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THE THEORY OF EVOLUTION 1. Describe the theory of common descent. 2 Define \"hom

ID: 3166223 • Letter: T

Question

THE THEORY OF EVOLUTION 1. Describe the theory of common descent. 2 Define "homology." 3. Examine the following phylogenetic tree. Which two organisms probably have the greatest number of homologies? Which two are the descendants of the most recent common ancestor? Put these taxonomic groups in order from most inclusive to least inclusive. Order, Genus, Family, Species, Phylum 4. 5. Draw the relationship among these three organisms that is implied by their classification: 1. Asparagus. Order Liliales, Family Lillaceae, Asparagus officinalis 2. Yam. Order Liliales, Family Discoreacea, Discorea species 3. Daffodil. Order Liliales, Family Liliaceae, Narcissus pseudonarcissus

Explanation / Answer

1. The theory of common descent states that all living organisms have descended from a single ancestor. This theory is derived from the physical observation of various phenotypical traits as well as by examining the patterns of the embryonic development in organisms. This theory further explains the variation of the species with change in geographical regions, shared and derived traits among various organisms, adaptability of the organisms, the reproductive firness of the populations. Molecular advancements further states that the process of conversion of DNA into proteins is essentially conserved among all organisms.

2. Homology is the existence of the shared ancestry. This can be related to the similarities in the genetic structure and body structures among different taxa. This also includes similar patterns of development among organs such as matching primordia in successive segements of a partcular organism. Examples of homologous organs are forelimbs of vertebrates, wings of bats etc.