This ecology trivia quiz has 180 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
He introduced it in his sprawling 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
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.
Q 03The word 'ecosystem' first appeared in print in 1935 in a publication by which British ecologist?
Arthur Tansley
He wanted a word that stressed the transfer of materials between organisms and their physical surroundings, not just the organisms themselves.
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
He also became the first editor of the Journal of Animal Ecology, and his 1958 book on biological invasions founded a whole subdiscipline.
Q 07Which ecologist developed the concept of trophic levels in 1942 and coined 'decomposers'?
Raymond Lindeman
His landmark paper on trophic dynamics built 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
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.
Q 10Which zoologist introduced the keystone species concept in 1969 after a starfish-removal experiment?
Robert Paine
The idea is that a few species hold a community together far out of proportion to their abundance, like the keystone in an arch.
Q 11Paine's 1969 paper paired the mussel Mytilus californianus with which predator as its primary example?
Ochre starfish
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.
Q 12Sea otters protect kelp forests mainly by eating which grazers?
Sea urchins
Otters that eat lots of them can end up with purple-stained teeth and bones.
Q 13The sea otter has the densest fur of any animal. Up to how many hairs per square centimetre?
150,000
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.
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
The 'paradox of the plankton' is the famous counterexample: dozens of species coexist on a handful of resources.
Q 23Which University of Chicago botanist first documented ecological succession in the Indiana Dunes?
Henry Chandler Cowles
He was inspired by Warming's studies of Danish dunes and worked the Indiana shore between 1899 and 1910.
Q 14In ideal conditions, how much can giant kelp (Macrocystis) grow vertically in a single day?
30–60 cm
That growth is anchored by a holdfast rather than true roots, since kelp takes nutrients straight from the water.
Q 15In which year were gray wolves reintroduced to Yellowstone's Lamar Valley?
1995
The first wolves were captured near Hinton, Alberta; the case has become the textbook example of a trophic cascade.
Q 16The last wolves in Yellowstone were killed by park rangers in which year?
1926
Two pups found near Soda Butte Creek were the final casualties, though the Park Service kept its predator-control policy until 1933.
Q 17Which animal's Yellowstone colonies rose from one in 2001 to nine a decade later, as wolves returned?
Beaver
With fewer elk browsing the willows, the streamside trees they need for food and dams came back.
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
Grinnell's habitat-based niche is now contrasted with later functional and mathematical definitions.
Q 20G. Evelyn Hutchinson defined the niche as an 'n-dimensional' what?
Hypervolume
Each dimension is an environmental condition or resource; the space in which a population can persist is the niche.
Q 24In succession theory, what is the supposedly stable community at the end of a sere called?
Climax
An influential 1916 theory held that climate alone determined a single such endpoint; later ecologists found the picture far messier.
Q 25Off which country does Surtsey, the volcanic island that rose from the sea in 1963, lie?
Iceland
The first vascular plant, the sea rocket Cakile arctica, was found on its northern shore in the spring of 1965.
Q 26Who defined symbiosis in 1879 as 'the living together of unlike organisms'?
Heinrich Anton de Bary
The German mycologist's definition covers every long-term way unlike species live together, but excludes brief encounters such as predation.
Q 27A remora riding a shark, feeding on scraps while the shark is unaffected, is a classic example of which interaction?
Commensalism
The host stays unmodified while the hanger-on often shows big structural 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
It sits alongside competition, where both parties lose fitness, in the grid of species interactions.
Q 29Cowbirds, whydahs and many cuckoos lay their eggs in other birds' nests. What is this strategy called?
Brood parasitism
The female European cuckoo even 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
The word fuses the Greek for fungus and root; the arbuscular type alone occurs in about 70% of plant species.