Natural and Unnatural History V

I’m traveling in the Galapagos currently.  Hopefully I’m having fun and seeing great birds and other species!  In the meantime here’s a little of what I will hopefully be seeing!

The Galapagos’s Natural and Unnatural History: Founder’s Effect

In the last missive, I laid forth a hopefully straightforward explanation of  evolution (by natural selection).  Today I’ll explore it’s relevance to the Galapagos.  We have a couple species we could explore: the Mockingbirds, the finches, or the tortoises, or a number of plant species.  But since we’re here presumably due to a shared passion for birds let’s stick with that class.  Did you know, it was actually the mockingbird that inspired Darwin, not the finches named for him?

Now, the initial post, geology, explored the location of the archipelago, 600 miles from the mainland.  That is noteworthy.  In the third post, human impact, I mentioned that there were discovers before humans and I didn’t mean Doctor Who.   When the volcanic islands first emerged from the sea they were very hot barren rock.  They cooled, but they were still barren rock.   We now know that the invisible air is filled with invisible particles including biotic ones. Dust travels from Africa to become the condensation nuclei in clouds above America; we measured radiation from Japan’s Fukishima reactor in Massachusetts; when the Eyjafjallajökull volcano of Iceland erupted, the aerosol debris grounded flights, stranding people throughout Europe for weeks.   I forget now where I read it, but there was fascinating work done looking at bare rock islands in Iceland after an eruption. The focus was measuring how quickly biotic life reached the resurfaced island through the air.  It was months.  That island was much closer to a biotic source, but it presents a viable mechanism for colonizing the Galapagos.  And thus (we presume) it happened.  Bacteria and algae made their way to the islands where together they formed a symbiotic union and began breaking down the rock to make soil.  They weren’t doing it for any higher purpose; they were only struggling to survive.  After all think of all their fellow travelers who missed landing on any island at all and perished.  After considerable time, soil formed.

The earliest plants were most likely to reach the island via the airways.  The vast majority of plants on the Galapagos have wind-borne seeds.  A ha.

Soon (geologically speaking) the animals will arrive.  The birds and the bats (of which there are two species) will also arrive by air, but the rest must make their way by some other fashion.  The fur seals and the sea lions swam, but the reptiles and the insects were likely swept off the mainland on rafts of plant material aimlessly drifting through the ocean.  Mammals, due to their need to eat often, are unlikely to survive the weeks it would take to drift on currents to the islands (but the rice rats did it).  Reptiles, being ectothermic (cold-blooded) and requiring less energy consumption can go extended periods without food; insects can either eat the plant material they’re riding on, or could be transported as eggs or in some stage of torpor, eggs being more likely of the last two.

It doesn’t take many.  The minimum requirement is a male and a female. These are the founders (think Gilligan’s Island or splinter groups).  Imagine a small flock of finches blown off the South American mainland and out to sea.  As a group, they resolutely fly forward seeing any shelter in a storm.  By great fortune, one might note breaking waves indicating land.  They land.   Though they do not realize it yet, they are home.  There is no going back.  They are the first.   For the earliest arrivals, storm-drenched and dazed, they are fortunate that there are no predators and no competitors to contend with.  A new struggle begins: this time it’s not a battle with the winds, but a battle with the new land.  If they cannot cope, they cannot survive.  Can they find food, can they alter their behaviors to fit this new land?

If they can find food and begin creating a life for themselves, in essence: if they survive, they can begin reproducing.  Recall the importance of mate choice on evolution as outlined in the fourth article. Whoever it is that landed on the island (and survived) will represent all future genes.  Their genes are the genes that will rebuild the genetic pool.  Because there are so few, the selection of genes is likely to be very skewed.  This is the founder’s effect.   If only small, light-weight birds were blown away from South America, then the gene pool will predominantly feature genes for smaller birds than on the mainland.  Further compounding the Founder’s Effect is that not all arrivals may reproduce.  With the diversity of genes present, some individuals may have traits that make them a very poor candidate for survival on the islands, and they perish.  Gene pool is further diminished.  That is selection.  Of all the small lightweight birds that arrived, imagine some were picky eaters and others were less fussy (generalists).  The fussier eaters, would be less likely to find food, and thus the future generation would be smaller birds than were more generalist in feeding habits than the population on the mainland.

For now they are the same species.  If reunited, they were merge and mix; the differences separating the two groups would be lost within a generation.  In this scenario, due to the distance, it is improbable.  So each group continues on separate trajectories.  The finches on the mainland continue in their lush tropic climate while the new finches in the arid Galapagos begin drifting, and morphing into something new as a result of their new environment.  Selection is at work.

