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10

They're not fast enough A hornet has a top speed of around 40 kph, while a rabbit is only a touch faster, a deer can hit 75 kph (all figures from Wikipedia). In order to act as hunting insects they need to match the speed of these large animals in large enough numbers to surround and overpower them but these animals could easily match their speed or outpace ...


7

They do exist. Many such examples can be found. Such as the most terrifying one, being social groups formed by Spiders, Anelosimus eximius documented here. Colonies of upto 9000 individuals have been documented by the scientists in their report. Also let's not forget Piranhas, another group of social animals, which take down much larger prey due to their ...


5

The evolutionary pressure on the location of the pituitary is likely not the reason why it resides at the basis of the brain. Instead, its (partly) neural origin makes it anatomically (and functionally) part of the brain. Why would it migrate out of the brain when it doesn't have to? What would the evolutionary pressure be on increasing the length of the ...


4

Welcome to Biology.SE Answering your question fully will require to write a whole book. Evolutionary Biology is a big field and I would recommend that your take some time to get an introduction (slightly more advanced than what you received in school). I am suggesting you take advantage of this free online resource. I am briefly making comments and ...


4

The difference in energy requirements of a motile species make photosynthesis an unsuitable form of primary energy generation for them. Since plants are sessile, their energy consumption rates are lower. Plants have approximate respiration:photosynthesis rates of 0.35-0.9, as can be seen in this table (click to enlarge): Once the energy consumption ...


3

To answer your question, we must first ask the question What is defined as intelligence? A googling will tell you that most people believe intelligence to be something related to apes or even more conservatively to humans. But, I find this to be a bit unpragmatic. The closest level of abstraction I find towards defining intelligence is this wiki on Animal ...


3

Unfortunately for you, such animals do exist (O'Donnell et al. 2005). This is a direct field observation of a swarm of army ants attacking and consuming a 60cm long earthworm, as well as consuming a 10cm long snake. From the linked article: We collected workers from two Cheliomyrmex andicola foraging raids. During raid 1 on 26 September 2003 at ...


3

Why so many molluscs exhibit sinistral winding? The estimates of the number of molluscs vary quite greatly between 50,000 and 200,000 species. Of those molluscs species, about 70'000 are Gasteropoda. Gasteropa is most diverse Mollusca phylum. The winding you describe is present in all Gasteropoda and is often called the torsion. So the answer to why there ...


2

To fully comprehend the concept of wobble base-pairing we need to consider the nucleotide sequences of the anti-codons in the tRNAs that have to "read" the genetic code when the mRNA is being translated on the ribosome. The nucleotide in the anti-codon's wobble position is, for example, often inosine. Under the rules for wobble base-pairing an Inosine can ...


2

Reiterating the above comments. Have a look at Tajima's D. It provides an estimate for the number of segregation sites for a population under a neutral mutation model. The general form of the estimation for a diploid population is $E[S]=4N\mu\sum_{i=0}^{n-1} \frac{1}{i}$. Here the mutation rate of is per-genome not per-site, so $\mu=L * 10^{-9}$ where $L$ ...


2

The fraction of polymorphic sites that exist in a population is dependent on the biology of the organism. For instance, you would expect to find different rates of polymorphism in related plants that have different breeding systems, e.g. in Silene [1]. Past bottlenecks are also expected to decrease polymorphisms [2]. So, the answer to your question would ...


2

If you think about it, monarchs must have a pretty strong genetic component to migration since often they only make one round trip at most in a lifetime. But its not as simple as passing a map in the DNA. If a mountain springs up on the route, the 'common sense' of the butterflies are still operational and they will tend to find their way around it. ...


2

Why be mobile? To follow the sun? Plants are mobile. Their seeds are. We have plants living on other plants. Once they have a spot on the sun though moving does not necessarily improve your situation, being stationary and defending your territory though does. (Growing taller, deeper roots, wider crowns)


2

I'll address fish here. It's hard to tell which way is up with many sea-dwelling invertebrates, e.g. sea cucumbers. Sea urchins often are oriented "sideways" if you count their mouths as "down". All animals normally orient themselves in the most advantageous manner dependent on their situation. Probably the most important determiners are field of vision and ...


