177 Fun Facts About Ecology

Which German scientist coined the term 'ecology' (Ökologie) in 1866?

Ernst Haeckel introduced 'Ökologie' in his 1866 Generelle Morphologie der Organismen, the same book in which he pushed Darwin's ideas onto German readers.

Haeckel's illustrated book Kunstformen der Natur (Art Forms in Nature) influenced which artistic movement?

Art Nouveau: the book's 100 plates of radiolarians, jellyfish and other sea creatures inspired designers such as René Binet, whose 1900 Paris Exposition gate copied a Haeckel radiolarian.

The word 'ecosystem' first appeared in print in 1935 in a publication by which British ecologist?

Arthur Tansley used 'ecosystem' in his 1935 paper in the journal Ecology, wanting a word that stressed the exchange of materials between organisms and their physical surroundings.

Who actually came up with the word 'ecosystem', at the request of the ecologist who published it?

Clapham was a young Oxford botanist at the time; his colleague got the credit because he was the one who published and championed the concept.

Which American ecologist wrote the 1953 textbook Fundamentals of Ecology with his brother?

The Odum brothers took a systems approach to whole ecosystems, and the book also fixed the modern meaning of a population's environmental ceiling.

Whose 1927 book Animal Ecology set out food chains, ecological niches and the 'pyramid of numbers'?

Charles Elton's Animal Ecology (1927) laid out food chains, niches and the pyramid of numbers; he later became founding editor of the Journal of Animal Ecology in 1932.

Which ecologist developed the concept of trophic levels in 1942 and coined 'decomposers'?

Raymond Lindeman's 1942 paper 'The Trophic-Dynamic Aspect of Ecology' formalised trophic levels and the term decomposers, building on Elton's grouping of species by what they ate.

Roughly what share of the chemical energy in its food does a consumer turn into its own tissue?

This 'ten-per cent law' is why food chains rarely stretch beyond four or five levels: there is simply not enough energy left at the top.

Which ecological pyramid can be inverted in a pond, where phytoplankton reproduce fast but live briefly?

The pyramid of biomass: a small standing crop of fast-reproducing phytoplankton can weigh less than the zooplankton and fish that eat it, whereas energy pyramids are always upright.

Which zoologist introduced the keystone species concept in 1969 after a starfish-removal experiment?

Robert Paine coined 'keystone species' in 1969 after removing the starfish Pisaster from Washington shorelines caused mussels to crowd out most other species.

Paine's 1969 paper paired the mussel Mytilus californianus with which predator as its primary example?

The ochre starfish, Pisaster ochraceus, a generalist that also eats chitons, limpets, snails and barnacles; later work found it acts as a keystone mainly on wave-exposed shores.

Sea otters protect kelp forests mainly by eating which grazers?

Sea urchins: without otters, urchin barrens replace kelp, and otters that eat lots of purple urchins can end up with purple-stained teeth and bones.

Up to how many hairs per square centimetre does the sea otter's fur pack?

Up to 150,000 hairs per square centimetre, the densest fur of any animal; with no blubber that coat is its only insulation, which is why fur hunting nearly wiped it out between 1741 and 1911.

In ideal conditions, how much can giant kelp (Macrocystis) grow vertically in a single day?

Giant kelp can add 30–60 cm of length in a day, among the fastest growth of any organism; it is anchored by a holdfast rather than roots because it takes nutrients straight from the water.

In which year were gray wolves reintroduced to Yellowstone's Lamar Valley?

1995: the first 14 wolves, captured near Hinton, Alberta, were released into the Lamar Valley that March; the case became the textbook example of a trophic cascade.

The last wolves in Yellowstone were killed by park rangers in which year?

1926: two pups found near Soda Butte Creek were the last wolves killed by rangers, though the Park Service did not formally abandon predator control until the 1930s.

Which animal recolonised Yellowstone's northern-range streams after returning wolves eased elk browsing on willows?

Beaver: with fewer elk stripping the willows, the streamside trees beavers cut for food and dams regrew, and beaver colonies multiplied on the northern range after the 1995 wolf reintroduction.

The 1960 'green world hypothesis' says the planet stays green because which group keeps herbivores in check?

It flipped the prevailing bottom-up view of communities, and is often shortened to the HSS hypothesis.

Joseph Grinnell's 1917 paper, probably the first to use 'niche' in research, concerned which bird?

The California thrasher: Grinnell's 1917 paper in The Auk tied the bird to chaparral habitat, a habitat-based niche now contrasted with later functional and mathematical definitions.

G. Evelyn Hutchinson defined the niche as an 'n-dimensional' what?

An n-dimensional hypervolume, from Hutchinson's 1957 'Concluding Remarks': each axis is an environmental condition or resource, and the region where a population can persist is its niche.

By what name is the principle that two species competing for the same limited resource cannot stably coexist known?

Ironically, Georgy Gause never actually formulated the principle that carries his name.

Georgy Gause's classic laboratory competition experiments used two species of which microorganism?

Paramecium: Gause grew P. aurelia and P. caudatum together on a bacterial diet and watched P. aurelia drive the other to extinction within weeks, the experiment behind competitive exclusion.

