GENERAL ARTICLE Gálapagos Islands and Darwin’s Theory of

GENERAL ARTICLE

Gálapagos Islands and Darwin’s Theory of Evolution

K R Shivanna

K R Shivanna after retiring

from the Department of

Botany, University of Delhi,

has been associated with

Ashoka Trust for Research in

Ecology and the

Environment, Bengaluru as

INSA Honorary Scientist. His

major interests are the

structural and functional

aspects of reproductive

biology of flowering plants.

The Gálapagos Islands are closely associated with Darwin’sname because the animals and plants living on these islandsprovided clues to Darwin to formulate his theory of evolutionby means of natural selection. Gálapagos is a group of 19 vol-canic, Pacific islands on the equator, about 1000 km west ofEcuador of South America. Being volcanic, there was no lifeon them when they were formed; all organisms presently liv-ing on the islands are the descendants of those that came fromthe South American mainland. Darwin visited these islandsin 1835 during his voyage around the world in HMS Beagleand stayed for five weeks, studying and collecting plants, ani-mals, and rock samples from the islands. His detailed studiesof the collections upon his return to London, particularly ontortoises, mockingbirds, and finches, revealed that all thesespecies living on the Gálapagos were endemic to the islandand did not occur anywhere else in the world, but all of themclosely resembled the species present on the South Ameri-can mainland. This realization made him speculate that theGálapagos inhabitants, after they arrived from the mainland,evolved into different species over the years, shaped by the en-vironment of the islands. He visualized evolutionary changesas a result of the competition amongst individuals under chan-ged environmental conditions, which acted as a selective agent.Under such selection, those individuals possessing favorablevariations survived and reproduced, passing on their varia- Keywords

Competition, endemic plants and

animals, finches, heritable varia-

tions, mockingbirds, natural selec-

tion, tortoises.

tions to their offspring, and those without them were elimi-nated. Over the years, the concept of evolution has becomeone of the most important, powerful and unifying concepts inbiology.

RESONANCE | April 2018 465

GENERAL ARTICLE

Introduction

When Darwin proposed his theory of evolution in 1859, manyestablished biologists, including Carolus Linnaeus, the father oftaxonomy, believed that all life forms, as they existed then, werecreated by God, and that species could not change over the courseof time (i.e., they were immutable). One of the basic requirementsof the theory of evolution formulated by Darwin was the presenceof heritable variations amongst individuals, on which natural se-lection operates. However, at that time, nothing was known abouthow heritable variations arise and how they are inherited. In fact,genetics did not exist as a discipline of biology; it came into be-ing only in the beginning of the 20th century, after the rediscoveryof Mendel’s laws of inheritance. Although Mendel published histheory of inheritance in 1866, some years after the publicationof Darwin’s book, Darwin never came to know about Mendel’swork. In spite of his lack of knowledge about the mechanismsof heredity or the material being inherited, Darwin was able tovisualize evolution by means of natural selection. Over the years,his theory became one of the most important concepts in biol-ogy, unifying all branches of biology and justifying TheodosiusDobzhansky’s oft-quoted statement "Nothing in biology makessense except in the light of evolution."

The obvious question that comes to our mind is what gave Darwinthe clues to formulate such an important and everlasting theory?A primary reason for this was Darwin’s visit to the GálapagosIslands. Darwin visited the Gálapagos Islands for five weeks in1835, during his voyageDarwin visited the

Gálapagos Islands forfive weeks in 1835during his voyage

around the world in theHMS Beagle. The

animals and plants livingon the Gálapagos Islands

gave definitive clues toDarwin regarding

evolutionary change.

around the world in HMS Beagle. Theanimals and plants living on the Gálapagos Islands gave defini-tive clues to Darwin regarding evolutionary change. Thus, theGálapagos Islands became permanently associated with Darwin’sname. Until the publication of Darwin’s book On the Originof Species by Means of Natural Selection in 1859, these islandswere hardly known to the general public. After the publicationof the book, the popularity of the Gálapagos Islands grew overthe years, and now they have become one of the tourist hotspots.Over 170,000 tourists, from all parts of the world, visit the Gála-

