NCERT Class 12 Biology Chapter 13 Biodiversity and Conservation PDF – Download Notes and Key Concepts

Class 12 Biology Chapter 13, Biodiversity and Conservation, highlights the variety of life forms found on Earth and explains why it is so important to conserve them. This chapter talks about different types of biodiversity, threats to biodiversity, reasons behind species extinction, and various conservation strategies. It also covers topics like national parks, biosphere reserves,

Class 12 Biology Chapter 13, Biodiversity and Conservation, highlights the variety of life forms found on Earth and explains why it is so important to conserve them. This chapter talks about different types of biodiversity, threats to biodiversity, reasons behind species extinction, and various conservation strategies. It also covers topics like national parks, biosphere reserves, and international efforts to protect endangered species. This chapter not only has theoretical importance but also builds environmental awareness among students.

I decided to write about this topic because biodiversity is not just a biology term—it is something we see and depend on in everyday life. From pollination by bees to forests that give us oxygen, every part of biodiversity supports our survival. But due to pollution, deforestation, and climate change, many species are now under threat. Understanding this chapter helps students realise how interconnected life forms are and why protecting even the smallest species matters. It also aligns well with questions asked in NEET and CBSE board exams. That’s why it’s important to download the PDF, revise regularly, and be aware of both textbook concepts and current environmental issues.

Main Topics Covered in Chapter 13 – Biodiversity and Conservation

Chapter 13 is a blend of scientific facts, real-world concerns, and examples from India and across the globe. Let’s break it down topic by topic.

What is Biodiversity?

Biodiversity refers to the variety of life forms on Earth, including animals, plants, fungi, and microorganisms. It is usually studied at three levels:

Genetic Diversity: Variation within a species
Species Diversity: Variety of species in a given area
Ecosystem Diversity: Different types of ecosystems (e.g., forests, deserts, wetlands)

India is known as one of the 12 mega diversity countries in the world due to its rich flora and fauna.

Patterns of Biodiversity

Biodiversity is not spread equally across the planet.

Latitudinal Gradient: Species diversity increases as we move from the poles to the equator
Species-Area Relationship: Greater the area, more species it can support
This concept was first studied by German naturalist Alexander von Humboldt

Importance of Biodiversity

Biodiversity provides a range of benefits:

Ecological balance: Helps maintain food chains
Economic benefits: Source of medicine, food, timber
Cultural value: Many plants and animals are part of our tradition
Ecosystem services: Soil formation, climate regulation, water purification

Loss of Biodiversity

Four major causes of biodiversity loss (also known as The Evil Quartet):

Habitat loss and fragmentation: Due to deforestation, urbanisation
Over-exploitation: Excessive hunting, fishing, and cutting of trees
Alien species invasion: Introduction of non-native species (e.g., Lantana in India)
Co-extinction: When one species goes extinct, others dependent on it also vanish

Biodiversity Conservation

There are two main strategies to conserve biodiversity:

In-situ Conservation

Protecting species in their natural habitat

Examples: National parks, wildlife sanctuaries, biosphere reserves
Notable Indian sites: Kaziranga, Jim Corbett, Sunderbans, Nilgiri

Ex-situ Conservation

Conserving species outside their natural habitat

Examples: Zoological parks, botanical gardens, seed banks, gene banks
Important institutions: National Bureau of Plant Genetic Resources (NBPGR)

Hotspots and Red Data Book

Biodiversity Hotspots: Areas with high species richness and endemism but under threat
India has 4 hotspots – Himalayas, Indo-Burma, Western Ghats-Sri Lanka, and Sundaland
IUCN Red Data Book: Lists endangered and threatened species globally
Examples: Indian vulture, Asiatic lion, Snow leopard

Sacred Groves

Traditional conservation method where communities protect forests due to religious beliefs

Found in states like Meghalaya, Rajasthan, Madhya Pradesh

Download PDF – NCERT Class 12 Biology Chapter 13

If you want to study this chapter in detail or revise it before your exams, downloading the official NCERT PDF is a great option. It contains all diagrams, explanations, and NCERT-based questions.

NCERT Class 12 Biology Chapter 13

NCERT Class 12 English Vistas Chapter 6: Memories of Childhood PDF Download & Complete Summary

Memories of Childhood is Chapter 6 in the Class 12 English Vistas textbook by NCERT. What makes this chapter special is that it’s not a single story—it’s made up of two autobiographical excerpts written by two women, Zitkala-Sa and Bama. Both narrate incidents from their early lives that reflect the discrimination they faced because of

Memories of Childhood is Chapter 6 in the Class 12 English Vistas textbook by NCERT. What makes this chapter special is that it’s not a single story—it’s made up of two autobiographical excerpts written by two women, Zitkala-Sa and Bama. Both narrate incidents from their early lives that reflect the discrimination they faced because of their identity. While Zitkala-Sa was a Native American who suffered cultural oppression, Bama grew up as a Dalit in South India, dealing with caste-based discrimination. These two stories are placed together in the chapter to show that such issues exist in many parts of the world.

I decided to write about this chapter because it’s different from the others in the book. It’s not fiction, but a real account of how young children feel when they are treated unfairly just because of their background. When I first read Bama’s story, I couldn’t stop thinking about how common such behaviour still is in many Indian towns. These stories make us more aware and sensitive. As students, we need to understand not just grammar and vocabulary but also social realities. This chapter is an important step towards building that understanding.

What is “Memories of Childhood” About?

This chapter includes two short autobiographical narratives that focus on childhood memories shaped by discrimination and injustice.

Part One: The Cutting of My Long Hair by Zitkala-Sa

This section is written by a Native American woman who was taken to a missionary school where they tried to make her behave like a “white” child. She describes how humiliating it was when her long hair was forcibly cut, which in her culture was a sign of defeat. She feels powerless, angry, and alien in a place that tries to erase her identity.

Part Two: We Too Are Human Beings by Bama

Bama’s story takes place in a village in Tamil Nadu. She is a young Dalit girl who notices how upper-caste people treat her community with disrespect. She sees a man carrying food for his master without touching it, just because of his caste. When she narrates this incident to her brother, he tells her about caste discrimination and advises her to study hard to earn respect and equality.

Main Characters:

Zitkala-Sa – A Native American girl forced to give up her culture at a white-run school
Bama – A young Dalit girl who slowly becomes aware of social injustice

Key Themes:

Discrimination based on race and caste
Childhood trauma and awareness
Loss of identity
Education as a tool for change

Why This Chapter Matters for Students

Real stories: It helps students connect emotionally to real-life problems faced by children
Relevant to society: Topics like caste and cultural identity are still important in today’s India
CBSE exam favourite: Frequently asked in long and value-based questions
Builds empathy: Helps students look beyond textbooks and understand people around them better
Teaches resilience: Both writers turned their pain into power through education and awareness