Ensatina (Joe DiDonato)

How the Enigmatic Ensatina Sheds Light on “Species”

From Park E-ventures, June 2013

On a misty day during a walk through Muir Woods, I saw a small brown and orange salamander.  It was a brief look, and I am a poor herpetologist, but I suspect it was an Ensatina—or Ensatina eschsholtzii to those with a systematics bent—that occurs in habitats from coniferous forests to chaparral in the Pacific states.

Ensatinas spend their time largely under logs and in moist places, where they mostly eat insects, spiders, earthworms, and other “bugs.” These salamanders are fascinating for a number of reasons, but are famous in biology circles as a textbook example of a ring species.

Before I get into the definition of a ring species, let me back up. Last month, I started to discuss the complexities of the idea of a species. First, the commonly used definition for a species is a group of organisms that can produce viable offspring. A horse and a donkey can produce a mule, but mules are not fertile, therefore horses and donkeys are separate species.

In the wild, however, populations of organisms are continuously diverging when gene flow is low or stops, and moving back together when genes flow between them. If populations separate for long enough with little or no gene flow, they will speciate—one species will become two—as changes accumulate between the populations over time. Knowing where to draw the artificial line to define a new species is challenging—and the charismatic Ensatina highlights this problem beautifully.

A ring species is one whose distribution is generally in the shape of a circle (or ring), often due to physical or geographic constraints; in the case of Ensatina, that ring is the mountains and forests surrounding California’s Central Valley. Ensatina occurs along the Pacific coast as far north as British Columbia all the way south to Baja California. (Click on image at left to see larger map.)

Moving south from Canada, Ensatinas slowly changed their pigmentation. When they hit the Central Valley, Ensatinas split around it, with some populations following the Coastal Range and some staying in the Sierra Nevadas. As they expanded southward along the mountain ranges, each arm changed little by little—but they have changed in very different ways. Our local Ensatina is orange underneath and brownish above. In contrast, south of Lake Tahoe, Ensatina is a mottled brown and orange.

Eventually the two arms of Ensatinas meet in southern California. By the time they rejoin in southern California, however, the Ensatinas from each arm had changed enough from each other that they generally could not, or would not, interbreed. In other words, they were as different as any two species should be.

If you were to sample them along the ring, it is clear there is a continuum of interbreeding individuals—thus they remain one species. However, two neighboring populations in southern California are quite different and if a biologist encountered one of each without knowing the species’ full distribution, she would surely call them different species.

This little salamander very neatly demonstrates how complex evolution can be. It also shows, with surprising clarity, how the idea of a species is merely a human construct borne out of our desire to categorize the world. But nature eschews our black-and-white views of the world in favor of creating beautiful shades of gray. As you begin your summer travels around California, be on the lookout for Ensatinas and notice how much variation you can see.

By Chris Briggs
Banding Program Manager
Golden Gate Raptor Observatory

Ensatina photo by Joe DiDonato, map by Tom Devitt


Return to Park E-ventures archive or read more articles about related:

Topics: Animals

 

 

