How long does it take a species to evolve?

[readinghiker]

Does anyone have a ballpark figure for the amount of time it takes one species to evolve into or diversify into another?

I am working on a shark fauna that comes from the Coniacian, and one of the genera is only known from one species that

was found in the Santonian (Scindocorax novimexicanus).  This site is one to two million years older, and the species is definitely

a part of the Scindocorax genus.  This is only the second occurrence of this anocoracid reported from New Mexico, and although the

teeth compare with that described from the Santonian, I'm wondering if the age difference would indicate a separate species.

The Scindocorax novimexicanus photo is a lingual view of a left anterior tooth, while the Scindocorax sp. photo is a labial view

of a left lateral tooth.

 

Thanks!

[Raggedy Man]

Evolution is a random number generator. 

[Jesuslover340]

To my knowledge, there is no known time for general speciation. 

[Malone]

I have the same sort of question, except in a sense devolve. The liliput effect. I think that atmospheric conditions have an effect. The size difference in creatures has evidently been reduced over time. There are numerous creatures with similar shapes of varying size.

[DPS Ammonite]

The answer to your question is maybe. 1 to 2 million years in enough time to evolve a new species and is short enough that the same species may still be alive.

 

Here's an answer to a related question: how long does an average species last? 

 

The first article suggests that species of mammals last 1 to 10 million years. I could not find an equivalent age for sharks. 1 to 2 million years seems a reasonable ballpark figure for a new species to come from an old one. Realize that all species might not leave evolved decedents. An approximate answer for sharks might be obtained by looking at charts that show the age range of each shark species. (Help find a chart).

 

The last article suggests species last an average of .5 to 10 million years. 

 

http://www.pbs.org/wgbh/evolution/library/03/2/l_032_04.html

 

Background extinction rate from Wikipedia: https://en.m.wikipedia.org/wiki/Background_extinction_rate

 

Another article: https://www.ncbi.nlm.nih.gov/m/pubmed/12348876/

 

.5 to 10 million years: https://books.google.com/books?id=1X8LzKQkr8cC&pg=PA4&lpg=PA4&dq=average+span+of+species+fossil+record&source=bl&ots=YcBPvdCAtP&sig=TX5IGExFV2cVLhaPL-MvV9NGIv0&hl=en&sa=X&ved=2ahUKEwjfrJvJgb7aAhXM-lQKHcGmAnMQ6AEwB3oECAUQAQ#v=onepage&q=average span of species fossil record&f=false

[Miocene_Mason]

Also consider punctuated equilibrium, one species lives for a long time with little change and then BOOM, rapid evolution. Evolution is a symptom, a dependent variable, rather than a root cause. What I mean by that is evolution time is dependent on the environment in which a species is subject to. Isolation and many other factors prompts fast evolution (Ex the radial speciation Of Australopithecus afarensis) , whereas some species may live for extraordinary amounts of time without change (Ex. Triops). In a few thousand years, the aptly named little eagle evolved into Haast’s eagle, a eagle large enough to pick up some people. So there is no set unit for evolution, as others have said.

[Malone]

Wow! That first article is terribly saddening! I would hope that many people would read it! Staggering! ( the first article that DPS Ammonite posted) in regards to the unknown aspect of nature: I have no doubt. I am endlessly amazed at the wonders I observe.

[aplomado]

Sometimes speciation happens very, very quickly.  There was news recently about a new species of finch evolving via hybridization:

https://www.princeton.edu/news/2017/11/27/study-darwins-finches-reveals-new-species-can-develop-little-two-generations

[Cam28]

Was about to say, domestic dogs have pretty much radiated from a common ancestor in the past hundreds or thousands of years right? I'm sure nature is not as picky-choosy but seems it can occur rapidly if need be, assuming they can survive & change generation enough

[ynot]

During normal conditions the process is very slow, but when there is pressure put on an ecosystem it can occur very fast (relatively speaking.)

Ecosystems can also be polluted with gene altering substances, which causes rapid changes within a given group.

This can happen in localized (google "Kesterson reservoir, California"), or global (iridium is common in meteorites) scales.

[FossilDAWG]

The pace of speciation varies considerably depending on population (or effective gene pool) size, amount of additive genetic variance, intensity of selection, etc.  If a small population of a widespread species becomes isolated from the main population, and it has a fair amount of genetic diversity, and it is under strong selection (for example to adapt to a different climate or different food source or different predators) then evolution can be very fast (i.e. several generations instead of thousands).

 

I have to say though that I think you are thinking about your shark teeth the wrong way.  Time really has nothing to do with the question you seem to be asking.  If two species are different you should be able to point to distinct morphological features, not just an age difference.  You would never say two identical teeth are different species.onky because one is a couple of million years older than the other.  Further in the case of sharks tooth position can produce a lot of differences, so really you should have a big enough sample to try to reconstruct tooth sets.  I would say if you only have one specimen you should.not be thinking in terms of describing any new species.

 

Don

[ashcraft]

The last I researched, there is little evidence for the slow evolution of one species into another (gradualism).  Species adapt to their conditions, but that does not appear to lead to speciation in itself.  It requires isolation of  populations, through geographic, feeding strategies, or genetic reasons, etc.  After extinction events, the survivors form small isolated populations that rapidly "evolve" due to various reasons such as genetic drift, bottle neck effects, selection pressure, etc.

