CSIR-NET LIFE SCIENCES

Unit 10: Ecology and Behavioral Biology

Complete Topic-Wise Syllabus

Ecology • Population • Community • Ecosystem • Conservation • Behaviour

A. Introduction to Ecology

🌍 1. Levels of Ecological Organization

Individual
Population
Community
Ecosystem
Landscape
Biosphere

🌍 Ecological Organization:

Individual → Population → Community → Ecosystem → Biosphere

🧍 2. Individual

Single organism
Physiological adaptations
Behavioural adaptations
Response to environmental conditions
Environmental tolerance

👥 3. Population

Group of individuals of the same species
Occupying a particular area
Potentially interacting and reproducing

🌿 4. Community

Assemblage of populations of different species
Species interactions
Community structure
Species diversity

🌎 5. Ecosystem

Biotic components
Abiotic components
Energy flow
Nutrient cycling
Food chains and food webs

🌐 6. Biosphere

Global ecological system
Includes all ecosystems
Interaction between living organisms and Earth's physical environment

☀️ 7. Abiotic Ecological Factors

Temperature
Light
Water
Humidity
pH
Salinity
Soil characteristics
Mineral availability
Climate

🌱 8. Biotic Ecological Factors

Competition
Predation
Parasitism
Mutualism
Herbivory
Pathogens
Social interactions

🦎 9. Ecological Adaptations

Morphological adaptations
Physiological adaptations
Behavioural adaptations
Structural adaptations
Camouflage
Mimicry
Thermoregulatory adaptations
Water-conservation adaptations

B. Population Ecology

👥 1. Population Characteristics

Population size
Population density
Population distribution
Age structure
Sex ratio
Birth rate
Death rate
Immigration
Emigration

📈 2. Exponential Growth

Exponential growth occurs when resources are abundant and population growth is not strongly limited by environmental resistance.

📈 Exponential Growth Equation:

dN/dt = rN

Where:
N = population size
r = intrinsic rate of natural increase
dN/dt = rate of population growth

📊 3. Logistic Growth

Logistic growth incorporates environmental carrying capacity and produces an S-shaped population growth curve.

📊 Logistic Growth Equation:

dN/dt = rN(1 − N/K)

K = carrying capacity

🎯 4. Carrying Capacity

Maximum population size that an environment can sustain under particular conditions
Determined by resource availability
May change with environmental conditions

⚖️ 5. Density-Dependent Factors

Competition
Predation
Disease
Parasitism
Territoriality
Food limitation

🌪️ 6. Density-Independent Factors

Floods
Droughts
Fire
Storms
Extreme temperature
Natural disasters

Density-Dependent	Density-Independent
Competition	Flood
Disease	Drought
Predation	Fire
Parasitism	Storm

📋 7. Life Tables

Age-specific survival
Age-specific mortality
Reproductive output
Survivorship
Life expectancy

📉 8. Survivorship Curves

Type I survivorship
Type II survivorship
Type III survivorship

📉 Survivorship Types:

Type I: High survival during early and middle life; mortality increases at old age.

Type II: Approximately constant mortality rate throughout life.

Type III: Very high juvenile mortality followed by high survival of remaining individuals.

👶 9. Age Structure

Pre-reproductive individuals
Reproductive individuals
Post-reproductive individuals
Population age pyramids

⚥ 10. Sex Ratio

Ratio of males to females
Influences reproductive potential
Can vary among species and populations

🧬 11. Life History Strategies

Age at first reproduction
Number of offspring
Offspring size
Parental investment
Reproductive lifespan
Survival strategy

⚡ 12. r-Selected Strategy

High reproductive rate
Many offspring
Small offspring
Low parental investment
Rapid population growth
Often associated with unstable environments

🐘 13. K-Selected Strategy

Fewer offspring
Larger offspring
High parental investment
Delayed reproduction
Longer lifespan
Often associated with relatively stable environments

r-Selected	K-Selected
Many offspring	Few offspring
Low parental care	High parental care
Early reproduction	Delayed reproduction
Short generation time	Long generation time

🏞️ 14. Metapopulation

Collection of spatially separated populations
Connected through dispersal
Local extinction
Colonization
Source populations
Sink populations

🌳 15. Habitat Fragmentation

Breaking continuous habitat into smaller patches
Reduction in habitat area
Isolation of populations
Edge effects
Reduced gene flow
Increased extinction risk

