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Did cats evolve from monkeys? or vice versa?

How similar are the genes of cats and monkeys?
What is the proof that they are related or that they are not related?

Most monkeys climb in trees and there are other similarities but I could not find any evidence on the internet.

Do cats and monkeys have a common ancestor?

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    $\begingroup$ I've +1'd this question because this question seeks a clarification in bold way from a common-people's view on the concepts of evolution, classification and similarities. To my views it is the common problem to many-other students because these concepts are often taught in a very unclear way any many people contains innumerable misconceptions about phylogeny trees and classification trees. $\endgroup$
    – user25568
    Commented Dec 15, 2016 at 8:05

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Cats and monkeys have a common ancestor, both are placental mammals, so at the very least they must have both evolved from the first placental mammal. Cats are members of the Laurasiatheria group and primates are members of Euarchontoglires. These groups of mammals probably split off from each other about 100 millionish years ago. For more information about mammalian phylogeny, look here.

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"Evolving from another species" versus "Most Recent Common Ancestor (MRCA)"

One cannot say about two extant species that one evolved from the other. It just doesn't make any sense. It is not only true for cats and chimpanzees (just to pick one species of monkey) but it is true for any pair of extant species. One extant species has never evolved from another extant species.

However, one can say from any pair of species (Eventual exception with viruses but don't pay attention to them now) that they have a common ancestor. Again, it is not only true for cats and chimpanzees but also for yeasts and ants or for chestnut trees and reticulated pythons. The interesting question is always, "when did the MRCA live?" or if you prefer "when was the time when the lineage that will one day yield to cat and chimpanzee was living?"

Do cats and monkeys have a common ancestor?

Yes! All life on earth shares a common ancestor. The question of interest is when did the Most Recent Common Ancestor lived between cats and monkeys lived?

Please consider having a quick look to this post for an introduction to phylogenetics.

Chimpanzee and cats evolutionary relationships

This question has been answered by @user137. Cats and chimpanzee are both mammals. Their most recent common ancestor was therefore also a mammal and this most recent common ancestor lived about 100 million years ago. This is the kind of information you can get with DNA comparison.

How do we know that?

@user137 already linked to an article that shows when the most common ancestor of cats and chimpanzee has lived. If you want, you can learn more about how such inferences can be made. As you like mathematics (I read from your profile), you might be not too scared (although it will take some time) of statistics and algorithmic to have a look at those Wikipedia articles:

To understand the stats, you may need first to follow a stats course, such as this one from Khan Academy but again it will take some time. Of course, aside from the multitude of tools that one can use to infer time to MRCA from genetic data, one can also make an inference from phenotypic comparison although this method is generally much less accurate.

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    $\begingroup$ 'One extant species has never evolved from another extant species.' Are you sure about that? What about Homo erectus and other hominin species a few tens of thousand of years ago? H. erectus is both basal in the tree to H. sapiens and co-existed. $\endgroup$
    – AlexDeLarge
    Commented May 11, 2017 at 12:34
  • $\begingroup$ @AlexDeLarge Yes, I am sure of that! The examples you are given are those of sister species, not cases where one is the ancestor of another one. This whole concept can be blurred by how inaccurate is the concept of species (see [here](How could humans have interbred with Neanderthals if we're a different species?)) but it is by large very much considered as if a species give rise to more than one species, then we ought to use two different species names for the descendents and therefore an "ancestor species" cannot live in the same time as a "offspring species" $\endgroup$
    – Remi.b
    Commented May 11, 2017 at 14:41
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    $\begingroup$ I'm not convinced. If species A gives rise to two founder populations that, according to whatever species concept, maybe even quickly evolve into species B and C then B and C evolved from A. There is no necessity for A to get extinct or evolve into something like species A* in that reasoning. $\endgroup$
    – AlexDeLarge
    Commented May 11, 2017 at 14:49
  • $\begingroup$ A does not become extinct, it becomes either B or C if you want. The whole issue is an issue of how you decide to group lineages into species but pretty much everyone does the same. When there is a speciation event, the two extant species are both considered different from the ancestor species. This is mainly to avoid confusion and avoid to fail to recognize that all extant species have evolved for the same amount of time. Calling one an ancestor make it feel like some extant species would have less time to evolve. $\endgroup$
    – Remi.b
    Commented May 11, 2017 at 15:01
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    $\begingroup$ It might be confusing, but the way you put it in your answer is not correct. In the example I give, A, B and C are all extant but the ancestors of B and C are members of A and this is by no means impossible. $\endgroup$
    – AlexDeLarge
    Commented May 11, 2017 at 15:10
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Before answering the question; I need to become clear about the concept of common ancestry.