Natural and Unnatural History IV

I’m traveling in the Galapagos currently.  Hopefully I’m having fun and seeing great birds and other species!  In the meantime here’s a little of what I will hopefully be seeing!

The Galapagos’s Natural and Unnatural History: Evolution By Natural Selection

No series of vignettes showcasing the Galapagos would be complete without a thorough discussion of Evolution by Natural Selection.  Evolution by Natural Selection, from here forward will be referred to simply as evolution, is the process by which the representation of genes within a population changes over time.  I’m fairly certain that’s pretty close to word perfect the definition I used in graduate classes, but quite a headache to puzzle out for everyone else.

There is an amazing parallel in the behaviors of individuals and genes explored by Richard Dawkin’s in The Selfish Gene.   Individuals compete for resources in order to reproduce.   Individuals who reproduce, or reproduce more, are represented by future generations.  Imagine the typical high school romance movie plot where the main character attempts to woo away the popular girl from the popular boy a la Can’t Hardly Wait or Mean Girls.  In the main character’s ideal world, he and she reproduce.  Thus, whatever their genes are, are represented in their children.  Now, continue and imagine the rejected suitor pines away forever and never reproduces.  No matter how wonder his/her genes are, they will be lost from future generations forever.

Now, in most cases, for every athlete that is thrown over for a chess enthusiast, there is a chess captain who is rejected in favor of a team captain.  Everyone pairs up with someone, and the genes are equally represented from one generation to the next.  When you have strong selection events, say all athletes being removed from the gene pool, then the representation in genes for the subsequent generation will be different.  That is evolution (by natural selection).  Even if it only happens for one generation and athletes come back into vogue the following generation. (Cause let’s face it, there are some out there who may be both ardent chess and sport participants keeping the genes alive).  But, if it happens for generations following generations and you have a sustained, directional push favoring chess players over athletes, the ratio of chess players to athletes will diminish and athletes could be lost entirely from the population.  Imagine that.

As individuals select mates for reproduction, the genes get carried along.  Sometimes the selection is intentional.  Deer selecting for large bucks with lots of points let’s say or cardinals choosing for the brighter red feathers; sometimes the genes aren’t as obvious, but nevertheless they’re carried along into future generations.    It’s the whole package that made the individual desirable (even if there are some poor genes in there). However, through reproduction, the genes get all jumbled up and the offspring are not replicates of their parents.  Hopefully, they’re better.  Because through the union, the hope is the best genes will find representation in the offspring.  Thus, the children will be more “fit”, than the parents.

This is remarkably relevant for a number of reasons.  First, many credit Darwin’s  visit to the Galapagos with setting him on the path that led him to his theory. Second, the Galapagos is a top notch destination for studying evolution in action.  Third, some really awesome aspects of evolution happened in the Galapagos, and is still happening!  So stay tuned.

Additional Reading:

  • The Selfish Gene. Richard Dawkins. 1976.

Natural and Unnatural History III

I’m traveling in the Galapagos currently.  Hopefully I’m having fun and seeing great birds and other species!  In the meantime here’s a little of what I will hopefully be seeing!

The Galapagos’s Natural and Unnatural History: Human Impact

One of the many names given to the Galapagos, and my personal preference, the Enchanted Isles, evokes a images of a microcosm of Eden.  And much like Eden, the man is the demise of the garden.

The Enchanted Isles might seem an ironic or sarcastic name, given that the islands at first appear barren and inhospitable to the first human discovers lead by the Bishop of Panama, Fray Tomas de Berlanga in 1535.  (In truth, the island had been discovered much earlier, but that will the subject of a different post!)  He was not impressed.   In his recorded observations, he noted the tameness of the avifauna, and marvels over the tortoises and iguanas, themes to be repeated by travelers for the next ~450 years.  In 1570, the location was first charted onto maps.  By then, the islands had been named “Insule de los Galopegos” (Islands of the Tortoises) and the “Enchanatas” (Bewitched Islands).  In the 1800’s the islands also became known as “Archipielago del Ecuador” and “Archipielago del Colon”.  The islands themselves have Spanish and English names, typically one of each and a few more besides.

After the Bishop and the mapmaker sailed through, the islands became the retreat of pirates, then penal settlements for political prisoners, and prostitutes. (Not a word I’d ever imagine using on a birding blog, but there you have it.)  Though I suspect there may have been prostitutes during times of the pirates, but that’s sheer supposition.   Between the pirates and the prisoners, the whalers took over briefly, wrecking many a whale and tortoise population. (The tortoises were removed as food sources for the whalers).

