Table of Contents
This artist’s reconstruction depicts North Dakota in the first months following the impact of an asteroid off Mexico’s coast 66 million years ago, showing a dark, dusty and cold world in which the last non-avian dinosaurs, illustrated by the species Dakotaraptor steini, were on the edge of extinction in this undated handout.
Significance
It was a catastrophic day on Earth when an asteroid struck Mexico’s Yucatan Peninsula 66 million years ago. This impact caused a global calamity, known as the Cretaceous-Paleogene extinction event, which wiped out three-quarters of the world’s species, including the dinosaurs.
Features
The immediate effects of the impact were devastating, including wildfires, earthquakes, a massive shockwave, and huge standing waves in the seas. However, the most significant long-term effect was the climate catastrophe that unfolded in the following years. Dust from the pulverized rock ejected into the atmosphere played a crucial role in the extinctions that followed.
Objectives
Researchers aimed to understand the role of dust in driving extinctions following the asteroid impact. By running paleoclimate simulations based on sediment unearthed in North Dakota, they discovered that the fine-grained dust blocked photosynthesis for up to two years, rendering the atmosphere opaque to sunlight. The primary objective was to shed light on the importance of dust in the extinction event.
Effects
The simulations showed that the dust remained in the atmosphere for 15 years, causing a drop in surface temperatures of about 27 degrees Fahrenheit (15 degrees Celsius). Plants were unable to harness sunlight for energy, leading to the collapse of primary productivity and a chain reaction of extinctions. Herbivores starved, carnivores perished, and marine ecosystems suffered as food webs collapsed.
Pros and Cons
The study highlights the significant role of dust in the extinction event, expanding our understanding of the complex processes involved in mass extinctions. From a negative perspective, the study reveals the devastating consequences of natural disasters like asteroid impacts, underscoring the vulnerability of life on Earth. However, it also provides valuable insights for predicting and mitigating potential future threats.
Fun Fact
A fascinating aspect of this research is that without the asteroid impact, dinosaurs might still dominate the Earth today. The demise of the dinosaurs and the subsequent rise of mammals were a direct result of this catastrophic event. It enabled mammals to become the dominant organisms on the planet, ultimately leading to the evolution of human beings.
By analyzing the significance, features, objectives, effects, and additional fun facts of this study, we can comprehensively understand the impact of the asteroid that led to the extinction of dinosaurs 66 million years ago.
Mutiple Choice Questions
1. What caused the extinction of dinosaurs?
a. Wildfires and earthquakes
b. Massive shockwave in the air and standing waves in the seas
c. Climate catastrophe caused by dust from the impact site
d. Sulfur released after the impact and soot from wildfires
Explanation: The extinction of dinosaurs was caused by a climate catastrophe that unfolded as a result of dust from the impact site. This dust blocked photosynthesis for up to two years and remained in the atmosphere for 15 years.
2. How much dust was ejected into the atmosphere from the impact site?
a. 200 gigatonnes
b. 1,100 gigatonnes
c. 2,000 gigatonnes
d. 11,000 gigatonnes
Explanation: The total amount of dust ejected into the atmosphere from the impact site was calculated to be about 2,000 gigatonnes, which is more than 11 times the weight of Mt. Everest.
3. Which factor played a larger role in the extinction than previously known?
a. Sulfur released after the impact
b. Soot from wildfires
c. Dust from the impact site
d. Quakes and shockwaves
Explanation: The study indicated that dust from the impact site played a larger role in driving extinctions than previously known. While sulfur and soot were also factors, dust had a significant impact on blocking photosynthesis and causing extinctions.
4. How long did the dust remain in the atmosphere?
a. 2 years
b. 5 years
c. 10 years
d. 15 years
Explanation: The fine-grained dust remained in the atmosphere for up to 15 years. This extended period of time resulted in a prolonged impact winter, with global temperatures plummeting and primary productivity collapsing.
5. What led to the demise of herbivores and carnivores?
a. Wildfires and earthquakes
b. Dust blocking photosynthesis
c. Sulfur released after the impact
d. Soot from wildfires
Explanation: The demise of herbivores and carnivores was caused by the collapse of primary productivity, which occurred due to the dust blocking photosynthesis. As plants died, herbivores starved, and without prey, carnivores perished.
6. How long did it take for pre-impact temperature conditions to return?
a. 5 years
b. 10 years
c. 15 years
d. 20 years
Explanation: It took approximately 20 years for pre-impact temperature conditions to return after the impact. This indicates the long-lasting impact of the extinction event on the Earth’s climate.
7. What group of organisms benefited from the extinction of dinosaurs?
a. Birds
b. Mammals
c. Marine reptiles
d. Amphibians
Explanation: The extinction of dinosaurs allowed mammals to become the dominant organisms on Earth. Mammals, including humans, had the opportunity to thrive and fill the ecological niches left vacant by dinosaurs.
8. What would have happened if the meteorite impact did not occur?
a. Dinosaurs would still dominate the Earth
b. Mammals would have become dominant earlier
c. Extinctions would not have occurred
d. Climate conditions would not have changed
Explanation: Without the meteorite impact, dinosaurs would likely still dominate the Earth. The extinction event caused by the impact paved the way for mammals to become the dominant organisms on the planet.
Brief Summary | UPSC – IAS
An asteroid that hit Mexico’s Yucatan Peninsula 66 million years ago caused the extinction of three-quarters of the world’s species and ended the age of dinosaurs. Researchers have now revealed that dust from the impact site played a potent role in driving extinctions by blocking photosynthesis and diminishing sunlight for up to two years. The simulations showed that the dust cloud remained in the atmosphere for 15 years, causing a drop in surface temperatures and collapsing the food webs of land and aquatic plants and organisms. This catastrophe led to the dominance of mammals and ultimately the rise of humans.