Which University of Chicago botanist first documented ecological succession in the Indiana Dunes?

Henry Chandler Cowles published his Indiana Dunes succession study in the Botanical Gazette in 1899, inspired by Eugen Warming's work on Danish dunes.

In succession theory, what is the supposedly stable community at the end of a sere called?

The climax community: Frederic Clements' 1916 Plant Succession held that climate alone fixed a single climax for each region, a view later ecologists found far too tidy.

Off which country does Surtsey, the volcanic island that rose from the sea in 1963, lie?

Iceland: Surtsey rose off the south coast in November 1963, and its first vascular plant, the sea rocket Cakile, was found on the northern shore in spring 1965.

Who defined symbiosis in 1879 as 'the living together of unlike organisms'?

Heinrich Anton de Bary, a German mycologist, gave the definition in his 1879 address Die Erscheinung der Symbiose; it covers every long-term association of unlike species but not brief encounters such as predation.

A remora riding a shark, eating scraps while the shark is unaffected, is a classic example of which interaction?

Commensalism leaves the host unchanged while the hanger-on often evolves big adaptations, like the remora's sucker disc.

When an interaction harms one species while the other is completely unaffected, it is called what?

Amensalism, as when a penicillium mould's secretions kill nearby bacteria at no cost to the mould; it sits beside competition, where both parties lose, in the grid of species interactions.

Cowbirds, whydahs and many cuckoos lay eggs in other birds' nests for the hosts to raise; what is this strategy called?

Brood parasitism goes as far as disguise: the female European cuckoo mimics a sparrowhawk so hosts flee the nest long enough for her to lay.

Which German botanist first described mycorrhizal fungi and coined 'mycorrhiza' in 1885?

Albert Bernhard Frank coined 'Mykorhiza' in 1885 from the Greek for fungus and root while studying truffles for the Prussian state; the arbuscular type alone occurs in most plant species.

Which forest ecologist's 1997 work revealed the mycorrhizal networks nicknamed the 'wood wide web'?

Suzanne Simard's 1997 Nature paper traced carbon moving between paper birch and Douglas fir through shared fungi; Nature's cover dubbed it the 'wood-wide web'.

What lets a clownfish nestle among an anemone's stinging tentacles without being harmed?

The mucus seems to mimic the anemone's own and lacks the trigger that fires its nematocysts.

What happens in an anemonefish group when the dominant breeder is lost?

The breeding male becomes female: clownfish are protandrous hermaphrodites, all born male, so when the dominant female dies her mate changes sex and the largest non-breeder becomes the new male.

How many cane toads were imported to Gordonvale, Queensland, in June 1935 to found Australia's population?

102 toads were shipped from Hawaii to Gordonvale in June 1935, one dying in transit; by 2011 their descendants were estimated at over 200 million.

Cane toads, a plague across northern Australia, are native to which region?

The Americas: the cane toad's native range runs from south Texas to the Amazon basin; Puerto Rico used them against sugar-cane pests from 1920, and Australia copied the idea against cane beetles.

Zebra mussels, which invaded the Great Lakes in the 1980s, are native to which waters?

The Black and Caspian Seas: zebra mussels crossed in ships' ballast water and were first found in Lake St. Clair, between Lakes Huron and Erie, in 1988.

Kudzu was introduced to the US at the 1876 Centennial Exposition in which city?

Philadelphia: Japan showed kudzu at the 1876 Centennial Exposition there; it stayed a garden plant until the 1930s, when the Soil Conservation Service paid farmers to plant it against erosion.

In r/K selection theory, what does the K in the logistic growth equation stand for?

Carrying capacity: K is said to come from the German Kapazitätsgrenze, the population ceiling in the logistic equation; K-strategists like elephants and whales invest heavily in a few offspring.

Robert MacArthur co-wrote the 1967 book The Theory of Island Biogeography with which biologist?

E. O. Wilson: MacArthur and Wilson's 1967 book argued an island's species count settles at a dynamic equilibrium between immigration and extinction.

Daniel Simberloff's island biogeography test fumigated six small mangrove islands where?

The Florida Keys: Simberloff and Wilson tented and fumigated mangrove islets in Florida Bay in 1966–67, and arthropod counts climbed back toward their old totals within a year, the most distant islet recovering fewest.

In which year did Rachel Carson publish Silent Spring?

1962: Silent Spring was serialised in The New Yorker that June and published by Houghton Mifflin in September; the chemical industry fought it, but it led to the 1972 US ban on DDT.

The title Silent Spring was inspired by a poem containing the line 'And no birds sing' by which poet?

John Keats: the line closes the first stanza of 'La Belle Dame sans Merci' (1819); 'Silent Spring' was first just the birds chapter's title before Carson's agent Marie Rodell suggested it for the book.

Which 1951 ocean bestseller won Rachel Carson a National Book Award and let her write full-time?

The Sea Around Us (1951) spent 86 weeks on the New York Times bestseller list and won the 1952 National Book Award; Carson wrote it while employed by the Fish and Wildlife Service.

