203 Fun Facts About Evolution

In biology, evolution is defined as the change in what over successive generations?

Heritable characteristics of populations are what shift: no single organism evolves during its lifetime, but the mix of inherited traits across a population changes as the generations pass.

Which two British naturalists independently conceived the theory of evolution by natural selection?

Charles Darwin and Alfred Russel Wallace: their papers were read together at the Linnean Society of London on 1 July 1858, after Wallace mailed Darwin an essay that matched his own unpublished theory.

Which phrase coined by Herbert Spencer did Darwin adopt in later editions of On the Origin of Species?

Survival of the fittest was Spencer's phrase of 1864; Wallace urged Darwin to borrow it because 'natural selection' made nature sound like a conscious chooser.

What is the ultimate source of all genetic variation in organisms?

Mutation, a change in the DNA sequence, supplies the raw material: selection, gene flow and drift can only spread, shuffle or remove variants that a mutation has already produced.

What is the chance fluctuation of allele frequencies from one generation to the next called?

Genetic drift is change by luck of the draw: which individuals happen to breed shifts allele frequencies, and in a small population a variant can vanish or take over within a few generations, helpful or not.

The neutral theory holds that most evolutionary change at the molecular level results from what?

Random drift fixing harmless mutations: because such neutral changes pile up at a fairly steady rate, the theory gave biologists a rationale for the molecular clock used to date when lineages split.

How is an organism's evolutionary fitness measured?

By its ability to survive and reproduce, counted in genes passed to the next generation: the winner is not necessarily the strongest, fastest or biggest animal, just the one leaving most descendants.

What is a 'throwback' trait like hind legs in dolphins, from reactivated dormant genes, called?

An atavism is an ancestral trait that resurfaces: in 2006 Japanese fishermen caught a bottlenose dolphin with an extra pair of fins near its tail, thought to be remains of its land-living ancestors' hind legs.

Which term describes natural selection that favours both extremes of a trait over the average?

Disruptive selection favours both extremes: among Africa's black-bellied seedcrackers, small-billed birds specialise on soft sedge seeds and large-billed birds on hard ones, so in-between bills lose out.

Cumbersome antlers, mating calls and bright male colours are products of which evolutionary process?

Sexual selection, Darwin's term for competition over mates, produces costly ornaments like antlers and bright plumage because they raise mating success even at a cost to survival.

In a famous long-term laboratory experiment, E. coli evolved the ability to use what as a nutrient?

Citric acid: after tens of thousands of generations, one of the twelve E. coli lines Richard Lenski started in 1988 began feeding on the citrate in its broth, which the species normally cannot use when oxygen is present.

Why do a bat's wing, a mouse's foot and a human hand share the same bones?

Descent from a common mammalian ancestor: evolution reworks inherited parts instead of starting afresh, so one set of bones was stretched into a bat's wing and shortened into a grasping hand.

Which of these human body parts is considered a vestigial structure?

The coccyx, or tailbone, is what is left of the tail our ancestors lost; every human embryo still grows a small tail for a few weeks before it shrinks away.

What is the term for a structure that evolved for one function but became useful for another?

An exaptation is a trait co-opted for a new job: feathers probably first evolved to keep their owners warm, and only later were pressed into service for flight.

Bones that form the jaw in other animals develop into which structure in mammals?

Part of the middle ear: the two bones that hinged the jaw of early reptile-like ancestors shrank into the malleus and incus, so mammals hear with bones their forebears chewed with.

A mutation in chickens can make embryos grow which features, lost by birds tens of millions of years ago?

Teeth: chicken embryos with the talpid2 mutation sprout cone-shaped teeth like an alligator's, showing that birds, toothless for at least 70 million years, still carry the genetic recipe.

Which evolutionary biologist defined the Biological Species Concept in 1942?

Ernst Mayr came to the question as a bird man: he had spent over two years collecting thousands of bird skins in New Guinea and the Solomon Islands before arguing that who can mate with whom, not looks, marks out a species.

Which mode of speciation, the commonest in animals, occurs when populations are geographically separated?

Allopatric speciation begins when a river changes course or a mountain range rises and splits a population; cut off, the two groups change independently until they can no longer interbreed.

Which effect, a loss of genetic variety when a few individuals start a new colony, drives peripatric speciation?

The founder effect: a handful of colonists carry only a sample of the parent population's genes, so the colony starts out different and, being small, shifts further by chance with each generation.

The grass Anthoxanthum odoratum undergoes parapatric speciation in response to what?

Metal pollution from mines: sweet vernal grass on old mine spoil evolved heavy-metal tolerance and a shifted flowering time, reducing interbreeding with neighbouring non-tolerant plants, a textbook case of incipient parapatric speciation.

The plant Arabidopsis suecica arose as a new species through which process, common in plants but rare in animals?

Hybridisation with chromosome doubling made Arabidopsis suecica: a cross of thale cress with a relative kept both parents' full chromosome sets, leaving it fertile by itself but unable to breed with either parent.

Which theory explains the fossil pattern of short bursts of evolution between long periods of stasis?

Punctuated equilibrium, proposed in 1972, holds that species stay stable for long spans and change rapidly at speciation in small isolated populations that rarely fossilise; it contrasts with phyletic gradualism.

Which mass extinction event was the largest in Earth's history, killing most marine species?

The Permian–Triassic extinction, about 252 million years ago, came closer than any other to ending animal life; the prime suspect is a vast outpouring of magma in Siberia known as the Siberian Traps.

Roughly what proportion of all species that have ever lived on Earth are now extinct?

More than 99% of all species are gone because extinction is the normal fate of a species: a typical one lasts less than ten million years before it dies out.

What does the acronym LUCA stand for?

Last universal common ancestor: LUCA was not the first living thing, only the most recent one from which everything alive today descends; a 2016 study traced 355 of its gene families.

How old is the Earth?

About 4.54 billion years: the figure comes from meteorites, because plate tectonics has recycled Earth's own first rocks; the benchmark is lead from an iron meteorite that fell at Canyon Diablo, Arizona.

Where were microbial mat fossils found in 3.48-billion-year-old sandstone?

