Hurricanes are extreme natural events. Scientists expect that hurricanes will become more and more common as climate change worsens.
After two back-to-back hurricanes struck Turks and Caicos, a group of small islands in the Caribbean, scientists found an example of “survival of the fittest” happening among the islands’ anole lizard population.
How did the hurricanes help the scientists do a unique study of the lizards?
This type of anole lizards (Anolis scriptus) are small brown lizards that can only be found in the Turks and Caicos Islands. Very little is known about these lizards, so scientists decided to study them.
Initially, the scientists wanted to learn more about the lizards’ behavior, diet, physical appearance, and habitat. They caught, measured, photographed, and videotaped the lizards. The scientists left the islands after they finished their studies. Shortly after, Hurricanes Irma and Maria hit.
The scientists realized that they had a unique chance to study the effects of the hurricanes on the lizards. They could compare their data about the lizards before and after the hurricanes struck.
Scroll Down for a Downloadable PDF of this article.
What did the scientists discover about the surviving lizards?
Six weeks after Hurricane Irma and three weeks after Hurricane Maria, the scientists headed back to Turks and Caicos. They studied the surviving lizards and compared them to those that didn’t survive.
Before returning to the islands, the scientists predicted that the surviving lizards would have features that helped them to grab and hold on to stems and branches tightly. Their guess was correct! The scientists found that the survivors had larger toepads and longer front legs compared to the lizards studied before the hurricanes. However, the scientists were surprised to find that the surviving lizards had shorter back legs.
Why did the surviving lizards have shorter back legs?
They did an experiment to find out how shorter back legs helped the lizards to survive. The experiment involved some lizards, a leaf blower, a perch that was like a plant stem or branch, and some safety nets.
The scientists turned on the wind blower and filmed the lizards while strong winds blew. They saw that the lizards tucked their front legs close to their bodies, but kept their back legs jutted out at a certain angle. Thus, the back legs caught the wind and caused some of the lizards to be blown away.
What happened to the next generation of anole lizards?
After 13 months, the scientists again returned to the islands. They wanted to know if the offspring of the hurricane survivors would have the same characteristics as their parents or the pre-hurricane population. They discovered that the next generation was like their parents and not the pre-hurricane population. This led the scientists to conclude that the hurricanes became agents of natural selection, and the lizards who were fittest survived, reproduced, and passed on their survival traits to the next generation.
After reading the passage, answer the following questions:
- Why did the scientists decide to study the lizards?
- Very little is known about them.
- The scientists wanted to know more about the lizards’ behavior, diet, physical appearance, and habitat.
- The scientists wanted to take pictures and videos of the lizards.
- All of the above.
- What did the scientists discover about the surviving lizards?
- They had larger toepads, longer front legs, and longer back legs.
- They had smaller toepads, longer front legs, and longer back legs.
- They had larger toepads, longer front legs, and shorter back legs.
- They had larger toepads, shorter front legs, and longer back legs.
- What did the scientists find out when they did the wind blower experiment?
- Longer back legs caught wind and caused the lizards to be blown away.
- Shorter back legs helped the lizards to grab their perch more tightly.
- Both a and b.
- None of the above.
- Which is true about the offspring of the surviving lizards?
- They had traits like their parents.
- They had traits like the pre-hurricane population.
- They had traits that were not like their parents nor the pre-hurricane population.
- The surviving lizards had no offspring.