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If this is a topic that really interests you, I'd suggest searching for papers/reviews/opinions written by Didier Raoult. Raoult is one of the original discoverers of the massive Mimivirus and his work will lead you to some truly fascinating discussions that I couldn't hope to reproduce here.
The main argument for why viruses aren't living is basically ...
45
Firstly, it's not true that you can't tell racial background from DNA. You most certainly can; it's quite possible to give fairly accurate phenotypic reconstruction of the features we choose as racial markers from DNA samples alone and also possible to identify real geographic ancestral populations from suitable markers.
The reason that human races aren't ...
36
but I get lost on the 'border' cases.
Not surprisingly, since there are no borders, and this is probably the greatest misunderstanding: Evolution is gradual. It’s not generally possible to say where a complex feature (or a species) starts and another one ends. We could in theory say, for individual mutations on the genetic level, in which generation they ...
32
Well, that's just it, we don't actually have much phenotypic variation. For example, compare this:
to this:
or this:
Or this:
to this:
This is phenotypic variation:
And of course, you can't beat the birds of paradise when it comes to variation (though, strictly speaking, these are different species):
So, as I hope is clear from the images above, ...
31
In short, we do not think about the uniqueness of the second part of the binomial (the species epithet) but about the uniqueness of the binomial itself (the genus and the species epithet). Thus, the unique binomial of mango is Mangifera indica and the unique binomial of bee is Apis indica. For more detail, see this question.
To complicate matters slightly, ...
30
1. Sheep are fearless
2. English common names are misleading when it comes to the genetic differences between goats and sheep
You posted a picture of Mountain Goats (Oreamnos americanus), which are a different genus than Domestic Goats (Capra aegagrus). Both Capra and Oreamnos are members of the Subfamily Caprinae, as are Domestic Sheep (Ovis aries).
...
23
Actually, your last paragraph is more the case than not.
There are currently three common definitions for delineating discrete species:
1) Phenotypically different from related species (looks or acts differently).
2) Produces viable offspring in the wild.
3) Some % of genetic difference.
There are strengths to all three:
1) Very easy to ascertain and ...
23
I think LuketheDuke's answer is an oversimplification of the biological species concept (possibly resulting from the dictionary having a poor definition). The definition he gives is one of many which are in current use, and is made redundant by many types of organism.
It is important to recognise that because reproduction is not the same process in all ...
21
It is only a question of definition. You can set the boundaries between living things and not living things anywhere.
Some philosophers have argued that using a clear boundary between living and non-living things is not such a good solution. In nature, there would rather be a continuum from a stone to a bacteria.
It is true that in thinking of viruses such ...
20
The answer is that in general, self-naming is severely frowned upon in the scientific community, but the act itself is not disallowed.
There have been at least two instances of self-naming recorded in literature, as stated in John Wright's book The Naming of the Shrew, page 34, where Jules Bourguignat named a species of snail after himself as Ferussacia ...
18
This is mostly a guess and loose suggestion, since the picture is not very clear (would need to see the larvae in more detail). However, Bagworm moths (Psychidae), Case moths (Coleophoridae) and Caddisfly larvae (Trichoptera, almost exclusively aquatic) all build similar cases. They construct their cases out if silk and often include debris, pebbles and ...
17
I agree with the answers already given, these are the reasons that viruses are not considered alive. I want to point out though that this isn't an area you find 100% agreement on; there is a decent subset of biologists who do consider viruses alive. I would say - completely on the basis of personal observation - that virologists themselves are the group most ...
16
Ernst Mayr, distinguished elder statesman of twentieth-century
evolution, has blamed the delusion of discontinuity — under its
philosophical name of Essentialism — as the main reason why
evolutionary understanding came so late in human history. Plato, whose
philosophy can be seen as the inspiration for Essentialism, believed
that actual things are ...
16
3. is right thing to do. You can mention in the introduction that "Campylobacter fetus, which was previously known as Vibrio fetus [Ref] ........."
You should not use the old name anywhere again (also for the sake of consistency), once you have made it clear that the species was renamed, in the Introduction.