Western Australia: 3.48-billion-year-old rocks of the Pilbara's Dresser Formation carry cracks, tufts and gas domes identical to those microbial mats leave on shorelines today, which is how they were read as life.

Which ape is, together with the chimpanzee, the closest living relative of humans?

The bonobo and the chimpanzee are equally our closest kin. The Congo River keeps the two apart, bonobos to its south and chimpanzees to its north, because neither ape swims well.

What do eukaryotic cells, such as those of animals and plants, have that bacteria lack?

A nucleus: eukaryotes wall their DNA inside one, while bacteria leave theirs loose in the cell. Our own red blood cells are the odd ones out: they push the nucleus out as they mature, which leaves more room for haemoglobin.

In which event do most major animal groups first appear in the fossil record?

The Cambrian explosion put most major animal groups into the rocks in a geologically short span; it was long thought to mark the very first animals, until older fossils turned up in the Ediacaran rocks beneath.

Which group of animals makes up the majority of animal species today?

Insects make up more than half of all known animal species, about a million named so far; they are the only invertebrates ever to evolve flight, which played a large part in their success.

The oldest known Homo sapiens fossils, about 300,000 years old, were found at Jebel Irhoud in which country?

Morocco: redated in 2017, the Jebel Irhoud skulls pushed the origin of our species back by about 100,000 years and showed it was not confined to East Africa, long seen as its cradle.

Which pre-Socratic philosophers first suggested one organism could descend from another?

Anaximander and Empedocles: the first held that humans began inside fish-like creatures in the water, the second that stray limbs once wandered alone and joined at random into living things.

Which Arab scholar wrote in his 1377 Muqaddimah that humans developed from 'the world of the monkeys'?

Ibn Khaldun, a historian often called a forerunner of sociology, pictured creation climbing step by step from minerals to plants to animals, with the monkeys as the last stage before man.

Whose 1809 'transmutation' theory was the first full-fledged evolutionary scheme?

Jean-Baptiste Lamarck held that traits built up by use, or withered by disuse, pass to offspring; the mechanism failed, but Darwin credited him with first arguing that species change by natural law, not miracle.

Whose 1798 Essay on the Principle of Population influenced Darwin's idea of a 'struggle for existence'?

Thomas Robert Malthus argued in his 1798 Essay that populations outgrow their food supply; Darwin read it in 1838 and drew from it the 'struggle for existence' that drives natural selection.

Which American palaeontologist showed Thomas Huxley a fossil horse series in 1876, classic evidence for evolution?

Othniel C. Marsh of Yale laid out his American fossil horses for Thomas Huxley, who was so struck that he rewrote the lecture he was about to give in New York; Marsh drew the chart he showed the audience.

What did Darwin call his provisional, and ultimately wrong, theory of heredity?

Pangenesis, Darwin's 1868 hypothesis, held that every cell sheds 'gemmules' that gather in the reproductive organs; Mendel's laws, rediscovered in 1900, displaced it.

Which scientist distinguished germ cells from somatic cells, showing heredity passes only via the germ line?

August Weismann argued that only germ cells carry heredity; to show that changes to the body are not passed on, he cut the tails off generation after generation of mice, and every pup was still born with one.

Who wrote in 1973 that 'nothing in biology makes sense except in the light of evolution'?

Theodosius Dobzhansky, a geneticist and a religious believer, wrote the essay for biology teachers to argue that faith and evolution need not clash: 'I am a creationist and an evolutionist,' he declared in it.

Which genes, first studied in fruit flies, lay out the head-to-tail body plan?

Hox genes, discovered through fruit-fly mutants with legs growing from the head, control where body segments form from head to tail and are shared across animals, a central subject of evo-devo.

What is the 1925 Tennessee case that convicted a schoolteacher of teaching evolution called?

The Scopes trial was staged: town leaders in Dayton recruited teacher John Scopes to be charged, hoping the publicity would put their town on the map. The jury took nine minutes to convict him, and the judge fined him $100.

Which 2005 court case ruled that teaching 'intelligent design' in public-school science classes was unconstitutional?

Kitzmiller v. Dover was decided by John E. Jones III, a judge appointed by George W. Bush, who ruled that intelligent design was religion, not science; Dover's voters had already thrown out the school board behind it.

Breeding together different cave populations of which blind fish produced offspring with working eyes?

The Mexican tetra, Astyanax mexicanus: Richard Borowsky's 2008 crosses between different blind cave populations produced sighted offspring, because different mutations had knocked out sight in each cave and complemented each other.

After studying a Madagascan orchid with a foot-long nectar tube in 1862, Darwin predicted which undiscovered pollinator?

A moth: Darwin reasoned that only a creature with a tongue nearly a foot long could reach the nectar, and just such a hawkmoth turned up in Madagascar about twenty years after his death.

Which ability did a duplicated light-sensing gene give Old World monkeys and apes?

Red-green colour vision came with a second copy of a light-sensing pigment gene on the X chromosome, tuned to a different colour. With both genes on the X, men, who have only one X, are far likelier to be red-green colour-blind.

What is the intentional breeding of domesticated plants and animals for chosen traits called?

Artificial selection turned one wild mustard plant into cabbage, broccoli, cauliflower and kale, each bred up from a different part of it; Darwin used breeders' results as his model for selection in nature.

Darwin wrote in 1837 that the 'tree of life' should perhaps be called what, its base branches being dead?

The coral of life: Darwin jotted the thought in his first notebook on species, and a few pages later drew his famous first branching diagram of related forms beneath the words 'I think'.

Superbugs such as MRSA have evolved resistance to which kind of medicine?

Antibiotics kill the susceptible bacteria and spare any that carry a protective genetic change; the survivors multiply and pass it on, so the next infection shrugs the drug off.

Which English naturalist gave an early biological definition of 'species' in his 1686 Historia Plantarum?

John Ray wrote it long after leaving Cambridge: he resigned his fellowship there in 1662 rather than swear the oath the Act of Uniformity required of him.

Where is Charles Darwin buried?

Westminster Abbey: Darwin had expected a grave in his village churchyard, but colleagues and members of Parliament pressed for the Abbey, where he lies a few feet from Isaac Newton.