Scientific exploration began in 1790, thus Darwin was not the first scientist to visit the Galapagos in 1835, just the first to realize what a gem it was.  Also, the maps made during Darwin’s travels were in use until the 1950s!

As each new wave of people came, they left their mark and changed the ecology.  The tameness of each species is noted by Darwin and others.  In fact, Darwin’s first notation regarding the finches named for him, regards the ease with which he killed one inquisitive finch who hopped up to investigate him.

Goats were introduced in 1813.  Also introduced to the island have been new species of birds, dogs, rats, pigs, and cats for a total of 36 vertebrate species.  To capture the enormity of the invasive forces at work:

  • A total of 36 vertebrate species  including 1 freshwater fish, 2 amphibians (frogs), 4 reptiles (all geckos), 10 birds, and 13 mammals. (Source)

  •  750 introduced plant species have been registered in Galapagos, with nearly 90% of them brought deliberately by humans for agricultural and ornamental purposes. The recent jump in the total number of introduced plants is more a result of increased interest in the problem coupled with more thorough surveys than of any exponential increase in the introduction rate. The majority of introduced plants are not overly invasive. (Source)

  • Approximately 543 alien insect species, more than 1/4 of the total insect fauna, have been registered in Galapagos. Most arrive in Galapagos on lumber, fruits and vegetables, and other organic material. The most serious threats to the Galapagos biota include two fire ant species, two wasp species, a scale insect, and an ectoparasitic fly.  (Source)

Each new species disrupts the balance among the present species.  Food is limited.  Thus bringing more guests to the table mean less food for those already present.  The same is true for other resources such as water, habitat, territory, etc.  These new species have no natural space in the ecosystem, thus they have no natural check to stymie their growth.

Humans are responsible for each of these introductions unintentional, well-meaning or otherwise.    The whalers removed 100,o00 tortoises during their stay.  During a two-month stay, one ship removed 5,o00 fur seals.

Much care has been taken in recent decades to limit human influence.  Invasive species are being eradicated, breeding programs are underway for tortoises, reintroduction programs are on-going, all sorts of scientists are out there watching, learning, restoring, and hoping.

However, a new trouble looms: tourism.  Even ecotourism, sustainable tourism, or conscious tourism isn’t enough.  While this type of tourism that looks at the impact of the tourism trade and seeks to limit the negative and expand the positive, has consequences. Each species, each individual has an impact, including each tourist.  That cannot be helped.  However the tourism industry, particularly for natural areas and remote regions continues to grow.   Cruise ships now visit the Galapagos, dramatically increasing the number of people visiting and the lure of building economies around tourism.  (Additionally on a sad note, with the growth of the sustainable tourism industry, there has been abuse of the labels by companies who recognize the profit in the labels.) In 2011, the Ecuadorian government attempted to limit cruise ship tourism:

  • “The rules [beginning February 1, 2012] will allow travellers to stay for a maximum of four nights and five days per ship, with a frequency of four landings within any 14-day period.” (Source)
  • The Galapagos receives 150,000 annual visitors yearly, mostly on  Isabela, Santa Cruz and San Cristobal. (Source)
  • In 2012, 170,000 visits were made to the Galapagos. (Source)
  • Additionally, there is an allotted number of tourists allowed per day per island.  (Source)

Additional Reading:

Sources:

Life’s Best Moments

image

Left my camera at the hotel on this day of all days. I was so worried about running out of space on my card that I remembered the new card, but forgot the camera. This is one of only three shots I managed of the penguin, and with my phone no less. Imagine what Darwin could have accomplished with a smart phone.

Natural and Unnatural History II

I’m traveling in the Galapagos currently.  Hopefully I’m having fun and seeing great birds and other species!  In the meantime here’s a little of what I will hopefully be seeing!

The Galapagos’s Natural and Unnatural History: Climate

Climate is a remarkable thing and it’s effect on the islands is profound.  The Galapagos are a series of islands that straddle the equator.  As such it means that seasons aren’t based on light availability.  There are 12 hours of daylight and 12 hours of night with the sun dawning around six and setting at six in the evening.

