CSIR NET Life Sciences Ecological Principles Syllabus

Ecological Principles syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Ecological Principles in CSIR NET Life Sciences, not a summary of it.

1. 1

   The Environment

   3 topics

   • Physical environment
   • Biotic environment
   • Biotic and abiotic interactions
2. 2

   Habitat and Niche

   5 topics

   • Concept of habitat and niche
   • Niche width and overlap
   • Fundamental and realized niche
   • Resource partitioning
   • Character displacement
3. 3

   Population Ecology

   5 topics

   • Characteristics of a population
   • Population growth curves
   • Population regulation
   • Life history strategies (r and K selection)
   • Concept of metapopulation
     • Demes and dispersal
     • Interdemic extinctions
     • Age structured populations
4. 4

   Species Interactions

   6 topics

   • Types of interactions
   • Interspecific competition
   • Herbivory
   • Carnivory
   • Pollination
   • Symbiosis
5. 5

   Community Ecology

   4 topics

   • Nature of communities
   • Community structure and attributes
   • Levels of species diversity and its measurement
   • Edges and ecotones
6. 6

   Ecological Succession

   4 topics

   • Types
   • Mechanisms
   • Changes involved in succession
   • Concept of climax
7. 7

   Ecosystem Ecology

   5 topics

   • Ecosystem structure
   • Ecosystem function
   • Energy flow and mineral cycling (C,N,P)
   • Primary production and decomposition
   • Structure and function of some Indian ecosystems
     • Terrestrial (forest, grassland)
     • Aquatic (fresh water, marine, estuarine)
8. 8

   Biogeography

   3 topics

   • Major terrestrial biomes
   • Theory of island biogeography
   • Biogeographical zones of India
9. 9

   Applied Ecology

   5 topics

   • Environmental pollution
   • Global environmental change
   • Biodiversity: status, monitoring and documentation
   • Major drivers of biodiversity change
   • Biodiversity management approaches
10. 10

    Conservation Biology

    3 topics

    • Principles of conservation
    • Major approaches to management
    • Indian case studies on conservation/management strategy
      • Project Tiger
      • Biosphere reserves

Ecological Principles flashcards for CSIR NET Life Sciences

23 of 55 cards from the Ecological Principles deck — real questions with worked answers.

1. What are the two broad components of the environment that organisms interact with?

   The abiotic (physical/non-living) component — e.g. light, temperature, water, soil, air — and the biotic (living) component — all other organisms (competitors, predators, prey, mutualists).

2. Define a habitat in ecology.

   A habitat is the physical place or type of environment where an organism or population naturally lives, characterized by its dominant physical and biotic features (e.g. a freshwater pond, a deciduous forest floor).

3. Define an ecological niche.

   The niche is the complete functional role and position of a species in its ecosystem — the total range of biotic and abiotic conditions it uses and tolerates, and how it interacts with resources. (Habitat = address, niche = profession.)

4. Distinguish the fundamental niche from the realized niche.

   The fundamental niche is the full range of conditions/resources a species could potentially use in the absence of competitors. The realized niche is the smaller, actually occupied portion after biotic interactions (especially competition) restrict it.

5. What is niche width (niche breadth)?

   Niche width is the range of resources or conditions a species uses. Broad niches = generalists; narrow niches = specialists.

6. What does niche overlap indicate, and what is its likely ecological consequence?

   Niche overlap is the sharing of the same resources by two or more species. Greater overlap implies greater potential for interspecific competition.

7. What is resource partitioning?

   The differential use of limited resources by coexisting species (by space, time, or food type) that reduces competition and allows them to coexist by occupying distinct realized niches.

8. Define character displacement.

   Character displacement is the evolutionary divergence in morphology or behavior of competing species where they occur together (sympatry), reducing niche overlap and competition; the traits are more similar in allopatry. Classic example: Darwin's finch beak sizes.

9. What is competitive exclusion (Gause's principle)?

   Two species competing for exactly the same limiting resources cannot coexist indefinitely; one will outcompete and eliminate the other unless they diverge in niche use.

10. List the key characteristics (attributes) of a population.

    Density, natality (birth rate), mortality (death rate), age structure, sex ratio, dispersion (spatial pattern), growth rate, and biotic potential.

11. What three types of spatial dispersion patterns occur in populations?

    Uniform (regular, due to competition/territoriality), random (no interaction, rare in nature), and clumped/aggregated (most common, due to resource patchiness or social behavior).

12. Write the equation for exponential (geometric) population growth in continuous form.

    dN/dt = rN, where N = population size, r = intrinsic rate of natural increase (per capita). Integrated form: Nt = N0·e^(rt). It produces a J-shaped curve.

13. Write the logistic growth equation and name the curve it produces.

    dN/dt = rN[(K − N)/K], where K is the carrying capacity. It produces a sigmoid (S-shaped) curve; growth slows as N approaches K and stops at N = K.

14. In logistic growth, at what population size is the growth rate (dN/dt) maximal?

    At N = K/2, where the population has the maximum number of new individuals added per unit time (point of inflection).

15. What is carrying capacity (K)?

    The maximum population size of a species that a given environment can sustain indefinitely given available resources; the upper asymptote of the logistic curve.

16. Differentiate density-dependent and density-independent population regulation.

    Density-dependent factors (competition, predation, disease, parasitism) have effects that intensify as density rises and regulate populations toward K. Density-independent factors (floods, fire, temperature, drought) affect populations regardless of density.

17. Contrast r-selected and K-selected species' life history traits.

    r-selected: small body size, short life, early maturity, many small offspring, little parental care, high mortality, unstable environments (e.g. insects, weeds). K-selected: large body, long life, late maturity, few large offspring, high parental care, populations near K, stable environments (e.g. elephants, humans).

18. What are the three types of survivorship curves?

    Type I (convex) — low juvenile mortality, most die when old (humans, large mammals); Type II (straight/diagonal) — constant mortality rate at all ages (birds, hydra); Type III (concave) — very high juvenile mortality, few survive to adulthood (fish, invertebrates, many plants).

19. Define a metapopulation.

    A 'population of populations' — a set of spatially separated local (sub)populations of the same species connected by occasional dispersal/migration, with local extinctions and recolonizations balancing over time (Levins concept).

20. In metapopulation dynamics, what are source and sink populations?

    A source has births exceeding deaths (net emigration, exports individuals); a sink has deaths exceeding births and persists only through immigration from sources.

21. Classify interspecific interactions by their effect on each species (+, −, 0).

    Mutualism (+/+), Competition (−/−), Predation/Parasitism/Herbivory (+/−), Commensalism (+/0), Amensalism (−/0), Neutralism (0/0).

22. What is interspecific competition and its two main mechanisms?

    Competition between individuals of different species for a shared limiting resource. Mechanisms: exploitation (resource) competition — indirect, via depleting a common resource; and interference competition — direct, via aggression, territoriality, or allelopathy.

23. Define herbivory and one common plant defense against it.

    Herbivory is consumption of plant tissue by animals (a +/− interaction). Plant defenses include chemical defenses (toxins/secondary metabolites like alkaloids, tannins) and morphological defenses (thorns, spines, tough cuticle).

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