At which university did the young Darwin neglect his medical studies to investigate marine invertebrates?

Edinburgh bored and horrified him: Darwin found the lectures dull and fled an operation on a child, done without anaesthetic; he never went back to the theatre, and left without a degree.

How many years did Darwin's voyage aboard HMS Beagle last?

Five: the Beagle left Plymouth on 27 December 1831 and returned to Falmouth on 2 October 1836, nearly five years, though Darwin had been told it would take two.

Which publisher of Austen and Byron brought out On the Origin of Species?

John Murray printed 1,250 copies, and booksellers took up every available one at his trade sale, before the book had even reached the shops.

Whom did Charles Darwin marry in January 1839?

Emma Wedgwood was Darwin's first cousin; before proposing he drew up a list headed 'Marry' and 'Not Marry', and decided a wife would be a 'constant companion' and 'better than a dog anyhow'.

Which Galápagos animals did the islands' vice-governor tell Darwin he could assign to their home island at a glance?

Giant tortoises: vice-governor Nicholas Lawson said he could tell which island any tortoise came from, a remark Darwin admitted he paid too little attention to until his collections were already mixed.

Which ailment plagued Darwin throughout his years aboard HMS Beagle?

Seasickness struck Darwin as soon as the Beagle left Plymouth and never let go, so he was glad to spend most of the voyage exploring on land while the ship surveyed the coast.

Which book, read during the Beagle voyage, convinced Darwin that landscapes are shaped by slow, gradual change?

Lyell's Principles of Geology: FitzRoy gave Darwin the first volume before sailing, and at the very first landfall, in the Cape Verde islands, he was already reading the cliffs Lyell's way.

Darwin dug up bones of Megatherium, a giant extinct relative of which living animal?

The sloth: Megatherium was a ground sloth as heavy as a bull elephant, and finding such giants buried in the land where their small relatives still live set Darwin thinking about how species succeed one another.

The Wallace Line, dividing Asian from Australasian wildlife, runs through the narrow strait between Bali and which island?

Lombok lies only a short sail from Bali, but the strait between them is so deep that it stayed open sea when ice-age land bridges joined other islands, so the two kept different animals.

Wallace is sometimes called the father of which scientific discipline?

Biogeography: Wallace's 1876 book The Geographical Distribution of Animals carved the world into six great wildlife regions, a map of where animals live that zoologists still work from.

In which river basin did Wallace begin his extensive fieldwork?

The Amazon: Wallace spent 1848 to 1852 collecting along the Amazon and Rio Negro, losing most of his specimens when his ship burned on the return voyage.

What term did Mendel use for a trait that vanished in the first generation and returned in a quarter of the next?

Recessive: green seeds disappeared when Mendel crossed green with yellow, then came back in about one plant in four of the next generation, showing that the hidden factor had been carried intact, not blended away.

In the garden of an abbey in which city, now the Czech Republic's second-largest, did Gregor Mendel run his experiments?

Brno's Augustinian abbey of St Thomas took Mendel in as a young friar; he later became its abbot, and the paperwork of the office left him no time for the breeding work that made his name after his death.

Thomas Henry Huxley's combative public defence of evolution earned him which nickname?

Darwin's Bulldog: Huxley fought the public battles the retiring Darwin avoided, yet until the Origin appeared he had been a sceptic who doubted that species changed at all.

Which word did Thomas Huxley coin in 1869 to describe his own stance on religious questions?

Agnosticism: Huxley built the word from the Greek for 'not known', as the opposite of the 'gnostics' of church history who claimed special knowledge, to label someone who admits to not knowing.

Which bishop supposedly asked Huxley whether he descended from a monkey via his grandfather or grandmother?

Samuel Wilberforce, Bishop of Oxford, is said to have put the jibe to Huxley at the British Association's 1860 meeting; no word-for-word record survives, and Huxley's famous reply preferring the ape is known only from later accounts.

Which Scottish publisher secretly wrote the 1844 evolutionary bestseller Vestiges of the Natural History of Creation?

Robert Chambers hid his authorship because he feared the scandal would ruin his publishing firm; the secret was officially revealed only in 1884, thirteen years after his death.

Which anatomist is said to have coached the Bishop of Oxford before his 1860 debate with Huxley?

Richard Owen, the anatomist who coined the word 'dinosaur', had already savaged the Origin in an anonymous review; he and Huxley were also feuding over whether the brains of apes and humans differ.

To which bird family do Darwin's finches actually belong?

Tanagers: DNA shows that every one of the birds descends from a single flock of small mainland tanagers, kin of today's dull-coloured grassquit, that reached the islands and then split into more than a dozen species.

Which Galápagos birds, rather than the finches, first alerted Darwin to species differing from island to island?

Mockingbirds: Darwin saw that they differed from one island to another and noted where each was caught, while he took so little care over the finches now named after him that his specimens were mingled together.

Which of Darwin's finches lives outside the Galápagos, on an island belonging to Costa Rica?

The Cocos finch lives only on Cocos Island, far out in the Pacific off Costa Rica; DNA shows that its ancestors flew there from the Galápagos, not from the mainland.

The rise of dark peppered moths in 19th-century England is an example of what phenomenon?

Industrial melanism: soot killed the pale lichen on tree trunks and left dark moths the better hidden, so the black form took over industrial England; once clean-air laws cut the smoke, the pale form came back.

Bernard Kettlewell's 1950s experiments showed which predators picking off peppered moths that stood out against tree bark?

Birds: Kettlewell released marked moths in a sooty wood near Birmingham and a clean one in Dorset and found birds taking whichever colour stood out; a later repeat of the work by Michael Majerus confirmed it.

On which Arctic island, Canada's northernmost, were the first Tiktaalik fossils found in 2004?

Ellesmere Island: Neil Shubin's team went there because its rocks were the right age and kind, river deposits about 375 million years old, to hold a fish on its way onto land, and it still took them years of searching.

From which geological period does Tiktaalik date?

Late Devonian: Tiktaalik lived about 375 million years ago, in the Late Devonian, and its fins had sturdy interior bones that let it prop itself up in shallow water.