All groups of organisms seem to have only 1 common ancestor (earliest ancestor of all life-forms on Earth), as generally accepted.

While discussing about evolution; when people frequently talk about "common ancestry";

firstly, they talk about latest common ancestry. If we pick any 2 species without any basis (for-say a pea plant and a dog); and try to search back their latest common-ancestor; there should exist some-or-some life-form (usually extinct, commonly hypothetical).

secondly; that latest common ancestry too; would must 'exist' between any 2 randomly chosen life-forms. Latest common ancestry is of not much use if we think it in a present-or-absent way. It only makes sense when we use it in a quantitative way ("how much common or distant") within 1 particular lineage-of-interest.

Example: in the following sample * phylogenetic tree;

Fig-1. sample tree

(* drawn on basis of this, this and this)

People often informally say "Macaca mulatta monkey and human have a latest common ancestor" or "cats and human have a latest common ancestor" but that would not make any useful sense. But it will make a proper sense only if we say "monkeys share more close common ancestry with a human than cats" or "cats share more close common ancestry with a human than plants". or more elaborately; "cats share more closer-distance of common ancestry with human than the distance of common ancestry cats share with plants."

An answer to your main question(s);

  1. We can say neither of "cats evolved from monkeys" or "monkeys evolved from cats" in a true sense. They evolved from a certain group of organisms (their latest common ancestor) that doesn't exist today.

Here is a diagram from http://genomewiki.ucsc.edu/ (slightly modified by marking the cat and monkey)

Fig-2. GenomeWiki phylogeny map mammals

( original file, page)
(Rhesus macaque is common-name of Macaca mulatta monkey)

The website http://evolution.berkeley.edu/ has wonderfully explained, evolution proceeds like a tree, not like a ladder.

Fig-3. Not ladder

Still, we can argue that, at the branching-point, out of 2 evolving groups, only one evolving group could have shown alteration and another group was just unaltered parent group, like this;

Fig-4. variation in one branch only

Still, we could not apply that for cat and monkey; because if we consider one of the 2 branches after red circle at fig. 2 (for argument say it is on cat's side) exact same as parental-species; we could not say "monkeys had arrived from the cat". That ancestor could neither be considered as a cat or cow or horse etc.

  1. Cats and monkeys have enough similarities. Each of both contains 2 eyes, 4 limbs, 1 tongue, skin hairs, ear-pinnae and such and such. Is it too difficult to recognize?

Yes, we have mainly 2 tools to recognize common ancestry...

A. similarity (including macroscopic through biochemical to molecular-genetic);

and

B. Fossil records, which are much difficult to find (mainly structural, also ancient-DNA evidence nowadays doing great help ** )

And yes, establishing common ancestry from similarity, is difficult, because there are lots of exceptions caused by 'convergent evolution'. But still, there is a strong correlation between similarity and closeness of ancestry; and it needs our discretion about which one similarity could be really due to same origin, or which one is due to convergent evolution or due to just a superficial similarity or coincidence.

Reference:

  1. Understanding Evolution website: http://evolution.berkeley.edu/ and their section on understanding evolutionary tree (http://evolution.berkeley.edu/evolibrary/article/evo_05).

  2. ** The Evolution of Plants by K. J. Willis and J. C. Mc.Elwain/ Oxford: that includes an elaborate discussion about ancient DNA in animals too.

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