Like the tropics we think of when we consider Costa Rica and the Amazon, the seasons are wet and dry.  The climate of the Galapagos is influenced by oceanic currents. The warm/wet season typically runs from January through June (garuas), but is highly variable in its start date.   During the cool/dry season (garua) seas are choppier due to prevailing winds, and while the lowlands experience virtually no precipitation and the highlands are continually receiving rains.  Temperatures typically range from 24 to 28 C (75-82F).

In the heart of the Pacific, the Galapagos are dramatically affected by climatic events of El Nino and La Nina.  Much of what I’ve read regarding climate and the Galapagos was published in the early 90s so the lack of recent data will leave holes in my knowledge and I’ll have to extrapolate a little.

El Nino, is a climatic event that affects the coastal waters off Peru every 3-5 years.  These events can last a few months to nearly two years. El Nino events typically start in December or January when the oceanic currents bringing cold water to the surface along the western coast of South America cease.  Instead water waters blanket the coast.  This has immediate local affects and long-term global influence.  The fishing industry is halted as the warmer waters hold fewer nutrients, so the food webs and fish stocks plummet.  The suspension of the current has ramifications across the planet.   Wet areas such as the Amazon basin receive significant less rainfall, other regions receive increased levels of precipitation

In the Galapagos, an El Nino year promise high levels of precipitation while a La Nina year means virtually no precipitation and cooler temperatures. While La Nina is in essence the opposite of El Nino (water temperatures along Peru’s shores decline), the start time of the phenomena is the same.  La Nina occurs every 3-7 years, frequently, but not always following an El Nino event.

Why the all the discourse on Spanish babies? As I mentioned earlier, Climate is the determining factor of success in the Galapagos.  As mentioned in Natural and Unnatural History I, the wet season is not based on the calendar, but on the initiation of the rains: if there are no rains, then there is no wet season.

Imagine life continuing if the heart stopped beating.  In the Galapagos: that’s precisely what the wet season is: one more throb of the heart.  In the span between beats, each organ holds for the next pulse of oxygen.  In the Galapagos, each species, and each individual waits for the next wave of rains to replenish life.  Life in the Galapagos has evolved to wait until rain starts.  When the rains don’t come, species teeter, like losing balance a top of cliff in suspended time. Hope rails, and individuals doggedly persevere.

During the drought of 1977 the total precipitation fell from an average annual 200 mm (can’t locate accurate precipitation levels for 1977). It was not enough for finches under observation by Peter and Rosemary Grant to breed.  Conducting their research, scientists discovered “dead fortis lying on the lava with feathers so dishelved they looked as if they had been combed the wrong way.”

“We just sat there, month after month.  We were depressed.  We were losing the breeding season, so we wouldn’t get a generation.  Plus, all these birds were disappearing.  We kept up doing the normal checks and censuses.  But our feeling was not the thrill of seeing evolution in action as one might conclude from reading subsequent papers, but the moderate despair of doing a research project and seeing your birds dying.” – Peter Boag, The International Finch Investigation Unit, recollections on 1977

The cactus finch population declined 60% while the fortis population declined 85% during that climatic event.   There’s no foretelling El Nino and La Nina, all you can do is wait and watch and hope.  Each year is the same: breeding begins, life resumes when the rains fall. When the rains finally fell, after one alarming delay, one researcher, “dance[d] in it for two solid hours praising the heavens,  a dervish of tangled hair and beard and ripped clothes, hollering into the rain.”

Contrast that with the strongest El Nino on record (at the time my sources were published): 1982-1983.  “The year before there had been no breeding at all (1981-1982).  Now  they bred like hell.  On Daphne (Island) , females produced up to forty eggs and fledged twenty-five young. The most prolific pair on Genovesa Island lad twenty-nine eggs in seven clutches, and twenty fledglings hopped out of the nest, a record for the island.”

At the time, the El Nino of 1982-1983 was considered the strongest El Nino on record. However, the El Nino of 1997-1998 really brought the phenomena to the forefront of media and is considered stronger than 1982-1983.  There were three additional El Nino periods in the interval.  From my recollections, (I was in high school at the time), 1997-1998 is the first El Nino I was aware of and I seem to recall excessive media coverage
remarking on the extraordinariness of this particular event and bringing to global awareness to climate fluctuations.

So, needless to say, climate is intimately tied to the Galapagos.

Quotes from “Beak of the Finch: A story of evolution in our time”. Jonathan Weiner.  1995.

Sources:

  • “Beak of the Finch: A story of evolution in our time”. Jonathan Weiner.  print. 1995.
  • “Galapagos: a natural history.” Michael. H. Jackson. print. 1993.

