Loss of Biodiversity
The evil quartet — habitat loss, over-exploitation, alien invasion and co-extinction. (Biology › Biodiversity and Conservation, NEET UG syllabus.)
What is Loss of Biodiversity?
The reduction in the variety of life on Earth at all levels, including genetic, species, and ecosystem diversity.
Key points
- Define biodiversity loss and explain its significance.
- Identify and explain the four major causes of biodiversity loss (the "Evil Quartet").
- Provide specific, relevant examples for each cause of biodiversity loss.
- Understand the interconnectedness and cumulative impact of these causes.
Common exam trap
Confusing habitat loss with habitat fragmentation; they are distinct but related processes.
Definitions
- Term
Biodiversity Loss
- Meaning
The reduction in the variety of life on Earth at all levels, including genetic, species, and ecosystem diversity.
- Term
Habitat Loss
- Meaning
The destruction or degradation of natural environments where species live, rendering them uninhabitable or unsuitable.
- Term
Habitat Fragmentation
- Meaning
The process by which large, continuous habitats are broken into smaller, isolated patches, often due to human activities.
- Term
Over-exploitation
- Meaning
Harvesting a renewable biological resource at a rate that is unsustainable, exceeding its capacity to regenerate, leading to its depletion.
- Term
Alien Species
- Meaning
Non-native species introduced to an ecosystem, often by human activity, intentionally or unintentionally.
- Term
Invasive Species
- Meaning
An alien species that spreads rapidly and causes ecological or economic harm to the native ecosystem.
- Term
Co-extinction
- Meaning
The loss of one species due to the extinction of another species with which it has a close, obligate ecological relationship.
Learning objectives
Define biodiversity loss and explain its significance.
Identify and explain the four major causes of biodiversity loss (the "Evil Quartet").
Provide specific, relevant examples for each cause of biodiversity loss.
Understand the interconnectedness and cumulative impact of these causes.
Appreciate the urgency and importance of biodiversity conservation efforts.
Prerequisites
Basic understanding of biodiversity (genetic, species, ecosystem diversity).
Knowledge of ecological interactions (e.g., predation, competition, mutualism).
Familiarity with the concept of extinction and endangered species.
Common mistakes
Confusing habitat loss with habitat fragmentation; they are distinct but related processes.
Not remembering specific examples for each of the 'Evil Quartet' causes.
Underestimating the impact of alien species invasions on native biodiversity.
Forgetting co-extinction as a distinct and significant cause of biodiversity loss.
Keywords
Biodiversity
Extinction
Evil Quartet
Habitat Loss
Habitat Fragmentation
Over-exploitation
Alien Species
Invasive Species
Co-extinction
Conservation Biology
Ecology
NEET Biology
Practice preview
Which of the following is NOT a component of the 'evil quartet' that drives biodiversity loss?…
easy
The introduction of a non-native plant species into an ecosystem, which then outcompetes native plants for sunlight and nutrients, leading to a decline in native plant populations, is an example of which component of the…
medium
Which of the following human activities is a direct contributor to habitat fragmentation?…
medium