All Archaeopteryx fossils come from limestone quarried near which German town?

Solnhofen limestone is so fine-grained that it was quarried for lithographic printing plates, which is why it kept the imprint of feathers; the first skeleton surfaced in 1861, two years after the Origin.

What does the name Archaeopteryx mean?

Ancient wing: the name joins the Greek for 'ancient' and 'wing', and the animal carried a bird's feathers and wings on a body that still had a reptile's teeth, clawed fingers and long bony tail.

Who discovered the Australopithecus skeleton 'Lucy' in Ethiopia in 1974?

Donald Johanson, with graduate student Tom Gray, found Lucy at Hadar in Ethiopia's Afar region on 24 November 1974; she was named after 'Lucy in the Sky with Diamonds', played repeatedly in camp that night.

Lucy's skeleton showed which trait predated big brains?

Walking upright: Lucy's pelvis and angled thigh bones were built for striding on two legs, yet her brain was still ape-sized; with about 40 percent of her skeleton recovered, the case was hard to dispute.

Humans have 23 pairs of chromosomes and other great apes 24 because of what change in our ancestors?

Two chromosomes fused: human chromosome 2 still carries the scar, a stretch of chromosome-tip DNA stranded in its middle and the remains of a second centromere, matching two separate chromosomes in chimpanzees.

Which archaic human is generally thought the first to leave Africa and use fire?

Homo erectus had the long legs and shorter arms of a full-time walker, the build that carried it out of Africa and across Asia; it lasted more than 1.5 million years, far longer than our own species has so far.

Under what genus and species name did Eugène Dubois publish Java Man in 1894?

Pithecanthropus erectus: Dubois's 1894 monograph named the Trinil skullcap, molar and femur Pithecanthropus erectus, 'upright ape-man'; the species was later folded into Homo erectus.

Eugène Dubois, who found Java Man in 1891, had reached the Dutch East Indies by enlisting as what?

An army surgeon's post was the only way Dubois could get to the colony to hunt for the 'missing link', so he gave up a university career in Amsterdam and enlisted.

Neanderthals are named after a valley in which country, where the first recognised bones turned up in 1856?

Germany's Neander Valley gave the species its name, though skulls found earlier in Belgium and Gibraltar were only recognised as Neanderthal afterwards.

Roughly what share of the DNA of people outside Africa comes from Neanderthals?

About 2%: the 2010 draft genome put the figure at 1 to 4 percent, evidence that modern humans leaving Africa interbred with Neanderthals instead of simply replacing them.

The first Denisovan was identified in 2010 from DNA in what remains from a Siberian cave?

A juvenile finger bone from Denisova Cave held DNA unlike any known human's, and traces of that lost lineage survive today in the genomes of Melanesians.

What nickname was given to the huge Harbin skull, named Homo longi in 2021 and linked to Denisovans in 2025?

Dragon Man is named after Heilongjiang, the 'Black Dragon River' province; the skull is said to have been hidden down a well for decades before scientists saw it.

Homo floresiensis, nicknamed the 'Hobbit', was discovered in 2003 in which cave?

Liang Bua, a limestone cave on Flores, was being dug by an Indonesian-Australian team looking for traces of the first modern humans to reach Australia when the tiny skeleton turned up.

Which explanation do most researchers favour for the small body size of Homo floresiensis?

Insular dwarfism: on a small island with limited food and few predators, large animals tend to evolve smaller bodies, as the extinct pygmy elephants of Flores also did.

Homo naledi was discovered in 2013 in which South African cave system?

Rising Star: cavers found the bones in the Dinaledi Chamber of the Rising Star cave system near Johannesburg in 2013, and Lee Berger's team recovered more than 1,550 specimens from at least 15 individuals.

Which living animals are the closest relatives of whales and dolphins?

Hippopotamuses were long classed with pigs on the strength of their teeth, until blood proteins and then DNA showed that whales and dolphins are their closest living kin.

In which country did Hans Thewissen's team unearth Ambulocetus, the 'walking whale', in 1992?

Pakistan: Ambulocetus came out of the Kala Chitta Hills of Punjab, an amphibious whale whose toes still ended in hooves, a legacy of its hoofed ancestors on land.

What is the independent evolution of similar traits in unrelated lineages called?

Convergent evolution hands unrelated lineages the same answer to the same problem: sabre teeth, for instance, arose independently in more than one line of predators.

Which virus evolves so quickly that its vaccine has to be redesigned almost every year?

Influenza keeps mutating the surface proteins our immune systems recognise, so antibodies raised against last winter's strains can miss this winter's.

The title of Richard Dawkins's The Blind Watchmaker answers which clergyman's argument that a watch implies a watchmaker?

William Paley's Natural Theology of 1802 argued that living things, like a watch found on the ground, imply a designer; the young Darwin was 'charmed and convinced' by it.

Lynn Margulis's 1967 paper 'On the Origin of Mitosing Cells' championed which account of how complex cells arose?

Endosymbiosis holds that mitochondria and chloroplasts began as free-living bacteria taken in by other cells; biologists stayed sceptical for years, until genetic evidence bore Margulis out.

With which British chemist did Lynn Margulis co-develop the Gaia hypothesis?

James Lovelock named the idea after the Greek Earth goddess at the suggestion of his neighbour, the novelist William Golding; it pictures Earth as a self-regulating system.

Under Hardy-Weinberg equilibrium with alleles A and a at frequencies p and q, what is the frequency of heterozygotes?

2pq: under Hardy-Weinberg the genotype frequencies are p² for AA, 2pq for Aa and q² for aa, which holds only without drift, selection, mutation, migration or non-random mating.

Which Lewis Carroll character names the idea that species must keep evolving to survive?

The Red Queen tells Alice 'it takes all the running you can do, to keep in the same place'; Leigh Van Valen borrowed her in 1973 because every species' rivals are evolving too.

Which feature of ant and bee colonies struck Darwin as a 'special difficulty' for natural selection?

Sterile workers that never breed seemed 'actually fatal to my whole theory', since they leave no offspring to inherit their traits; Darwin answered that selection can act on the family.