 

Keep in mind that different species really aren't different.  Coyotes, wolves, jackals, etc. can interbreed, do interbreed, and produce viable offspring.  Truly different species?  Can chihuahuas and mastiff's interbreed?  Same species?

 

Brent Ashcraft

[readinghiker]

2 hours ago, FossilDAWG said:

The pace of speciation varies considerably depending on population (or effective gene pool) size, amount of additive genetic variance, intensity of selection, etc.  If a small population of a widespread species becomes isolated from the main population, and it has a fair amount of genetic diversity, and it is under strong selection (for example to adapt to a different climate or different food source or different predators) then evolution can be very fast (i.e. several generations instead of thousands).

 

I have to say though that I think you are thinking about your shark teeth the wrong way.  Time really has nothing to do with the question you seem to be asking.  If two species are different you should be able to point to distinct morphological features, not just an age difference.  You would never say two identical teeth are different species.onky because one is a couple of million years older than the other.  Further in the case of sharks tooth position can produce a lot of differences, so really you should have a big enough sample to try to reconstruct tooth sets.  I would say if you only have one specimen you should.not be thinking in terms of describing any new species.

 

Don

Don,  I appreciate the post!  I have a couple of hundred teeth of this shark, and they are all morphologically similar to the only  known species (Scindocorax novimexicanus) of this

shark genus.  Scindicorax novimexicanus was discovered in a Santonian site, and I was tail-end author on the monograph that described the faunal assemblage.  This would be the

second occurrence of this species, and it is from the Coniacian, and was found in an assemblage about 50 miles away from the first site.  Although I am now convinced that it is the

same species, it does extend the bio time line of this animal back around 2 million years, which is important in and of itself!

[doushantuo]

Does anyone know the Yule tree?

[DPS Ammonite]

10 hours ago, doushantuo said:

Does anyone know the Yule tree?

Ben, please enlighten us. Is this sort of like Rosebud in Citizen Kane; where we scratch our heads for a long time until the answer is revealed?

[Malone]

12 hours ago, doushantuo said:

Does anyone know the Yule tree?

I have heard of a Yule log associated with Christmas.

[doushantuo]

I'll not follow up upon my remark,with the following exception:

 

 

 

 

[FossilDAWG]

13 hours ago, readinghiker said:

Don,  I appreciate the post!  I have a couple of hundred teeth of this shark, and they are all morphologically similar to the only  known species (Scindocorax novimexicanus) of this

shark genus.  Scindicorax novimexicanus was discovered in a Santonian site, and I was tail-end author on the monograph that described the faunal assemblage.  This would be the

second occurrence of this species, and it is from the Coniacian, and was found in an assemblage about 50 miles away from the first site.  Although I am now convinced that it is the

same species, it does extend the bio time line of this animal back around 2 million years, which is important in and of itself!

That's a much better situation than the one I mistakenly thought applied.  I agree that time/stratigraphic range extensions constitute interesting information worth reporting.  Is this a whole new fauna you have discovered, of which S. novimexicanus is one member?

 

Don

[Auspex]

13 hours ago, readinghiker said:

it does extend the bio time line of this animal back around 2 million years

For conversational purposes, 2 million years is used bu paleobiologists as the 'average' duration of a species.

[readinghiker]

On April 27, 2018 at 9:43 AM, FossilDAWG said:

That's a much better situation than the one I mistakenly thought applied.  I agree that time/stratigraphic range extensions constitute interesting information worth reporting.  Is this a whole new fauna you have discovered, of which S. novimexicanus is one member?

 

Don

Don,

  Yes, this is a whole new fauna I am working on.  I screened about 200 pounds of anthills, and came up with over 12,000 teeth!  I have tentatively named a new ptychotrygon based on the enamaloid folding on the labial facies of the teeth, and am slowly working through the rest.  There are scapanorhynchids, lamnids, squalicoraxes, hybodonts, and many other sharks and rays.  There are at least two types of pycnodonts, and there was a lone mammal incisor as well (not to mention reworked Pennsylvanian fusulinids).  Sorry about  the delay in responding...

I am getting ready to retire from teaching middle school, and am finding myself swamped!

Randy

[doushantuo]

I think this one is rather apt....(2,8 Mb)

millin_evol_ecl2017.pdf

 

I commented on rapid haplotype evolution of rodents previously

The emphasis is pretty much on morphological evolution in this thread.

A change in the Wmt signalling pathway is "evolution" too...

As is genetically based change in songbird vocalizations..

Or a change in bathymetry,as recently document in bolivinid barcoded forams

[readinghiker]

8 hours ago, readinghiker said:

Don,

  Yes, this is a whole new fauna I am working on.  I screened about 200 pounds of anthills, and came up with over 12,000 teeth!  I have tentatively named a new ptychotrygon based on the enamaloid folding on the labial facies of the teeth, and am slowly working through the rest.  There are scapanorhynchids, lamnids, squalicoraxes, hybodonts, and many other sharks and rays.  There are at least two types of pycnodonts, and there was a lone mammal incisor as well (not to mention reworked Pennsylvanian fusulinids).  Sorry about  the delay in responding...

I am getting ready to retire from teaching middle school, and am finding myself swamped!

Randy

Don,

 

  Delete fusilinids and insert forms.  My mind seems to be going the way of my students!

[readinghiker]

Just now, readinghiker said:

Don,

 

  Delete fusilinids and insert forms.  My mind seems to be going the way of my students!

Forams, not forms.  Spellcheck should be banned from scientific sites!