We are being tasked with weakening Dr. Tyson's conclusion.
Dr. Tyson's conclusion is that the footprints left among other footprints in hardened volcanic ash at site G are clearly early hominid footprints.
Why? They show human characteristics.
We also know that Dr. Rees rejects this conclusion because if they did belong to hominids, the footprints indicate that the hominids who made them would have had to walk in an unexpected cross-stepping manner.
Answer choice (B) states: "Certain species of bears had feet very like human feet, except that the outside toe on each foot was the biggest toe and the innermost toe was the smallest toe."
We see that Dr. Tyson's sole reasoning as to why the footprints belong to hominids is that they show human characteristics. Well, if we take answer choice (B) to be true, then it weakens Dr. Tyson's conclusion since this specific species of bear has feet that are very like human feet and it accounts for the "cross-stepping" pattern since the way the feet are described allows for a four-legged creature as opposed to a bipedal creature that is walking in an odd fashion.
So, answer choice (B) seriously undermines Dr. Tyson's conclusion because the footprints could very well belong to a certain species of bear.
Hope that was helpful! Please let us know if you have any other questions.
YivillarMarch 2, 2015
Thank you.
MeredithAugust 29, 2019
How do you know that type of foot set up as described in B would lead to a four legged animal?
VictoriaAugust 29, 2019
Hi @Meredith,
The type of foot set up as described in answer choice B does not necessarily have to lead to a four-legged animal. What is important about answer choice B is that it provides an alternative explanation for the "unexpected cross-stepping manner."
The reason that Dr. Rees rejects Dr. Tyson's conclusion is that, if the footprints were made by hominids, "they would have had to walk in an unexpected cross-stepping manner, by placing the left foot to the right of the right foot." If we picture this, the footprint on the right side would look like a left human foot, i.e. the big toe would be on the outside.
Answer choice B tells us that "certain species of bears had feet very like human feet, except that the outside toe on each foot was the biggest toe and the innermost toe was the smallest toe." This would undermine Dr. Tyson's conclusion that the footprints were left by hominids because the bear's feet both look like human feet and, as their biggest toe is on the outside, would explain the cross-stepping pattern.
Hope this helps! Please let us know if you have any further questions.