In which 1976 book did Richard Dawkins coin the word 'meme' for an idea that spreads from mind to mind?

The Selfish Gene shortened the Greek 'mimeme', something imitated, so that the new word would sound like 'gene'; Dawkins's examples were tunes, catchphrases and fashions.

With whom did Stephen Jay Gould develop the theory of punctuated equilibrium in 1972?

Niles Eldredge, a specialist in trilobites, published the idea first in 1971; Gould called it the only new thinking on the subject and asked that they present it jointly.

Which Harvard ant specialist worked out with Robert MacArthur in 1967 how many species an island can hold?

E. O. Wilson then tested the idea with his student Daniel Simberloff: they fumigated tiny mangrove islets in the Florida Keys and watched the wildlife return within a year.

Which big cat is so genetically uniform, after an ancient population crash, that unrelated animals accept each other's skin grafts?

The cheetah's gene pool was squeezed through a bottleneck about 12,000 years ago, leaving animals so alike that 14 skin grafts swapped between unrelated cats all took.

Which three scientists are considered the 'great trio' of the modern synthesis in population genetics?

Fisher, Haldane and Wright worked out mathematically how selection acts on Mendelian genes, showing that Darwin's and Mendel's ideas, long thought to clash, fit together.

Which idea about life's origin did J. B. S. Haldane's 1929 article on abiogenesis introduce?

The primordial soup: Haldane's 1929 essay proposed that ultraviolet light acting on a prebiotic ocean produced a 'hot dilute soup' of organic compounds, an idea Alexander Oparin had independently reached in 1924.

Which measure did Sewall Wright discover along with methods to compute it in pedigree animals?

The inbreeding coefficient: Wright defined F in 1921-22 as the probability that two alleles at a locus are identical by descent, with path-coefficient methods to compute it from pedigrees of livestock.

Batesian mimicry is named after a naturalist who studied butterflies in which country's rainforests?

Brazil: Bates stayed eleven years, paying his way by shipping specimens home to a London agent who sold them on commission.

In Müllerian mimicry, what kinds of organisms converge in appearance?

Two or more well-defended ones: when several unpalatable species share one warning pattern, a predator needs fewer bad meals to learn it, so each species loses fewer members.

To which country do the Galápagos Islands belong?

Ecuador annexed the islands in 1832, three years before Darwin's visit, and for more than a century used them as a place to send its prisoners.

A bishop's becalmed ship drifted to the Galápagos by accident in 1535 while sailing from Panama to which country?

Peru was where Bishop Tomás de Berlanga was bound, sent to settle a quarrel between the conquistadors Pizarro and Almagro, when the winds died and currents swept him west.

Beagle captain Robert FitzRoy later coined which everyday weather term?

Forecast: FitzRoy coined the term 'weather forecast' after founding in 1854 the Meteorological Office, which issued the first public storm warnings and daily forecasts in The Times from 1861.

Robert FitzRoy served as the second governor of which colony from 1843 to 1845?

New Zealand: FitzRoy took over from William Hobson in 1843 and tried to protect both settlers and Maori from speculative land sales, but was recalled two years later.

Which Birmingham discussion group of industrialists counted Charles Darwin's grandfather as a founder?

The Lunar Society met at the full moon so that members had light to travel home by, and cheerfully called themselves 'lunaticks'.

Which naturalist established extinction as a scientific fact and is called the founding father of paleontology?

Georges Cuvier showed in 1796 that mammoth bones differed from living elephants, establishing extinction as a fact; he held that periodic catastrophes had wiped out such species, and is called the founding father of palaeontology.

Which Cambridge polymath coined the words 'scientist' and 'uniformitarianism'?

William Whewell coined 'scientist' in answer to a challenge from the poet Coleridge; he also named 'catastrophism' and gave Faraday 'anode' and 'cathode'.

Which Scottish scientist is known as the 'Father of Modern Geology'?

James Hutton read immense spans of time in tilted and worn-down rock layers, concluding in 1788 that he could find 'no vestige of a beginning, no prospect of an end'.

Which gases, plus water, did the 1952 Miller-Urey experiment use to simulate early Earth?

Methane, ammonia and hydrogen: Miller sealed those gases with water vapour in a closed apparatus and passed electric sparks through it to simulate lightning, producing amino acids.

Which molecule do many scientists propose preceded both DNA and proteins in early life?

RNA: the RNA world hypothesis, named by Walter Gilbert in 1986, proposes that self-replicating RNA came before DNA and proteins, since RNA can both carry genetic information and act as a catalyst, as ribozymes do.

Around 2.4 billion years ago, cyanobacteria began filling Earth's atmosphere with which gas?

Oxygen first rusted the iron dissolved in the seas, laying down the banded iron formations that now supply most of the world's iron ore, and only then built up in the air.

Which organ did Darwin admit it seemed 'absurd in the highest possible degree' to suppose natural selection had formed?

The eye, Darwin went on, could still be built by selection through numerous gradations, each useful to its owner, starting from a mere nerve coated with pigment.

Which metal is unusually abundant in the K-Pg boundary clay, pointing to an asteroid?

Iridium: in 1980 Luis and Walter Alvarez reported that the boundary clay at Gubbio, Italy, is rich in the metal, which is rare in Earth's crust but common in asteroids.

The K-Pg extinction, which killed three-quarters of species, cleared the way for which animals to diversify into the emptied niches?

Mammals, until then living in the dinosaurs' shadow, branched within the following period into forms as different as horses, whales, bats and primates.

The crater left by the asteroid that ended the age of dinosaurs lies buried beneath which peninsula?

Yucatán hides the Chicxulub crater under younger limestone, but an arc of sinkholes at the surface traces the buried rim, where the rock above gives way more easily.

The buried Chicxulub crater was found in the late 1970s by geophysicists prospecting for what?

Oil was the target when Glen Penfield and Antonio Camargo mapped a huge buried ring for a state oil company in 1978; its link to the dinosaurs' end was made only around 1990.

Who discovered the Burgess Shale in 1909?

Charles Walcott, head of the Smithsonian, is said to have found the first fossils when his horse stopped at a rock in the path; he returned to quarry the site for years.

