What is a Phylogenetic Relic?

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What is a Phylogenetic Relic?

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A phylogenetic relic, from phylo meaning biological grouping and genetic meaning gene-based) is a bodily organ that has lost its true use and only still exists because there is no particularly strong selection pressure against its existence. A common examples in humans is the appendix. The appendix is thought to be a phylogenetic relic of a bodily organ present in many herbivores called the cecum, which contains special bacteria for digesting cellulose, the hard material in plants. Our appendix lacks these bacteria, hence we cannot digest cellulose. The pineal gland was once thought to be a phylogenetic relic, until the 1960s when it was discovered that it produced melatonin, a hormone that modulates circadian rhythms. The uniqueness and mysteriousness of the pineal gland caused René Descartes to call it the “seat of the soul,” a bodily organ which connected humans to God, though we haven’t seen this theory advanced in the biology journals lately. Sometimes the term phylogenetic relic

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A phylogenetic relic, from phylo meaning biological grouping and genetic meaning gene-based) is a bodily organ that has lost its true use and only still exists because there is no particularly strong selection pressure against its existence. A common examples in humans is the appendix. The appendix is thought to be a phylogenetic relic of a bodily organ present in many herbivores called the cecum, which contains special bacteria for digesting cellulose, the hard material in plants. Our appendix lacks these bacteria, hence we cannot digest cellulose. The pineal gland was once thought to be a phylogenetic relic, until the 1960s when it was discovered that it produced melatonin, a hormone that modulates circadian rhythms. The uniqueness and mysteriousness of the pineal gland caused René Descartes to call it the “seat of the soul,” a bodily organ which connected humans to God, though we haven’t seen this theory advanced in the biology journals lately. Sometimes the term phylogenetic relic

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