What is the process by which DDT concentrates as it moves up the food chain called?

Biomagnification: fat-soluble DDT is stored in body fat and passed up each trophic step, so top consumers carry doses many times higher than the plankton and insects at the bottom.

Nitrogen gas makes up what percentage of Earth's atmosphere?

About 78% by volume, with oxygen at 21%; almost none of that nitrogen is usable until bacteria, lightning or the Haber-Bosch process fix it into other forms.

Symbiotic nitrogen-fixing bacteria such as Rhizobium live in the root nodules of which group of plants?

Legumes: peas, beans, clover and alfalfa house Rhizobium in root nodules, which is why farmers rotate them through tired fields to add nitrogen.

Which process closes the nitrogen cycle by turning nitrates back into nitrogen gas?

Denitrification: anaerobic bacteria such as Pseudomonas reduce nitrate to nitrogen gas in waterlogged soils and sediments; nitrification runs the other way, turning ammonia into nitrite and nitrate.

Which reservoir holds Earth's largest pool of actively cycled carbon, about 50 times more than the atmosphere?

The deep ocean holds roughly 37,000 billion tonnes of carbon, about 50 times the atmosphere's, but exchanges it with the surface only over centuries via the slow thermohaline circulation.

Which nutrient cycle is unusual in that the atmosphere plays almost no part in it?

Phosphorus rarely forms a gas, so its cycle runs through rock, soil and water rather than the air; phosphine appears only in isolated anaerobic conditions.

Which British ecologist introduced the biodiversity hotspot concept in 1988 and 1990?

Norman Myers: his 2000 Nature criteria require at least 1,500 endemic vascular plants and loss of at least 70% of primary vegetation; the list had grown to 36 hotspots by 2016.

The Great Barrier Reef is made up of over how many individual reefs?

Over 2,900 individual reefs: with some 900 islands they stretch about 2,300 km along Queensland, the largest single structure built by living organisms.

During coral bleaching, stressed corals expel which photosynthetic symbionts living in their tissue?

Zooxanthellae, single-celled dinoflagellates that supply up to 90 percent of a coral's energy; once expelled, the coral turns white and begins to starve.

The 1971 Convention on Wetlands takes its name from a city in which country?

Iran: the treaty was adopted on 2 February 1971 in Ramsar, a resort town on the Caspian coast, and World Wetlands Day marks that date each year.

Which region is the world's largest tropical wetland?

The Pantanal, mostly in Brazil's Mato Grosso do Sul and spilling into Bolivia and Paraguay, covers around 150,000 square kilometres and holds one of the densest jaguar populations on Earth.

Marjory Stoneman Douglas famously described which wetland as a 'River of Grass' in 1947?

The Everglades: Douglas's 1947 book The Everglades: River of Grass described its sheetflow, a broad, shallow river creeping south from Lake Okeechobee across southern Florida.

The taiga, or boreal forest, holds which record among Earth's biomes?

It is dominated by pines, spruces and larches and grades into alpine tundra through stunted krummholz at altitude.

Robert Whittaker's classic biome classification uses which two abiotic factors?

Precipitation and temperature: Whittaker's 1975 diagram plots mean annual values of the two to map the biomes, a simpler take on Holdridge's 1947 life-zone system.

Which ecologist coined 'ecotone' for a transition zone between communities?

Frederic Clements coined 'ecotone' from eco- and the Greek tonos, tension; the extra species variety found at such junctions is called the edge effect.

The textbook lynx and snowshoe hare population cycle came from which firm's fur records?

Hudson's Bay Company pelt returns, which Charles Elton analysed in the 1920s and 30s, show lynx and hare numbers rising and falling together in roughly ten-year cycles.

The Lotka-Volterra equations are the classic model of which ecological relationship?

Predator and prey: Lotka (1925) and Volterra (1926) independently wrote the paired nonlinear equations, which assume the prey always finds ample food and the predator eats nothing else.

Which chemist formulated the Gaia hypothesis in the 1970s with microbiologist Lynn Margulis?

James Lovelock, who also invented the electron capture detector, published Gaia with Lynn Margulis in 1974; the Geological Society of London gave him its Wollaston Medal in 2006 partly for the idea.

Which novelist suggested naming the Gaia hypothesis after the Greek Earth goddess?

William Golding, Lovelock's neighbour in the Wiltshire village of Bowerchalke, offered the name on a walk in the late 1960s; the author of Lord of the Flies knew his Greek myth.

Biosphere 2, the largest closed ecological system ever built, stands in which US state?

Arizona: the 3.14-acre glass complex at Oracle, north of Tucson, was sealed with a crew of eight from 1991 to 1993; the University of Arizona took ownership in 2011.

What turned out to be quietly draining oxygen from Biosphere 2 during its first two-year closure?

Isotope work by Columbia scientists showed carbon dioxide reacting with exposed concrete to form calcium carbonate, locking away oxygen too.

At deep-sea hydrothermal vents, what forms the base of the food chain in place of plants?