🔗 16. Habitat Connectivity

Wildlife corridors
Landscape connectivity
Dispersal pathways
Gene flow between populations
Reduction in isolation

C. Community Ecology

🌐 1. Community Structure

Species richness
Species evenness
Species diversity
Relative abundance
Trophic structure
Spatial structure

🍃 2. Trophic Levels

Primary producers
Primary consumers
Secondary consumers
Tertiary consumers
Decomposers

🍃 Basic Trophic Structure:

Sun → Producers → Herbivores → Primary Carnivores → Higher Carnivores → Decomposers

🕸️ 3. Food Chains

Linear transfer of energy and nutrients
Grazing food chain
Detritus food chain

🕸️ 4. Food Webs

Interconnected food chains
Multiple feeding relationships
Energy transfer through several pathways
Greater complexity than individual food chains

⭐ 5. Keystone Species

Species with disproportionately large effects on community structure
Removal can cause major ecological changes
May regulate abundance of other species

🥊 6. Competition

Interaction involving use of limited resources
Intraspecific competition
Interspecific competition
Resource competition
Interference competition

🦁 7. Predation

Predator consumes prey
Population regulation
Natural selection
Defensive adaptations
Camouflage
Mimicry

🤝 8. Mutualism

Both interacting species benefit
Pollination
Mycorrhiza
Nitrogen fixation

🪱 9. Parasitism

Parasite benefits
Host is harmed
Endoparasites
Ectoparasites
Host-parasite coevolution

Interaction	Species 1	Species 2
Mutualism	+	+
Competition	−	−
Predation	+	−
Parasitism	+	−

🌱 10. Ecological Succession

Directional change in community composition over time
Primary succession
Secondary succession
Pioneer species
Intermediate communities
Climax or mature communities

🪨 11. Primary Succession

Begins on previously unoccupied surfaces
No developed soil initially
Examples include newly exposed rock

🌾 12. Secondary Succession

Occurs after disturbance in an existing ecosystem
Soil remains present
Usually proceeds faster than primary succession

⚖️ 13. Community Stability

Resistance
Resilience
Disturbance
Species diversity
Functional redundancy

D. Ecosystem Ecology

☀️ 1. Energy Flow

Solar energy as major energy input
Primary production
Energy transfer between trophic levels
Respiration
Heat loss

🌱 2. Primary Production

Gross primary productivity (GPP)
Net primary productivity (NPP)
Photosynthetic production
Respiratory losses

🌱 Important Relationship:

NPP = GPP − Respiration

NPP represents the biomass/energy available to consumers after plant respiratory costs.

🔺 3. Energy Pyramids

Pyramid of energy
Pyramid of biomass
Pyramid of numbers
Trophic transfer efficiency

♻️ 4. Carbon Cycle

Photosynthesis
Respiration
Decomposition
Ocean-atmosphere exchange
Fossil fuel combustion
Carbon sequestration

♻️ 5. Nitrogen Cycle

Nitrogen fixation
Nitrification
Assimilation
Ammonification
Denitrification

🦠 Nitrogen Cycle:

N₂ → Nitrogen fixation → NH₃/NH₄⁺ → Nitrification → NO₂⁻ → NO₃⁻ → Plant assimilation → Decomposition → NH₄⁺ → Denitrification → N₂

🪨 6. Phosphorus Cycle

Weathering of rocks
Soil phosphate
Plant uptake
Food-web transfer
Decomposition
Sedimentation

💧 7. Water Cycle

Evaporation
Transpiration
Condensation
Precipitation
Infiltration
Runoff
Groundwater flow

🌎 8. Ecosystem Services

Provisioning services
Regulating services
Cultural services
Supporting services
Pollination
Water purification
Climate regulation
Soil formation

E. Human Impacts on Ecosystems

🏗️ 1. Land Use Change

Deforestation
Urbanization
Agricultural expansion
Mining
Infrastructure development
Habitat fragmentation

🌍 2. Land-Cover Change

Forest conversion
Wetland loss
Grassland conversion
Desertification
Soil degradation

🌡️ 3. Climate Change

Global warming
Changes in precipitation
Extreme weather events
Sea-level rise
Range shifts
Phenological changes
Coral bleaching

☣️ 4. Pollution

Air pollution
Water pollution
Soil pollution
Plastic pollution
Heavy metals
Pesticides
Eutrophication

🌿 5. Invasive Species

Non-native species
Competition with native species
Predation
Disease transmission
Habitat modification
Reduction of native biodiversity

⚠️ Major Anthropogenic Pressures:

