1. Dinosaurs (Non-Avian):
- The extinction event led to the extinction of all non-avian dinosaurs, which included iconic groups such as the Tyrannosaurus rex, Triceratops, and Stegosaurus. This marked the end of the dominance of dinosaurs that had lasted for over 150 million years.
2. Marine Reptiles:
- The K-T extinction also caused the demise of marine reptiles, such as mosasaurs, plesiosaurs, and giant marine turtles. These marine creatures were diverse and abundant before the event but experienced a dramatic decline during this period.
3. Pterosaurs:
- Pterosaurs, flying reptiles that coexisted with dinosaurs, also became extinct during the K-T event. They were the largest flying animals that ever existed, with wingspans reaching up to 40 feet (12 meters).
4. Ammonites:
- Ammonites, a group of shelled marine invertebrates, were heavily impacted by the extinction. They had a diverse range of species and were abundant in ancient oceans, but the K-T event led to their near-total disappearance.
5. Planktonic Foraminifera:
- Planktonic foraminifera, tiny marine organisms with calcareous shells, experienced a significant decline during the K-T extinction. They are important components of marine food webs and their decline affected the entire marine ecosystem.
6. Mammals:
- The K-T extinction provided an opportunity for mammals to flourish and diversify. Before the event, mammals were relatively small and occupied niche roles compared to dinosaurs. However, with the extinction of larger competitors, mammals underwent rapid evolution and eventually came to dominate terrestrial ecosystems.
7. Birds:
- Birds, believed to have evolved from small, feathered dinosaurs, survived the extinction event. They diversified and occupied ecological niches left vacant by the disappearance of other animals, eventually becoming the dominant group of flying vertebrates.
8. Insects:
- Insects, as a group, were relatively resilient during the K-T extinction. While some insect species became extinct, many survived and continued to play crucial ecological roles in pollination, nutrient cycling, and decomposition.
In summary, the K-T extinction event profoundly impacted the animal kingdom. It led to the extinction of numerous groups of animals, including the dinosaurs, marine reptiles, and many others. However, it also paved the way for the diversification and dominance of mammals, birds, and other surviving lineages, shaping the biodiversity of the world we see today.