The Burgess Shale fossils, in the Canadian Rockies, date to which period?

Middle Cambrian: mudslides buried the animals so quickly on the sea floor that even soft bodies were preserved, among them the five-eyed Opabinia.

Piltdown Man, a famous fake, combined a human skull with which animal's jaw?

An orangutan jaw had been stained to look ancient and its teeth filed down to seem human, then planted beside pieces of a human skull.

Which amateur archaeologist did a 2016 study point to as the forger behind Piltdown Man?

Charles Dawson, the solicitor who 'found' the remains, was singled out because every specimen had been stained and filled in the same way, pointing to a single forger.

Who described the Taung Child, a juvenile hominin skull from South Africa, in 1925?

Raymond Dart saw a human ancestor in the little skull, but leading British anatomists took it for a young ape, and his view needed more than twenty years to win acceptance.

Puncture marks in the Taung Child's eye sockets suggest which predator killed the young hominin?

An eagle is the suspect because the damage matches that on monkeys killed by eagles today; the child, an Australopithecus africanus, was about three years old.

Which Swedish geneticist won the 2022 Nobel Prize for work on the genomes of extinct hominins?

Svante Pääbo spent decades learning to recover DNA from ancient bone, where it survives only in traces swamped by DNA from bacteria and from the people who handled it.

Lactase persistence, the ability to digest milk as an adult, is especially high in which population?

Northern Europeans mostly carry a gene variant that keeps lactase switched on for life; it spread with dairy herding, and only about 5 percent of them lose the ability.

Which American chemist joined Émile Zuckerkandl in 1962 in noticing that proteins change at a steady 'molecular clock' rate?

Linus Pauling and Zuckerkandl saw that haemoglobin differences between species mount up roughly in step with the time since their lineages split, so molecules could date the splits.

Which two-word term did Darwin coin in the Origin for odd survivors such as the platypus and the lungfish?

Living fossil: Darwin wrote that such forms 'may almost be called living fossils', having endured because they lived in a confined area with less severe competition.

Which human reflex is often cited as a vestigial leftover from our furrier ancestors?

Goosebumps are tiny muscles tugging at hairs we have mostly lost; in a thickly furred ancestor the same reflex raised the coat and made the animal look larger.

Which Swede formalised binomial nomenclature and is called the father of modern taxonomy?

Carl Linnaeus gave every species a two-part Latin name, replacing the long, unwieldy descriptions naturalists had used, and coined Homo sapiens for our own.

In which village, then in Kent, did Darwin live and work from 1842 until his death?

Downe: Darwin spent forty years at Down House, turning its gardens into an open-air laboratory; the village later added an 'e' to its name, but the house never did.

Which creatures did Darwin breed for years, joining two London fanciers' clubs, to study how far a species can vary?

Pigeons as different as the carrier and the tumbler, Darwin argued in the Origin's first chapter, all descend from the wild rock pigeon, which showed how far selection can go.

People carrying one copy of the sickle cell allele gain some resistance to which disease?

This heterozygote advantage keeps the allele common where malaria is endemic.

What did Luria and Delbrück's 1943 'fluctuation test' on bacteria show about mutations?

They arise at random: resistant colonies turned up in wildly different numbers from one culture to the next, as expected if mutants appeared by chance before the virus was added.

As a child, Mary Anning dug out the first correctly identified skeleton of which marine reptile?

An ichthyosaur: her brother Joseph spotted the skull in 1811 and Mary uncovered the rest of the skeleton; in 1823 she went on to find the first complete plesiosaur.

In which Dorset town did Mary Anning collect her Jurassic marine fossils?

Lyme Regis: Anning collected along the Blue Lias cliffs of Lyme Regis on Dorset's Jurassic Coast, where winter landslides exposed new fossils that had to be grabbed before the sea took them.

What does the name Homo habilis mean?

Handy man: the name was given in 1964 because the species was thought to be the first maker of stone tools, though older tools have since been found.

Ardi, a 4.4-million-year-old human relative found in Ethiopia, kept which tree-climbing feature?

A grasping big toe let Ardi clamp onto branches, yet her hands show no trace of knuckle-walking, so her discoverers argue our ancestors never moved like chimpanzees.

What collective nickname is given to Leakey's protégées Goodall, Fossey and Galdikas?

The Trimates was Leakey's own name for them: he sent Goodall to chimpanzees, Fossey to mountain gorillas and Galdikas to orangutans, hoping living apes would shed light on early humans.

At which Tanzanian site did Louis and Mary Leakey make their famous discoveries?

Olduvai Gorge, in the eastern Serengeti, is where Mary Leakey found the 'Zinj' skull in 1959 and where the first Homo habilis fossils followed a year later.

In what were the famous Laetoli hominin footprints preserved?

Volcanic ash: a rain shower turned the freshly fallen layer to something like wet cement, the walkers crossed it, and a second ashfall sealed their prints for 3.6 million years.

Every domestic dog descends from a now-extinct population of which wild animal?

Grey wolf: dogs split from wolves that no longer exist and, living alongside people, evolved traits that appeal to us, 'puppy dog eyes' among them.

Which sea creatures did Darwin spend eight years dissecting and classifying before he wrote the Origin?

Barnacles filled Darwin's days from 1846 to 1854; the four monographs made his name as a naturalist and showed him at first hand how body parts are reshaped for new uses.

The sight of a feather in the tail of which animal, Darwin wrote in 1860, 'makes me sick'?

The peacock's train looked far too costly to be explained by survival alone; the puzzle pushed Darwin to argue that such ornaments evolve because peahens prefer them.

Erasmus Darwin, Charles's grandfather, set out his ideas on evolving life in The Temple of Nature, written in what form?

A long poem, published after his death, carried evolutionary ideas that his grandson would elaborate sixty years later; Erasmus had first aired them in his medical treatise Zoonomia.

Wall lizards moved to the Adriatic islet of Pod Mrčaru in 1971 evolved new gut valves after switching to which diet?

Mostly plants: within about 36 years the descendants of five founding pairs had bigger heads, stronger bites and cecal valves that slow food down so gut microbes can ferment it.