Chemosynthetic bacteria and archaea oxidise hydrogen sulfide from the vent fluid to fix carbon without light, feeding tube worms, clams, limpets and shrimp.

Periodical cicadas of the genus Magicicada emerge en masse at intervals of how many years?

13 or 17 years: the prime-numbered cycles make it hard for any predator to sync with them, and emerging by the billions at once is a textbook case of predator satiation.

The Wallace Line runs through the strait between Bali and which neighbouring island?

Lombok: the Lombok Strait is only about 35 km wide, yet Wallace found Asian birds and mammals on Bali and Australian ones on Lombok, a deep-water gap never bridged by land.

Lichens are hybrid colonies: filaments of fungus living symbiotically with which other organisms?

Algae or cyanobacteria live among the fungal filaments, and the whole thing behaves like a self-contained miniature ecosystem, with bacteria embedded in its cortex too.

African honeyguide birds are famous for deliberately leading humans to what?

Bee colonies: the greater honeyguide leads Hadza and Yao honey-hunters to wild hives, then feasts on the wax and grubs left behind, being among the few birds that digest beeswax.

Oxpeckers perch on rhinos and zebras eating ticks, but they also feed on what from their hosts?

Blood from wounds: red-billed oxpeckers keep sores open and drink from them, which is why a 2000 Zimbabwe study found cattle with oxpeckers healed slower, muddying the classic mutualism.

A female fig wasp enters the fig through a tiny natural opening called what?

The ostiole, a bract-lined pore at the fig's tip; forcing through it usually tears off her wings and antennae, and the fig itself is an inverted flower-head called a syconium.

Which naturalist's Naturgemälde of Chimborazo first showed that climate zones correspond across continents?

Alexander von Humboldt climbed Chimborazo to 19,286 feet in 1802, then a record, and his 1807 Essay on the Geography of Plants mapped vegetation bands by altitude and latitude.

Who coined the word 'biosphere' in 1875?

Eduard Suess, the Austrian geologist, used 'Biosphäre' in his 1875 book Die Entstehung der Alpen; Vladimir Vernadsky's 1926 The Biosphere later made the idea famous.

In the open ocean, the sunlit photic zone typically extends down to about what depth?

About 200 m in clear open ocean, the limit for net photosynthesis; in murky, nutrient-rich lakes the photic zone can be just a few centimetres deep.

In forests, which group is the primary decomposer of leaf litter?

Fungi: their hyphae secrete enzymes that break down lignin and cellulose, which bacteria handle poorly; earthworms and woodlice mainly shred litter, so many ecologists file them as detritivores.

Henry Walter Bates, of Batesian mimicry, studied butterflies in the rainforests of which country?

Brazil: Bates spent 1848 to 1859 collecting on the Amazon, and his 1862 paper on Heliconius butterflies described harmless species copying the warning colours of distasteful ones.

What are the three types of tundra?

Arctic, Alpine and Antarctic: Arctic tundra rings the pole on permafrost, alpine tundra sits above the treeline on mountains worldwide, and Antarctic tundra covers the Peninsula and sub-Antarctic islands.

What is the ecotone between tundra and forest called?

The timberline, or tree line, beyond which cold and wind stop trees growing; in the Arctic it runs as a broad band of stunted, wind-sculpted spruce between taiga and tundra.

What key feature defines a savanna's tree cover?

Trees are spaced so the canopy stays open: the gaps let enough light reach the ground to support a continuous grass layer, which is what separates savanna from closed forest.

Which type of climate shapes California's chaparral shrubland?

Mediterranean: hot dry summers and mild wet winters produce chaparral's hard sclerophyllous evergreen leaves and its dependence on infrequent crown fires.

Between which latitudes do mangroves mainly grow?

Mainly between 30° N and 30° S, with the greatest mangrove area within 5° of the equator; winter frost sets the poleward limit.

Why are mangroves taxonomically diverse despite looking alike?

Their adaptations remove salt and take in extra oxygen.

The Valdivian temperate rainforests are found in which region?

Southwestern South America: the Valdivian forests run down the Chilean coast and into Argentina, home to the alerce, a conifer that can live over 3,000 years.

Why are estuaries among the most productive habitats on Earth?

Mixing of sea and fresh water supplies high nutrient levels: rivers carry nitrogen and phosphorus into sheltered tidal water, which is why estuaries serve as nurseries for so many fish.

In what year were Burmese pythons officially recognised as breeding in the Everglades?

2000: that year the National Park Service confirmed pythons were breeding in Everglades National Park, after released and escaped pets had been sighted there since the 1980s.

Lionfish, native to the Indo-Pacific, have invaded which three seas?

The West Atlantic, Caribbean and Mediterranean: lionfish spread from Florida through the Caribbean from the 1980s and entered the Mediterranean via the Suez Canal around 2012; divers are urged to spear them for food.

Which island's native birds were mostly wiped out by the brown tree snake?

Guam: the brown tree snake arrived in military cargo around 1949 and wiped out ten of the island's twelve native forest bird species.

Under what commercial name, adopted in 2022, are invasive Asian carp sold in the US?

