic activity. Indeed, if you do ...


3

Something like what you describe does exist, and is called a molecular clock. The rate of change in certain genes and non-coding sequences has been correlated to other evidence (fossil record, etc.) in such a way as to allow you to estimate in absolute terms how long a given set of mutations would take to occur naturally. Keep in mind that only certain ...



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