I don't think there is any written convention ...
15
There are quite some different definitions of being "alive", but a common one includes the need to have responsiveness, growth, metabolism, energy transformation, and reproduction (found from the Encyclopedia Britannica). Viruses depend on host cells to do all this, so seen alone as a virus outside a host cell, they are not alive.
There's another short, but ...
15
Basically just search "thing you want" and "phylogeny" and you'll find a million results on Google. For you, I might recommend the Botanist in the Kitchen blog, which has a whole page on the subject and has assembled this phylogeny, including many, many others. It's pretty impressive!
14
Interfamilial hybrids have never, to my knowledge, been recorded occurring naturally (without human intervention).
In plants, somatic inter-familial hybrids have been produced for a wide variety of species pairs in the lab (e.g. between carrot and barley; Kisaka et al. 1997).
In animals, there are some historical reports of hybrids between chickens (...
14
That whole thing of being more complex is non-sense, you can't say that for animals and you can't say that for plants either. It all depends on how you look at it. Average number of cells? Size of genome? Size of the proteome? Adaptability to different environments? Mental abilities? You can't place human on the top of any of them (maybe we could argue about ...
14
I decided to summarize a competing hypothesis to make our answers more balanced. I also tried to address the question about the degree of human morphological diversity compared to other animals.
According to Woodley (2010), it is plausible that H. sapiens does not belong to one species and subspecies (i.e. is polytypic). Some of the data he uses to support ...
14
The plant is of Lamiaceae family and its common name is Shell Flower or Bells of Ireland.
Its "scientific" aka latin name is Moluccella laevis.
13
You are correct that the reason is similar to that of convergent evolution of the eye.
Both snakes and legless lizards are lizards (Squamata) that have lost their legs. However they have done so entirely separately much as octopus and human eyes have evolved entirely separately. An easier analogy is between whales and sea cows. Both are legless mammals but ...
13
No. Nobody considers red blood cells to be prokaryotic, perhaps most importantly because they are part of a eukaryotic organism. Red blood cells begin life with the full complement of organelles, including a nucleus and mitochondria, but our RBCs shed their organelles during maturation. In actuality, though, only mammalian RBCs lack nuclei; other animals' ...
13
There is an International Commission on Zoological Nomenclature, to which submissions for new organisms' names is strongly recomended. The discoverer does have some leeway within this system if there is no Latin name that well-describes this species. Your example is one of many.
Chapter 31, for example, clearly states:
31.1.1. A species-group name, if a ...
12
Animals and plants are both classified as Eukaryotes, and as such can form large, complex, multi-cellular organisms. There are several major differences at the cellular level that distinguish the 2 Kingdoms (Animalia and Plantae). Without getting technical, the most crucial difference in relation to your question is that plants contain chlorophyll, and as ...
12
You should also bear in mind that the fact that they are great climbers does not make them fearless. For example, if I were to find myself floating 500 meters above the ground, I would be terrified. The fact that birds do not appear to be scared in the same situation does not make them fearless, it just makes them fliers.
Similarly, I am sure a fish would ...
12
Long story short, use sequence information if you can.
The long story long:
Sequence information and the trees generated from them are strictly more reliable than morphological characters. For instance: sharks are pretty much the same shape they were millions of years ago, but they've been accumulating genetic differences 'invisibly' that allows us to group ...
12
That is the species name it is often the same for unrelated organisms, that is why we use a two name system. Binomial nomenclature (literally, two term naming system) goes Genus species respectively.
The first part of the binomial identifies the genus (which should not be the same unless they are closely related) and the second is the species name which is ...
11
Background
There are basically three highest taxonomic levels: bacteria, archaea and eukaryotes. Many sources distinguish only prokaryotes and eukaryotes, subdividing prokaryotes into bacteria and archaea. Other sources posit archaea as a third domain on the highest level. That's a long debate though and fortunately not the topic here.
By appearance, the ...
11
The pollex was a Roman length measurement, approximately equivalent to an inch. The pollex was also known as the uncia, which is where the word "inch" comes from. There were 12 unciae in a pes ...
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