Summarize the experimental evidence that Daphnia require three cues to trigger sexual reproduction. Discuss what these cues indicate about the environment.

Video transcript

Hi everyone. Let's look at our next question. It says insecticide endosulfan can suppress pheromone production, pheromones are used to indicate reproductive receptivity from many organisms such as red spotted newts supposedly lake near an agricultural area becomes contaminated with endosulfan. What will be the possible effect of this on the population of red spotted newts living on the lake? Well, as our problem told us, um pheromones play an important role in the reproduction of red spotted newts. The female form pheromones attract males to the females and the male pheromones increase female receptivity to mating. So when we have a situation where the area where these newts live is contaminated with this endosulfan that suppresses their pheromone production. Well, when the pheromone production is suppressed, the newts are less likely to successfully mate and reproduce. And as a result their population is going to decrease. So let's look at our answer choices here. And sure enough, we see choice A. Is the population size will decrease. So that's going to be our answer. But let's just look at our other answer choices. Choice B says the population size will increase, well, again, the presence of the end of sulfur in suppressing pheromone production is going to result in a population decrease. Not increase population. See a choice, he says the population size will remain the same. Also incorrect, since again we expect to see a decrease in population due to less successful mating. And finally, choice D the population side will exceed the carrying capacity of the lake. Um When we're not changing the carrying capacity of the lake, that would be the number of newts it's able to sustain with this given resources. Um And since our population is actually decreasing, will definitely not be exceeding the carrying capacity, Choice D is not our answer. So again, the possible effect of a lake becoming contaminated with end of cell phone where red spotted newts live on the effect of the population of those red spotted newts is choice A The population size will decrease. See you in the next video.