Copi, launched by the Illinois Department of Natural Resources in June 2022 to get diners eating silver and bighead carp, which had been introduced to US fish farms in the 1970s.

Who released at least 13 wild rabbits for hunting in Victoria in October 1859?

Thomas Austin, a settler at Barwon Park near Geelong, had the rabbits shipped from England for sport shooting; within a few years their descendants had overrun Victoria.

Which pathogen was released in Australia in 1950 to cut rabbit numbers?

Myxoma virus: released along the Murray in 1950, myxomatosis cut the rabbit population from about 600 million to 100 million within two years.

Between which years was Western Australia's rabbit-proof fence built?

It failed to stop the spread.

The Nile perch's spread through Lake Victoria devastated which group of native fish?

Cichlids: Lake Victoria's haplochromine cichlids, perhaps 500 species, lost around 200 of them after the Nile perch, introduced in the 1950s, boomed through the lake in the 1980s.

Water hyacinth is anecdotally known as the 'terror' of which region?

Bengal: the South American floater earned the name 'terror of Bengal' after choking the region's waterways; its mats can double in area in a fortnight.

Which trees does the invasive beetle Agrilus planipennis, found near Detroit in 2002, kill?

Ash: the emerald ash borer, Agrilus planipennis, was detected in Michigan in 2002; its larvae tunnel under the bark and have killed tens of millions of ash trees across North America.

In what year was the IUCN Red List founded?

1964: the IUCN began the Red List, then published as Red Data Books, that year; its categories run from Least Concern to Extinct.

Martha, the last passenger pigeon, died in 1914 at which zoo?

The Cincinnati Zoo: Martha died there on 1 September 1914, aged about 29, and was frozen in a 300-pound block of ice for shipping to the Smithsonian.

In which US state was the last confirmed wild passenger pigeon shot, in 1900?

Ohio: a boy shot the last confirmed wild passenger pigeon in Pike County in March 1900; the stuffed bird, nicknamed Buttons, is held by the Ohio History Connection.

Which living bird is the dodo's closest relative?

The Nicobar pigeon: a 2002 DNA study placed the dodo and the extinct Rodrigues solitaire as sister species whose nearest living relative is this iridescent Southeast Asian pigeon.

Roughly how much protected land does the Serengeti region contain?

About 30,000 square kilometres, taking in Serengeti National Park, the Ngorongoro Conservation Area and Kenya's Maasai Mara; some 70 large mammal and 500 bird species live there.

Which New Mexico area did Aldo Leopold propose as the Forest Service's first wilderness?

The Gila: on Leopold's proposal the Forest Service set aside the Gila Wilderness in June 1924, the first such area in the United States, shortly before he left New Mexico for Madison.

In which state is the shack where Aldo Leopold wrote A Sand County Almanac?

Wisconsin: Leopold bought a worn-out farm on the Wisconsin River in Sauk County in 1935, and the rebuilt chicken coop he called the Shack is where the essays took shape.

The Population Bomb (1968) was published by Ballantine together with which organisation?

The Sierra Club: the book appeared as a Sierra Club–Ballantine paperback in 1968 and sold over two million copies, though co-author Anne Ehrlich went uncredited at the publisher's insistence.

Which Stanford research site did Ehrlich help protect in 1973?

Jasper Ridge: Ehrlich's long-term checkerspot butterfly studies there began in 1960, and Stanford formally set the ridge aside as a biological preserve in 1973.

Which 1954 series began David Attenborough's presenting career?

Zoo Quest, first broadcast in December 1954, followed London Zoo collecting trips to Sierra Leone and Guyana; Attenborough took over presenting when zoo curator Jack Lester fell ill.

Which producer first proposed to Attenborough the series that became Life on Earth?

Christopher Parsons of the BBC Natural History Unit in Bristol pitched a series on the whole history of life in 1973 and was executive producer when Life on Earth aired in 1979.

A top-down trophic cascade starts when which group is effective enough to control prey?

Removing top predators through hunting can trigger knock-on effects down the food web.

Which conditions are typically greater at habitat edges than in the interior?

Wind exposure, light and temperature fluctuations: without a closed canopy the edge is brighter, windier and swings more between day and night, which is why small fragments show such strong edge effects.

Who coined the term 'metapopulation' in 1969?

Richard Levins coined 'metapopulation' in a 1969 paper on pest control, calling it 'a population of populations'; Ilkka Hanski later made it the basis of conservation models.

Which maxim paraphrases the competitive exclusion principle?

'Complete competitors cannot coexist' is how Garrett Hardin summed up the principle in his 1960 Science paper: two species that need exactly the same limiting resource cannot share it indefinitely.

Which Canadian province hosts the Experimental Lakes Area, famed for phosphorus research?

Ontario: the 58 lakes of the ELA near Kenora hosted David Schindler's 1970s whole-lake experiments, which pinned algal blooms on phosphorus and drove bans on phosphate detergents.

Below what dissolved oxygen level does a body of water count as hypoxic?

2 mg per litre: below that most fish flee or die, and mass mortality sets in under 0.5 mg per litre, against the 8 or more that well-mixed cool water holds.

