Question

The Cretaceous-Tertiary extinction event was caused when an asteroid impacted Earth approximately 66 million years ago, near what is now the Gulf of Mexico. The indirect effects of the impact affected the entire globe. The event resulted in the extinction of nearly 75 percent of all plant and animal species on Earth, including the majority of dinosaur species. Which of the following likely best describes why most of these species went extinct?

Rapid climate and habitat change
A population with high genetic biodiversity is better able to respond to environmental stressors
.Genetic variation within each species and number of species present

Answer 1

The answer is: Rapid climate and habitat change

The key factors that led to the mass extinction event during the Cretaceous-Tertiary extinction were:

1. The asteroid impact would have caused huge amounts of dust and particles to be ejected into the atmosphere, blocking sunlight for a period of time. This would have disrupted photosynthesis, wiping out plant life which in turn impacted herbivores and carnivores higher up the food chain.
2. The impact winter following the asteroid impact would have caused global cooling and changes in rainfall patterns. These rapid climate changes disrupted habitats and food sources for many species.
3. The impact also likely caused tsunamis, wildfires, and acid rain which further devastated ecosystems.

Genetic diversity and number of species present would not have been the primary factors in why most species went extinct. Rather, it was the abrupt and extreme climate change and loss of habitats due to the asteroid impact that species could not adapt to quickly enough to survive.

So the most likely correct answer is Rapid climate and habitat change caused by the asteroid impact and consequences.

Hope this explanation helps! Let me know if you have any other questions.