Comments

* * *
This is also a very good post which I really enjoyed reading. It is not everyday that I have the possibility to see something like this. abc home warranty best home warranty companies first american home warranty reviews 
Submitted by first american home warranty reviews on January 28, 2015 
* * *
Here at Toronto Secure Locks we offer an unbeatable fast Professional Locksmith service, so if you’re locked out, need your locks changing or replacing or even need a safe opening we can help any time of day, we also provide an Access control, CCTV http://www.locksmithtorontoarea.com/ http://0544342878.com http://mysaite.ru 
Submitted by werrwer on January 27, 2015 
* * *
With our ladies you can breathe easy because an escort does not come with dubious claims, stress or any other demands.  
Submitted by London Escorts w2 on January 27, 2015 
* * *
is like small lizard, where i can find that ? Gambar DP BBM Lucu can make you smiling all day 
Submitted by lepi.web.id on January 24, 2015 
* * *
A very awesome blog post. We are really grateful for your blog post. You will find a lot of approaches after visiting your post. I was exactly searching for. Thanks for such post and please keep it up. Great work NJ Party Bus 
Submitted by ali on January 24, 2015 
* * *
very good work thanks for sharing and keep it up GED Online Program 
Submitted by Online GED Courses on January 24, 2015 
* * *
I am a big believer in posting comments on sites to let the blog writers know that they’ve a dded something advantageous to the world wide web. 
Submitted by https://www.rebelmouse.com/neuropathymiraclereviews/ on January 24, 2015 
* * *
Baseball is amongst the most favorite sports on this planet, especially in the states of North america. According to help Encyclopaedia Britannica, baseball would be the national passion of Us residents. www.scorespro.com  
Submitted by www.scorespro.com on January 22, 2015 
* * *
I am continually amazed by the amount of information available on this subject. What you presented was well researched and well worded in order to get your stand on this across to all your readers. Zynga poker Cheats  
Submitted by william on January 21, 2015 
* * *
This is really a nice and informative, containing all information and also has a great impact on the new technology. Thanks for sharing it Brave frontier hack  
Submitted by william on January 21, 2015 
* * *
Keep up the good work , I read few posts on this web site and I conceive that your blog is very interesting and has sets of fantastic information. Dearborn Protocol Adapter 5  
Submitted by Adapter  on January 21, 2015 
* * *
This article is very well written and executed. The author have comprehend it very well and have great knowledge about it. Derm Exclusive Fill And Freeze 
Submitted by Freeze on January 21, 2015 
* * *
I recently came across your blog and have been reading along. I thought I would leave my first comment. I don't know what to say except that I have enjoyed reading. Nice blog. I will keep visiting this blog very often. safe testosterone boosters 
Submitted by boosters on January 21, 2015 
* * *
Great post I would like to thank you for the efforts you have made in writing this interesting and knowledgeable article. wedding limo  
Submitted by wedding  on January 21, 2015 
* * *
How dy would you mind letting me know which web host you’re utilizing? I’ve loaded your blog in 3 completely different web browsers and I must say this blog loads a lot quicker then most. Can you suggest a good internet hosting provider at a reasonable the law of attraction 
Submitted by attraction on January 21, 2015 
* * *
Hi all, here every person is sharing such knowledge, thus it’s pleasant to read this website, and I used to pay a quick visit this webpage daily. Check This Out  
Submitted by Check  on January 21, 2015 
* * *
Thanks for sharing the post.. parents are worlds best person in each lives of individual..they need or must succeed to sustain needs of the family. off page seo  
Submitted by off  on January 21, 2015 
* * *
Thank you so much for sharing this great blog.Very inspiring and helpful too.Hope you continue to share more of your ideas.I will definitely love to read. new years eve new york 2015  
Submitted by 2015 on January 21, 2015 
* * *
Thank you so much for sharing this great blog.Very inspiring and helpful too.Hope you continue to share more of your ideas.I will definitely love to read. official site  
Submitted by ficial  on January 21, 2015 
* * *
Thank you so much for sharing this great blog.Very inspiring and helpful too.Hope you continue to share more of your ideas.I will definitely love to read. Exam Results Online  
Submitted by Results  on January 20, 2015 
* * *
Nice post, thanks for the useful information on car rental services in thailand. Satılık hoparlör  
Submitted by hoparlör on January 20, 2015 
* * *
Im no expert, but I believe you just made an excellent point. You certainly fully understand what youre speaking about, and I can truly get behind that. 8 Ball pool hack  
Submitted by william on January 20, 2015 
* * *
bgfryui http://yozdyn.com/ zpizxkcd [url=http://enbtrf.com/]zpizxkcd[/url] 
Submitted by hello on January 19, 2015 
* * *
Great post, you have pointed out some excellent points, I as well believe this is a very superb website. Angry birds star wars 2 hack  
Submitted by william on January 19, 2015 
* * *
This is a very good tips especially to those new to blogosphere, brief and accurate information… Thanks for sharing this one. A must read article. girlsdoporn  
Submitted by calvinbrock735 on January 19, 2015 
* * *