Habitat loss + Climate change + Pollution + Invasive species + Overexploitation

F. Biodiversity and Conservation

🌈 1. Biodiversity

Genetic diversity
Species diversity
Ecosystem diversity
Functional diversity

🌍 2. Importance of Biodiversity

Ecosystem stability
Food resources
Medicinal resources
Genetic resources
Pollination
Nutrient cycling
Cultural value
Economic value

⚠️ 3. Threats to Biodiversity

Habitat destruction
Overexploitation
Pollution
Climate change
Invasive species
Diseases

🚨 Highest Threat Categories:

Critically Endangered → Endangered → Vulnerable

These three categories are collectively referred to as the major threatened categories in the IUCN Red List framework.

🧬 5. Conservation Genetics

Genetic diversity
Effective population size
Inbreeding
Genetic drift
Loss of alleles
Genetic bottlenecks
Inbreeding depression
Gene flow

📉 6. Population Viability Analysis (PVA)

Assessment of extinction risk
Population size
Demographic stochasticity
Environmental stochasticity
Genetic factors
Habitat conditions

🌳 7. In-situ Conservation

Conservation within natural habitats
National parks
Wildlife sanctuaries
Biosphere reserves
Community conserved areas

🧪 8. Ex-situ Conservation

Conservation outside natural habitats
Botanical gardens
Zoological gardens
Seed banks
Gene banks
Cryopreservation
Field gene banks

In-situ	Ex-situ
Natural habitat	Outside natural habitat
National parks	Seed banks
Wildlife sanctuaries	Botanical gardens
Biosphere reserves	Zoos
Community conservation	Cryopreservation

👥 9. Community-Based Conservation

Local community participation
Traditional ecological knowledge
Indigenous knowledge
Sustainable resource use
Local stewardship
Participatory conservation

🌏 10. Conservation Policies

International conservation agreements
National biodiversity legislation
Protected-area policies
Species protection
Genetic-resource conservation

G. Acts and Policies

🇮🇳 1. Biological Diversity Act, 2002

Conservation of biological diversity
Sustainable use of biological resources
Fair and equitable sharing of benefits
Regulation of access to biological resources
Protection of associated knowledge

📌 CSIR-NET Focus:

Remember the three broad objectives:

Conservation + Sustainable Use + Fair & Equitable Benefit Sharing

🌾 2. Agricultural Biodiversity

Crop genetic diversity
Traditional crop varieties
Landraces
Wild relatives of crops
Livestock genetic resources
Genetic resources for food security

🌱 3. International Treaty on Plant Genetic Resources for Food and Agriculture

Conservation of plant genetic resources
Sustainable use
Global cooperation
Access to plant genetic resources
Benefit sharing
Food and agricultural security

🌾 4. Seed Gene Banks

Long-term conservation of seeds
Low-temperature storage
Low-moisture conditions
Periodic viability testing
Regeneration when required
Documentation and characterization

🌱 Seed Gene Bank:

Collection → Drying → Packaging → Low-temperature storage → Viability monitoring → Regeneration → Characterization → Distribution

🌡️ 5. Climate Change and Plant Genetic Resources

Climate-resilient crop varieties
Conservation of wild relatives
Genetic diversity for adaptation
Drought tolerance
Heat tolerance
Salinity tolerance
Ex-situ and in-situ conservation

🌾 6. PPVFR

Protection of plant varieties
Recognition of plant breeders' rights
Farmers' rights
Protection of traditional varieties
Registration of plant varieties
Benefit sharing

📜 7. Biodiversity-Related Legislation

Conservation of biological resources
Protection of threatened species
Regulation of access to genetic resources
Sustainable utilization
Protection of traditional knowledge

H. Behavioural Ecology

🐾 1. Introduction to Animal Behaviour

Animal behaviour
Behavioural adaptations
Innate behaviour
Learned behaviour
Behavioural flexibility

🔬 2. Proximate Causes of Behaviour

Immediate mechanisms
Neural control
Hormonal control
Physiological mechanisms
Environmental stimuli
Developmental processes

🧬 3. Ultimate Causes of Behaviour

Evolutionary significance
Fitness consequences
Natural selection
Reproductive success
Adaptation

🐾 Tinbergen's Four Questions:

Mechanism – How does the behaviour occur?
Development – How does it develop?
Function – Why does it improve fitness?
Evolution – How did it evolve?

