UGC NET Environmental Science Unit-III: Environmental Biology Syllabus

Unit-III: Environmental Biology syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Unit-III: Environmental Biology in UGC NET Environmental Science, not a summary of it.

1. 1

   Ecology as an Interdisciplinary Science

   8 topics

   • Origin of Life and Speciation
   • Human Ecology and Settlement
   • Ecosystem Structure and Functions
     • Structures - Biotic and Abiotic components
     • Functions - Energy flow in ecosystems, energy flow models, food chains and food webs, Biogeochemical cycles, Ecological succession
     • Species Diversity, Concept of Ecotone, Edge Effects, Ecological Habitats and Niche
     • Ecosystem Stability and Factors Affecting Stability, Ecosystem Services
     • Basis of Ecosystem Classification
     • Types of Ecosystem: Desert (hot and cold), forest, rangeland, wetlands, lotic, lentic, estuarine (mangrove), Oceanic
   • Biomes: Concept, Classification, and Distribution
     • Characteristics of Different Biomes: Tundra, Taiga, Grassland, Deciduous forest biome, Highland Icy Alpine Biome, Chapparal, Savanna, Tropical Rainforest
   • Population Ecology
     • Characteristics of Population, Concept of Carrying Capacity, Population Growth and Regulations
     • Population Fluctuations, Dispersion and Metapopulation, Concept of ‘r’ and ‘k’ Species, Keystone Species
   • Community Ecology
     • Definition, Community Concept, Types and Interaction - Predation, Herbivory, Parasitism, Allelopathy, Biological Invasions
   • Biodiversity and Its Conservation
     • Definition, Types, Importance of Biodiversity and Threats to Biodiversity
     • Concept and Basis of Identification of ‘Hotspots’; Hotspots in India, Measures of Biodiversity
     • Strategies for Biodiversity Conservation: In Situ, Ex Situ and In Vitro Conservation, National Parks, Sanctuaries, Protected Areas and Sacred Groves in India
     • Concepts of Gene Pool, Biopiracy, and Bio-prospecting, Concept of Restoration Ecology, Extinct, Rare, Endangered and Threatened Flora and Fauna of India
   • Concept of Industrial Ecology
2. 2

   Toxicology and Microbiology

   2 topics

   • Absorption, Distribution and Excretion of Toxic Agents, Acute and Chronic Toxicity, Concept of Bioassay, Threshold Limit Value, Margin of Safety, Therapeutic Index, Biotransformation
   • Major Water Borne Diseases and Air Borne Microbes
3. 3

   Environmental Biotechnology

   1 topic

   • Bioremediation – Definition, Types and Role of Plants and Microbes for In Situ and Ex Situ Remediation, Bioindicators, Biofertilizers, Biofuels and Biosensors

Unit-III: Environmental Biology flashcards for UGC NET Environmental Science

18 of 53 cards from the Unit-III: Environmental Biology deck — real questions with worked answers.

1. What is the Oparin-Haldane hypothesis on the origin of life?

   It proposes that life arose abiogenically in the primitive ocean ('primordial soup') from simple inorganic molecules through chemical evolution, driven by energy (UV, lightning, heat) in an oxygen-free reducing atmosphere of CH4, NH3, H2, and water vapour.

2. What did the Miller-Urey experiment (1953) demonstrate?

   That amino acids and other organic monomers can form spontaneously by passing electric sparks through a mixture of CH4, NH3, H2 and water vapour, supporting abiotic chemical evolution in a reducing primitive atmosphere.

3. Define speciation and name its two main geographic modes.

   Speciation is the evolutionary process by which new biological species arise. Main modes: allopatric (via geographic isolation) and sympatric (within the same area without physical barrier); also parapatric and peripatric.

4. Differentiate allopatric and sympatric speciation.

   Allopatric speciation occurs when populations are separated by a physical/geographic barrier preventing gene flow; sympatric speciation occurs within a single overlapping area through mechanisms like polyploidy, disruptive selection or behavioural isolation, without geographic separation.

5. What is the difference between prezygotic and postzygotic reproductive isolating mechanisms?

   Prezygotic mechanisms prevent mating or fertilization (temporal, ecological, behavioural, mechanical, gametic isolation); postzygotic mechanisms reduce viability/fertility of hybrids after fertilization (hybrid inviability, sterility, breakdown).

6. What is human ecology?

   The interdisciplinary study of the relationships and interactions between humans and their natural, social and built environments, including how human populations adapt to and modify their surroundings.

7. Name the main types of human settlement patterns.

   Rural settlements (compact/nucleated, dispersed/scattered, semi-clustered, hamleted) and urban settlements; settlement shapes include linear, rectangular, circular, star-shaped and T/cross-shaped patterns.

8. What is demographic transition?

   A model describing the shift of a population from high birth and death rates (pre-industrial) through declining death rates then declining birth rates, to low birth and death rates as a society develops economically; classically in four/five stages.

9. Define ecosystem and its two basic components.

   An ecosystem is a functional unit of nature where living organisms (biotic) interact among themselves and with the non-living physical environment (abiotic), exchanging energy and matter. Components: biotic (producers, consumers, decomposers) and abiotic (climate, soil, water, nutrients).

10. Name the trophic levels in an ecosystem in order.

    Producers (autotrophs, T1) → Primary consumers (herbivores, T2) → Secondary consumers (carnivores, T3) → Tertiary consumers (top carnivores, T4) → Decomposers act across all levels.

11. State the 10% law of energy transfer (Lindeman).

    Only about 10% of the energy available at one trophic level is transferred to and stored as biomass at the next higher trophic level; the remaining ~90% is lost mainly as metabolic heat (respiration).

12. Differentiate gross primary productivity (GPP) and net primary productivity (NPP).

    GPP is the total rate of organic matter (energy) fixed by producers through photosynthesis; NPP = GPP minus respiration losses (R) by producers, i.e. NPP = GPP − R, representing biomass available to consumers.

13. What are the three types of ecological pyramids?

    Pyramid of numbers (number of organisms per level), pyramid of biomass (dry weight per level), and pyramid of energy (energy flow per level). The pyramid of energy is always upright.

14. Why is a pyramid of biomass sometimes inverted, as in an aquatic ecosystem?

    In aquatic systems, phytoplankton (producers) have small standing biomass but very high turnover/reproductive rate, supporting a larger biomass of zooplankton consumers at any instant, giving an inverted biomass pyramid.

15. Differentiate grazing and detritus food chains.

    A grazing food chain starts with living green plants (producers) eaten by herbivores; a detritus food chain starts with dead organic matter (detritus) consumed by detritivores and decomposers. Detritus chains dominate most terrestrial ecosystems.

16. What is a biome?

    A large-scale ecological community/region characterized by a distinctive climate (temperature and precipitation) and dominant vegetation type and adapted animal life, e.g. tropical rainforest, desert, tundra, grassland.

17. Which two climatic factors primarily determine the distribution of terrestrial biomes?

    Temperature and precipitation (rainfall), as visualized in the Whittaker biome diagram which plots biomes against mean annual temperature and mean annual precipitation.

18. What are the characteristic features of the tundra biome?

    Cold treeless biome at high latitudes/altitudes with permafrost, very low temperatures, short growing season, low precipitation, and vegetation of mosses, lichens, sedges and dwarf shrubs; low biodiversity.

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