Which of the following is an example of a mutualistic relationship? a. moles catching and eating earthworms from the moles' underground tunnels; b. cattails and reed canary grass growing together in wetland soils; c. cleaner fish removing and eating parasites from the teeth of sharks; d. Colorado potato beetles consuming potato plant leaves; e. more than one of the above

Video transcript

Welcome back. Here's our next problem. A barnacle can root itself in the reproductive system of a crab. And while the crab does not die as a result of this interaction, its reproductive capabilities are greatly reduced. This type of symbiotic relationship is called. So we'll look at this. We have the crab and the barnacle. So let's think about this symbiotic relationship. Um In this case when the barnacle embeds itself in the reproductive system of the crab, um all reproduction is cut off for the crab and the crab cares for the barnacle as it would care for a brood of eggs. Um And in fact this even can change the behavior of male crabs who don't normally take care of eggs but will care for the barnacle. So the crab is harmed by this interaction. It's not predation. The crab isn't killed and eaten, but since it has decreased reproduction, it's not passing on its genes to the next generation. It's not um it's harmed as a species. The barnacle benefits in being cared for by the crab. So when you have a symbiotic relationship where one organism is being harmed and the other benefits. This is choice B parasitism. Um You could think of a parasite that makes it pretty easy to remember. Um Honestly, this is a little bit creepy. I think when I think about parasites, one of the creepier topics in biology choices, let's look for other answer choices just to understand why they're not correct choice A is mutual is um I can think of mutual benefits and mutual is um both organisms benefit from the symbiotic relationship. So this is a non creepy symbiotic relationship, but not our answer here, not what's going on in this crab and barnacle relationship? Choice C. Is commencing is um Incrementalism one organism benefits the other is neither harmed, but it's not nor does it benefit. So that's not the case here. Since the crab by losing its reproductive potential is harmed. And finally, Choice D. A. Mental ism. This is when neither benefits And one organism is harmed. But since the barnacle benefits from the care of the crab, um that's not the description that we would use for the situation. So, again, this symbiotic relationship between the barnacle um that roots itself in the reproductive system of the crab is called choice B. Parasitism. See you in the next video.