466 RESONANCE | April 2018

GENERAL ARTICLE

pagos Islands every year. The Gálapagos Islands serve The Gálapagos consistof 19 islands scatteredabout the equator, over60,000 km2 of thePacific Ocean, about1000 km from the coastof Ecuador, SouthAmerica.

as livinglaboratories to study evolution, making these islands ‘the Meccaof biologists’. Here, I describe briefly the nature of the GálapagosIslands, their unique animals, and plants, and highlight the natureof the clues from the Gálapagos that prompted Darwin to thinkabout evolution through natural selection.

General Features of the Gálapagos Islands

The Gálapagos consist of 19 islands scattered about the equa-tor, over 60,000 km2 of the Pacific Ocean, about 1000 km fromthe coast of Ecuador, South America (Figure 1). Four of the is-lands are currently inhabited by humans, with a total populationof about 30,000. The islands are volcanic in origin and compar-atively young; the youngest (Fernandina) is about 800,000 yearsold, and the oldest (Espanola) is about 3.8 million years old. Thecoastal zone of many of these islands is composed of dark solidi-fied lava, with a few plants of lava cactus scattered about. Furtherup on the islands is sparsely distributed vegetation comprisinglargely herbs and shrubs (Figure 2). Trees are present only athigher elevations of some of the larger islands. Many different-sized craters of extinct volcanos dot the islands. The islands har-bor unique animals, which, lacking fear due to the absence ofpredators, allow close inspection.

Unique Animals and Plants of the Gálapagos

Being volcanic in origin, there was no life on the Gálapagos Is-lands when they were formed. All the plants and animals livingthere at present are descendants of the castaways that arrived bysea or air from the nearest South American All the plants and

animals living there atpresent are descendantsof the castaways thatarrived by sea or air fromthe nearest SouthAmerican mainland.

mainland. As theseislands are isolated from the mainland, the species that arrived onthe Gálapagos Islands gradually adapted to the conditions uniqueto their new homes. A large proportion of animals and plants thatlive on the islands are endemics and do not occur anywhere elsein the world. Almost 50% of the birds and fishes and 90% of thereptiles are endemic. Amongst the well-known endemic species,


GENERAL ARTICLE

Figure 1. (a) The loca-

tion of the Gálapagos Is-

lands (circled, upper left),

in relation to South America

(b) The Gálapagos Islands

shown in the circle magni-

fied.

(a) (b)

Figure 2. Dark solidified

lava along the coast of many

islands and scant vegetation

seen further away.

which gave clues to Darwin to formulate his theory of evolution,are the giant tortoises (Chelonoidis spp.), Darwin’s finches (madeup of 4 genera), and mockingbirds (Nesomimus spp.) (Figure 3a–c). Some of these species are confined to one or a few islands.Amongst other endemic animals present on the islands are landand marine iguanas, colorful crabs, and sea lions (Figure 4 a–d).Out of about 100 crab species present, the red rock crab (Grap-sus grapsus) is the most colorful and most common on many ofthe islands. The marine iguana (Amblyrhynchus cristatus) is theonly lizard in the world that depends on the sea for its food; itconsumes green and red algae growing at the bottom of the ocean


GENERAL ARTICLE

Figure 3. The three most

important animals on the is-

lands with respect to formu-

lation of the theory of evo-

lution: (a) Giant tortoise (b)Darwin’s finch, (c) Mock-

ingbird .a b c

near the shore. Marine iguanas Out of the 26 land birds,25 are found nowhereelse in the world. Thecormorant of Gálapagosis the only non-flyingcormorant species in theworld. The Gálapagospenguin is the onlyspecies found on theequator.

