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This ecology trivia quiz has 177 free questions with answers and covers the science of how organisms interact with each other and their environment: food chains and the ten-per-cent law, trophic levels and inverted pyramids, keystone species from Paine's starfish to sea otters, the Yellowstone wolves, ecological niches, succession on new volcanic islands, the three kinds of symbiosis, r/K selection, biomes and biodiversity hotspots, and the carbon, nitrogen and phosphorus cycles. It also asks about the people who built the field, from Haeckel and Humboldt to Tansley, Elton, Odum, Rachel Carson and MacArthur and Wilson, and about invaders like cane toads, zebra mussels and kudzu. It suits biology and environmental science students, teachers looking for a ready-made round, pub quiz hosts and anyone who likes knowing why the world is green. Easy questions cover terms every student meets; the hard ones ask who really coined 'ecosystem' and where a fig wasp gets in. Every answer has been checked against a reliable source, and each question shows its citation once you have answered.
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Q 01Which German scientist coined the term 'ecology' (Ökologie) in 1866?
Ernst Haeckel
Ernst Haeckel introduced 'Ökologie' in his 1866 Generelle Morphologie der Organismen, the same book in which he pushed Darwin's ideas onto German readers.
Q 02Haeckel's illustrated book Kunstformen der Natur (Art Forms in Nature) influenced which artistic movement?
Art Nouveau
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.
Q 03The word 'ecosystem' first appeared in print in 1935 in a publication by which British ecologist?
Arthur Tansley
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.
Q 04Who actually came up with the word 'ecosystem', at the request of the ecologist who published it?
Arthur Roy Clapham
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.
Q 05Which American ecologist wrote the 1953 textbook Fundamentals of Ecology with his brother?
Eugene Odum
The Odum brothers took a systems approach to whole ecosystems, and the book also fixed the modern meaning of a population's environmental ceiling.
Q 06Whose 1927 book Animal Ecology set out food chains, ecological niches and the 'pyramid of numbers'?
Charles Elton
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.
Q 07Which ecologist developed the concept of trophic levels in 1942 and coined 'decomposers'?
Raymond Lindeman
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.
Q 08Roughly what share of the chemical energy in its food does a consumer turn into its own tissue?
About 10%
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.
Q 09Which ecological pyramid can be inverted in a pond, where phytoplankton reproduce fast but live briefly?
Biomass
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.
Q 10Which zoologist introduced the keystone species concept in 1969 after a starfish-removal experiment?
Robert Paine
Robert Paine coined 'keystone species' in 1969 after removing the starfish Pisaster from Washington shorelines caused mussels to crowd out most other species.
Q 11Paine's 1969 paper paired the mussel Mytilus californianus with which predator as its primary example?
Ochre starfish
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.
Q 12Sea otters protect kelp forests mainly by eating which grazers?
Sea urchins
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.
Q 13Up to how many hairs per square centimetre does the sea otter's fur pack?
150,000
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.
Q 21By what name is the principle that two species competing for the same limited resource cannot stably coexist known?
Gause's law
Ironically, Georgy Gause never actually formulated the principle that carries his name.
Q 22Georgy Gause's classic laboratory competition experiments used two species of which microorganism?
Paramecium
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.
Q 23Which University of Chicago botanist first documented ecological succession in the Indiana Dunes?
Henry Chandler Cowles
Q 14In ideal conditions, how much can giant kelp (Macrocystis) grow vertically in a single day?
30–60 cm
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.
Q 15In which year were gray wolves reintroduced to Yellowstone's Lamar Valley?
1995
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.
Q 16The last wolves in Yellowstone were killed by park rangers in which year?
1926
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.
Q 17Which animal recolonised Yellowstone's northern-range streams after returning wolves eased elk browsing on willows?
Beaver
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.
Q 18The 1960 'green world hypothesis' says the planet stays green because which group keeps herbivores in check?
Predators
It flipped the prevailing bottom-up view of communities, and is often shortened to the HSS hypothesis.
Q 19Joseph Grinnell's 1917 paper, probably the first to use 'niche' in research, concerned which bird?
California thrasher
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.
Q 20G. Evelyn Hutchinson defined the niche as an 'n-dimensional' what?
Hypervolume
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.
Henry Chandler Cowles published his Indiana Dunes succession study in the Botanical Gazette in 1899, inspired by Eugen Warming's work on Danish dunes.
Q 24In succession theory, what is the supposedly stable community at the end of a sere called?
Climax
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.
Q 25Off which country does Surtsey, the volcanic island that rose from the sea in 1963, lie?
Iceland
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.
Q 26Who defined symbiosis in 1879 as 'the living together of unlike organisms'?
Heinrich Anton de Bary
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.
Q 27A remora riding a shark, eating scraps while the shark is unaffected, is a classic example of which interaction?
Commensalism
Commensalism leaves the host unchanged while the hanger-on often evolves big adaptations, like the remora's sucker disc.
Q 28When an interaction harms one species while the other is completely unaffected, it is called what?
Amensalism
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.
Q 29Cowbirds, whydahs and many cuckoos lay eggs in other birds' nests for the hosts to raise; what is this strategy called?
Brood parasitism
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.
Q 30Which German botanist first described mycorrhizal fungi and coined 'mycorrhiza' in 1885?
Albert Bernhard Frank
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.