Unit 10 Ecology and Environment Syllabus NEET 2026

Ecology is the branch of biology that studies interactions between organisms and their environment. It explains how living organisms depend on one another and on physical surroundings such as air, water, soil, and climate.

This unit mainly focuses on population interactions, ecosystem structure and functioning, biodiversity, and conservation strategies. Important topics include ecological relationships, energy flow, ecological pyramids, biodiversity hotspots, endangered species, and protected areas.

Organisms and Environment 

Organisms interact continuously with their surroundings and adapt according to environmental conditions such as temperature, water, light, and food availability.

Population Interactions

Different organisms living in the same habitat interact in various ways.

• Mutualism → Both species benefit from the interaction.
  Example: Lichens and mycorrhiza.

• Competition → Organisms compete for food, space, and resources.

• Predation → One organism feeds on another organism.
  Example: Tiger and deer.

• Parasitism → One organism benefits while the host is harmed.
  Example: Cuscuta and tapeworm.

Population Attributes

A Population is a group of individuals of the same species living in a particular area.

Important Population Attributes include:

• Population growth

• Birth rate

• Death rate

• Age distribution

Population size changes continuously due to births, deaths, immigration, and emigration.

Ecosystem

An Ecosystem is a functional unit where living organisms interact with each other and with the physical environment.

Components and Productivity

An Ecosystem consists of:

• Biotic components → Producers, consumers, decomposers

• Abiotic components → Air, water, soil, temperature

Productivity refers to the rate of biomass production in an ecosystem, while decomposition helps recycle nutrients through microbial activity.

Energy Flow and Ecological Pyramids

Energy enters the ecosystem through sunlight and passes through different trophic levels.

Types of Ecological Pyramids

• Pyramid of number

• Pyramid of biomass

• Pyramid of energy

The pyramid of energy is always upright because energy decreases at each trophic level.

Biodiversity and Conservation

Biodiversity refers to the variety of living organisms present on Earth at the genetic, species, and ecosystem levels.

Biodiversity and Its Importance

Biodiversity helps maintain ecological balance and supports food supply, medicines, agriculture, and ecosystem stability.

Tropical regions generally show greater biodiversity compared to temperate regions.

Loss of Biodiversity and Conservation

Major Causes of Biodiversity loss include:

• Habitat destruction

• Pollution

• Climate change

• Overexploitation

• Invasive species

Conservation methods help protect species and ecosystems from extinction.

Conservation Methods

• Biosphere reserves

• National parks

• Wildlife sanctuaries

• Sacred groves

Hotspots, Endangered Species and Red Data Book

Biodiversity hotspots are regions with high species richness and endemism that require protection.

Endangered organisms are species facing a high risk of extinction. The Red Data Book maintains records of threatened species and supports conservation efforts.

How to Prepare Ecology and Environment for NEET 2026

This unit helps you understand how living organisms interact with each other and with the environment using NCERT concepts.

• Read NCERT carefully

Focus on ecological interactions, biodiversity, food chains, ecological pyramids, and conservation methods.

• Practice Ecology and Environment NEET PYQs regularly

Solving previous year questions helps in understanding important concepts, repeated topics, and assertion-reasoning questions from ecology.

• Solve chapter-wise Ecology MCQs

Regular practice with PW MCQs improves speed and accuracy in topics such as population interactions, ecosystem, biodiversity, and conservation.

• Use Ecology mind maps for quick revision

PW Mind maps help in revising ecological interactions, food chains, energy flow, and biodiversity conservation in a structured way before exams.

• Revise diagrams and ecological pyramids

Practice diagrams related to ecosystem structure, energy flow, and ecological pyramids.