Chapter Summary
Ecosystem is a functional unit of nature where living organisms interact among themselves and with their physical environment. It involves energy flow, nutrient cycling, productivity, food chains, food webs, ecological pyramids, and ecosystem services.
50 Questions and Answers
An ecosystem is a community of organisms interacting with each other and their physical environment.
Biotic (living organisms) and abiotic (non-living factors like air, water, soil).
The rate at which producers synthesize biomass in an ecosystem.
Total rate of photosynthesis including the organic matter used in respiration.
NPP = GPP - respiration losses; it represents the energy available to consumers.
The rate at which consumers convert the food they eat into their own biomass.
It is the natural, gradual process by which ecosystems change and develop over time.
The first species to colonize a bare area during ecological succession.
The stable and final stage of ecological succession in an area.
A food chain starting with dead organic matter, decomposed by microorganisms.
A food chain beginning with green plants (producers) eaten by herbivores.
A grassland ecosystem where grass is eaten by grasshoppers, rabbits, and deer; these are preyed on by birds, snakes, and lions.
A graphical representation of the number, biomass, or energy of organisms at each trophic level.
Pyramid of numbers, pyramid of biomass, and pyramid of energy.
Pyramid of energy.
The role and position of a species in its environment, including interactions and resource use.
It is the rate of biomass production per unit area per unit time.
The measure of human demand on natural resources in terms of ecosystem capacity.
The benefits people obtain from ecosystems, like pollination, oxygen, nutrient cycling, and climate regulation.
Croplands and aquariums.
Natural ecosystems form without human intervention, while artificial ones are man-made and managed.
The self-regulating process by which ecosystems maintain stability.
Autotrophic organisms like green plants and algae that produce food by photosynthesis.
Herbivores that feed directly on producers, e.g., deer, rabbit.
Carnivores that feed on herbivores, e.g., frog, fox.
Top carnivores feeding on secondary consumers, e.g., lions, tigers.
Microorganisms like bacteria and fungi that break down dead organisms and recycle nutrients.
Forests, ponds, lakes, and grasslands.
Large regional ecosystems characterized by specific climate, vegetation, and animal life.
Excessive nutrients in water bodies leading to algal blooms and oxygen depletion.
Pond succession is a process where a pond is gradually transformed into a terrestrial ecosystem.
The ability of an ecosystem to recover after disturbances.
Energy flow drives all ecosystem functions and is unidirectional from producers to consumers to decomposers.
Only 10% of energy is transferred from one trophic level to the next.
Raymond Lindeman.
The total biomass present in a trophic level at a given time.
The amount of inorganic nutrients present in soil, water, and air at a given time.
Primary succession and secondary succession.
Succession that starts in a lifeless area with no soil, e.g., bare rock.
Succession that occurs in an area where life existed earlier but was disturbed.
The ratio of energy output at one trophic level to energy input from the level below.
Herbivores like grasshoppers and rabbits.
A species that has a disproportionately large impact on its ecosystem relative to its abundance.
Tigers in forests help control herbivore populations, maintaining balance.
The movement and exchange of nutrients through the biotic and abiotic parts of ecosystems.
Biogeochemical cycles where elements circulate through atmosphere, e.g., nitrogen and carbon cycles.
Biogeochemical cycles where elements circulate through earth’s crust, e.g., phosphorus and sulfur cycles.
A state of dynamic equilibrium where species and environment are in harmony.
The ability of an ecosystem to remain balanced and resist disturbances.
Ecosystem management ensures sustainable use of resources, biodiversity conservation, and climate regulation.