I think you should keep attention to differentiate between phylograms and phylogenetic trees.

All cladograms are phylogentic trees,

All phylograms are phylogentic trees.

But phylograms use the length of the branches to indicate the amount of character changes, while cladograms don't.

In a similar fashion a chronogram indicates the robust fossil record of each entity and thus uses branch lenth to indicate the time a taxon existed.

edit: removed a few typos

Hi

I think if a term is more general, it will use more. when we wants to speak about cladogram, we wants just talk about something specific but phylogram contain more type of dendrograms.

Regards

Sorry, this may be a long answer... I'm not certain it is the "popularity" of the term, but rather of the popularity of the techniques used. While Cladograms and Phylograms are indeed related, I think they are different. In my opinion, Cladograms use a variety of data to group organisms. These data can include phenotypes and various observations, and the clades "imply" evolutionary relationship. Conversely, phylograms also use data to group organisms, but the type of data used is such that the groupings "infer" evolutionary relationship.

For example, suppose you have a number of plants, and you decided to "group" them. You could decide that all the flowering plants are in one group, then sub divided those into blue, red and white flowers, then tall, medium and short, and so on. Your grouping could "imply" evolutionary relationships, but you probably never would say that all the blue flowers had a common ancestor, to the exclusion of the red flowers. In this case you would have a "cladogram". Now let's say you did a much more in depth analysis, and included plant size, shapes, seeds, geographical distribution and many more factors, your groupings would now infer evolutionary relationships, and thus they would be "phylograms".

Now to finally answer your original question, for the last 20-25 years, nearly every study trying to "group" organisms has used molecular data. Molecular data ALMOST inherently infers evolutionary relationships, and thus for the last many years, people have been producing only phylograms. So I think the increased use of the word phylogram results directly from the increased use of molecular genetics, not because of popularity of the word.

I see "cladistics" as a subset of "phylogenetics". It refers to the methods introduced by Willi Hennig. My favorite review of this distinction is (even after 32 years):

@Article{Felsenstein:QRB,

author = "Joseph Felsenstein",

year = "1982",

title = "Numerical Methods for Inferring Evolutionary Trees",

journal = "Quarterly Review of Biology",

volume = "57",

pages = "379--404"

}

I think you should keep attention to differentiate between phylograms and phylogenetic trees.

All cladograms are phylogentic trees,

All phylograms are phylogentic trees.

But phylograms use the length of the branches to indicate the amount of character changes, while cladograms don't.

In a similar fashion a chronogram indicates the robust fossil record of each entity and thus uses branch lenth to indicate the time a taxon existed.

edit: removed a few typos

It seems Phylogenetics Vs. Cladistics war is more or less a war between two schools; Hennig's "Phylogenetic Systematicists" Vs. Mayr's "Evolutionary Taxonomists". Term Phylogeny got popular with Haeckel's recapitulation theory way before the term "Cladistics" (in 1965 by Mayr), so "Phylogeny" is more original. Evolutionary taxonomy is more or less extinct now, so as term cladistics. Thanks Kosch, for pointing out another striking difference. Now the question is phylogenetic trees based on phenetics, such as NJ, UPGMA etc. Can you indeed call them phylogenetic trees, as they group taxa based only on overall similarity?

Phylogenetic Trees are based on ancestry, and branch length depicts time.  Additionally, phylogeny is more hypothesis based and can be tested.

Cladograms are linear, branch lengths have no meaning, and the information is based on superficial evolutionary data.

Today, Cladistics is a synonym of "Phylogenetics". Nevertheless, methods that did not took ancestry into account --as phenetics-were deemed "Phylogenetics" at a certain point. NJ, and UPGMA are phenetic, not cladistic (see Farris, 1983*). "Cladistics", in a broader sense, just means that you use clades (a part of graph theory) to infer relationships assuming that the branching pattern reflects ancestry. These clades can be depicted with branch lengths (lines in the sense of graph theory) proportional, or not, to a given parameter--usually number of transformations that optimize at the ancestral node. When brach lengths are depicted proportional to a given parameter, this graph is called phylograms.

Notice, that by the end of the day, MP, ML and Bayes enthusiasts are all cladistics. ;)

Cladograms ARE phylogenetic trees given that they depict ancestry. Usually, researchers using Maximum Parsimony as optimality criterion use cladograms with arbitrary branch lengths to reassure that those lengths do not imply time (although it could...)