are seen sunbathing on the rocksor sandy shores, usually in groups. The land iguana (Conolophussubcristatus), on the other hand, is rarer and eats cactus frondsand other leafy vegetation, but never ventures into the sea. TheGálapagos semi-aquatic sea lions (Zalophus wollebaeki) are fairlysocial; their movement is very graceful in the sea but awkwardon the land. They are generally seen sunbathing on sandy/rockyshores and gliding through the surf in the water close to the shore.The Gálapagos harbor a large number of bird species. Out of the26 land birds, 25 are found nowhere else in the world. The cor-morant of Gálapagos is the only non-flying cormorant species inthe world. The Gálapagos penguin is the only species found onthe equator. The blue-footed booby (Sula nebouxii) is one of thecommon birds with characteristic blue feet (Figure 4 e–g). Theyare long-winged seabirds that dive into the sea in groups to huntfish. The red-footed booby (Sula sula) has characteristic red feet.Both the boobies are clumsy in takeoffs and landings and hencethe name booby (stupid).

Amongst plants, cacti are the most unique to the islands. Thereare six species of cacti, all endemic to the Gálapagos. They in-clude the lava cactus, prickly pear cactus (giant cactus), (Figures5a and 5b) and candelabra cactus. They are found in the low-land arid zone extending up to the elevation of about 50 m. Thecacti form an important diet for land iguanas, giant tortoises, cac-tus finches, and mockingbirds. Mangroves are common in manycoastal zones. Apart from cacti, some of the other endemic plant


GENERAL ARTICLE

Figure 4. Some of the

other endemic animals of

Gálapagos: (a) Land iguana,

(b) Marine iguana, (c) Red

rock crab, (d) Sea lion,

(e) Flightless cormorant, (f)Blue-footed booby, and (g)Penguin.

a b c

species include Scalesia pedunculata (a rare tree species of Aster-aceae, Figure 5c), Miconia robinsoniana (Melastomataceae), andthe Gálapagos tree fern.

Over the years the Islands went through serious conservation prob-lems. For centuries, thousands of giant tortoises were being cap-tured and taken on board the whaling ships as the food source dur-ing their voyages. This greatly reduced the population of tortoiseson the islands. Also many of the domesticated animals broughtby human settlers escaped to the wild and multiplied rapidly af-fecting the food source of the native animals. These concerns arebeing addressed effectively (see Boxes 1 and 2).

The Role of the Gálapagos Fauna in the Formulation of Dar-win’s Theory

When Darwin undertook his voyage on the HMS Beagle, he be-lieved in the prevailing religious doctrine that God had created allplants and animals in their present form, and that they were im-mutable (could not change over time). However, his observationsduring the voyage, on variations found in animals and plants inthe Gálapagos Islands, and further analyses of his collections afterhis return to London with inputs from his friends, especially JohnGould, the Chief Ornithologist of the British Museum, led him tostart doubting the Creationist viewpoint. Three groups of animals


GENERAL ARTICLE

Figure 5. Some of the

unique plants on Gálapagos:

(a) Lava cactus (Brachyc-

ereus nesioticus), (b) Giant

cactus (Opuntia echios), and

(c) Scalesia pedunculata.

living on the islands (mockingbirds, tortoises, and finches) playeda prominent role in this change.

Mockingbirds: Although Darwin’s finches have gained more pop-ularity in connection with his theory of evolution, mockingbirds(Nesomimus spp.) were the first to attract Darwin’s attention.Darwin had collected mockingbirds from three islands and hadmaintained the birds from each island separately. He observedthat the birds from each island were different and thought theywere different varieties adapted to the prevailing environment ofeach island, a view that would not completely oppose Creation-ism. However, John Gould, after studying them carefully, in-formed Darwin that the mockingbirds collected from different is-lands were independent species, and were not known previouslyfrom other areas. The data on mockingbirds enthused Darwin tothink afresh about the origin of mockingbirds on the Gálapagos.