🍃 4. Foraging Behaviour

Searching for food
Food selection
Optimal foraging theory
Energy gain
Search time
Handling time
Predation risk

📢 5. Animal Communication

Chemical signals
Visual signals
Auditory signals
Tactile signals
Vocal communication
Pheromones

⚔️ 6. Conflict and Aggression

Territorial aggression
Resource competition
Dominance hierarchy
Threat displays
Ritualized aggression
Costs and benefits of fighting

🦅 7. Migration

Seasonal movement
Long-distance migration
Breeding migration
Feeding migration
Navigation mechanisms

🧭 8. Navigation

Sun compass
Star compass
Geomagnetic sensing
Landmarks
Olfactory cues

🚶 9. Dispersal

Movement away from birthplace
Reduction of inbreeding
Colonization of new habitats
Gene flow
Population expansion

👥 10. Social Behaviour

Group living
Dominance hierarchy
Cooperation
Altruism
Kin selection
Reciprocal altruism
Social learning

❤️ 11. Sexual Selection

Intrasexual selection
Intersexual selection
Mate choice
Sexual dimorphism
Secondary sexual characteristics
Mate competition

❤️ Sexual Selection:

Intrasexual selection: Competition among individuals of the same sex for access to mates.

Intersexual selection: Mate choice based on preferred characteristics.

💑 12. Mating Systems

Monogamy
Polygyny
Polyandry
Promiscuity
Mate guarding
Pair bonding

🐣 13. Parental Care

Protection of offspring
Feeding
Brooding
Nest building
Predator defense
Parental investment
Trade-off between current and future reproduction

🐣 Parental Investment:

Any parental behaviour that increases the survival and reproductive success of current offspring but may reduce the parent's ability to invest in future offspring.

📚 Unit 10 – Ecology & Behavioral Biology Quick Revision

A → Introduction to Ecology

B → Population Ecology

C → Community Ecology

D → Ecosystem Ecology

E → Human Impacts

F → Biodiversity & Conservation

G → Acts & Policies

H → Behavioral Ecology

🎯 High-Yield CSIR-NET Topics

Levels of ecological organization
Abiotic and biotic factors
Ecological adaptations
Exponential and logistic growth
Carrying capacity
Density-dependent and density-independent factors
Life tables
Survivorship curves
Age structure and sex ratio
r-selected and K-selected life histories
Metapopulation dynamics
Habitat fragmentation and connectivity
Food chains and food webs
Trophic levels
Keystone species
Competition, predation and parasitism
Mutualism
Primary and secondary succession
Community stability
GPP and NPP
Energy pyramids
Carbon cycle
Nitrogen cycle
Phosphorus cycle
Water cycle
Ecosystem services
Land-use and land-cover change
Climate change
Pollution
Invasive species
Biodiversity and its levels
IUCN threat categories
Conservation genetics
Population Viability Analysis
In-situ and ex-situ conservation
Community-based conservation
Biological Diversity Act, 2002
Agricultural biodiversity
Plant Genetic Resources for Food and Agriculture
Seed gene banks
Climate change and plant genetic resources
PPVFR-related concepts
Proximate and ultimate causes of behaviour
Tinbergen's four questions
Optimal foraging
Animal communication
Conflict and aggression
Migration and navigation
Social behaviour
Kin selection and altruism
Sexual selection
Mating systems
Parental care

📈 Population Ecology Formula Revision:

Exponential growth: dN/dt = rN

Logistic growth: dN/dt = rN(1 − N/K)

K = Carrying Capacity

🌱 Ecosystem Energy Flow:

Sun → Producers → Primary Consumers → Secondary Consumers → Tertiary Consumers → Decomposers

Energy decreases at successive trophic levels because substantial energy is lost as heat and through metabolic processes.

🌳 Conservation Strategy:

Identify Threat → Assess Population → Protect Habitat → Maintain Genetic Diversity → Reduce Human Pressure → Monitor Population → Restore Ecosystem

🐾 Behavioural Ecology Core:

Stimulus → Behaviour → Immediate Mechanism → Development → Fitness Consequence → Evolution

🧠 One-Line Unit 10 Revision:

Ecology explains how organisms interact with their environment, populations, communities and ecosystems; conservation protects biodiversity; behavioural ecology explains how behaviour contributes to survival and reproductive success.

🎓 CSIR-NET Life Sciences – Unit 10

Ecology • Population • Community • Ecosystem • Conservation • Behaviour

Study → Understand → Revise → Practice → Master

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Saturday, 8 August 2026