180 Fun Facts About Ecology

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

He introduced it in his sprawling 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?

The book collects over 100 detailed, multi-colour plates of radiolarians, jellyfish and other sea creatures, and its flowing forms turned up in architecture and design.

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

He wanted a word that stressed the transfer of materials between organisms and their physical surroundings, not just the organisms themselves.

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'?

He also became the first editor of the Journal of Animal Ecology, and his 1958 book on biological invasions founded a whole subdiscipline.

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

His landmark paper on trophic dynamics built 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?

Energy pyramids are always upright, since energy is lost at every step; a standing crop of tiny, fast-cycling producers can weigh less than the fish that eat them.

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

The idea is that a few species hold a community together far out of proportion to their abundance, like the keystone in an arch.

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

Pisaster ochraceus is a generalist that also eats chitons, limpets, snails and barnacles; later work found it only acts as a keystone on wave-battered shores.

Sea otters protect kelp forests mainly by eating which grazers?

Otters that eat lots of them can end up with purple-stained teeth and bones.

The sea otter has the densest fur of any animal. Up to how many hairs per square centimetre?

Unlike most marine mammals it has no blubber, so 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?

That growth is anchored by a holdfast rather than true roots, since kelp takes nutrients straight from the water.

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

The first wolves were captured near Hinton, Alberta; the case has become the textbook example of a trophic cascade.

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

Two pups found near Soda Butte Creek were the final casualties, though the Park Service kept its predator-control policy until 1933.

Which animal's Yellowstone colonies rose from one in 2001 to nine a decade later, as wolves returned?

With fewer elk browsing the willows, the streamside trees they need for food and dams came back.

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?

Grinnell's habitat-based niche is now contrasted with later functional and mathematical definitions.

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

Each dimension is an environmental condition or resource; the space in which a population can persist is the 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?

The 'paradox of the plankton' is the famous counterexample: dozens of species coexist on a handful of resources.

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

He was inspired by Warming's studies of Danish dunes and worked the Indiana shore between 1899 and 1910.

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

An influential 1916 theory held that climate alone determined a single such endpoint; later ecologists found the picture far messier.

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

The first vascular plant, the sea rocket Cakile arctica, was found on its northern shore in the spring of 1965.

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

The German mycologist's definition covers every long-term way unlike species live together, but excludes brief encounters such as predation.

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

The host stays unmodified while the hanger-on often shows big structural adaptations, like the remora's sucker disc.

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

It sits alongside competition, where both parties lose fitness, in the grid of species interactions.

Cowbirds, whydahs and many cuckoos lay their eggs in other birds' nests. What is this strategy called?

The female European cuckoo even 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?

The word fuses the Greek for fungus and root; the arbuscular type alone occurs in about 70% of plant species.

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

She showed that fungi could shuttle carbon between trees, work done at the University of British Columbia.

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?

This protandrous sequential hermaphroditism means every clownfish starts life male, and the largest non-breeder steps up to become the new male.

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

One died in transit; by 2011 their descendants were estimated at over 200 million.

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

They had been used to control sugar cane pests in Puerto Rico since 1920, and Australia imported them to eat cane beetles.

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

They arrived in ships' ballast water and were first detected in Lake St. Clair in 1988.

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

It stayed a garden plant until the Dust Bowl, when it was marketed to farmers as a way to stop soil erosion.

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

It comes from the German Kapazitätsgrenze; 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?

The book's central idea is that 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?

Recolonisation confirmed that species numbers fall the further an island sits from the mainland source.

In which year did Rachel Carson publish Silent Spring?

Editors had found DDT an unappealing subject for years; the book met fierce opposition from chemical companies but reversed US pesticide policy.

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

'Silent Spring' was originally meant just as the title of the chapter on birds before Carson's agent suggested it for the whole book.

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

It was the middle volume of her sea trilogy, written while she still worked for the Fish and Wildlife Service.

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

Birds of prey end up carrying far higher doses than the plankton or insects at the bottom.

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

Almost none of it 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?

That is why farmers plant peas, clover or alfalfa to enrich tired soils.