I was amazedI know that you explain it very well. And I hope that other readers will also experience how I feel after. http://grand77.asia/asiapoker77/  
Submitted by http://grand77.asia/asiapoker77/ on January 18, 2015 
* * *
You have a good point here!I totally agree with what you have said!!Thanks for sharing your views...hope more people will read this article!!! alternativ investering 2015  
Submitted by adil on January 17, 2015 
* * *
I admire what you have done here. I like the part where you say you are doing this to give back but I would assume by all the comments that this is working for you as well. Arcane legends cheat  
Submitted by william on January 17, 2015 
* * *
Awesome and interesting article. Great things you've always shared with us. Thanks. Just continue composing this kind of post. udemy coupons 2015 
Submitted by hello on January 15, 2015 
* * *
That appears to be excellent however i am still not too sure that I like it. At any rate will look far more into it and decide personally! Dog Fence Wire 
Submitted by shahid on January 15, 2015 
* * *
Someone Sometimes with visits your blog regularly and recommended it in my experience to read as well. The way of writing is excellent and also the content is top-notch. Thanks for that insight you provide the readers! schlüsseldienst mannheim 
Submitted by shafqat on January 15, 2015 
* * *
I think this is one of the most significant information for me. And i’m glad reading your article. But should remark on some general things, The web site style is perfect, the articles is really great : D. Good job, cheers Perfection or Motivation 
Submitted by maryam on January 15, 2015 
* * *
Keep up the good work , I read few posts on this web site and I conceive that your blog is very interesting and has sets of fantastic information. Bellingham marijuana 
Submitted by jasmin on January 15, 2015 
* * *
An fascinating discussion is value comment. I think that it is best to write extra on this matter, it won’t be a taboo topic however generally people are not enough to talk on such topics. To the next. Cheers best engagement rings 
Submitted by jasmin on January 15, 2015 
* * *
Great articles and great layout. Your blog post deserves all of the positive feedback it’s been getting. Coral Flowers 
Submitted by jhonalex on January 15, 2015 
* * *
Nice post mate, keep up the great work, just shared this with my friendz free xbox live 1 month 
Submitted by jhonalex on January 15, 2015 
* * *
Hello There. I found your blog using msn. This is an extremely well written article. I will be sure to bookmark it and return to read more of your useful information. Thanks for the post. I’ll certainly comeback.Dubai Web Hosting 
Submitted by jasmin on January 15, 2015 
* * *
Your article has piqued a lot of positive interest. I can see why since you have done such a good job of making it interesting. knee doctor 
Submitted by jasmin on January 15, 2015 
* * *
Your content is nothing short of brilliant in many ways. I think this is engaging and eye-opening material. Thank you so much for caring about your content and your readers. portable carbon monoxide detector 
Submitted by asdd on January 15, 2015 
* * *
Thank you very much for writing such an interesting article on this topic. This has really made me think and I hope to read more. Pennsauken commercial and industrial electrician 
Submitted by jhonalex on January 15, 2015 
* * *
Thank you for some other informative blog. Where else could I get that type of information written in such an ideal means? I have a mission that I’m just now working on, and I have been at the look out for such information. All about coffee 
Submitted by jasmin on January 15, 2015 
* * *
Really great post, Thank you for sharing This knowledge.Excellently written article, if only all bloggers offered the same level of content as you, the internet would be a much better place. Please keep it up!القسط الهندي 
Submitted by asadalikhatri on January 15, 2015 
* * *
This is my first time visit here. From the tons of comments on your articles,I guess I am not only one having all the enjoyment right here! torrent 
Submitted by jhonalex on January 14, 2015 
* * *
The easy to implement concepts and techniques taught in the Capture His Heart system are designed to help you get inside a man's mind, body, and soul so you can make him fall in love with you, commit to you, and connect with you on a deep, emotional, and primal level.http://www.rebelmouse.com/mikefiorecapturehisheartreview  
Submitted by asadalikhatri on January 14, 2015 
* * *
This type of message always inspiring and I prefer to read quality content, so happy to find good place to many here in the post, the writing is just great, thanks for the post. Social Media marketing Nairobi 
Submitted by adil on January 14, 2015 
* * *
Great Information sharing .. I am very happy to read this article .. thanks for giving us go through info.Fantastic nice. I appreciate this post. ipcamerareview 
Submitted by adil on January 14, 2015 
* * *
Superbly written article, if only all bloggers offered the same content as you, the internet would be a far better place.. carlsbad new mexico 
Submitted by jasmin on January 14, 2015 
* * *
Thanks for posting this info. I just want to let you know that I just check out your site and I find it very interesting and informative. I can't wait to read lots of your posts. apps gone free 
Submitted by jhonalex on January 14, 2015 
* * *
I can see that you are an expert at your field! I am launching a website soon, and your information will be very useful for me.. Thanks for all your help and wishing you all the success in your business. Good weight loss method  
Submitted by jasmin on January 14, 2015 
* * *
