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22

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 ...


22

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). ...


22

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 ...


21

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 ...


20

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 ...


15

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 ...


12

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 ...


12

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 ...


11

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 ...


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 ...


10

The branch of science you are looking for is taxonomy, that is the science of identifying and naming species, and arranging them into a classification. Modern taxonomy was born from the studies of the Swedish zoologist Carl Linnæus (1707-1778), who first introduced, in his books Systema Naturae (Systems of Nature) and Species Plantarum (Plants Species) the ...


10

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 ...


10

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 ...


9

Lactobacillus sanfranciscensis first shows up in pubmed in Gänzle et al. (1998). They reference Trüper and De'Clari (1997) for the name Lactobacillus sanfranciscensis. The latter say: As none of them makes sense in the nominative apposition construction, we hereby correct these names to forms that are in agreement with Rule 12c as follows. ... ...


9

The Tree of Life project has a browse-able tree of all major taxa, but not necessarily all species. You can start at the root of the tree here. Tree of life uses modern phylogenetic nomenclature rather than more traditional Kingdom-Phylum-Class-etc. Part of the problem that you will run into is that common names differ across regions/countries/languages. ...


9

I don't know if these are his earliest descriptions but Darwin did describe several species of Planaria, such as Planaria vaginuloides, P. oceania, plus a new genus, Diplanaria in 1844. Darwin, C. R. 1844. Brief descriptions of several terrestrial planariæ, and of some remarkable marine species, with an account of their habits. Annals and Magazine of ...


8

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 ...


8

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 ...


8

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 ...


8

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!


8

"Caud." refers to the tail (lat: cauda) and, judging from the description, "poll." seems to be another word for inch. So the translation should be something like: Body length: 8 inches, tail length: 9 inches.


7

When it comes to plants and animals, common names clearly differ from region to region. A first effort to univocally classify them was done in the 16th century by Carl Linnæus (see my answer to this question for some historical background). The nomenclature of plants is governed by the International Code of Nomenclature for algae, fungi, and plants (ICN), ...


7

I don't have a definitive answer, but I suspect Hymenoptera is "just a name," albeit a name that has lasted through the phylogenetic nomenclature revolution. Hymenoptera was erected by Linnaeus in the 10th edition of Systema Naturae (1758). The description of Hymenoptera (membrane wing; p. 553 [hope your Latin is better than mine]) follows that of ...


7

The term you are looking for is psychrophile or cryophile. There are examples of microbes adapted to very cold conditions in Bacteria, Archaea, and Eukarya. There are also fairly complex animals capable of surviving very low temperatures - Tardigrades, for example. There are multiple issues that organisms face in withstanding extremely low temperatures - ...


7

The reason that Archaea were determined to be a separate (and only the third) kingdom so late (1977 according to this reference) was because archaea often completely resemble eubacteria. They are unicellular and have no organelles and appropriately they were grouped with other prokaryotes because of their morphology and cellular physiology. But by the ...


7

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 ...


7

I've discovered that searching for Darwin on the Encyclopedia of Life (EOL) appears to prioritise in its search results those species named by Darwin rather than for him. The first page of results includes many barnacle species (as noted by 3cat). The first five species are: Amphibalanus amphitrite (Striped Barnacle) Megabalanus coccopoma (Titan Acorn ...


6

I went to the Yeastbank website at Weihenstephan for some info. The keyword here is "Stamm," which is German for stem, clade, clan, or strain. So, I would take this to mean that the 34/70 is an isolate (#70) of strain 34. Two of 34/70's strengths, according to the link above are it makes clean beer and gives a pleasant taste profile due to its low yeast-like ...


6

Nico provides a nice answer, but implies that the names are more fluid than they actually are. It is possible to get an current standard nomenclature, and to update it each time the ICN releases a new edition. The ICN requires that any changes be made by an international botanical congress, and changes are included when a new addition of the ICN is ...


6

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 ...



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