Runoff from which river system feeds the Gulf of Mexico's annual summer dead zone?

The Mississippi: nitrogen and phosphorus washed off Midwest farmland feed algal blooms off Louisiana each summer, and the 2017 dead zone reached a record 22,700 square kilometres.

Peruvian fishermen named the El Niño current after whom?

The Christ Child: the warm current tended to arrive off Peru around Christmas, so fishermen called it El Niño de Navidad.

What is the cooling phase of the ENSO cycle called?

La Niña, 'the girl', is the cool phase in which strong trade winds pile warm water in the west Pacific and cold upwelling chills the coast of Peru; El Niño is the warm phase.

Which discipline studies periodic events such as leaf-out and bird migration dates?

Phenology, from the Greek for 'appearance', tracks first leaf, first butterfly flight and egg-laying dates; Kyoto's cherry-blossom records run back over 1,200 years.

Monarch butterflies overwinter in Mexico on which tree?

The oyamel fir, Abies religiosa, which grows at 2,400–3,600 m in the mountains west of Mexico City; monarchs cluster on its boughs from November until their March return north.

Since 1976, monarch roosting sites have been identified in which two Mexican states?

Michoacán and México: the dozen colonies, found in 1975 and announced in 1976, cluster in the oyamel forests around Angangueo and Sierra Chincua, about 100 km west of Mexico City.

Between 1950 and 2020, average ocean surface pH fell from about 8.15 to what?

About 8.05: a 0.1 drop in pH is roughly a 30% rise in hydrogen-ion concentration, so seawater stays alkaline while becoming markedly more acidic than in 1950.

Ground must stay below 0 °C for how long to count as permafrost?

Two years or more: ground at or below 0 °C for two consecutive years qualifies, while the oldest permafrost, in the Yukon, has stayed frozen for around 700,000 years.

Fish that hatch in fresh water, mature at sea and return upriver to spawn are called what?

Anadromous, from the Greek for 'running up'; Pacific salmon are the extreme case, dying after a single spawning run, while catadromous eels do the reverse.

Which nutrients do dead salmon carry from the ocean into forests and wetlands?

Nitrogen, sulfur, carbon and phosphorus: bears drag carcasses into riparian woods, and marine nitrogen isotopes from salmon show up in the rings of Alaskan spruce.

Which principle says island colonists tend to become bigger if small and smaller if large?

Foster's rule, or the island rule, proposed by J. Bristol Foster in 1964: small mammals such as rodents grow larger on islands while large ones such as elephants shrink.

Which two dinosaurs are cited as ancient examples of insular dwarfism?

Europasaurus and Magyarosaurus: both were sauropods only about 6 m long, stranded on Late Jurassic German and Late Cretaceous Romanian islands; Pleistocene dwarf elephants are more recent examples.

Bergmann's rule links larger body size to which kind of environment?

Colder: Carl Bergmann argued in 1847 that bigger bodies lose less heat per unit mass, which is why polar bears outweigh tropical sun bears.

Who formulated the rule that cold-climate animals have shorter, thicker limbs, in 1877?

Joel Asaph Allen published the rule in 1877: shorter limbs and ears cut surface area relative to volume, so arctic foxes keep heat that long-eared desert fennecs shed.

What is the cladistic term for convergent evolution?

Homoplasy: a trait shared by lineages that did not inherit it from a common ancestor, as with flight in insects, birds, pterosaurs and bats; homology is the opposite case.

What term describes the productive area able to regenerate what people take from nature?

Biocapacity: the Global Footprint Network totals a country's cropland, forest, grazing land, fishing grounds and built land by productivity; when the ecological footprint exceeds it, the country runs an ecological deficit.

What problem do wildlife corridors chiefly mitigate?

Habitat fragmentation: corridors such as the Banff wildlife overpasses on the Trans-Canada Highway let animals move between patches, keeping isolated populations genetically connected.

How does rewilding differ from other forms of ecological restoration?

It aims to reduce human influence on ecosystems: rather than managing toward a fixed historical baseline, rewilding restores processes such as grazing and predation and accepts the novel ecosystems that result.

Pleistocene Park lies on which Siberian river?

The Kolyma: the park sits near Chersky in Yakutia's Kolyma lowlands, where Sergey and Nikita Zimov have stocked bison, horses and musk oxen to recreate the mammoth steppe.

In which forest were the last wild lowland European bison shot in 1921?

Białowieża: a poacher shot the last wild lowland wisent there in 1921, and the species survived only through 54 captive animals; the last Caucasian wisent followed in 1927.

How many chromosome pairs does Przewalski's horse have, versus 32 in domestic horses?

33 pairs, or 66 chromosomes, against 64 in domestic horses, yet the two produce fertile hybrids; the species was reintroduced to Mongolia's Hustai National Park from 1992.

In which year did the California condor become extinct in the wild?

1987: the last wild condor was trapped in April that year, bringing the whole species to 27 birds in captivity at the San Diego and Los Angeles zoos.

