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96

Short answer The concept of species is poorly defined and is often misleading. The concepts of lineage and clade / monophyletic group are much more helpful. IMO, the only usefulness of this poorly defined concept that is the "species" is to have a common vocabulary for naming lineages. Note that Homo neanderthalis is sometimes (although it is rare) called ...


53

Actually, we not only consider that all human beings belong to the same species (Homo sapiens) but even that we belong to the same subspecies (Homo sapiens sapiens). So, does it really makes sense? Concept of species First, please note that the concept of species is more arbitrary than the most layman would think. I wrote my opinion about the concept of ...


28

Chart of C-values (the mass of DNA in a single haploid cell); there is no logical order to the groups: [source] Base pairs in haploid genome (some examples): Escherichia coli (bacterium): ~4.5 million Caenorhabditis elegans (nematode worm): ~100 million Homo sapiens (we all know what these are): ~3 billion Pinus taeda (coniferous tree): ~22 billion ...


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

Rice and Salt$^1$ bred fruit flies for 35 generations and from one line of flies created two groups that were isolated from each other reproductively. They could not interbreed because they no longer bred in the same environment. Depending on one's definition of 'species' this could be a case of artificial speciation. $^1$Rice WR, Salt GW (1988), Speciation ...


18

The definition of species is open for debate, and this is especially the case when you try to define it from a paleontology perspective. Homo neanderthalensis was first discovered and defined in the 1860's, long before we were able to sequence their genome, which was published in 2010. There genome was different enough that most scientists would still say ...


15

As a couple of counterexamples, species in the classes Symphyla (Pseudocentipedes) and Pauropoda within Myriapoda have 8-11 and 12 leg pairs respectively, so between 16 to 24 legs (sometimes with one or two leg pair stronlgy reduced in size). (species in Symphyla, from wikipedia) Another common and species-rich group with 14 walking legs (7 leg pairs) is ...


14

Food hierarchy and food web Ecological trophic interactions are better represented by food webs rather than simple hierarchical relationships. As a consequence, the concepts of primary/secondary/tertiary/... consumers sometimes poorly apply to reality. Obligate and Optional Many species are able to feed on a various source of nutrients. As a consequence, ...


14

This is technically called Functional extinction. With no viable reproducing population the species will almost certainly become extinct. Note that humans could potentially mess with this through the use of reproductive technologies.


13

In addition to @Remi.b's answer on the species concept, and the perils of using human definitions to try to encompass biological reality, you need to understand what "interbreeding" meant to humans and neanderthals. Fertile crosses between sapiens and neandertalis were very rare, probably less than one successful cross per generation, and there's some ...


13

Uniprot has a list of the controlled vocabulary for common and scientific names of species listed here. An example entry: ACAER E 111511: N=Acanthodactylus erythrurus C=Spanish fringe-toed lizard S=Lacerta erythrura In the example the N is the scientific binomial name (Canthodactylus erythrurus), C is the common name (...


12

Maybe not a direct answer to your question, depending on what you mean with "unencoded data file", but the Global Biodiversity Information Facility (GBIF) has an API where you extract data for species names. Their database includes common names (aka vernacular names) when they have that, and often common names from different languages. Using this API, you ...


11

The whole point of Darwin's theory was that transition from one species to another is extremely slow and gradual. There are plenty of quotes in "Origin of Species" stating this, and also affirming that there is no clear boundary between species and subspecies, or "races". Quotes from Origin of Species > Variation under Nature (Chapter 2) Quote 1 ...


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

Until recently, cats were not extensively selectively bred, but were allowed to roam freely and therefore interbred randomly. Darwin pointed this out, contrasting cats to species that were routinely "enclosed": On the other hand, cats, from their nocturnal rambling habits, can not be easily matched, and, although so much valued by women and children, we ...


10

It looks like an Eastern Hognose Snake, which is characterized by an upturned nose and high likelihood of playing dead. These are described as variable in coloration: "Two color phases are common in Virginia: (1) a patterned phase (79.6%, n = 98), characterized by a series of 19-27 (average = 23.2 ± 2.4, n = 12) black or dark-brown blotches along ...


9

All the different breeds of dogs - from Irish setters to greyhounds - are all part of the same species, canis lupus familiaris. The common, domesticated dog is actually a subspecies of the grey wolf. The different breeds do have different genetic characteristics (just as humans have, say, different eye or hair colors), but they're a all one and the same. The ...


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 ...


9

The hybridization situation you describe could be found in ring species, and is partially related to this concept. For instance, the three species A, B and C could have partially overlapping distributions, such as: In such a situation (assuming that the relative distributions have been stable over evolutionary time), A and C might be able to produce ...


8

Yes, we can say the number of species is limited as you conjecture. However, quick estimation shows that the limitation has no apparent usefulness: A reasonable estimate of the largest known genome is 150 GB (150,000,000,000 or 1.5e11 nucleobases). The limit would be 4 raised to that power. That limit is so high that it is too large for most calculators ...


8

Diane Dodd's experiments on Drosophila pseudoobscura would be another example of lab-based speciation. http://www.jstor.org/stable/2409365?__redirected To summarise - four populations each adapted to feeding on a starch-based diet and a maltose-based diet were evolved in the lab to test effects on mating preferences; compared to what is expected by random,...


8

All breeds of dogs are members of the same (sub) species: Canis lupus familiaris. "Breeds" of dogs are not scientific designations but are collections of traits recognized as unique by different breeding organizations. As such, certain breeds are recognized as unique in some organizations do not exist in others (see here for examples).


8

I know nothing about lizards, but this looks like a Carolina anole (Anolis carolinensis), also known as a green anole. Apparently they can change colour:


8

This most likely is Microlinyphia pusilla. Note that this is a male, females look quite different. A picture that closely resembles yours can be found here https://www.ispotnature.org/node/402405 And in case you want to know, the Dutch name is 'kleine heidehangmatspin'


8

I know that there are animals that are "simpler" than other animals but are there any that are half-evolved? Why aren't there living half ape and half humans? Oh come on. You know if Australopithecines or Homo habilis still existed you would be asking "Why aren't there living half Homo habilis and half humans"? And when the other Great Apes go extinct you'...


7

The reason why cats are superb jumpers has not received much attention, but one article in Nature was entirely devoted to just this (Diamond, 1988). Here follows a partly quoted and partly adapted text from this article: First , because mass increases as the cube, but surface area as the square of linear dimensions, falling large animals are in general more ...


7

TL;DR: Living fossils are the children of long-dead fossilised creatures that were good at being alike, other animals are the children that were good at being different. The boring answer is that living fossils are around because nothing has happened to make them go extinct. The more exciting answer is a tale of intrigue and lies stretching back hundreds ...


7

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 species....


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