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38 votes
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Who are humans' closest relatives, after primates?

Short answer It is a flying lemur (there exist only 2 species). Flying lemurs and primates are together a sister clade to treeshrews. Easy source of information Have a look at the post The best ...
Remi.b's user avatar
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24 votes

Who are humans' closest relatives, after primates?

The most closely related animals to primates are colugos (order Dermoptera). The next most closely related after colugos are tree shrews (order Scandentia). The next most closely related after tree ...
Gwen's user avatar
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22 votes
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Why would a 2019-nCoV protein sequence in the NCBI database match a protein submitted in 2018?

2019-nCoV is a virus that originated from the bat (at least this is the current hypothesis). It shows 96% squence similarity to the BatCoV RaTG13 sequence (see reference 1), showing its origin. It ...
Chris's user avatar
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18 votes
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Darwin's first sketch of a phylogenetic tree

This is from Darwin's Notebook B: Transmutation of species from 1837–1838. From what I understand, the tree is a hypothetical depiction of descent used to discuss differences and relatedness between ...
fileunderwater's user avatar
14 votes

If we sequenced the genome of every species, would all phylogenies agree?

Horizontal gene transfer Don't expect to have a tree! Horizontal gene transfer happens and therefore we would end up with a network, not a tree. Gene trees Different DNA sequences have different ...
Remi.b's user avatar
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11 votes
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The best free and most up to date phylogenetic tree on the internet?

Available ressources I would recommend oneZoom.org is probably the best ressource. oneZoom.org is based on openTreeOfLife.org (for phylogenetic relationships) and eol.org (Encyclopedia Of Life) (...
Remi.b's user avatar
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9 votes

Defining "species" (Are species an emergent property or an ensemble of quantitative differences?)

Can we give a robust definition of species? No. Species constantly evolve, diverge, converge, interbreed, and mix and shuffle and trade and spread genes. To draw a box at any particular point in ...
S Pr's user avatar
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8 votes

Why are turtles classified as reptiles and not amphibians?

In addition to @Gerardo's answer: Reptiles The term Reptiles as used in popular language does not represent a monophyletic group. When using the term Reptiles, one is typically thinking of turtles, ...
Remi.b's user avatar
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8 votes
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Why is traditional rank based taxomomy considered by some as logically inconsistent with phylogenetic knowledge?

You can find discussions of problems with rank-based taxonomy in light of phylogenetics in Ereshefsky 1994, de Queiroz 1996 and Ereshefsky 2002. To summarize, the main problems they identify are: It'...
Gaurav's user avatar
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8 votes
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Branch length in phylogenetic trees

When you estimate a phylogenetic tree, be it by likelihood, parsimony, or distance (like NJ), the lengths will be given in units of substitutions per site, with no time information. For example from ...
Leo Martins's user avatar
8 votes
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What is the best argument for maximum parsimony method in phylogenetic tree construction?

The idea of parsimony is that when constructing phylogenetic trees a simple hypothesis (e.g., four evolutionary changes are necessary to connect two taxa) is more likely to be true than a more complex ...
AliceD's user avatar
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7 votes

Is there a downloadable list of all species along with their traditional classification?

ITIS To expand on the answer from @Rodrigo, the Integrated Taxonomic Information System seems to be a reasonable answer. It gives you a database of every taxonomic node in the Tree of Life™ and each ...
hackerb9's user avatar
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6 votes

Branch length in phylogenetic trees

This answer is mainly inspired by a long discussion in the chat with @LeoMartins. Branch length represents some measurement of lineage divergence Branch length represents some measurement of lineage ...
Remi.b's user avatar
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6 votes
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Has the most recent common ancestor of all living birds lived after dinosaur mass extinction?

I suppose that by the mass extinction, you are referring to the Cretaceous–Paleogene extinction event that happened 66 mya. The Most Recent Common Ancestor (MRCA) ...
Remi.b's user avatar
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6 votes
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Why is the null hypothesis of trait evolution Brownian motion?

I think that the simple answer to this question is that the present comparative methodology was largely established by Felsenstein 1985, American Naturalist. For mathematical convenience, he suggested ...
Maximilian Press's user avatar
5 votes

Why are turtles classified as reptiles and not amphibians?

Turtles are not amphibians because they have (largely) non-permeable skin whereas amphibians can absorb oxygen through their skin. There are also differences in their reproductive cycle: turtles are ...
Jack Aidley's user avatar
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4 votes
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Why do fetuses have membranes between fingers and toes?

Short answer The transient membranes between the fingers and toes in embryos are a myth. Background The presence of transient membranes in developing embryos supposedly points to our fishy ...
AliceD's user avatar
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4 votes

The Perplexing Trilobite: What is the Evidence Supporting The Hypothesis That They are Not Crustaceans?

Trilobites had bodies divided into 3 lobes lengthwise. Hence the name trilobite = 3-lobed critter. The head or cephalon of the trilobite is large, nearly as broad as the body and marked by sutures. ...
Draco Freon's user avatar
4 votes
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Are "constraint trees" in phylogenetic analysis cheating? How can I correctly use them?

I understand where you are coming from when you say that it feels like cheating. However, there are a coupled of things to keep in mind. First let's consider why your tree topology might not reflect ...
Mahakaran's user avatar
4 votes
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What is the difference between phylogenetic tree "construction" and "reconstruction"?

There is no difference! In both cases, they refer to the building of a phylogenetic tree from data. The expression 'phylogenetic tree construction' is less common.
Remi.b's user avatar
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4 votes

Did Carl Linnaeus ever name a species he never saw?

Just to add to Gerardo's great answer, there is a lovely paper that describes a specific instance in which Linnaeus described a bird species, Certhia pinus, on the basis of two illustrations (by ...
Gaurav's user avatar
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4 votes

When did birds and mammals diverge?

The Most Recent Common Ancestor (MRCA) of birds and mammals was the first amniotes. Fossil record The latest known fossil of amniotes are 312 million years old (Bentou and Donoghue, 2007). Genetic ...
Remi.b's user avatar
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4 votes
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When did birds and mammals diverge?

You can check it easily in the timetree website: http://www.timetree.org/ Put a mammalian species as taxon 1 (Homo sapiens) and a bird as taxon2 (Gallus gallus) in the first pair of boxes and hit run....
biojl's user avatar
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4 votes

What is the best argument for maximum parsimony method in phylogenetic tree construction?

Generally speaking, parsimony consists in not making unnecessary ad hoc hypotheses. In the case of phylogeny, parsimony can be used at two stages: when inferring the number of character changes for a ...
bli's user avatar
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4 votes
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How old is the Pogona genus?

Another way to ask this question: How old is the most recent common ancestor of Pogona lizards and their closest relatives? Diporiphora is a sister clade of Pogona, as stated in Hugall et al. 2008.1 ...
acvill's user avatar
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4 votes
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Why is Archosauria a subclass and not a class?

See Bryan Krause's comment, but I'll add that the reason is historical. Linnaeus identified three classes of tetrapods (mammals, birds, and reptiles/amphibians), and reptiles and amphibians were later ...
Eonema's user avatar
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