Dmitry Belyayev's Siberian foxes began wagging their tails and growing spotted coats after generations of breeding for which single trait?

Tameness was the only thing selected: from 1959 just the friendliest foxes were allowed to breed, and floppy ears and other dog-like features came along unasked.

In 1975, Japanese scientists found bacteria digesting man-made waste compounds in ponds beside what?

A nylon factory: the pond bacteria had evolved enzymes to digest by-products of nylon manufacture, substances not known to have existed before nylon was invented in 1935.

Who discovered the first living coelacanth among a fisherman's catch in South Africa in December 1938?

Marjorie Courtenay-Latimer, curator of the East London museum, spotted the fish in Captain Hendrik Goosen's catch on 22 December 1938; J. L. B. Smith identified it, and the genus Latimeria honours her.

The second living coelacanth species, found in the late 1990s, lives in the seas of which country?

Indonesia: Latimeria menadoensis was spotted in a Manado fish market in Sulawesi in 1997 by Mark Erdmann and described in 1999; the first species, L. chalumnae, lives off the Comoros and South Africa.

The name 'coelacanth', coined by Louis Agassiz in 1839, comes from Greek words meaning what?

Hollow spine: Agassiz was naming a fossil with hollow fin spines, almost a century before anyone knew that a coelacanth was still alive.

Rock pocket mice on separate lava flows each evolved dark fur; what did a 2003 DNA study reveal?

Different genes were at work: one population's dark coats trace to mutations in a gene called Mc1r, but the other shows no such changes, so selection found two routes to one colour.

On which islands did a single finch-like colonist give rise to more than fifty species of honeycreeper?

Hawaii's honeycreepers descend from a relative of the rosefinches that arrived from Asia; some evolved long, curved bills unlike any other finch's, and most of the species have since died out.

The horse's 50-million-year evolution transformed which dog-sized forest dweller into the modern single-toed animal?

Eohippus had four toes on each front foot; its descendants evolved mostly in North America, where horses then died out about 10,000 years ago until the Spanish brought them back.

The London Underground mosquito was first described in the 18th century from specimens collected where?

Egypt: Peter Forsskål named the mosquito Culex molestus there for its biting, and genetic work now traces the form to the Mediterranean or Middle East, long before any Tube tunnel.

Which English philosopher coined 'survival of the fittest' after reading Darwin, who later borrowed the phrase himself?

Herbert Spencer used it in his 1864 Principles of Biology, linking Darwin's biology to his own economic ideas. Darwin adopted the phrase in the fifth edition of his famous book.

Which Scottish Nobel laureate warned in 1945 that underdosing penicillin would breed bacteria that resist it?

Alexander Fleming cautioned in June 1945 that microbes are 'educated to resist penicillin' when too little is used. It is natural selection: the survivors of a weak dose found the next generation.

Natural selection gave Southeast Asia's free-diving Bajau people an unusually large version of which organ?

Spleen size in the Bajau is about 50 percent greater than in their land-based neighbours. The organ contracts during a dive and releases a reserve of oxygen-carrying blood.

Charles Darwin once wrote to a colleague that the sight of a feather in which bird's tail made him sick?

Peacock trains looked far too costly for natural selection to explain, which is why the feather troubled him. He later argued that generations of choosy peahens had bred the ornament.

Which household pests had evolved resistance to DDT by 1947, only a few years after wide spraying began?

Houseflies shrugged off DDT so fast that hopes of ending insecticide resistance collapsed. Every new class of insecticide since has met resistant pests within two to 20 years.

On which tiny Galápagos island did Peter and Rosemary Grant spend decades watching natural selection reshape wild birds?

Daphne Major is where the Grants spent six months of every year from 1973 catching, tagging and measuring birds. Their records showed natural selection working within a couple of years.

Darwin predicted a long-tongued pollinator, found only after his death, for a deep-spurred orchid from which island?

Madagascar is the only home of the orchid, whose nectar lies at the bottom of a spur about 33 cm long. A moth with a tongue to match turned up 21 years after Darwin died.

A gene variant inherited from Denisovans helps which people thrive in thin, high-altitude air?

Tibetans carry a version of the EPAS1 gene that improves oxygen transport at altitude. It entered modern humans through ancient interbreeding, then spread because carriers fared better.

What military phrase do biologists use for predators and prey endlessly evolving to outdo each other?

An arms race in nature is a spiral of adaptations and counter-adaptations, each advance forcing a reply from the other side. It can also pit a parasite against its host.

Natural selection acts on which full set of an organism's observable traits, including uninherited ones like a suntan?

Phenotype covers everything observable about an organism, from structure to behaviour. Only the inherited part can evolve, which is why a suntan is never passed on to children.

Paler skin is thought to have spread far from the equator because it makes more of which nutrient?

Vitamin D forms in skin under ultraviolet light, so lighter skin was a health benefit where sunlight is weak. Nearer the equator, darker skin shields the body's folate from the same rays.

Tomcod evolved resistance to the PCBs that General Electric dumped for decades into which American river?

Hudson tomcod carry a gene variant that blunts the chemicals' toxic effects, found in 99 percent of the river's fish against under 10 percent elsewhere. GE's capacitor plants released PCBs there for about three decades.

Common garter snakes have evolved resistance to which pufferfish poison, also made by the rough-skinned newts they eat?

Tetrodotoxin jams the sodium channels that nerves need to fire, but in resistant snakes the channel protein is shaped so the toxin cannot bind. A single newt has killed a man who swallowed it.

Which British biologist's 1964 rule explains how natural selection can favour animals that help their relatives breed?

W. D. Hamilton showed mathematically that a gene for helping can spread when the benefit to relatives outweighs the helper's cost. Richard Dawkins called him 'the greatest Darwinian of my lifetime'.

Which small fish, armoured with bony plates in the sea, has evolved lighter armour in many freshwater lakes?

Stickleback populations in fresh water carry fewer bony plates than their marine cousins, and some lack side plates altogether. The lost armour is a textbook case of rapid evolution in isolated waters.

Which invasive amphibians, released in Queensland in the 1930s, evolved longer legs at the front of their advance?