Tortoises: The giant tortoises are the most famous and popularanimals on the islands. The Gálapagos giant tortoise (Chelonoidisnigra) is the largest tortoise found anywhere on the Earth and canweigh up to 400 kg. Darwin was aware, even while he was inthe Gálapagos, that tortoises of different islands showed charac-teristic differences in their shells. Local residents and sailorscould tell, just by looking at the shell, from which island the


GENERAL ARTICLE

tortoise had been captured. Thus, variations of tortoises on dif-ferent islands also supported the idea that species had evolved ondifferent islands through adaptations to local conditions. Post-Darwinian studies have shown that the Gálapagos giant tortoisecomplex (Chelonoidis) is made up of at least 12 species.

Finches: Darwin’s name became associated with Gálapagos finchesafter some ornithologists of the 20th century used the term ‘Dar-win’s finches’ in their publications. AlthoughRather than being

created and placed ondifferent islands, it

appeared that the speciesof birds on different

islands were related asthey had descended from

common SouthAmerican ancestors that

had landed on theislands. They had

speciated byaccumulating

modifications inresponse to varyingenvironments while

being isolated ondifferent islands. Darwin

eventually wrote in theOrigins, “...the view

which most naturalistsentertain, and which Iformerly entertained –

namely, that each specieshas been independently

created is erroneous."

Darwin had col-lected a large number of finches from the Gálapagos Islands, finchesfrom different islands were mixed up in his collection. Gould re-ported that there were 13 species of finches in Darwin’s collec-tion. They differed largely in their body size and the size andshape of their beaks. Darwin compared his collections with thoseof others on the Beagle, including captain FitzRoy, who had la-beled them by island. He realized that most of the species offinches were confined to individual islands although some islandsharbored more than one species. The distribution of finches ondifferent islands also suggested that different species had evolvedon different islands. The Gálapagos finches have later been stud-ied intensively by a number of ornithologists, particularly Peterand Rosemary Grant (see Box 3).

After detailed analyses of the data on Gálapagos mockingbirds,tortoises, and finches, Darwin realized that although all thesespecies were endemic and distinct from one another, they closelyresembled the species found on the nearest South American main-land. Rather than being created and placed on different islands, itappeared that the species of birds on different islands were relatedas they had descended from common South American ancestorsthat had landed on the islands. They had speciated by accumulat-ing modifications in response to varying environments while be-ing isolated on different islands. Darwin eventually wrote in theOrigins, “...the view which most naturalists entertain, and whichI formerly entertained – namely, that each species has been inde-pendently created is erroneous."

Subsequent intensive studies, including molecular phylogeneticinvestigations by others, have shown that all species of tortoises,


GENERAL ARTICLE

mockingbirds, and finches living on Gálapagos Islands are mono-phyletic (evolved from a single species) in origin. All the fourspecies of mockingbirds are descendants of a single species, mostprobably Mimus longicaudaus of the Ecuadorian mainland. Allthe finches have evolved from a common ancestor that colonizedthe islands from South America. The shape and size of the beakshave been the result of their adaptation to differing food sourcesavailable on the islands – seeds and fruits of different species, in-sects, and cactus flowers. Gálapagos tortoises have also evolvedfrom a common ancestor, Chaco tortoise (Chelonoidis chilensis),a much smaller species found in Argentina and Paraguay. Thesestudies have confirmed Darwin’s speculation about the origin andevolution of these species on the Gálapagos Islands.

Once Once Darwin wasconvinced about themutability of species, hehad to explain thecausative factor(s) forsuch evolutionarychanges.

Darwin was convinced about the mutability of species, hehad to explain the causative factor(s) for such evolutionary changes.The clue for this came from reading Thomas Malthus’s, An Essayon the Principles of Population in which the author had arguedthat human populations tend to outgrow their resources and thisresults in competition amongst their members for available re-sources. Darwin visualized the operation of similar competitionamongst plant and animal populations in their natural habitat. Hesurmised that, under such competition, individuals that possessedfavorable traits would be naturally selected. Some traits would beessential for survival in certain environments and individuals notpossessing them would be eliminated. Some traits would allowindividuals possessing them to be better at securing resources,surviving and reproducing than individuals that did not possesssuch traits. Such traits that are essential or advantageous, if her-itable from parent to offspring, might increase over successivegenerations. Thus, natural selection could result in the modifica-tion of the population, with certain traits being favored and otherseliminated.

