The term "sixth mass extinction/sixth extinction" is often mentioned in the news in the context of the discussion of
Detailed Explanation:
Answer: Option 4 — Mankind's over-exploitation/misuse of natural resources, fragmentation/loss of natural habitats, destruction of ecosystems, pollution and global climate change.
The term "sixth mass extinction" refers to the ongoing biodiversity crisis driven primarily by anthropogenic (human-caused) factors. Unlike previous mass extinctions caused by natural phenomena, the current extinction event is characterized by unprecedented rates of species loss due to human activities including habitat destruction, overexploitation of species, pollution, introduction of invasive species, and climate change. Scientists estimate that species are currently going extinct at rates 100 to 1,000 times higher than the natural background rate, making this a human-driven ecological catastrophe comparable to the five previous mass extinctions in Earth's 4.5-billion-year history.
📝 Short Notes: Mass Extinctions
| Extinction Event | Time Period | Species Lost | Cause |
|---|---|---|---|
| Ordovician-Silurian | ~445 million years ago | ~85% | Climate change, glaciation |
| Late Devonian | ~375 million years ago | ~75% | Ocean anoxia, climate change |
| Permian-Triassic ("Great Dying") | ~252 million years ago | ~96% | Volcanic eruptions, climate change |
| Triassic-Jurassic | ~201 million years ago | ~80% | Volcanic activity, climate change |
| Cretaceous-Paleogene | ~66 million years ago | ~76% (including dinosaurs) | Asteroid impact, volcanic activity |
| Sixth Extinction (Holocene) | Ongoing (present) | Unknown (in progress) | Human activities |
- Current extinction rate: 100-1,000 times higher than natural background rate
- Primary drivers: Habitat loss (deforestation, urbanization), overexploitation (hunting, fishing), pollution, invasive species, climate change
- Most affected groups: Amphibians, marine mammals, large predators, island species
- IUCN Red List: Over 40,000 species currently threatened with extinction
- Holocene extinction: Another name for the sixth extinction, referring to the current geological epoch
Question 1 of 2 Threats to Biodiversity
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First question in this topic
Which of the following can be threats to the biodiversity of a geographical area?...