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(Photo Credit: Tim Howard)

The finches of Galapagos are an iconic symbol of evolution in action: each species neatly adapted to its island's environment, thanks to enormous time spans and total isolation. But isolation is not so easy to maintain these days. Despite heroic efforts by the government of Ecuador to control the movement of critters from island to island, sometimes even just putting your foot on the ground can radically affect a landscape, or even alter the fate of Darwin’s famous finches.

Comments [13]

Doug from Western New York

Excellent episode.

Anytime that attention is brought to the finches of the Galapagos I find it necessary to remind myself and anyone else who will listen that Charles Darwin is not the person who studied and made the connection between the variety of those birds and the process of adaptive radiation. The British ornithologist David Lack did the research on the islands as well as in museum collections, published the results and eventually published a book on the subject, in which he honored Darwin by coining the term "Darwin's Finches".

Jul. 09 2017 03:41 PM
Cathoryn from The Future

We were always taught (in K - 12) that ape-human mashups wouldn't survive or procreate. Did teachers lie so that we wouldn't become racist?

I'd accept that I am literally part monkey, because I look (more) like a monkey.

I know the following is going to sound racist, but remember, chimps have white faces:

Lucy the chimp was attracted to human males; it wouldn't be a stretch to assume that male chimps are attracted to human females. A human female wouldn't be able to stop a chimp.

Mar. 19 2016 04:12 PM
Adam from United States


Did you really just cite a Jehovah Witness article? Really? Talk about an agenda.

Dec. 20 2014 02:40 PM
Eric from Davis, CA

Sarah, I saw a similar article in Nature about the cotton balls. A gram of permethrin treated cotton was sufficient to completely eradicate the parasites in 85% of the test nests. Best of all, the finches readily take the treated cotton themselves as nest-building material. Let's hope it's enough to save the species!

Aug. 27 2014 08:04 PM

An interesting little update on the finches. Pesticide-soaked cotton balls. Now I assume that this will cause some other issue..but still, an interesting method.

Aug. 05 2014 05:08 PM

I looked up the definition of the word species, using the web. so of course, i believed it. It also raised a question in my mind. How does one defined species create a viable, procreating offspring with another species? By definition, a species is a group which can successfully interbreed. So were these different species or different variations of the same species.

Jul. 27 2014 04:16 AM
Andrew from Chicago, IL

I also enjoyed this episode. Although, I'm still trying to get the image of a hanged tortoise out of my head. Sounds horrible.

And RIP Lonesome George...

And I'd love an update about the Finches sometime down the line if possible.

Jul. 24 2014 12:46 PM
Erin from Riverside, CA

I loved this episode. Thank you so much for trying to infuse pop culture with a little conservation.

However, I do not agree with the framing of hybrid small-medium tree finches on Floreana Island as a "happy ending". Many hybrids have superior fitness, take the Denisovans and Tibetan humans as an example. However, most species want to mate with their own kind - humans included - only 1-4% of a Euro-Asian individual's genome is Neanderthal.

It is often only the most tragic of situations that leads to such unnatural hybrids. So while it scientifically cool to watch vertebrate speciation, we are losing TWO species to get one. That makes me sad.

Jul. 23 2014 02:36 PM
Scott from Brazil

Chase, your (and Jehovah's Witnesses) lack of personal understanding of biological species concepts is not argument against speciation or natural selection. But I certainly don't blame your skepticism when exposed to such blatantly cartoonish misinterpretations of evolution.

The reality is that while there is the capacity for rapid evolution, most natural selection is in fact "stabilizing selection" to keep things well-suited to the current conditions. Traits fluctuate with small changes around a long-term mean. Speciation can happen when there is genetic isolation (impassive geographic features, alterations in mating behavior, etc), and natural selection acts on each sub population pushing both the selected genes and linked parts of the genome in different directions. When those linked genes have changed enough that hybrids don't form a viable population, there is speciation.

However, given that some hybrids can happen (ligers, for example), obviously species is a loose concept. It gets much tougher when you think of bacteria that don't mate at all, just divide, and can transfer genes across entirely different orders! Species is a term we give to populations to help categorize them to our category-happy human minds. The same goes for the false divide between "micro" and "macro" evolution, a split that does not exist in biology outside of an undergraduate classroom (or a creationist text). Nature doesn't really care about our definitions.

As for the rest of that pamphlet, I'd like to introduce you to the Anthropic Principle. The pamphlet talks about how many coincidences must happen for live to exist the way it does. But that's obvious, because we're here to observe it. Life evolved to best fit the circumstances our planet provided. If things were different, life would be different, and we'd be saying "Wow, look at these impossible coincidences!" to an entirely different set of circumstances. Given the huge number of planetary systems in the universe, and even the possibility of multiple universes, the slim possibility that life exists in any one place suddenly doesn't seem so improbable over the entire span and duration universe.

Hope that helps.

Jul. 22 2014 06:58 PM
Edith S. Robbins from LI, NY

An addition to the comment by Chase Wilson. The Grants years studying finches on the island Daphne is described in a book called "The Beak of the Finch". The yearly fluctuations in beak size are minutely cataloged. It might be called by some as microevolution or by others as adaptation although it is clear that the changes described do not become permanent.

Jul. 21 2014 09:07 AM

Evolution is over many many generations.

Jul. 19 2014 11:04 AM

Great episode you guys! Thanks for all your hard work :D

Jul. 18 2014 10:17 PM
Chase Wilson from Kirkland, WA

"In the 1970’s, a research group led
by Peter R. and B. Rosemary Grant of
Princeton University began studying
these finches and discovered that after
a year of drought on the islands, finches
that had slightly bigger beaks
survived more readily than those with
smaller beaks. Since observing the size
and shape of the beaks is one of the primary
ways of determining the 13 species
of finches, these findings were assumed
to be significant. “The Grants
have estimated,” continues the NAS brochure,
“that if droughts occur about once
every 10 years on the islands, a new species
of finch might arise in only about
200 years.”24
However, the NAS brochure neglects
to mention that in the years following the
drought, finches with smaller beaks again
dominated the population. The researchers
found that as the climatic conditions
on the island changed, finches with longer
beaks were dominant one year, but
later those with smaller beaks were dominant.
They also noticed that some of the
different “species” of finches were interbreeding
and producing offspring that
survived better than the parents. They
concluded that if the interbreeding continued,
it could result in the fusion of two
“species” into just one.25
So, does natural selection really create
entirely new species? Decades ago, evolutionary
biologist George Christopher
Williams began questioning whether natural
selection had such power.26 In 1999,
evolutionary theorist Jeffrey H. Schwartz
wrote that natural selection may be helping
species adapt to the changing demands
of existence, but it is not creating
anything new.27
Indeed, Darwin’s finches are not becoming
“anything new.” They are still
finches. And the fact that they are interbreeding
casts doubt on the methods
some evolutionists use to define a species."

'Was Life Created?' pg 21

Jul. 18 2014 10:14 PM

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