Evolution through natural selection can sometimes be fast, butchanges in life forms may take thousands or hundreds of thou-sands of years. The prevailing belief during Darwin’s time wasthat the Earth was only 6000 years old. However, during his voy-


GENERAL ARTICLE

age on the ship, Darwin had read the book, Principles of Geology,by the famous geologist, Charles Lyell, in which the author hadreasoned that it must have taken millions of years for the Earthto mold the land into its current conformation. This was an im-portant information for Darwin. The Earth being much older than6000 years would imply sufficient time for life forms to changegradually. Darwin was also familiar with artificial selection (se-lection by humans) of a large number of varieties of domesticatedanimals such as dogs, cats,Natural selection could

result in the modificationof the population, with

certain traits beingfavored and others

eliminated.

horses, and pigeons, and vegetablessuch as cabbage, cauliflower, Brussel’s sprouts and broccoli, bybreeders. He realized the similarities in selection of favored vari-ations by nature and by humans and commented: “Why if mancan by patience select variations most useful to himself, shouldnature fail in selecting variations useful, under changing condi-tions of life, to her living products?”

Publication of Darwin’s Book

Darwin communicated his ideas to Lyell in January 1842, and inJune the same year he drafted a 35-page draft of his theory. In1844, he wrote a 230-page detailed essay, to be expanded withhis research results and published if he died prematurely. But hedid not publish his theory and went on collecting additional ev-idences. In 1856, Lyell urged Darwin to publish his theory toestablish priority, but Darwin did not heed his advice and contin-ued to enlarge and refine his theory. He felt that it was “...quiteunphilosophical to publish results without the full details whichhave led to such results...” Some other reasons suggested for thedelay in the publication of his theory include fear of religious per-secution, social disgrace, and concern about upsetting his clergy-men friends or his wife, Emma. In 1858, Darwin received a 20-page manuscript from another English naturalist, Alfred RusselWallace, who was working in the Malaysian Archipelago. Sur-prisingly, Wallace had also formulated the theory of evolution bynatural selection. He had requested Darwin to send it to Lyell forpublication if Darwin thought it worthwhile. This shocked Dar-win, who wrote to Lyell that “your words have come true with a


GENERAL ARTICLE

Box 1. The Story of Lonesome George and Other Giant Tortoises

Because of overexploitation of giant tortoises of the Gálapagos Islands, the population of some of the

subspecies almost went extinct on some of the islands. On Pinta Island, one male giant tortoise was the only

member of the subspecies Chelonoidis nigra abingdonii left. It was named ‘Lonesome George’, brought to

the Darwin Research Station and housed along with two females from closely related species, in the hope

of obtaining progeny. Although Lonesome George mated with both the females and they laid a total of 30

eggs, all of them turned out to be inviable. Lonesome George died in 2012 at the age of about 100 years.

The body of Lonesome George was frozen and sent to the American Museum of Natural History, New

York, for restoration by taxidermists. After restoration work, it was exhibited at the New York Museum for

some time. The restored body of Lonesome George was flown back to Gálapagos on 17 February 2017 and

is now on permanent display at the Charles Darwin Research Station.

The longest-lived Gálapagos tortoise ‘Harriet’ was born around 1830. She was reportedly taken from the

Gálapagos Islands by Darwin himself when he visited the islands and eventually sent to a zoo in Australia.

She died in the zoo in 2005, at the age of 175 years.