Natural and Unnatural History I

I’m traveling in the Galapagos currently.  Hopefully I’m having fun and seeing great birds and other species!  In the meantime here’s a little of what I will hopefully be seeing!

The Galapagos’s Natural and Unnatural History: Geology

The Galapagos are an archipelago of volcanic islands.  Think Hawaii or Japan.  Basically there is a hot spot (a region where magma breaks through the earth) that piles up igneous rock.  These areas if they grow tall enough eventually become volcanic islands.

The Galapagos has 13 large islands, 6 small islands, and 40 small islets.

Why plural?  That’s because the continents are slowly drifting.  So after a good amount of time that created island is no longer over the hotspot and no longer forming.  Instead, there’s a new island forming.

Hot spots come and go as the plates shift.  Spewing is sporadic.  That’s why you don’t get one even large lump of an island.   However, the waters around the island will be shallower due to the spewage that didn’t become islands.

In times of lower sea levels there were fewer, larger islands.  This has wonderfully amazing ramifications for adaptive radiation.

The Galapagos islands began forming about 5-10 million years ago and are continuing to form today, albeit very slowly.  The islands are drifting east growing and eroding with time.

Ariel Galapagos, above and below water.  Photo courtesy of Georgia Regents University, Augusta.

Ariel Galapagos, above and below water.
Photo courtesy of Georgia Regents University, Augusta.

Creating a List, Packing my Bags

For the journey of a lifetime: The Enchanted Isles, where “it seems to be a little world within itself” due to the remarkable natural history of the island archipelago (Darwin).  The Galapagos Islands, made famous by Darwin’s revelations regarding Evolution by Natural Selection, or Transmutation, as it was known then, continue to figure prominently for scientists, adventurers, travelers, and dreamers. (All of which pertain to me).  Darwin was the first to realize the significance of the differences between very similar species across the archipelago.  These differences were known by the locals, but the importance was not considered.

Galapagos: Iguanas and Finches, oh my!

Galapagos: Iguanas and Finches, oh my!  Photo of a presentation at Hofstra University in preparation for our travels.

‘I never dreamed that islands about 50 or 60 miles apart, and most of them in sight of each other, formed of precisely the same rocks, placed under a quite similar climate, rising to a nearly equal height, would have been differently tenanted; but we shall soon see that this is the case. It is the fate of most voyagers, no sooner to discover what is most interesting in any locality, than they are hurried from it; but I ought, perhaps, to be thankful that I obtained sufficient materials to establish this most remarkable fact in the distribution of organic beings.’ (Darwin)

Darwin spend the rest of his life (and he was a young man when he journeyed to the Galapagos) pondering the significances of the similarities and differences between finches, mockingbirds, and tortoises and creating a compelling argument to sway his colleagues, politicians, religious leaders, and folks back home.  We know this today as “Origin of the Species”.

Montclair State University has teamed up with Hofstra University to send a group of faculty and students  to the Galapagos and the Amazon for 20 days in January 2014.  The organization for the trip began last spring and I was invited to travel with MSU despite graduating in May.  We will spend 10 days visiting San Crisobal, Isabela, and Santa Cruz among other places within the Archipelago whose names will have more meaning once I am there. Right now whenever I hear or think of one of the locations my mind because exceedingly gleeful, my cognitive abilities momentarily diminish and I just experience glee.   Highlights are to include the Charles Darwin Research Station and volunteering with Conservation International. (Side note: I’m pretty sure my undergraduate keynote speaker was Peter A. Seligmann, CEO and founder, of Conservation International.)

‘I am very anxious for the Galapagos Islands. I think both the geology and the zoology cannot fail to be very interesting.’ (Darwin)

After the Galapagos, our trip isn’t over.  We will spend some time in Ecuador visiting the highlands and the Amazon.   We will visit Cotopaxi Volcano and the Tiputini Research Station in pristine Amazon wilderness.

So far I’ve only really had a chance to study the Galapagos natural history and what I can hope to see.  I think my greatest hope is not to see the Mockingbirds, the true avian inspiration Darwin’s epiphany, the credited finches, but a Galapagos Penguin, the only penguin found on the Equator and thus in the Northern Hemisphere.   Regarding the rest of our travels and what we might see: who can say?  There are 1600 birds in Ecuador.  I’ll be happy with whatever comes my way!

I leave tomorrow, that is if the weather cooperates. We’re supposed to fly out tonight evening a few hours after the snow is expected to stop.  Either way, it’ll be an adventure!

Additional Notes of Interest: