The Ancestor's Tale

The Ancestor's Tale: A Pilgrimage to the Dawn of Life

First edition (UK)
Author	Richard Dawkins & Yan Wong
Language	English
Subject	Evolutionary biology
Publisher	Houghton Mifflin (US) Weidenfeld & Nicolson (UK)
Publication date	1st edition 2004, 2nd edition 2016
Publication place	United Kingdom
Media type	Print
Pages	673 pages in 1st edition and expanded to 800 pages in 2nd ed.
ISBN	978-0544859937
OCLC	1062329664
Dewey Decimal	576.8 22
LC Class	QH361 .D39 2004
Preceded by	A Devil's Chaplain
Followed by	The God Delusion

The Ancestor's Tale: A Pilgrimage to the Dawn of Life is a science book by Richard Dawkins and Yan Wong that delves into the topic of evolution. The book adopts a unique approach, retracing the path of humans in reverse chronological order through evolutionary history. Along the way, it introduces readers to various species, referred to as humanity's cousins, as they converge on shared common ancestors. Drawing on scientific principles and research, "The Ancestor's Tale" offers an accessible and thought-provoking exploration of life's origins and the intricate relationships that connect all living beings.

Synopsis

The book follows a path backwards in time through evolution and meets different groupings of organisms. In this backward chronology, the ancestors of any set of species must eventually meet at a particular moment. The last common ancestor is the one that they all share which the authors call a "concestor". The oldest concestor, LUCA, short for Last Universal Common Ancestor, is the ancestor of all surviving life forms on Earth. The evidence for this is that all organisms share the same genetic code and it is not thought that this code was invented twice. There is no sign of other independent origins of life, and as the book explains, if new life did now arise, its organisms would probably be quickly eaten by existing lifeforms.

The Ancestor's Tale" follows what it calls a "pilgrimage", to discover our ancestors and meet other "pilgrims" (i.e. groups of species) who join as the book reaches a common ancestor that humanity shares with them. The reader reads of 40 rendezvous before hitting the origin of life itself.

The book's structure is inspired by Geoffrey Chaucer's late-14th century work The Canterbury Tales and its pilgrims. For instance, how new species come about, how the axolotl never needs to mature, how hard it is to classify animals, and why our fish-like ancestors moved to the land.

Concestors

The authors use the term concestor, coined by Nicky Warren, for the most recent common ancestor at each rendezvous point. At each rendezvous point, we meet the concestor of ourselves and the listed species or collection of species. The concestor does not have to have been much like those creatures. After the "rendezvous", our fellow "pilgrims" have had as much time to evolve and change as we have. Along the way, the authors introduce new pilgrims who join us on the trip backwards through time.

Chapters

Prologue

Rendezvous point	Time	Significant event	Story
n/a	0.01 mya	Neolithic Revolution	The Farmer's Tale describes the Neolithic Revolution
n/a	0.04 mya	Great Leap Forward	The Cro-Magnon's Tale describes the Great Leap Forward.

Primates

Rendezvous point	Time	New Pilgrim	Story
0		All Humankind	The Tasmanian's Tale illustrates the identical ancestors point starting from which all living people trace exactly the same set of ancestors back in time.
			Eve's Tale touches upon coalescent theory, Mitochondrial Eve, Y-chromosomal Adam and polymorphism. The story ends with speculation that the ABO blood group system in humans and chimps are examples of trans-specific polymorphism; a type-B human may be more closely related to a type-B chimp than type-B human is related to type-A human, from the perspective of the genes (or alleles) responsible for the antigens.
			The Ergast's Tale recounts how a mutated form of the FOXP2 gene could have allowed Homo ergaster to acquire language.
			The Handyman's Tale explains how Homo habilis acquired high 'brain to body mass ratio', at the same time introducing logarithmic scale and scatterplot as tools for scientific studies.
			Little Foot's Tale examines how hominid first learned to walk on two legs.
1	6 mya	Chimpanzees	Human pilgrims join their evolutionary cousins, chimpanzees and bonobos. See also Chimpanzee–human last common ancestor
2	7 mya	Gorillas	The Gorilla's Tale considers human's changing attitude towards the great apes, ending with a discussion on racism, speciesism and the Great Ape Project. See also Gorilla–human last common ancestor
3	14 mya	Orangutans (Pongo)	The Orangutan's Tale introduces the principle of parsimony and its use in construction of family tree (cladogram) of species. Orangutan is the last of the great apes to join the pilgrimage. See also Orangutan–human last common ancestor
4	18 mya	Gibbons (Hylobatidae)	The Gibbon's Tale further elaborates on neighbor-joining, parsimony and textual criticism techniques used to construct cladograms. When the simple principle of parsimony proves inadequate to handle 'long branch attraction' problems caused by convergence. The phylogenetic tree and computational phylogenetic methods such as maximum likelihood analysis are introduced. The tale ends with yet another example of trans-specific polymorphism: sexual dimorphism; the male testis-determining factor gene (SRY) has never been in a female body, at least since long before gibbons and humans diverged. This serves to highlight the fact that different phylogenetic trees can be created by tracing different sets of genes; the one mainstream 'species tree' is nothing more than a summary of multitude of gene trees, a 'majority vote' among gene trees. Gibbon is the last ape to join the pilgrimage. See also Gibbon–human last common ancestor
5	25 mya	Old World monkeys (Cercopithecidae)	Old World monkeys, being in the same Catarrhini clade as apes, are closer cousins to apes than to New World monkeys. Old World monkeys are sometimes called the 'tailed apes'. It is not known if the actual common ancestor had a tail or not.
6	40 mya	New World monkeys (Platyrrhini)	The Howler Monkey's Tale is a story of how gene duplication of genes can create new genes. Over time, these duplicates mutate and drift. Mammals were nocturnal when dinosaurs existed in this world and were dichromatic, but humans are trichromatic. Trichromatic genes originated from a duplication of the opsin gene. Trichromatic vision helps to detect food, and more succulent leaves so over time New and Old world monkeys gained this type of vision through chromosomal translocation. New World monkeys 1st attained trichromacy in the female population by making green and red alleles for the same locus for the opsin gene on the X-chromosome, an example of polymorphism. An example of heterozygote advantage is that the males who have only one copy of the X-chromosome remained dichromats with either a green or a red opsin. Howler monkeys are a type of New World monkey who took it one step further and achieved trichromacy for both sexes by its X-chromosome which obtained two loci for both the green and the red allele. New World monkeys floated over the Atlantic Ocean most likely once and are now found only in South America.
7	60 mya	Tarsiers	Nocturnal animal with enormous eyes. Unlike other nocturnal mammals the eyes do not have a tapetum lucidum which reflects light from the back of the eye for a second exposure on the retina to maximize light capture. The ancestor of the tarsier was a diurnal animal which lost the tapetum lucidum to prevent images from reflected light. Update from the first edition is that the earliest fossil Archicebus was discovered in China. An artist's reconstruction of Archicebus achilles.
8	65 mya	Lemurs and Bushbabies	The pilgrimage meets with the rest of the strepsirrhine cousins: the lemurs, pottos, bushbabies, and lorises. The Aye-Aye's Tale showcases the strange lemurs which are only found on the island of Madagascar. Madagascar was originally part of the Gondwana super-continent which included present Africa continent and Indian subcontinent. Gondwana broke off into drifting blocks of land, some of which became Africa, India and Madagascar. As an estranged island, Madagascar became a speciation hotbed. A small founding population of strepsirrhine primates diversified into all niches of the ecosystem, in the absence of monkeys. Madagascar, with a landmass 1/1000 of Earth's total land area, houses unique species that account for 4% of all species of animals and plants.

The Cretaceous–Paleogene extinction event occurred 65 million years ago, due to an asteroid impact event which created the Chicxulub Crater, possibly aided by large scale volcanic activities in the Deccan traps.

Non-primate mammals

Rendezvous point	Time	New Pilgrim	Story
9	70 mya	Colugos	The mass extinction event made it possible for many different species of shrew-like, nocturnal insectivores to evolve to fill the new ecological voids.
10	70 mya	Treeshrews	Tree shrews look like squirrels but are not rodents. The first edition had #9 and #10 as one connection and this is open to future discovery as there are conflicting studies. This is similar to the Gibbon's Tale.
11	75 mya	Rodents and Rabbitkind (Glires, Supraprimates or euarchontoglires)	Rodents make up more than all the other mammals by individuals and have been carried to every corner of the earth. The large connections coming in are dormice, pikas, squirrels.
			The Mouse's Tale talks about the close similarity between humans and mice and that we both share about 20,000 genes. The phenotypic difference comes from the study of epigenetics which is the expression of the DNA. The genome is not a blueprint where the more complex the animal, the more complex the blueprint ought to be. It is more like a language where the same language can create different books.
			The Beaver's Tale brings back a Dawkins concept he wrote about in The Extended Phenotype. A beaver's body is a phenotype. Like that, a beaver dam is an 'extended phenotypes' of the same beaver genes. Better beaver genes make better beaver bodies, beaver dams and beaver lakes.
12	85 mya	Laurasiatheres	An extremely diverse group of 2,000 species join here, including Carnivora (dogs, cats, bears and seals), Perissodactyla (horses, zebras, tapirs and rhinos), Cetartiodactyla (deer, giraffes, cattle, pigs and hippos), Chiroptera (bats), Insectivora (moles and shrews), etc. They are grouped together based on similar gene sequences and have no common anatomical features. The name comes from the thought that these mammals evolved on the super-continent of Laurasia, after it split from Gondwana when Pangaea broke up.
			The Hippo's Tale is the whale's tale. All cetaceans, including whales, dolphins and porpoises, are descendants of land-living mammals of the Artiodactyl order (even-toed ungulate animals). Both cetaceans and artiodactyl are now classified under the super-order Cetartiodactyla which includes both whales and hippos. Whales are the closest living relatives of hippos; they evolved from a common ancestor at around 54 million years ago. This story illustrates how a species can flip into evolutionary overdrive when it enters into a new environment, while its closest relatives remain unchanged for a long time in their static environment.
			The Seal's Tale illustrates how a sex ratio of 50:50 (males to females) is found in most sexually reproducing animals from both monogamous and polygamous species. In a harem-based (polygynous) system such as that of elephant seals where 4 per cent of males account for 88 per cent of all copulations, the actual sex ratio of 50:50 seems to produce an excess of males who consume resources but end up leaving no offspring. This puzzle is solved by the concept of Fisher's principle (named 'parental expenditure') proposed by R.A. Fisher. This led to further work by Robert Trivers on parental investment to elucidate sexual selection. More importantly, the elephant seal typifies sexual dimorphism, as a bull elephant seal can grow to be three times the size of a cow seal, thanks to sex-limited genes which exist in both male and female bodies, but remain turned off in females. Our immediate human ancestors were probably mildly polygynous.
13	90 mya	Xenarthrans and Afrotheres	These are the last of the placental mammals like elephants, elephant shrews, dugongs, manatees, hyraxes and aardvarks as well as others. The Afrotheres come from Africa and the Xenarthrans from South America. This split looks almost simultaneous. The placement of the three groups remain in doubt, but we are probably more closely related to the Xenarthrans.
			The Sloth's Tale replaces the Armadillo in the 2nd edition, but the story is the same. South America broke off from Gondwana in Early Cretaceous period, then joined North America which broke off from Laurasia. During its long period of isolation, South America was host to marsupials which flourished and took up all carnivorous niches. The placental mammals and now-extinct ungulates evolved to fill the rest of the ecosystem. When South America joined North America during the Great American Interchange 3 million years ago, animals and plants crossed the Isthmus of Panama in both directions, introducing new species to a new land and driving some local species to extinction. Jaguars and other carnivorous placental mammals were introduced to South America, while armadillos migrated to North America.
14	160 mya	Marsupials	Placental mammals meet up with the pouched mammals. Even though present-day marsupials are mostly found in Australia and New Guinea, they originally flourished in North America. Evidence points to the migration of a single species of opossum-like marsupial from South America to Australia before 55 million years ago, when it was still possible to make the journey through Antarctica before Australia pulled too far away from Gondwana. Once settled in the now isolated Australia, these founding marsupials evolved into distinct species and in 40 million years took up the entire range of 'trades' previously occupied by dinosaurs, in the absence of any placental mammals.
			The Marsupial Mole's Tale highlights that the mole niche has been filled by a founding marsupial similar to Golden moles in that they swim through the sand with the tunnel collapsing behind them unlike True Moles There are also marsupial mice (Dasyuridae), marsupial flying squirrels (sugar glider) and marsupial wolf (thylacine), not to mention the equivalent of antelopes and gazelles, the kangaroos and wallabies which despite great differences in shape, cover the same range of diet and way of life as their African counterparts. There are however no marsupial whales or bats as these niches can not be isolated from mammals.
15	180 mya	Monotremes	There are only five surviving species of monotremes. The Echidna probably evolved from the Platypus. They share some mammalian features such as warm-bloodedness, hair and milk production. But they resemble reptiles and birds with a cloaca and egg-laying mode of reproduction.
			The Duckbill's Tale warns us about the fallacy of labelling a half-mammal and half-reptile animal such as the platypus as primitive. The Platypus has had precisely the same time to evolve as the rest of mammals, even if it does not resemble our concestor 15. On its large bill, it has evolved a highly developed form of electroreception served by 40,000 electric sensors, and 60,000 mechanical push rods, which aid it in search of crustaceans in the mud. In humans, the brain dedicates a dis-proportionally large fraction of cells to the two hands, as illustrated by the Penfield homunculus. When the same somatotopic map is drawn for the platypus brain, the bill dominates. Males have poisonous stings in their hindquarters that target the nerve receptors directly.

Non-mammal chordates

Rendezvous point	Time	New Pilgrim	Story
16	320 mya	Sauropsids	The term reptile is not a true clade name, as it fails to include birds which share a common ancestry. Dinosaurs, unfortunately as an extinct species, cannot join us. But their only surviving descendants, the birds, take their place in the pilgrimage.
			The Lava Lizard's Tale is about the animals that inhabit the Galapagos Islands and known for their immense diversity.
			The Galapagos Finch's Tale is an example of how quickly evolution can happen. Peter Grant and his students went to the Galapagos Islands every year to study finches. In 1977, a drought caused a drop in the food supply. The team calculated that the survivors were more than 5% larger. Also, the average beak size was larger in the surviving group. Larger birds with larger beaks were more efficient at dealing with the big seeds which had survived the drought. Also, males were larger than females, and thus the males' larger beaks increased their survival over the females. An increase in survival created a 5:1 sex ratio and competition among the males. The winners of the sexual competition were the largest males with the largest beaks. So natural selection was causing the population to evolve larger body size and larger beaks again, but this time through sexual reproduction. When the drought ended, the large, tough seeds became rare in comparison with the smaller, softer seeds. Now smaller finches with smaller beaks had the advantage because large finches needed more of them to maintain their larger bodies which caused the evolutionary trend of the drought years to reverse.
			The Peacock's Tale is a visualization of sexual selection. Peacock's true tail used to be made out of black feathers, but over time changed through sexual selection. Females prefer males with larger & more attractive feathers so over time, through sexual selection, the feathers became more beautiful. In humans, the female sex evoked faster and grew less hairy. The male sex was "dragged in its wake".
			The Dodo's Tale describes the bird's loss of wings upon first arriving in Mauritius. A pigeon's descendants lost their wings due to the absence of predators. The dodo trusted the Portuguese sailors. Their trust and inability to fly caused their extinction in less than two hundred years by the introduction of dogs, pigs, and rats who ate their eggs and religious refugees who destroyed dodo's habitat by building sugar plantations. Many species of birds have evolved flightless forms on islands.
			The Elephant Bird's Tale is a complete rewrite in the second edition. It discusses the large Moa-like bird of Madagascar and its possible connection to the roc legend.
17	340 mya	Amphibians	Mammals and reptiles (the amniotes) join the amphibians to meet the ancestor of all land vertebrates with four feet, the tetrapod. Amphibians include frogs, toads, salamanders, newts and caecilians. While amniotes either give live births or lay waterproof eggs, the amphibians retain the ancestral practise of laying eggs in water. Unlike the waterproof skin of amniotes, the amphibian skin allows body water to evaporate through it, restricting amphibians to land areas with access to fresh water. Almost no amphibians live in saltwater which explains why they are seldom found on islands. The concestor probably already had settled on five digits on each limb.
			The Salamander's Tale uses examples of ring species to illustrate how a continuous series of interbreeding animals in the spatial dimension is conceptually equivalent to that in the time dimension. The Ensatina salamanders in the Central Valley in California form a continuous ring (actually a horseshoe shape) around the valley. Any two neighbouring population of Ensatina around the horseshoe can interbreed. Still, the plain Ensatina eschscholtzii on the western end of the horseshoe cannot interbreed with the large blotched Ensatina klauberi on the eastern end. Larus gulls form another ring species which starts at the herring gull in Great Britain and end at the lesser black-backed gull in north-western Europe. The authors liken both ring species in space to the ring in time that unites humans and chimpanzees via generations of ancestors over 6 million years, with concestor 1 in the midpoint.
			The Narrowmouth's Tale shows how speciation may still continue via parapatric speciation, when two closely related toad species meet again after initial geographical isolation. Gastrophryne olivacea (Great Plains narrow-mouth toad) and Gastrophryne carolinensis (eastern narrow-mouth toad) are closely related and can interbreed when their habitats overlap. But reinforcement, a selection process which increases reproductive isolation via character displacement, causes both species to differentiate their mating calls from each other by shifting pitch and duration in opposite directions; the more the two populations overlap, the more distinct their mating calls become.
			The Axolotl's Tale is about metamorphosis, a biological process which turns juveniles or larvae into drastically dissimilar adult forms for reproduction, and about pedomorphosis, another process which enables juveniles of some species to become sexually mature without ever developing into their usual adult forms. Species which undergo metamorphosis include butterflies, barnacles and salamanders. Species which exhibit neoteny, a type of pedomorphosis, include human, ostrich, pekingese and axolotl. A textbook example of neoteny, the axolotls are members of the tiger salamander complex, yet they become sexually mature in larva form, remaining aquatic and gilled. With a treatment of thyroxine, it is possible to induce an axolotl to develop into a salamander, demonstrating that axolotl genome still retains information on its lost adult form. On the other hand, the newt, a type of salamander, first develops from tadpole into a land-based salamander, but later reverts to its juvenile tadpole form, and returns to the water to reproduce. The axolotl's tale reminds us that paedomorphosis often allows species to break out of an evolutionary dead-end by sudden changes.
18	415 mya	Lungfish (Dipnoi)	Despite their morphological similarities, the lungfish and coelacanth are very different genetically, as expected of species which lived separately for more than 400 million years. One lungfish has the record for largest genome at 133 billion base pairs compared to our 3 billion base pairs.
			The Lungfish's Tale traces the missing links from ray-finned fish through Tiktaalik. Since the first edition footprints found in Zachełmie, Poland has pushed back the date of first tetrapods by 18 million years. It is possible that this concestor was not trying to get to land but from tide pool to tide pool.
19	420 mya	Coelacanths (Latimeria)	The Coelacanth's Tale describes the discovery of this living fossil once thought extinct and that calling it a living fossil might not be correct. The authors also explain transposable elements.
20	430 mya	Ray-Finned Fish (Actinopterygii)	The current pilgrimage consisting of all descendants of lobe-finned fish is joined by the equally successful ray-finned fishes which includes sturgeon, paddlefish, eel, herring, carp, salmon, trout, seahorse, cod, etc. to meet concestor 19, the bony fish. Of all ray-finned fishes, most belong to the large infraclass teleostei.
			Some teleost fishes evolved unfishy shapes to cope with their chosen ecological niches. The leafy sea dragon, for instance, abandons the typical streamline fish shape which works so well for the majority of fishes. Instead, it adopts a leafy form to hang motionless in kelp forest, pretending to be a piece of seaweed. The razorfish takes up an elongated, laterally compressed body, together with a long, flattened snout. It swims in a head-down vertical stance, allowing it to hide amongst tall spines of a sea urchin. The snipe eel is ridiculously thin, while the gulper eel sports jaws which look disproportionally large for its body. Lastly, the ocean sunfish resembles a vast, two-ton disc or millstone, as its Latin name, Mola mola, suggests. The Leafy Sea Dragon's Tale demonstrates how animal shapes are malleable, ever-changing to meet the requirements of each animal's way of life.
			The Pike's Tale describes the swim bladder. Contrary to common assumptions, the swim bladder did not evolve into lungs. Instead, the bony fish ancestor possessed a primitive lung which was co-opted by teleost fishes for buoyancy control, and in some cases as an ear drum for hearing. The teleost fishes rely on gills for breathing underwater. They re-purposed the primitive lung, turning its ability to absorb and release gas into the bloodstream to allow fish to move vertically in a water column.
			The Mudskipper's Tale was in the 1st edition and deleted in the 2nd edition.
			The rapid speciation of haplochromine cichlid fishes endemic to Lake Victoria, Lake Malawi and Lake Tanganyika exemplifies adaptive radiation and species flock. The Cichlid's Tale recounts how, by constructing an "unrooted haplotype network" using phylogenetic analysis on mitochondrial DNA of living species, researchers were able to infer the time and the location of each major speciation event. The haplotype network differs from a normal phylogenetic tree in that each node represents a haplotype, not a species, and the node size is determined by several species in which the haplotype is found.
			The Blind Cave Fish's Tale illustrates how normal organs can degenerate into vestigial organs. Different populations of Mexican tetra (Astyanax mexicanus) have ventured into dark caves separately, and each has evolved regressive traits such as white skin colouration or blind eyes. This could be explained by the opportunity cost theory; resources wasted on building the eye in a pitch-black cave deprive the fish of other traits more useful for such environment. Blind fish do not roll back the mutations that led to eyes. Dollo's Law explains that evolution cannot be precisely and exactly reversed.
			The Flounder's Tale is a tale of imperfection. The flounder's contorted head and eyes allow it to lie on its side on the ocean floor, and betray the lack of an intelligent designer. Natural selection works without foresight and makes gradual improvements on existing body plans. Because each creature at every step of the process must remain fit for its environment, evolution cannot make sudden and drastic changes to build a better future organism at the expense of the current generation.
21	460 mya	Sharks (Chondrichthyes)	Sharks, rays and the related animals are supported by a cartilaginous skeleton that never ossifies to become bone. Their skin is covered in dermal denticles, tiny scale-like protrusions, from which teeth may have evolved. Sharks lack a swim bladder for buoyancy and instead rely on constantly swimming, retaining urea in their blood, and having large livers with plenty of oil to remain afloat. Concestor 21 was an ancestor to all gnathostomes, animals with lower jaws, a structure which evolved from the gill arches.
22	525 mya	Lampreys and Hagfish (Cyclostomata)	Jawless and limbless fishes, the lampreys and hagfish, join the pilgrimage to meet the concestor of all vertebrates. The jawless fish and the concestor 22 are borderline vertebrates. Unlike the rest of vertebrates, they retain the notochord, a stiffening cartilage rod running along the back of an animal, well into adulthood. In all other vertebrates, the vestigial notochord appears in the embryo briefly and is replaced by segmented, articulate backbones in adults. On the other hand, both the jawless fish and the jawed fish share characteristics common to all members of the phylum Chordata at some time in their life cycle, including the notochord, pharyngeal slit, and the post-anal tail.
			The Lamprey's Tale further develops the gene's eye view of ancestry and pedigree that earlier tales alluded in The Eve's Tale and The Gibbon's Tale. In humans, four haemoglobin genes are known to be cousin genes of each other. An ancestor globin gene from an ancient vertebrate split into two genes, alpha and beta, which ended up in two different chromosomes and continued to evolve independently. Both alpha and beta further split into more independently evolving genes. All jawed fish show such alpha/beta split as predicted by evolution. However, lampreys and hagfish are ancient enough that they predate this gene split. Jawless fishes, whenever investigated, do not possess split globin genes. As Dawkins explained in the chapter 'All Africa and her progenies' in his book River out of Eden, there are two ways to trace ancestry: via animals and individual genes. The two mechanisms produce very different results. Ancestry of animals forms a family tree (more correctly, a graph because sexually reproducing animals may share female and male parents). On the other hand, the ancestry of an individual gene is always a single chain going back to the first self-replicating RNA, since a gene is either a faithful copy or a mutated form of its single parent gene. The Ancestor's Tale is written from an animal's perspective, following the family tree of human backwards in time. But the book could have been written from the gene's point of view. Starting from any gene (e.g. the alpha haemoglobin), each gene duplication event could become a rendezvous point where pilgrimage of genes join their cousin genes.
23	535 mya	Sea Squirts (Urochordata)	The lancelet and sea squirt have been switched in the second edition based on DNA studies. A sea squirt resembles a sedentary bag of seawater anchored to a rock. It feeds on food particles strained from water. Anatomically, the sea squirt looks very different from the joining pilgrimage of all vertebrates and protochordates, that is, until its larvae are examined. The sea squirt larva looks and swims like a tadpole. It possesses a notochord and a dorsal nerve tube and moves by undulating its post-anal tail from side to side. Vertebrates may have branched off from ancient sea squirt larvae via neoteny, in a process reminiscent of The Axolotl's Tale. But recent DNA analysis on larvaceans favours Darwin's initial interpretation, that one branch of ancient tadpole-like protochordates evolved a new metamorphosis stage to turn into sedentary sea squirts. Sea squirts have some of the fastest recorded rates of molecular evolution.
24	540 to 775 mya	Lancelets (Amphioxiformes)	Lancelets are a text book example of a chordate. Equipped with a notochord, a nerve tube on the dorsal side and gill slits, they typify the phylum Chordata. But lancelets are not primitive nor our remote ancestor. They are as modern as all other members in the pilgrimage.
			The Lancelet's Tale continues to develop the theme introduced in The Duckbill's Tale, that all living animals have had equal time to evolve since the first concestor, and that no living animal should be described as either lower or more primitive. The authors extend this concept to apply to fossils as well. Even though it is tempting to label fossils as our remote ancestor, they are more accurately described as our distant cousins who have been frozen in time.

Non-chordate animals

From the lancelets onward, the authors provide dates under duress stating that "dating becomes so difficult and controversial that my courage fails me".

Rendezvous point	Time	New Pilgrim	Story
25	550 mya	Ambulacrarians	This diverse group includes the echinoderms, along with some organisms labelled "worms" and even Xenoturbella, which until 2016 could not be classified at all, but analysis of its genes finally established its position as a distant relative of the echinoderms.
26	560 mya	Protostomes	Differences between protostomes and deuterostomes The protostomes join the deuterostomes, and this joint is the originator of the kingdom Animalia. Protostomes (meaning 'mouth first') and deuterostomes (meaning 'mouth second') are based on the way animal embryos diverge after gastrulation where the blastula (a hollow ball of cells) indents to form a cup. In the sub-kingdom of protostomia, the indentation eventually becomes the mouth. In deuterostomia which includes humans, the indentation eventually becomes the anus; the mouth is formed later. This ancestor is sometimes referred to as Urbilaterian. This brings in the Insecta which represent three-quarters of all animal species on Earth.
			The Ragworm's Tale talks about the evolution of left-right symmetry in bilaterians.
			The Brine Shrimp's Tale discusses the possibility of chordates having a back-swimming ancestor.
			The Leaf Cutter's Tale discusses town like ant societies and their agricultural use of fungi.
			The Grasshopper's Tale talks about the futility of discriminating between races.
			The Fruit Fly's Tale introduces Hox genes.
			The Rotifer's Tale talks about the wonderful paradox of sexual and asexual reproduction.
			The Barnacle's Tale talks about palaeontology and the deceptiveness of weird-looking organisms.
			The Velvet Worm's Tale talks about the Cambrian explosion.
27	570 mya	Acoelomorph Flatworms	Still under debate on how this group fits in due to a long period of molecular evolution similar to the Gibbons Tale. These flatworms lack an anus or a coelom. The organs do not sit in a coelom but a parenchyma and is the reason for the name of the group.
28	590 mya	Cnidarians	The Jellyfish's Tale discusses how some underwater organisms migrate between different depths due to day and night cycles.
			The Polypifer's Tale covers Charles Darwin's explanation on how the coral reefs were formed. Then the section considers apparent similarities of ecological communities such as tropical forests or coral reefs to single body organisms. The cooperation of the organisms emerges because it is useful for the specific individuals who are willing to cooperate rather than because it is useful to the community as a whole.
29	600 mya	Ctenophores (Comb jellies)	It is not completely clear whether Ctenophora should be placed here as an outgroup to all animals and actually at rendezvous 31. But this would mean that they either independently invented muscle, nerves, cell layers or that the sponges lost them: only 100 species but quite numerous. DNA studies are also complicated by incomplete lineage sorting like with the Gibbon.
30	620 mya	Placozoans	Only one species identified. It looks like a multicellular amoeba.
31	650 mya	Sponges	The last animal of the chain. Do not move but have a coordinated movement between cells. Also, seems to be two lines of sponges based on molecular data. Sponge cells are totipotent.
			The Sponge's Tale is an early 1907 experiment on mixing different sponge species cells to form new adult forms.

Non-animal eukaryotes

There are essential differences between the 1st and 2nd editions of the book in this section. Another rendezvous has been added (#33), and the unknown rendezvous has been partially resolved.

Rendezvous point	Time	New Pilgrim	Story
32	800 mya	Choanoflagellates (Choanoflagellatea)	The Choanoflagellate's Tale is about the evolution of multicellularity. Choanoflagellates are the closest living relatives of the multicellular animals, and can form temporary colonies from a free-living unicellular stage. Sponges have choanocytes, cells that resemble single-celled choanoflagellates, providing an indication about how multicellularity may have evolved. This common ancestor is sometimes called urmetazoan and several theories have been developed on its evolution.
33	900 mya	Filastereans (Filasterea)	New addition to 2nd edition based on 2008 work. Pushes all others back one.
34	1000 mya	DRIPs (Mesomycetozoea)	The acronym comes from the letters of the four genera that were first known. These are single-cell parasites of fish and other freshwater animals. DNA sequencing has added about 50 species. Of course, this concestor could not have been a parasite of a fish.
35	1200 mya	Fungi	Only 99,000 of the 4 million estimated species have been identified.
36	(?)	Uncertain	A protozoan grouping called Apusozoa made up of 3 protist groups breviata, ancyromonads and apusomonads.
37	(?)	Amoebozoans (Amoebozoa)	'Amoeba' is a description rather than a classification because many unrelated eukaryotes exhibit an amoeboid form.
38	(?)	Very large group of light harvesters and their kin: excavates, SAR supergroup, 20 species of single-celled glaucophytes, over 4,000 species of red algae, and hundreds of thousands of species of green plants.	The Cauliflower's Tale tells the story about how geometrical considerations of constructing the most efficient supply tube network in tissues dictate a scaling exponent of 3/4 for such different structures as cauliflower and our brain.
			The Redwood's Tale explains different methods of radiometric dating such as Uranium–lead dating and Potassium-argon dating for old rocks all the way to Carbon dating to date material within the last 20,000 years.
			The Humped Bladderwort's Tale explains C value which is the amount of DNA in an organism.
			The Mixotrich's Tale is about the protist inside an Australian termite that has four different symbionts inside and on the surface of the organism.

Great Historic Rendezvous

This is a significantly shorter section in the second edition. The authors describe the critical beginnings of eukaryotic cells and describe the endosymbiotic theory proposed by Lynn Margulis.

Prokaryotes

Prokaryotes can move genetic material between unicellular and multicellular organisms other than by the ("vertical") transmission of DNA from parent to offspring by way of horizontal gene transfer.

Rendezvous point	Time	New Pilgrim	Story
39	(?)	Archaea	Archaea possess genes metabolic pathways more closely related to eukaryotes such as the enzymes involved in transcription and translation (biology).
40	(?)	Eubacteria	The Rhizobium's Tale talks about the evolution of the wheel in the flagella and how hard it is for larger organisms to develop wheels
			Taq's Tale on the versatile enzyme used for PCR.

Origin of life

The authors elaborate at length about the possible origins of life through the RNA world, enterobacteria phage Qbeta, the Miller–Urey experiment, Spiegelman's Monster and the possible hypercycle of DNA, RNA, and enzymes which work together to support each other in a primordial world.

Reception

Carl Zimmer of the New York Times stated that the book is one of the best to understand evolutionary trees.

The Guardian thought it was awkward to move backward in time starting from humans and thought this required linguistic gymnastics with new definitions of before and after a certain evolutionary point. Matt Ridley at The Guardian liked the approach of a Chaucer Pilgrim traveling backwards and the perspective of not seeing other animals as failures.

Translations

Translations

Edition	Name	Translator	Year
Bulgarian	Сказанието на прадедите	Krassimira Mateva (Красимира Матева)	2013
Chinese (Traditional)	祖先的故事	Gu Xiaozhe (顧曉哲)	2020 (2nd edition)
Czech	Příběh předka	Pavel Růt	2008
Danish	Vores forfædres fortælling	Lotte Follin	2019 (2nd edition)
Dutch	Het verhaal van onze voorouders	Mark van Nieuwstadt	2007
French	Il était une fois nos ancêtres	Marie-France Desjeux-Lefort	2007
German	Geschichten vom Ursprung des Lebens	Sebastian Vogel	2008
Hungarian	Az Ős meséje – Zarándoklat az élet hajnalához	Kovács Lajos	2006
Italian	Il racconto dell'antenato	L. Serra	2004
Korean	조상 이야기	Lee Han-eum (이한음)	2005
Persian	داستان نیاکان
Polish	Opowieść przodka	Sobolewska Agnieszka	2018
Portuguese	A grande história da evolução	Laura Teixeira Motta	2009
Spanish	Historia de nuestros ancestros	Víctor Vicente Úbeda	2008
Turkish	Ataların hikâyesi	Ahmet Fethi	2015
Serbian	Priče naših predaka	Tatjana Bižić	2013
Russian	Рассказ предка	S. I. Dolotovskaya (С. И. Долотовская)	2015

See also

• Evolutionary history of life
• Phylogenetic tree
• Timeline of evolution
• Timeline of human evolution

External links

• Video introduction by Richard Dawkins
• Richard Dawkins talks to Ira Flatow on "Science Friday"
• Family and kid's experiential programs based on Ancestors Tale, by Connie Barlow, with video, slides and scripts.
• OneZoom, an interactive fractal explorer of the tree of life, used to make the visualizations in The Ancestor's Tale.