Apart from the Gálapagos giant tortoise, the Seychelles group of islands is the only other group of islands

in the world inhabited by giant tortoises. They are much smaller than those of Gálapagos Islands. The

all-time verified record holder for the world’s longest-lived tortoise belongs to the Seychelles group; it is

‘Tui Malila’ (Geochelone radiata), who died in Tonga in 1965 at the age of 189 years (1777–1965). It

was a reportedly given to the royal family of Tonga by Captain James Cook. Another Seychelles tortoise

‘Adwaita’ (meaning ‘unique’ in Sanskrit), that died in 2006 in Alipur Zoological Garden of Kolkata, India,

was believed to have lived to the age of 255 years, but this has not been confirmed. Presently, the oldest

living tortoise or for that matter, the oldest of any living land animal, is ‘Jonathan’ – the giant tortoise

(Aldabrachelys gigantea hololissa) from one of the islands of Seychelles, living in the garden of the official

residence of the Governor of St. Helena, in South Atlantic Ocean. Jonathan is 183 years old.

Figure A. Lonesome George, photographed in 2006 at Charles Darwin Research Station (left). Stuffed

Lonesome George on display at Darwin Research Station (right). Source: Wikipedia Commons


GENERAL ARTICLE

Box 2. Conservation Concerns and Actions

Since their discovery, the Gálapagos Islands were used as a hideout by pirates who used to attack Spanish

ships carrying gold and silver from South America back to Spain. Since the late eighteenth century, the

islands were used as transit camps for the whalers operating in the Pacific Ocean. As the giant tortoises,

available in abundance on these islands, could remain alive with little or no food or water for up to one

year, they provided an endless supply of fresh meat for their long voyages. Thousands of Gálapagos giant

tortoises were captured and taken on board the whaling ships over the years. This indiscriminate collection

greatly reduced the population of tortoises on the islands (see Box 1). There were additional problems on

the islands with human habitation. When the settlers started coming to the islands, they brought with them

domesticated animals such as goats, pigs, and cattle, and also several domesticated plants. Along with

them, rats and mice, and seeds of some weed species also arrived on their boats as stowaways. Over the

years, many of the domesticated animals escaped to the wild and proliferated rapidly with the availability

of abundant food sources and the absence of predators. They competed with the tortoises and other native

animals for food. Rats and mice started consuming the eggs and young ones of tortoises and birds. Some of

the specific island varieties of tortoises became almost extinct. Most of the introduced plants also escaped to

the wild and competed with the native plants. These developments threatened native species on all inhabited

islands.

In 1959, when the world celebrated the centenary year of the publication of Darwin’s book On the Origin of

Species by Means of Natural Selection, all uninhabited areas of Gálapagos Islands (over 97%) were declared

as a National Park, and the Charles Darwin Research Station was established on the Gálapagos. Since

then, all fresh immigration to the islands have been stopped and effective conservation measures have been

initiated. The movement of tourists is now strictly controlled, and tourists cannot visit uninhabited islands

without a guide trained by the National Park Authority. The Darwin Research Station is doing extensive

work on conserving native fauna and flora, especially tortoise species. It is propagating threatened species

of tortoises in captivity by incubating eggs under controlled conditions, raising the young ones for 4–5 years

in the Station (by which time, they are safe from the introduced predators such as rats and dogs), and then

releasing them in their native habitats. The populations of native animals have thus started increasing.

Domesticated goats on the Gálapagos that escaped to the wild soon after colonization by humans, multiplied

rapidly and reached a population size of around 250,000 across these islands by 1990s. They ate practically

any plant available and caused massive destruction of the vegetation, affecting the food source of native

animals, particularly tortoises. An international workshop of experts was held in 1997 to design an all-

encompassing action plan. ‘Project Isabela’ was initiated in 1997 to cull feral goat populations and to

restore the ecosystem. Cutting-edge technology, including the use of helicopters for aerial hunting and GIS

tracking, ensured swift and efficient removal of feral goats. By the end of 2005, feral goats were eliminated

completely from the islands. The operation ended in 2006. The cost of the project was 8.1 million USD.

Soon after, the vegetation of the islands recovered dramatically.


