New answers tagged evolution
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I know this is too late, but since this is something I'm struggling with too I thought I'd post here in case others also find there way here. I don't have an answer but, here are some quotes that might help (I found them at least partially helpful).
Yang (2004): "Marginal reconstruction is more suitable when one wants the sequence at a particular node, as ...
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http://www.talkorigins.org/faqs/woodpecker/woodpecker.html
Hopefully this should answer your doubts, it both debunks the "impossibility" of such evolutionary pattern and explains how it happened.
The unusual appearance of the woodpecker’s "tongue skeleton" has inspired creationists to use it as an example of a structure too bizarre to have evolved ...
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"has human intelligence evolved as a costly male signal which has, over time, been passed to females too, but whom are just not as interested to use it to attract mates?"
(I am ignoring that last part)
So you suggest intelligence (the modern human brain) evolved solely as a sexual dimorohism which then migigated over time?
I find that particular ...
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The evolutionary origin is alleged to be recent: Other animals do not have a preference for dissonance and consonance. (McDermott & Hauser, 2004).
Humans have new auditory regions in the brain for predicting and processing speech, and processing the emotions conveyed in the voice. The human voice mostly has harmonics in the 3rd and 4th note due to the ...
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Yes it is thought to provide safer milk, less vulnerable to every bacteria that respires and multiplies on sucrose, and which lets the baby grow faster due to higher sugar content.
Milk has evolved from pouch mucus, antimicrobal secretions of the immune system, Lysozyme in mucus is a glycoside hydrolase which ruptures bacteria cell walls. So the origins of ...
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I think there is.
We know that each and every organism has sufficient resources provided by Nature for its survival.
Lets do a case study.
Let us say a population of 10 foxes lives in a jungle (whose biodiversity is undisturbed by any Non-Natural factors ).So, this particular jungle is well equipped to ensure the survival of 10 foxes.
Now, if we by any ...
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The simplest way to look at it is there is a near infinite number of ways to be more complex but a very limited number of ways to be simpler. There is even fewer ways of being simple. So even with just pure random variation, over time all things being equal you will end up with more complex organisms.
This becomes even more true when you take competitor ...
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If you read the subsequent paragraph it is clear that he is speaking of the difficulty in drawing borders between species.
It is not possible to draw definitive species boundaries, especially if you follow species over time rather than classifying organisms with a snapshot in time: these issues come up time and time again on this Stack. Some examples:
How ...
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It isn't necessarily true that individuals with different numbers of chromosomes are infertile. Even though common wisdom has it that horse (64 chromosomes)/donkey (62 chromosomes) hybrids are invariably infertile mules, that's not true; a significant number of fertile horse/donkey offspring have been documented. Here is an example where the chromosomes ...
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It seems like one of the rare cases in which the duplication of the specific chromosome is not lethal, but actually advantageous. This means it can happen from time to time to see this extra chromosome by errors in cell-division.
Now although its unlikely, it eventually happened, that two birds with the same duplicated chromosome meet and mate: They ...
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From what I can tell there isn’t any work done on this specific form of infanticide. Here is a review on the subject Here
My assessment would lead me to believe the more r selected a species is the more likely infanticide (if it happens at all) done by the individual would be toward kin. This would probably be due to a need for resources.
One thing to ...
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"Do species mutate their genes so they can reach an optimum state". No, for several reasons.
Species do not mutate their genes. Individuals suffer mutations.
Many species are in an environment that changes as fast as they can evolve, because of geophysical change, or other species including H.Sapiens. In these cases there is no optimal state to reach.
...
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In a comment I ask you for specific passages that give you this impression (since when I read The Red Queen I came away with the opposite impression). You provided the following quote.
in my 2003 copy published by Harper Perennial, at page 31: "[The
coelacanth] has stayed the same - a design that persists without
innovation, like a Volkswagen beetle. ...
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Good question--I think the first point to address is "a means to an end" seems to imply willful action. That is, evolution (according to Ridley) would be a conscious effort by a species to optimize the gene pool for survival of future generations; a rationalization for each species to mutate and diverge.
This is not the case, for a couple of reasons. First, ...
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As long as the enviroment doesn't change the species could reach an "optimum state" , thats why some species like cocodriles or horsehoe crab are considered as "living fossils".
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The argument that blood plasma resembles sea-water, in essence, relies on the notable similarity in concentration of two ions in plasma and sea-water, compared with their intracellular concentration: sodium and potassium.
The concentration of sodium-ion in sea-water is about 450 mM, whereas the concentration of potassium-ion is only about 10 mM (ref)
The ...
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Even shorter answer: This can be easily (well, not that easily since you need to convert mols to milligrams) answered by looking at your last lab result.
Say you had Na: 135 mmol/ml on there which would be a plausible value. That's 135*22.88/1000 mg/ml or 3.1 g/l. Sea water has around 19 g/l, so that's a clear, definite "no".
It wouldn't be quite such a ...
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Short answer
Early sea water had a very different osmolality than blood plasma.
Background
The reference range of serum osmolality is 275–295 mosm/kg (mmol/kg) (MedScape). The osmolarity of sea water is about 1000 mOsm/l (Wikipedia), but it can vary substantially between different seas, namely between 642 and 1,480 mOsm/kg (Ninawe & Banik, 1998). ...
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