What share of the world's fixed nitrogen did the Haber-Bosch process supply by 2020?

Between fertiliser, legume crops and combustion, humans have more than doubled the annual flow of nitrogen into biologically usable forms.

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

Nitrification runs the other way, converting ammonia into nitrites and nitrates that plants can take up.

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

The catch is that it exchanges carbon with the surface only over hundreds of years, via the slow thermohaline circulation.

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

The element rarely forms a gas, so it moves through rock, soil and water instead, and phosphine only appears in isolated conditions.

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

His 2000 criteria demand at least 1,500 endemic vascular plants and loss of at least 70% of primary vegetation; by 2016 the hotspot count stood at 36.

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

Along with some 900 islands it stretches over 2,300 km and is the biggest single structure built by living organisms.

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

Those single-celled partners provide up to 90 percent of a coral's energy, so a bleached coral starts to starve.

The 1971 Convention on Wetlands is named after the city where it was signed. Which country is that city in?

World Wetlands Day falls on 2 February, the date the treaty was adopted in Ramsar.

Which South American region is the world's largest tropical wetland?

It lies mostly in the state of Mato Grosso do Sul and holds one of the largest and healthiest jaguar populations on Earth.

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

The name captures its sheetflow, a broad, shallow river creeping slowly 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?

His scheme simplified Leslie Holdridge's 1947 life-zone system, which had made the same bet on rain and heat.

The word 'ecotone', for a transition zone between communities, was coined in 1904 by which ecologist?

The greater variety of species found at such junctions is known as the edge effect.

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

Trapping data from 1847 to 1903 show hunter and hunted rising and falling in lockstep, roughly a decade apart.

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

They are a pair of nonlinear differential equations, and one of their assumptions is that the prey always finds ample food.

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

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?

The author of Lord of the Flies had a classical education and offered the name over a village walk.

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

The 3.14-acre glass structure at Oracle was sealed with a crew of eight from 1991 to 1993 and is now run by the University of Arizona.

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?

These bacteria and archaea run on chemicals rather than light, feeding tube worms, clams, limpets and shrimp.

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

Emerging in prime-numbered years in overwhelming numbers is a textbook case of predator satiation.

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

The gap is only about 35 km wide, yet the species on either side differ strikingly, Asian on one side and Australian on the other.

Which organisms partner with fungi to form a lichen?

A lichen behaves like a self-contained miniature ecosystem, with bacteria embedded in its cortex as well.

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

They feast on the grubs and beeswax left behind, being among the few birds that regularly digest wax.

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

That habit makes the relationship less tidy than the classic mutualism it is usually presented as.

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

Forcing her way in usually costs her wings and most of her antennae; the fig itself is a stem-like structure called a syconium.

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

His party climbed to 19,286 feet in 1802, then a record, and his 1807 Essay on the Geography of Plants launched the study of species along gradients.

The word 'biosphere' was invented in 1875 by which Austrian geologist, later popularised by Vernadsky?

Vernadsky's later book The Biosphere argued that life itself is a geological force shaping the planet.

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

In murky, nutrient-rich lakes it can be just a few centimetres deep.

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

Earthworms and woodlice digest dead matter internally, which is why some ecologists file them as detritivores instead.

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

In his mimicry a harmless species copies the warning signals of a harmful one to fool the animals that would eat both.

What are the three regions and types of tundra?

Tundra soil stores methane and CO2 in permafrost, making it a carbon sink.

What is the ecotone between tundra and forest called?

It is also known as the timberline.

What key feature defines a savanna's tree cover?

Light reaching the ground supports an unbroken layer of grasses.

Which type of climate shapes California's chaparral shrubland?

Its shrubs have hard sclerophyllous evergreen leaves and depend on infrequent crown fires.

Between which latitudes do mangroves mainly grow?

The greatest mangrove area lies within 5° of the equator.

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?

Temperate rainforests also occur in Japan and the Black Sea-Caspian region.

Why are estuaries among the most productive habitats on Earth?

