1. Which of the following features would be used to construct a phylogenic tree?  
    A.  homologous structures
    B.  fossil record data
    C.  DNA-DNA hybridization
    D.  amino acid sequences
    E.  All of the above.

Expert Answers

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The answer to your question is option (d). Homologous structures, fossil record data, DNA-DNA hybridization, and amino acid sequences are all features used to construct a phylogenetic tree.

Phylogenetic trees are like family trees. They show the evolutionary ancestry of different “clades”. A major branch that juts off the main trunk of a phylogenetic tree is considered a clade. A clade is group of similar organisms that are thought to have evolved from a common ancestor.

Phylogeny uses the three broad categories of morphology, genetics, and behavior to find similarities between and classify organisms into groups.

Options (a) and (b) in your question related to the morphology realm of phylogeny. Fossil records can reveal homologous structures. Homologous structures are structures that have similar mechanical designs, but are found in different organisms. Animals that share homologous structures are thought to also share a common ancestor. The arm of a human, leg of a dog, and fin of a whale are examples of homologous structures.

Options (c) and (d) lie within the genetics realm of phylogeny. The more DNA or amino acid sequences two species share, the more closely related they are thought to be.

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