GENERAL ARTICLE

Box 3. Darwin’s Finches – 4 Decades of Investigations by Peter and Rosemary Grant

Two British evolutionary biologists, Peter and Rosemary Grant (wife and husband team), from Princeton

University, have studied Darwin’s finches on a small uninhabited island, Daphne Major of Gálapagos, for

40 years (1973–2012). They banded each bird on the island, weighed them, measured their beaks, and

kept track of their lineages. By combining detailed ecological, behavioral, and feeding data, they could

observe evolutionary events following ecological upheavals. During 1977 there was a severe drought. The

vegetation withered and available seeds for birds became scarce. Small, soft fruits from which birds could

easily extract seeds were quickly exhausted, leaving only large, tough fruits from which seeds were difficult

to extract. There was a struggle for survival, in which only about 300 birds out of 1300 survived. The birds

that survived were larger, with long, strong beaks that were effective in opening hard fruits; small birds with

smaller beaks died.

In 1984–85 the island witnessed heavy rains resulting in the availability of plenty of small soft fruits and

much less large hard fruits. Now the birds with large beaks started dying and those with smaller beaks, well

adapted to open smaller fruits survived and produced most of the offspring. Thus, droughts and excessive

rains acted as strong selection agents leading to competition and survival of the fittest. Both the Grants are

now 80 years old. They have received almost every award available in their field in recognition of their

monumental work. They have discussed their studies of four decades in their recent book, 40 Years of

Evolution published in 2014 by Princeton University.

Figure B. Peter and Rosemary Grant studying finches in front of the only cave present on the island. They

also used the cave for cooking and to store their supplies. The island Daphne Major (right), big enough to

support several hundred finches but small enough to study all the birds inhabiting the island.

vengeance ...” adding that “... all my originality, whatever it mayamount to, will be smashed.” Lyell and Hooker discussed andagreed that a joint publication putting together Wallace’s pageswith extracts from Darwin’s 1844 essay should be presented atthe Linnaean Society; it was presented on 01 July 1858. How-ever, it did not receive much attention. Darwin finalized the book,


GENERAL ARTICLE

On the Origin of SpeciesSurprisingly, Wallacehad also formulated thetheory of evolution by

natural selection. He hadrequested Darwin to

send it to Lyell forpublication if Darwinthought it worthwhile.

by Means of Natural Selection soon andsent it to the publisher John Murray in July 1859. The book waspublished on 24 November 1859 priced at 15 shillings with a firstprinting of 1250 copies. All copies were sold on the first day it-self. The last sentence of the book ends with “... from so simple abeginning endless forms most beautiful and most wonderful havebeen, and are being evolved.” During Darwin’s lifetime, the bookwent through six editions, with cumulative changes and revisionsto deal with the criticisms raised. Over the years, the concept ofevolution has become the most important, powerful, and unifyingconcept in biology.

Suggested Reading

[1] Darwin C, On the Origin of Species by Means of Natural Selection, John Mur-

ray, London, 1859.

[2] On the Origin of Species, Wikipedia.

Address for Correspondence

K R Shivanna

Odekar Farm, Nandihalli

Tumkur Taluk 572 138

Karnataka, India.

Email: [email protected]

[3] Darwin’s Finches, Wikipedia.

[4] Grant PR and Grant BR, 40 Years of Evolution, Princeton University, New

Jersey, 2014.

[5] A R Wallace, On the Tendency of Varieties to Depart Indefinitely From the

Original Type, Journal of the Proceedings of the Linnaean Society (Zoology), 3:

pp.53–62, 1858. (Reprinted in Resonance, Vol.13, No.3, pp.283–291, 2008).

[6] Lonesome George, Wikipedia.

[7] V Nanjundiah, The Origin of Species After 150 Years: One Hundred and Fifty

Years Without Darwin are Enough, Resonance, Vol.14, No.2, pp.124–153, 2009.


Documents

GENERAL ARTICLE Gálapagos Islands and Darwin’s Theory of