Researchers are seeking evidence to confirm a close evolutionary relationship between two extant species. Which of the following pieces of evidence would be LEAST likely to help the researchers demonstrate this relationship?
Please choose from one of the following options.
ANSWER: A
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The question asks the test taker to identify which piece of evidence would NOT support the hypothesis that two extant (living) species have a close evolutionary relationship.
A fossil that shared traits with both species would support the idea that the two species have a recent common ancestor.
One tool evolutionary biologists use to determine relationships between species is their embryonic development. Similar embryonic stages would support the researchers’ hypothesis.
Another tool for evolutionary biologists is DNA. The most commonly sequenced genes for testing evolutionary relationships are ones that are essential to almost all organisms, such as the genes for ribosomes.
Analogous structures are structures that serve the same function, but come from a different evolutionary origin. Identifying these structures would be an argument AGAINST the researchers’ hypothesis.
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What I don't understand is how analogous structures would be an argument AGAINST the researchers' hypothesis. Wouldn't it support the hypothesis that there is a close evolutionary relationship between these 2 species?
If anything, I thought the answer would be C, because the genes encoding ribosomes would be very similar between 2 distantly related species as eukaryotic ribosomes haven't evolved much (you'd expect the same genes for ribosomes between humans and dolphins)
Please choose from one of the following options.
- A: The identification of several analogous structures between the species
- B: The sequence of a ribosome-coding gene from each species
- C: A fossil that shares traits with both species
- D: The discovery of similar stages of embryonic development
ANSWER: A
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The question asks the test taker to identify which piece of evidence would NOT support the hypothesis that two extant (living) species have a close evolutionary relationship.
A fossil that shared traits with both species would support the idea that the two species have a recent common ancestor.
One tool evolutionary biologists use to determine relationships between species is their embryonic development. Similar embryonic stages would support the researchers’ hypothesis.
Another tool for evolutionary biologists is DNA. The most commonly sequenced genes for testing evolutionary relationships are ones that are essential to almost all organisms, such as the genes for ribosomes.
Analogous structures are structures that serve the same function, but come from a different evolutionary origin. Identifying these structures would be an argument AGAINST the researchers’ hypothesis.
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What I don't understand is how analogous structures would be an argument AGAINST the researchers' hypothesis. Wouldn't it support the hypothesis that there is a close evolutionary relationship between these 2 species?
If anything, I thought the answer would be C, because the genes encoding ribosomes would be very similar between 2 distantly related species as eukaryotic ribosomes haven't evolved much (you'd expect the same genes for ribosomes between humans and dolphins)
