GENETICS AND EVOLUTION
EVOLUTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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These are the same animal.
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These animals have a common ancestor.
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These animals are not likely related.
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These animals are likely becoming one species.
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Detailed explanation-1: -You look at two species and see very similar DNA. What does this likely tell you? These are the same animal.
Detailed explanation-2: -Homologous features If two or more species share a unique physical feature, such as a complex bone structure or a body plan, they may all have inherited this feature from a common ancestor. Physical features shared due to evolutionary history (a common ancestor) are said to be homologous.
Detailed explanation-3: -When a recent common ancestor is shared between two organisms, they are said to be closely related. In contrast, common descent can also be traced back to a universal common ancestor of all living organisms using molecular genetic methods.
Detailed explanation-4: -DNA evidence for evolution Biologists often compare the sequences of related (or homologous) genes. If two species have the “same” gene, it is because they inherited it from a common ancestor. In general, the more DNA differences in homologous genes between two species, the more distantly the species are related.
Detailed explanation-5: -Homologous structures provide evidence for common ancestry, while analogous structures show that similar selective pressures can produce similar adaptations (beneficial features). Similarities and differences among biological molecules (e.g., in the DNA sequence of genes) can be used to determine species’ relatedness.