*Yes, this is a hard reading but will answer most of your doubts.

Farris, J. S. 1983. The logical basis of phylogenetic analysis. In: Platnick, N. I., Funk, V. A. (Eds.), Advances in Cladistics: Proceedings of the third meeting of the Willi Hennig Society. Columbia University Press, New York, pp. 7-36.

Stepped over this older threat because of an upcoming post on the Genealogical World of Networks, I'm working on.

The answer is pretty simple, you just have to take the words literally.

Cladistics is about clades, defined as subtrees in rooted trees (there's a nice chapter in Felsenstein's 2004 book, Inferring Phylogenies, on this; also pointing out why we actually should clearly distinguish between clades, a portion of a graph, and monophyla, an interpretative concept) and goes back to Farris (1983) and not Hennig (1950). Hennig "just" provided a new (indeed better, because it can be tested) concept for monophyly involving his "Kladistik" (which differs in quite some bits from what later became "Cladistics")

We had last year two posts on this

Let's distinguish between Hennig and Cladistics

http://phylonetworks.blogspot.com/2017/10/lets-distinguish-between-hennig-and.html

Clades, cladograms, cladistics, and why networks are inevitable

http://phylonetworks.blogspot.com/2017/10/clades-cladograms-cladistics-and-why.html

PS Victor's statement that NJ trees are "phenetic" is wrong (a common error): the NJ algorithm produces phylogenetic trees fulfilling either the minimum evolution (ME) or least-squares (LS) optimality criteria (depending how set up). The algorithms for UPGMA and NJ are both cluster-algorithms (so "phenetic", if you want), but for the NJ it has been shown in the original paper that it succeeds in finding a good estimate for the ME or LS tree (which UPGMA does only by accident). NJ is just a shortcut to find a ME or LS-optimised phylogenetic tree from a distance matrix (again, see e.g. Felstenstein, 2004, Inferring Phylogenies, Sinauer). A perfect matrix, where each cladogenesis is represented by at least two subsequent synapomorphies will result in a perfect distance matrix, and the ME or LS tree inferred from this matrix, will be the true tree and also identical to the single MPT inferred from the character matrix (or an ML tree). If convergences outcompete synapomorphies, the MPT will have clades that are not monophyletic, as will (to a lesser degree it seems) the ME or LS tree, whereas compatibility and probabilistic methods can handle this to some degree.

Phylogenetics is about phylogeny, evolutionary pathways, and goes back to Darwin and Wallace's age. The first phylogenetic trees – trees depicting ancestor-descendant relationships, which, funningly, no cladogram, ie a rooted tree without branch lenghts, can do; and phylograms, rooted tree with branch lengths, only indirectly by zero-length terminal branches – were published in the 19th century, one of the earliest at my Alma mater, the University of Tübingen, by Hilgendorf (https://en.wikipedia.org/wiki/Franz_Martin_Hilgendorf; who also published possibly the first phylogenetic network). Haeckel did a lot to advocate phylogenetic trees, and also coined monophyly, if I remember correctly)

Regarding first phylogenetic trees including a definition of what a phylogenetic tree is, see this post: http://phylonetworks.blogspot.com/2013/06/the-first-darwinian-evolutionary-tree.html

I gave it a quick search, and found this nice set of lecture slides giving a quite comprehensive introduction into "evolutionary (phylogenetic) trees" and three of the methods to infer them: "Parsimony; Distance matrix based; Maximum likelihood"

https://www.ncbi.nlm.nih.gov/CBBresearch/Przytycka/download/lectures/PCB_Lect11_Phylogen_Trees.pdf

Cladistics is hence, as pointed out in some answers above, a (quite restricted) subset of phylogenetics (and not even synonymous with Hennig's "Kladistik"). So to be on the safe side, always go for phylogenetics,

And largely irrelevant these days. Most of us are aware (openly or shyly) that clades in rooted trees often correspond to monophyla, ie groups of inclusive common origin, but not necessarily do so. Just take the many cases where different genomes tells different stories: the nuclear, mitochondrial and plastid trees may have different highly supported clades, but there can only be one monophylum. Which we try to infer based eg. on the coalescent tree (which is a special form of coalescent network).