Estuaries are classed as ecotones between river and marine environments.

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

Hurricane Andrew had destroyed a python breeding centre in 1992.

Which 1992 storm destroyed a Florida python breeding centre, releasing hundreds of snakes?

Python sightings topped 30,000 between 2008 and 2010.

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

Divers in Florida and Texas are encouraged to catch them for sport and food.

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

The snake arrived accidentally after World War II.

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

Silver, bighead, grass and black carp were introduced in the 1970s; Illinois launched the rebrand in June 2022.

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

By 1866 hunters had killed 50,000 on his estate, Barwon Park.

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

It slashed the population from about 600 million to 100 million.

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

It failed to stop the spread.

The Nile perch was introduced to Lake Victoria and which artificial Egyptian reservoir?

It has also been introduced to the artificial Lake Nasser.

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

The free-floating plant is native to South America.

Which trees does the emerald ash borer attack?

Larvae feed under the bark and emerge as adults after one to two years.

In what year was the IUCN Red List founded?

It is also known as the Red Data Book.

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

The species once numbered around 3 billion, possibly 5 billion.

Roughly how many passenger pigeons once lived in North America?

It was the most abundant bird on the continent.

Which living bird is the dodo's closest relative?

Its closest relative overall was the extinct Rodrigues solitaire.

Roughly how much protected land does the Serengeti region contain?

About 70 large mammal and 500 bird species live there.

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

He was stationed in New Mexico until 1924.

Into how many languages has A Sand County Almanac been translated?

It has sold more than two million copies since 1949.

Who co-wrote The Population Bomb with Paul Ehrlich but went uncredited?

The publisher insisted on a single author.

Which Stanford research site did Ehrlich help protect in 1973?

He had begun working there in 1959.

Which 1954 series began David Attenborough's presenting career?

His career has spanned seven decades.

Which producer suggested the title Life on Earth for Attenborough's landmark series?

It was planned at the BBC Natural History Unit in Bristol.

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?

Small fragments show especially pronounced edge effects.

Who coined the term 'metapopulation' in 1969?

He called it 'a population of populations'.

Which maxim paraphrases the competitive exclusion principle?

Georgy Gause is credited with it although he never actually formulated it.

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

Cultural eutrophication comes from sewage, wastewater and fertiliser runoff.

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

Mass mortality occurs once oxygen drops below 0.5 mg per litre.

How large was the largest dead zone recorded?

A 2017 report blamed the US meat industry for the largest-ever Gulf of Mexico dead zone.

Peruvian fishermen named the El Niño current after whom?

It was most noticeable around Christmas.

What is the cooling phase of the ENSO cycle called?

El Niño is the warming phase of sea surface temperatures.

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

Examples include first butterfly flights and egg-laying dates.

Monarch butterflies overwinter in Mexico on which tree?

They begin their northern return migration in March.

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

Twelve sites lie northwest and west of Mexico City.

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

Seawater remains alkaline, but the extra hydrogen ions raise acidity.

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

The oldest permafrost has been frozen for around 700,000 years.

Roughly what share of exposed Northern Hemisphere land is underlain by permafrost?

That is around 18 million square kilometres worldwide.

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

All Pacific salmon die after spawning.

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

Bears spread the carcasses into riparian woodlands.

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

It covers both island gigantism and insular dwarfism.

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

Pleistocene dwarf elephants are more recent examples.

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

Carl Bergmann described the pattern in 1847.

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

It concerns surface-area-to-volume ratio in warm-blooded animals.

What is the cladistic term for convergent evolution?

Flight in insects, birds, pterosaurs and bats is the classic example.

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

The ecological footprint compares demand against it.

What problem do wildlife corridors chiefly mitigate?

They are also called habitat or green corridors.

How does rewilding differ from other forms of ecological restoration?

It is open to novel ecosystems with new species and interactions.

Pleistocene Park lies on which Siberian river?

Sergey and Nikita Zimov are trying to recreate the mammoth steppe.

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

The last Caucasian wisent was shot in 1927.

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

It has been reintroduced to Hustai National Park in Mongolia.