Cane toads on the advancing frontier have larger legs, thought to help them travel farther. Speed has a price: about 10% of the leading-edge animals have developed arthritis.

Which virus, released in the 1950s to kill Australia's wild rabbits, soon evolved into far milder strains?

Myxoma virus strains in Australia and Europe weakened until they killed 50 to 95 percent of infected rabbits, down from nearly all. Wild rabbits evolved some immunity in turn.

On the Hawaiian island of Kauai, most male field crickets evolved within 20 generations to stop doing what?

Singing drew a deadly parasitic fly that homes in on the sound, so a flat-winged form that leaves males silent spread to over 90% of them. The silent males were first noticed in 2003.

Which Scottish fruit farmer set out natural selection in an 1831 book on naval timber, decades before Darwin?

Patrick Matthew wrote of 'the natural process of selection' in Naval Timber and Arboriculture, then let the idea drop. Darwin learned of it only after 1859 and credited him in later editions.

Which human skin reflex is often called a leftover from furrier ancestors who fluffed up to look bigger?

Goose bumps raise hairs now too fine to matter, but in furry animals the same reflex traps warm air and makes the body look larger to enemies. Chimpanzees still use it in threat displays.

Sinosauropteryx, described from China in 1996, was the first dinosaur outside the bird lineage found with what?

Feathers on Sinosauropteryx formed a coat of very simple filaments, more fuzz than plumage. Preserved pigment structures even reveal the animal's colour pattern.

The extinct thylacine was nicknamed the Tasmanian wolf for its dog-like looks, yet belonged to which mammal group?

Marsupials rear their young in a pouch, and the thylacine's very name comes from the Greek for pouch. Its powerful jaws, raised heels and dog-shaped body evolved separately from true canids.

Human chromosome 2 shows it formed from two fused ancestral chromosomes by carrying which tip sequences in its middle?

Telomeres normally sit only at the ends of a chromosome, so a stray set far from either end marks an ancient end-to-end join. It is why humans have twenty-three pairs while other great apes have twenty-four.

Which German zoologist championed 'ontogeny recapitulates phylogeny', the disproven idea that embryos replay ancestry?

Ernst Haeckel built the influential recapitulation theory, later disproven, and summed it up in that dictum. He left a lasting mark all the same, coining the words ecology and phylum.

Which method, pioneered by Ernest Rutherford, ages rocks by comparing unstable atoms with their breakdown products?

Radiometric dating works because each unstable isotope decays at a known constant rate. It is the main source of absolute ages for rocks and the fossils found in them.

Which fossil sea creature was named 'king lizard' before anatomists realised it was an early whale with tiny hind limbs?

Basilosaurus kept its mistaken name because naming rules protect the first one given. One 16-metre animal had hind limbs just 35 centimetres long, far too small to walk on.

The small fold of tissue in the inner corner of the human eye is a remnant of what?

A third eyelid, the nictitating membrane, is still fully functional in some other mammals. In humans only the little fold, the plica semilunaris, survives.

Which Galápagos birds did Darwin notice differed from island to island, prompting him to record where each was caught?

Mockingbirds from one island plainly differed from the Chatham Island specimen, so Darwin began labelling each catch by island. Back in London they proved to be three separate species.

Which term describes parts like a whale's flipper and a horse's foreleg, built from matching bones for different jobs?

Homologous structures keep one underlying layout however different their uses. The pattern was explicitly analysed by Pierre Belon in 1555, three centuries before Darwin explained it.

Which protein, about 100 amino acids long, has exactly the same sequence in humans and chimpanzees but not in horses?

Cytochrome c is so highly conserved that 34 of its 104 amino acids were identical across more than thirty species in one study. The few differences track how long ago two lineages parted.

Bacteria, oak trees and humans all read their DNA with almost the same lookup table, known by what name?

The genetic code fits in a simple table of 64 three-letter entries and is highly similar among all organisms. So widely shared a system points to one beginning for all life on Earth.

Humans and most other mammals carry broken remnants of genes that egg-laying ancestors used to make what?

Egg yolk protein starts out as vitellogenin, and nearly all mammals now carry only disabled copies of the genes for it. The egg-laying platypus and echidnas kept one that still works.

Humans and chimpanzees share matching genome scars left by ancient infections with which family of viruses?

Retroviruses leave copies of themselves in a host's genome that pass to every later generation. Humans and chimps share several such inserts, and all primates carry sets that match their family tree.

Which English surveyor, nicknamed 'Strata', showed that each rock layer can be identified by the fossils it contains?

William Smith found the same succession of fossil groups from older to younger rocks all over England while inspecting mines and canal cuttings. It let him draw the first nationwide geological map.

Which fish, down to six species spread over three continents, are the closest living relatives of land vertebrates?

Lungfish can breathe air and have fleshy lobed fins with a well-developed internal skeleton, the makings of a limb. Their kin on land include amphibians, reptiles, birds and mammals.

A whale's blowhole is the evolutionary counterpart of which feature of the human head?

Nostrils moved gradually from the snout to the top of the head as whales evolved. A sperm whale's single blowhole is in fact its left nostril, the right one having no opening at all.

Darwin suggested that which small pouch of the human gut once helped earlier hominids digest fibrous plants?

The appendix hangs off the cecum, a pouch that is far larger in plant-eaters such as horses and koalas. A koala's cecum houses the bacteria that break down the cellulose in leaves.

Charles Darwin spent eight years classifying which small sea creatures before turning fully to evolution in 1854?

Barnacles showed him how immense the variation in nature is, and the work helped win him the Royal Medal in 1853. Only then did he turn fully to the question of how species originate.

MRSA, a hospital-acquired infection resistant to a whole group of antibiotics, is a strain of which bacterium?

Staphylococcus aureus strains carrying the mecA gene survive penicillin-like drugs that stop other strains building cell walls. Heavy antibiotic use then clears away their competitors.

Glyptodon, an extinct giant with a domed shell of bony plates, was an oversized relative of which living animals?

Armadillos are the living kin of the glyptodonts, whose carapaces were built from hundreds of interlocking plates of bone. Glyptodon survived in South America until about 11,000 years ago.