What is the California condor's wingspan, the widest of any North American bird?

About 3.0 metres, just under ten feet; the condor weighs 8–14 kg and can soar for hours on thermals without flapping.

In which year was the bald eagle removed from the US endangered species list?

2007: the bald eagle came off the list on 28 June 2007, having been downgraded from endangered to threatened in 1995 as nesting pairs in the lower 48 passed 4,000.

How deep was the largest recorded bald eagle nest, found in Florida in 1963?

6.1 metres deep and 2.9 metres wide, the St Petersburg, Florida nest weighed close to three tonnes and stands as the largest bird's nest on record.

Which pesticide drove the peregrine falcon to endangered status before its 1970s ban?

DDT: its breakdown product DDE thinned peregrine eggshells until they cracked under the incubating bird; after the 1972 US ban, releases rebuilt the population and it was delisted in 1999.

Which two other names has the peregrine been known by in Australia and North America?

Black-cheeked falcon and duck hawk: Australians named it for its dark malar stripe, North Americans for its habit of taking waterfowl; females are about a third larger than males.

In 2016, the IUCN reclassified the giant panda to which Red List category?

Vulnerable: the IUCN downlisted the panda from Endangered in September 2016 after China's fourth survey counted 1,864 wild adults, up 17% in a decade.

Which two northern white rhinos were the last of their kind after Sudan died in 2018?

Najin and her daughter Fatu, both female and kept at Ol Pejeta Conservancy in Kenya, left the subspecies functionally extinct once Sudan, the last male, died in March 2018.

Bycatch from illegal fishing of which fish is driving the vaquita to extinction?

Totoaba: gillnets set illegally for its swim bladder, prized in China, drown vaquitas, the smallest living cetacean, whose numbers fell to roughly ten by the early 2020s.

Where does the vaquita live?

The northern Gulf of California: the vaquita lives only in shallow water near the Colorado River delta, the smallest range of any cetacean; it was described as a species in 1958.

Which two bodies rejected the Anthropocene as a formal epoch in 2024?

The ICS and IUGS: the Subcommission on Quaternary Stratigraphy voted the proposal down in March 2024 and the International Union of Geological Sciences upheld the rejection, leaving the Holocene in place.

Which atmospheric chemist popularised 'Anthropocene' at a 2000 conference in Mexico?

Paul Crutzen, the ozone-chemistry Nobel laureate, blurted out 'Anthropocene' at a 2000 IGBP meeting in Cuernavaca, then co-wrote a newsletter note with Eugene Stoermer that launched the term.

Kelp forests plus coral reefs cover 0.1% of Earth but give what share of primary productivity?

0.9%: in Whittaker's classic tally, algal beds and reefs yield about 1.6 billion tonnes of plant matter a year from just 0.6 million square kilometres, a productivity per area rivalling rainforest.

Roughly how many species of fully marine seagrasses exist?

About 60 species in four families, flowering plants that returned to the sea 70 to 100 million years ago; Posidonia meadows in the Mediterranean include clones thought to be thousands of years old.

Which sea is the only named one without land boundaries?

The Sargasso: bounded only by the Gulf Stream, North Atlantic, Canary and North Equatorial currents of the North Atlantic Gyre, it is named for its floating mats of Sargassum weed.

Which 1920s Danish voyages found the European eel's Atlantic breeding grounds?

The Dana expeditions: Johannes Schmidt's cruises aboard the Dana from 1920 to 1922 traced ever-smaller eel larvae to the Sargasso Sea, fixing the spawning ground there.

Why can't the Great Pacific Garbage Patch be seen from satellites?

Its debris density is too low: the patch is mostly microplastic fragments, a few particles per cubic metre spread over a region the size of Iran, rather than a visible raft.

Which yachtsman claimed to discover the garbage patch after a 1997 race?

Charles Moore, sailing home to California from the 1997 Transpac race, crossed days of floating plastic; The Ocean Cleanup later put the patch at 1.6 million square kilometres.

Which two mountain ranges create most rain shadows in the western United States?

The Sierra Nevada and Cascades wring Pacific moisture from westerly winds, leaving the endorheic Great Basin and Death Valley in their rain shadow.

What is stunted, wind-twisted vegetation at the tree line called?

Krummholz, German for 'crooked wood'; in Newfoundland the same wind-pruned mat of spruce and fir is called tuckamore.

Roughly what share of Earth's land surface is covered by biological soil crusts?

About 12 percent: a 2018 global estimate put biocrusts of lichens, mosses and cyanobacteria on roughly an eighth of Earth's land, fixing carbon and nitrogen and holding arid soils in place.

Which type of plant contains volatile oils that promote the spread of fire?

Active pyrophytes such as eucalyptus carry volatile oils that feed flames, while passive pyrophytes merely resist fire with thick bark; pyrophiles need fire to complete their reproductive cycle.

Which conifer's cones are sealed with resin that only fire melts away?

Lodgepole pine: its serotinous cones stay resin-sealed for years until heat above about 45 °C melts the seal, which is why its seedlings carpeted Yellowstone after the 1988 fires.

