According to the punctuated equilibria model, a. given enough time, most existing species will branch gradually into new species. b. most new species accumulate their unique features relatively rapidly as they come into existence, then change little for the rest of their duration as a species. c. most evolution occurs in sympatric populations. d. speciation is usually due to a single mutation.

Video transcript

hi everyone. Our next problem says the theory that states that evolution happens through a short burst of an intense speciation event followed by a lengthy period of no morphological change is called. Well, this theory that involves quick, short speciation events with long pauses is called the punctuated equilibrium model. That's our choice B. But let's say we're on a test and we can't remember what this is called. So we want to look at the choices were given choices and looking at the words for clues. See which description, which name would make sense for these two aspects that are given to us in the problem describing this theory. So we look at choice. A divergent evolution will diverge means to become different and we might recall that divergent evolution involves a common ancestor in which we get multiple species coming from it that become different from evolved to become different from one another. So that does happen. But that doesn't really fit with, you know, we just know we have speciation happening here with pauses, it doesn't really fit to describe specifically this theory. So we can probably eliminate that as we said, Choice B. That clue of punctuated, we sort of think of, you know, breaks between things and equilibrium meaning, you know, an evenness no change. So punctuated equilibrium to gives us a clue because that describes both aspects of this theory. Given to us in the problem choice C says parallel evolution model parallel. We imagine two things running along next to each other. But again that doesn't describe, starts and stops bursts and pauses. So that would give us a clue to eliminate choice. See, and finally, Choice the rapid speciation model? Well, we do have rapid speciation here, but that only describes one half of the two aspects of this theory, so this wouldn't be sufficient. So that would give us a clue that choice D. Is not our answer. So again, these short bursts, followed by long pauses. His choice be punctuated equilibrium model. We'll see you in the next video.