2

He may be referring to the fact that many nocturnal animals wait for the cover of darkness to be able to get their food safely or in order to cloak themselves to approach their prey better. However, this seems to be a matter of personal opinion. He wants you to think that we are smarter because we have to hide and hunt in broad daylight. I haven't been able ...


2

This answer is towards the question, what forces primarily drive evolution such that we can observe a million species today? which is what the user wanted answered. To answer this question, we can start off at many places. So I wanted to start off at Kimura's neutral theory of evolution which encompasses both Natural selection and genetic drift. I wanted to ...


2

With all due respect to Dr. Wilson, this is just an anthropocentric, post hoc ergo propter hoc logical fallacy. Dr. Wilson looked around the world we live in, saw that most intelligent creatures navigate by sight and/or sound and concluded that those sense are a prerequisite for intelligence. I see absolutely no evidence to support this theory. First of ...


2

A Poisson process follows these postulates: $\lim\limits_{h\to0+}\frac{P(N_h=1)}h=\lambda$ i.e. the probability of occurrence one event in a very small interval of time is equal to the macroscopic rate or intensity ($\lambda\,$). $P(N_h\geqslant2)=o(h)$ i.e. the probability of occurrence of more than one events in an infinitesimal interval is essentially ...


1

Your math is wrong. Assume for simplicity that speciation is binary: that is, a speciation event divides one species into two. 50 million species is between 2^25 and 2^26. So producing that number of species in 3 billion years would require any lineage to speciate on the order of once per 120 million years. Remember, as per comments above, that evolution ...


1

We can only observe correlations Let's just talk about statistics. You can see a correlation between two things only if there is variation for these two things. It therefore, make no sense to look at a single trait that has no variance and ask "is it genetically coded?". The only thing that makes sense is to understand what variables explain the observed ...


1

You are asking explanations about a creationist argument. One could provide explanations about some hypothesis that you may found in a science paper but not explanations for a creationist argument just because, by definition, a creationist argument is not supported by any evidence and logical thoughts. However, you may want to link to a creationist website ...


1

There is at least one species of highly mobile animal that can photosynthesize, depending on your definition of "highly mobile": Sea Sheep? This Adorable Sea Slug Eats So Much Algae It Can Photosynthesize The catch is that this animal does not produce its own chloroplast.


1

@Remi.b I think we can do better than 1962. Let's fast-forward here to 2014, in the post-genomic era. I think this paper provides some data relevant to your query: Possible mechanisms for Chromothripsis .


1

Looking at this 2001 review paper by Rieseberg: http://evolution.powernet.ru/library/Scienc9.pdf (especially Box 2), drift and inbreeding are suggested ways that chromosomal rearrangements can become fixed. These forces are strongest small, isolated populations, such as populations experiencing the founder effect. Another model discussed in that paper is ...


1

You have to be very careful when saying what evolved into what. In fact you can only say that e.g. ancestors of modern amphibians evolved from the ancestors of modern fish. Ad. 1 Have a look at this simplified picture of the evolutionary tree of life Ad. 2 Yes all living organism including plants, bacteria, fungi, and animals can be placed on one ...


1

This is speculation on my part, but it could be a sort of hard-wired biodiversity conservation. And as others have noted, it's not restricted to humans. In fact, this "weakness" to cuteness seems to extend throughout the animal kingdom, especially in mammals. There are numerous examples in nature of one species - even a predator - caring for the young of ...


1

I just found a research about possibility of organism with loop DNA (Mostly bacteria) could use there DNA as antenna to transmit and receive radio wave around 1kHz http://www.wired.com/2011/04/bacterial-radio/ But as other said. Communication mostly evolve from sensory organ. So the radio wave has too much noise and could not give useful information about ...



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