Or think of a misplaced root or ingroup-outgroup long-branch attraction that easily turn a grade into a clade an vice versa. Especially parsimony trees can be severely misleading (see eg. this recent paper by Scotland RW, Steel M. 2015. Circumstances in which parsimony but not compatibility will be provably misleading. Systematic Biology 64:492–504)

Plus, there are many evolutionary/biological processes that inflict reticulation in phylogenies, ie. ancestor-descendant relationships that cannot be modelled by a tree at all. A phylogenetic tree is just a subform of a phylogenetic network, ie. a phylogenetic network without reticulation.

A notably exception is classification. Cladistic classification, ie. putting names to clades in inferred trees (under the implicit assumption that all clades represent monophyla fide Hennig), is still the holy goal, although in reality, we often bend the rules and use (more general) phylogenetic classification concepts. Oaks being an example: the first multigene trees placed them in two separated, well-supported clades, but no-one was bold enough to divide this (most likely monophyletic) genus into two genera fitting the two clades in the trees or include the chestnuts etc in the oaks.

We formalised the two oak clades last year as subgenera, the new infrageneric classification of oaks is hence essentially a cladistic one based on nuclear oligo-gene and phylogenomic trees. But we are confident that it is also a phylogenetic one, ie. our subgenera and sections are not only clades, but also monophyla: Denk T, Grimm GW, Manos PS, Deng M, Hipp AL. 2017. An updated infrageneric classification of the oaks: review of previous taxonomic schemes and synthesis of evolutionary patterns. In: Gil-Pelegrín E, Peguero-Pina JJ, and Sancho-Knapik D, eds. Oaks Physiological Ecology. Heidelberg, New York: Springer, p. 13–38. Free Pre-Print at https://doi.org/10.1101/168146 [major change: Ponticae and Virentes accepted as additional sections in final version]

Cladistic classification is however impractical (to impossible) when being extended to fossils, we summarised the different concepts (those used in reality) up in Fig. 8 of our 2017 Osmundales paper, open access: https://doi.org/10.7717/peerj.3433/fig-8

Why is there so much confusion? Apparently many still hang on to parts of the 80s intellectual cladist package as summarised by Joe Felsenstein (this list can be found in his 2001 piece for Systematic Biology, open access at https://academic.oup.com/sysbio/article/50/4/465/1637137). So you not rarely get odd (and wrong) comments from (anonymous) reviewers (I got them quite often, since often used networks for phylogenetics and frequently had to deal with fundamentally "a-cladistic" data)

Quoted from Felsenstein (Syst. Biol., 2001, p. 466):

"The cladists of that era had accepted a number of points as an intellectual package. At one point in the mid-1980s I tried to summarize the package and came up with these points, in order of importance

• Use Hennig’s terminology—autapomorphy, symplesiomorphy, and so forth—rather than terms like ancestral or derived. [still very common]
• Classify cladistically; use only monophyletic groups. [still the official standard]
• Do biogeography by vicariance (pace Hennig).
• Use only computer programs written by leaders in the Hennig Society, all others are fundamentally flawed. [rarely openly stated, but I experienced this during review still in the zeroes]
• Use only parsimony methods. Compatibility methods are evil.
• Do not weight characters. [has become rare, but some still frawn about it]
• Be hostile to molecular data.
• Consider your methods to be hypothetico-deductive.
• Fossils are to be treated the same as living species. [this is still standard, and beyond cladistics]
• Parasites always have exactly the same phylogenies as their hosts.
• It is important to go around saying that one cannot infer ancestor–descendant relationships. [this is a wide-spread belief, partly out of necessity: tree-inference programmes do not allow placing ancestors on the nodes or internal branches, all OTUs have to be tip taxa]
• It is important to go around saying that species are individuals, not classes. [many still think species are the only "natural" biological unit, fundamentally different from eg. genera]
• Be skeptical of the reality of the species as nonoperational. [see above]
• History: William of Ockham told Popper to tell Hennig to use parsimony." [still a belief, especially in palaeontology]

The attached graphics show (Fig2) one of the earliest phylogenetic trees, and how it would look like as a cladogram.

The other (Fig5C) the problem of how to deal with ancestors in cladistic classification. The graph on the left is a median network, a parsimony-based network comprehensively showing the signal in the data (all possible MPTs, taxa can be tip or internal). The clades in red colour are paraphyletic, the ones in blue font are.

Both figures are from the above mentioned Clades, Cladistics and why networks are inevitable post on the Genealogical World of Phylogenetic Networks.