What groups of organisms are most in danger extinction?

* Amphibians: Amphibians are the most threatened group of vertebrates, with over 40% of species facing extinction. The main threats to amphibians are habitat loss, climate change, pollution, and disease.

* Reptiles: Reptiles are the second most threatened group of vertebrates, with over 20% of species facing extinction. The main threats to reptiles are habitat loss, climate change, pollution, and hunting.

* Mammals: Mammals are the third most threatened group of vertebrates, with over 15% of species facing extinction. The main threats to mammals are habitat loss, climate change, hunting, and pollution.

* Birds: Birds are the fourth most threatened group of vertebrates, with over 12% of species facing extinction. The main threats to birds are habitat loss, climate change, pollution, and hunting.

* Fish: Fish are the fifth most threatened group of vertebrates, with over 10% of species facing extinction. The main threats to fish are overfishing, habitat loss, climate change, and pollution.

* Invertebrates: Invertebrates are the most diverse group of animals, and they are also the most threatened. Over 1 million species of invertebrates are at risk of extinction, and the main threats to them are habitat loss, climate change, pollution, and invasive species.