I recently came across your blog and have been reading along. I thought I would leave my first comment. I don't know what to say except that I have enjoyed reading. Nice blog. I will keep visiting this blog very often. Pet Care Guide 
Submitted by adil on January 14, 2015 
* * *
Thank you for taking the time to publish this information very useful! wedding photography crawley  
Submitted by Anonymous on January 14, 2015 
* * *
Great post! I am actually getting ready to across this information, is very helpful my friend. Also great blog here with all of the valuable information you have. Whirlpool oven repair 
Submitted by ErinaJones on January 14, 2015 
* * *
Its a great pleasure reading your post.Its full of information I am looking for and I love to post a comment that "The content of your post is awesome" Great work. best soccer cleats 
Submitted by asad on January 13, 2015 
* * *
This is such a great resource that you are providing and you give it away for free. I love seeing websites that understand the value of providing a quality resource for free. It is the old what goes around comes around routine. How to prevent diabetes 
Submitted by jasmin on January 13, 2015 
* * *
Thanks for sharing the info, keep up the good work going.... I really enjoyed exploring your site. good resource... Into the Wild Quotes 
Submitted by zeshan on January 13, 2015 
* * *
Thanks for the post and great tips..even I also think that hard work is the most important aspect of getting success.. Android free downloads 
Submitted by asdd on January 13, 2015 
* * *
I recently found many useful information in your website especially this blog page. Among the lots of comments on your articles. Thanks for sharing. free workout plans 
Submitted by adil on January 13, 2015 
* * *
Excellent article. Very interesting to read. I really love to read such a nice article. Thanks! keep rocking. small security cameras 
Submitted by jasmin on January 13, 2015 
* * *
Awesome and interesting article. Great things you've always shared with us. Thanks. Just continue composing this kind of post. rosacea 
Submitted by jasmin on January 13, 2015 
* * *
It was wondering if I could use this write-up on my other website, I will link it back to your website though.Great Thanks. cyprus bank account  
Submitted by jasmin on January 13, 2015 
* * *
I see the superlative substance on your locales and I radiantly acknowledge encountering them. HomeCentric.org  
Submitted by HomeCentric.org on January 13, 2015 
* * *
I agree with your blog and i will be back to check it more in the future so please keep up your work. michael kors outleti love your content & the way that you write. girlsdoporn  
Submitted by calvinbrock735 on January 13, 2015 
* * *
I'm come a cross for your website and discovered it based on my need and demand. casa domnesti  
Submitted by casa domnesti on January 12, 2015 
* * *
Now that was a really healthy dialogue right there. Gets your blood pumping really fast and strong. Thanks a lot for sharing this with us. changi properties westwood ave ec  
Submitted by changi properties westwood ave ec on January 12, 2015 
* * *
In all of the jurisdictions, it is absolutely extremely hard to obtain the description in the term “offshore company” within their Business Serves or perhaps Business Ordinances or perhaps Regulations. Every single region provides your ex description connected with the businesses in line with your ex laws. bubblegum casting  
Submitted by bubblegum casting on January 12, 2015 
* * *
Strategic Group has grown to become one of Alberta’s largest private owners and developers of commercial real estate. Our diverse portfolio includes: office buildings, retail centres, industrial facilities, residential units and development projects... bubblegum casting  
Submitted by bubblegum casting on January 12, 2015 
* * *
I have visited to this site many times and everytime I find useful jobs for me so I would suggest please come to this site and take the chance from here.. bubblegum casting 
Submitted by Anonymous on January 11, 2015 
* * *
I have to say that the information here was the most complete that I found wherever. Patch  
Submitted by Patch on January 11, 2015 
* * *
It's really nice and meanful. it's really cool blog. Linking is very useful thing.you have really helped lots of people who visit blog and provide them usefull information.http://youtu.be/vpONEF9ORkI  
Submitted by asadalikhatri on January 11, 2015 
* * *
This is cool!! I have see this article too on Nonton TV Online yesterday. 
Submitted by Nonton TV Online on January 11, 2015 
* * *
If maybe you need information about Cara Memutihkan Wajah you can visiting my blog sir 
Submitted by Cara Memutihkan Wajah on January 11, 2015 
* * *
Shampo Kuda Asli say i love your article, meybe on next time i will visit again on your blog 
Submitted by Shampoo Kuda Asli on January 11, 2015 
* * *
One can fight to keep the differences in income as small as possible also under this economic system.arsenal vs stoke  
Submitted by Anonymous on January 10, 2015 
* * *
Girlfriend Activation System (GFAS): Christian H. Reveals His Weirdly Effective, 3-Step "Obsession Story" System For Attracting And Dating Amazing Women...how to make a girl want you to be her boyfriend  
Submitted by asadalikhatri on January 10, 2015 
* * *
I am actually getting ready to across this information, is very helpful my friend. Also great blog here with all of the valuable information you have. disney world pictures  
Submitted by Anonymous on January 10, 2015 

 

Leave a comment

Name
Comment
Enter this word:


Browse Park E-ventures by Topic

Topic
Program 
 

Browse Park E-ventures by Date