Ecology Basics — Set 1

Correct Answer: B. Ernst Haeckel

• **Ernst Haeckel** = German biologist who first coined the term 'Ecology' in 1866, defining it as the study of organisms' relationships with their environment. • **'Oikos' + 'Logos'** — the Greek roots of Ecology: 'Oikos' meaning house/home and 'Logos' meaning study, together forming the concept of studying nature's 'household'. • 💡 Wrong-option analysis: A.G. Tansley: coined 'Ecosystem' in 1935, not 'Ecology'; Charles Darwin: proposed theory of evolution, not ecology term; Eugene Odum: modernised ecosystem ecology but did not coin the term.

Correct Answer: B. Ecosystem

• **Ecosystem** = the basic functional unit of nature where living organisms interact among themselves and with the surrounding physical environment, including both biotic and abiotic components. • **A.G. Tansley, 1935** — the scientist who coined the term 'Ecosystem', describing it as an integrated system of living beings and their physical environment. • 💡 Wrong-option analysis: Biome: a large geographical area with similar climate and vegetation, not a functional unit; Population: only one species in one area; Community: all biotic organisms together, excluding abiotic factors.

Correct Answer: B. Temperature

• **Temperature** = an abiotic (non-living physical) factor that significantly influences the distribution and survival of organisms in any ecosystem. • **Abiotic vs Biotic** — abiotic components include temperature, sunlight, water, and soil pH; biotic components include all living organisms like producers, consumers, and decomposers. • 💡 Wrong-option analysis: Green plants: biotic — living producers; Bacteria: biotic — living decomposers or producers; Fungi: biotic — living decomposers.

Correct Answer: C. Autotrophs

• **Autotrophs** = primary producers that synthesize their own food from inorganic raw materials using light energy (photosynthesis) or chemical energy (chemosynthesis). • **First trophic level** — autotrophs always occupy the base of every food chain, making all other life dependent on them for energy. • 💡 Wrong-option analysis: Saprotrophs: feed on dead organic matter, cannot self-produce food; Decomposers: break down dead material, a type of heterotroph; Heterotrophs: must consume other organisms for food, opposite of autotrophs.

Correct Answer: D. Ecotone

• **Ecotone** = a zone of junction or transition between two or more diverse ecosystems, such as mangroves between terrestrial and marine ecosystems. • **Edge Effect** — the phenomenon seen in ecotones where species density and diversity are often greater than in either flanking community. • 💡 Wrong-option analysis: Ecosphere: another term for the biosphere; Ecotype: a genetically distinct population adapted to local conditions; Eclat: not an ecological term at all.

Correct Answer: C. Producers

• **Producers** = always occupy the first trophic level at the base of any ecological pyramid, converting solar energy into chemical energy available for all other levels. • **First trophic level** — producers like green plants form the largest and most energy-rich base, with successive levels consisting of primary, secondary, and tertiary consumers. • 💡 Wrong-option analysis: Decomposers: operate outside the main pyramid structure, breaking down all levels; Herbivores: occupy the second trophic level, not the base; Carnivores: occupy third or higher trophic levels.

Correct Answer: B. Lindeman's Law

• **Lindeman's 10% Law** = states that only about 10% of energy is transferred from one trophic level to the next; the remaining 90% is lost as heat or used in metabolic processes. • **Energy loss limits food chains** — this 90% loss at each step explains why food chains rarely exceed 4-5 trophic levels in nature. • 💡 Wrong-option analysis: Newton's Law: laws of motion/gravity, not ecology; Liebig's Law: law of minimum, about limiting nutrients; Shelford's Law: law of tolerance, about range of conditions for species survival.

Correct Answer: B. Food Chain

• **Food Chain** = a linear sequence showing the transfer of nutrients and energy from one organism to another through 'eat-and-be-eaten' relationships. • **Producer to top predator** — a food chain begins with a producer and ends with a top predator or decomposer; in nature, multiple interlinking chains form a food web. • 💡 Wrong-option analysis: Food Web: a complex network of multiple interconnected food chains, not a single sequence; Ecological cycle: refers to biogeochemical cycling of nutrients; Energy flow: the broader concept of energy movement, not the eat-and-be-eaten sequence specifically.

Correct Answer: C. Ecological Succession

• **Ecological Succession** = the orderly, predictable process of change in species composition of a given area from pioneer species to a stable 'climax community'. • **Primary vs Secondary** — primary succession begins on bare rock with no prior life; secondary succession follows after a disturbance destroys an existing community. • 💡 Wrong-option analysis: Homeostasis: maintenance of internal equilibrium within an organism; Eutrophication: nutrient enrichment causing algal bloom, a form of water pollution; Bioaccumulation: build-up of toxins in organism tissues over time.

Correct Answer: C. Pyramid of Energy

• **Pyramid of Energy** = always upright because energy is irreversibly lost as heat at each trophic level, following the second law of thermodynamics. • **Second Law of Thermodynamics** — energy cannot be created or destroyed but is degraded to heat; this guarantees the energy pyramid is always wider at the base. • 💡 Wrong-option analysis: Pyramid of Species: not a standard pyramid type; Pyramid of Biomass: can be inverted in aquatic/marine ecosystems; Pyramid of Number: can be inverted in a single-tree ecosystem with many parasites.