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

All remaining wild birds were captured for breeding.

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

It weighs up to 14 kg, nearly as much as a trumpeter swan.

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

It had been upgraded from endangered to threatened in 1995.

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

It was also 2.9 metres wide.

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

It has since recovered thanks to nest protection and releases.

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

Females are considerably larger than males.

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

A 2015 survey counted 1,864 wild pandas over 1.5 years old.

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

Both are female, making the subspecies functionally extinct.

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

The vaquita is the smallest living cetacean.

Where does the vaquita live?

It was defined as a species in 1958.

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

Eugene Stoermer coined the term informally in the 1980s.

Which scientist is credited with first coining 'anthropocene' informally in the 1980s?

Paul Crutzen later re-invented and popularised the term.

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

Kelp forests were even found in tropical waters near Ecuador in 2007.

Roughly how many species of fully marine seagrasses exist?

They evolved from land plants that recolonised the ocean 70 to 100 million years ago.

Which sea is the only named one without land boundaries?

It is bounded by the four currents of the North Atlantic Gyre.

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

Johannes Schmidt led them from 1920 to 1922.

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

It contains only about 4 particles per cubic metre.

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

The Ocean Cleanup later estimated it at 1.6 million square kilometres.

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

The endorheic Great Basin lies in their rain shadow.

What is stunted, wind-twisted tree-line vegetation called, from German for 'crooked wood'?

In Newfoundland it is called tuckamore.

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

Biocrusts fix carbon and nitrogen and stabilise soils in arid lands.

Which type of plant contains volatile oils that actively encourage fires?

Pyrophiles need fire to complete their reproductive cycle.

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

Giant sequoias also need fire to open gaps in the canopy for seedlings.

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

He won two Pulitzers, including for The Ants in 1991.

Which two books won E. O. Wilson the Pulitzer Prize for General Nonfiction?

They won in 1979 and 1991 respectively.

Which palaeontologist mentored both Jane Goodall and Dian Fossey?

Goodall began at Gombe in 1960; Fossey started with gorillas in 1966.

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

Her work showed chimps use tools and wage organised warfare.

Dian Fossey founded which research centre in Rwanda?

Her book Gorillas in the Mist appeared two years before her 1985 murder.

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

David Lack popularised it in his 1947 book.

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

The finches belong to the tanager family, not the true finches.

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

They spend six months of every year capturing and tagging birds there.

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

They showed natural selection can be seen within a couple of years.

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

The Holocene extinction is sometimes called the sixth extinction.

Which four examples of mutualism are listed as prominent?

Mutualism gives each species a net benefit.

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

That area is about half the size of France.

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

The largest wetlands include the Amazon basin and the West Siberian Plain.

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

Camel caravans long carried salt, gold and ivory across the Sahara.

Which two other wetlands rank among the world's largest with the Pantanal and Amazon?

The Sundarbans lie in the Ganges-Brahmaputra delta.

Warder Clyde Allee first demonstrated the effect named after him in the 1930s using which animals?

More fish in a tank survived better, leading him to argue that aggregation and cooperation can raise individual fitness.

Liebig's law of the minimum was actually first developed in 1840 by which agricultural scientist?

Liebig later popularised the idea that growth is set by the scarcest resource, not the total available.

Liebig's law is commonly illustrated with what everyday object, whose capacity is set by its shortest part?

Dobenecks used the image of 'Liebig's barrel' to show a plant's growth limited by the nutrient in shortest supply.

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

It holds that each organism has a minimum, maximum and optimum for environmental factors acting in concert, refining Liebig's law.

The ecological footprint concept was developed as whose PhD dissertation at the University of British Columbia?

His supervisor William Rees wrote the first academic paper on footprints in 1992; the Global Footprint Network now promotes the metric.

According to the Global Footprint Network, humanity's 2022 footprint equalled how many Earths?

They estimate people are using natural capital 71% faster than the planet can renew it, a state called ecological overshoot.

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

The date is found by dividing world biocapacity by the global ecological footprint; in 2024 it fell on August 1.