Which childhood accident led E. O. Wilson to focus on tiny creatures like ants?

He was partly blinded while fishing: at seven a pinfish's spine pierced his right eye, and with poor distance vision he turned to insects he could hold close, doing his Harvard doctorate on ants.

Which 1975 E. O. Wilson book set off a furious nature-versus-nurture row?

Sociobiology: The New Synthesis (1975) argued that social behaviour, human behaviour included, has a genetic basis; a protester doused Wilson with a pitcher of water at a 1978 AAAS meeting over it.

Which palaeontologist mentored both Jane Goodall and Dian Fossey?

Louis Leakey, who believed living apes would illuminate early hominids, sent Goodall to Gombe in 1960 and Fossey to the mountain gorillas in 1966; Biruté Galdikas followed with orangutans.

Which chimpanzee group did Jane Goodall study at Gombe Stream National Park?

The Kasakela community, whose members David Greybeard and Flo became famous; Goodall documented tool use there in 1960 and the four-year Gombe war against the Kahama splinter group from 1974.

Dian Fossey founded which research centre in Rwanda?

Karisoke, founded in 1967 and named for the volcanoes Karisimbi and Bisoke it sits between; Gorillas in the Mist appeared in 1983, two years before Fossey's murder there.

Who first applied the term 'Darwin's finches' in 1936?

Percy Lowe, a British Museum ornithologist, used the phrase in a 1936 paper; David Lack's 1947 book Darwin's Finches made it standard.

Which South American bird is the closest known relative of the Galápagos finches?

The dull-coloured grassquit of the Andes is the closest known relative, which places the Galápagos finches in the tanager family rather than among true finches.

On which Galápagos island have Peter and Rosemary Grant studied finches since 1973?

Daphne Major, a volcanic islet so small the Grants could catch and measure nearly every finch on it, which is how they recorded beak size shifting after the 1977 drought.

Which award did the Grants win in 2005 for demonstrating evolution in action?

The Balzan Prize, awarded in 2005 for population biology; the Grants had shown beak size in Daphne Major finches shifting measurably within a couple of years of drought or flood.

Estimates in the 2010s put extinction rates at how many times the background rate?

100 to 1,000 times higher: a 2014 review led by Stuart Pimm put current losses at about 1,000 times the natural background, the pace that earns the Holocene the 'sixth extinction' label.

Which list contains only examples of mutualism?

Mycorrhizae, pollination, seed dispersal and coral zooxanthellae: in each, both partners gain, fungi trading soil phosphorus for sugars and corals housing algae for their photosynthate.

Coral reefs cover under 0.1% of the ocean but shelter at least what share of sea species?

A quarter: reefs covering about 284,000 square kilometres, roughly half the area of France, shelter at least 25% of known marine species.

Under the Ramsar treaty, marine areas are wetlands only if low-tide depth is at most what?

Six metres: the Convention counts marine water whose depth at low tide does not exceed six metres, which lets coral reefs and seagrass beds qualify as wetlands.

Roughly what fraction of Earth's land surface is arid or semi-arid?

About one-third: arid and semi-arid lands, where evaporation outstrips rainfall, make up roughly a third of the land surface, rising to about 40% if dry sub-humid zones are counted.

Which wetland in the Ganges–Brahmaputra delta is the world's largest mangrove forest?

The Sundarbans, some 10,000 square kilometres of mangrove straddling Bangladesh and India, is the only mangrove forest with a resident tiger population.

Warder Clyde Allee first demonstrated the Allee effect in the 1930s by showing which animals survive better in larger groups?

Goldfish in a crowded tank survived better, leading Allee to argue that aggregation and cooperation can raise individual fitness.

Liebig's law of the minimum was actually first formulated by which agricultural scientist?

Carl Sprengel set out the principle in 1828, a dozen years before Liebig's 1840 book popularised the idea that growth is set by the scarcest resource, not the total available.

Liebig's law of the minimum, on growth limited by the scarcest nutrient, is usually illustrated with what everyday object?

A barrel with uneven staves holds only what its shortest stave allows; Dobenecks coined the image, now called Liebig's barrel, for a plant limited by its scarcest nutrient.

Which American zoologist proposed the 'law of tolerance' in 1911?

Victor Shelford's law holds that each organism has a minimum, maximum and optimum for every environmental factor, so too much of a resource limits growth as surely as too little, refining Liebig's law.

The ecological footprint was developed as whose PhD dissertation at the University of British Columbia in the early 1990s?

Mathis Wackernagel wrote it under William Rees, who published the first academic paper on footprints in 1992; Wackernagel went on to co-found the Global Footprint Network in 2003.

In which unit are ecological footprints and biocapacity both expressed?

Global hectares: one is a hectare of world-average biological productivity, so a nation's footprint and its biocapacity can be compared in the same unit.

Who at the New Economics Foundation originally developed the Earth Overshoot Day concept?

Andrew Simms devised it at the New Economics Foundation in 2006 in partnership with the Global Footprint Network; the date divides world biocapacity by the global footprint, and in 2024 it fell on 1 August.