The geneticist James Crow wrote that successful scientific theori...

Question

The geneticist James Crow wrote that successful scientific theories have the following characteristics: (1) They explain otherwise puzzling observations; (2) they provide connections between otherwise disparate observations; (3) they make predictions that can be tested; and (4) they are heuristic, meaning that they open up new avenues of theory and experimentation. Crow added two other elements of scientific theories that he considered important on a personal, emotional level: (5) They should be elegant, in the sense of being simple and powerful; and (6) they should have an element of surprise. How well does the theory of evolution by natural selection fulfill these six criteria?

Accepted Answer

Welcome back. Here's our next question. All of the following are pieces of evidence of evolution by natural selection Except so we're going to be looking for the one choice that would not be evidence for evolution by natural selection. So let's just recall very briefly from our content videos, what you know, what is the definition of evolution by natural selection? Well, it would be the change in inheritable traits characteristic of a population over generations. Do two. The differential survival and reproduction of individuals due to differences in phenotype. So that's a long wordy way of reminding us that we have individual organisms that develop variations, mutations uh that cause differences in the phenotype of individuals of the same species and the environmental pressures around them cause certain of those phenotype is to have an advantage allowing those individuals to be more likely to survive and reproduce. And as certain phenotype sis lend an advantage those phenotype become favored in the genotype sis of the descendants. So the inheritable traits characteristic of an entire population change over generations and that can can cause um speciation. So you can start with an original ancestral species uh which begins to diverge if it takes advantage of two different environments or two different or it ends up in two different locations. So let's look at our answer choices to look for the one that is not evidence for this method of evolution. So choice a says many species share similar physical features. While this would be evidence because you could say that species that face similar environmental pressures. So similar food sources similar. Um You know whether they live in murky water or something and they have had the same phenotype sis favored the same phenotype give them a reproductive advantage uh due to that natural selection. So that is evidence for evolution by natural selection. So that's not our answer. Choice choice B says the unique features of island species. Well this is definitely evidence of evolution by natural selection. This was of course what led Darwin to the theory of evolution, seeing the finch species being existing in such different phenotype on different islands because it had adapted to take advantage of different food sources. So that's not our answer. Either choice C says conserved sequences in the DNA. Well this is uh evidence also because we see um we can trace back to ancestral species by looking at sequences that are conserved in species descended from a common ancestor. So we can see that they diverged from a common ancestor and became different from each other. We can see conserved sequences among related species. Um So that's not our answer. So finally we're on Choice D. No two individuals can have conserved DNA sequences as each individual is unique. Well this would not be evidence because it's not true. Um you know, all individuals that are members of a shared group have conserved sequences of DNA that show us that related nous between species or descent from a common ancestor. So which is not evidence of evolution by natural selection. That's choice D No. Two individuals can have conserved DNA sequences as each individual is unique. See you in the next video.

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