Test 2 Review - Test 2 Review Chapter 25 Phylogenetics...

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Test 2 Review Chapter 25 Phylogenetics- Evolutionary history of a species or group of species Systematics- an analytical approach to understanding the diversity and relationships o organisms, both present-day and extinct Studies both extinct and extant (living) Connects classification with evolution Phylogenies- In order to construct these biologists draw on the fossil records which provides information about ancient organisms Convergent Evolution- Similar environmental pressures and natural selection produce similar adaptations in organisms from different evolutionary lineages Homologies- Similarity in characteristics resulting from a shared ancestry Homologous Traits- traits in different species that are similar because of common ancestry Analogous Traits- Similar traits between two species that is due to convergent evolution rather than to descent from a common ancestor with the same trait Phylogenetic systematics- Taxonomy- Categorizing Variation D K P C O F G S o i h l r a e p m n y a d m n e a g l s e i u c i d u s r l s i n o m y e m s Binomial Nomenclature- the two-part format of the scientific name Homo Sapien Hierarchy of classification- The order in which categorizing occurs Phylogenetic Tree- Depicts hypotheses about evolutionary relationships Reflects the hierarchical classification of groups nested within more inclusive groups
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basis of a phylogenetic tree Clade- a group of species that includes an ancestral species and all its descendants Cladistics- The analysis of how species may be grouped into clades Monophyletic- A valid clade that consists of the ancestral species and all its descendants Paraphyletic- a lack of information about some members of a clade that consist of an ancestral species and some, not all, of the descendants Polyphyletic- a grouping of several species that lack a common ancestor Primitive character- a character that is shared beyond the taxon we are trying to define Derived character- an evolutionary novelty unique to a particular clade Parsimony (Occam’s Razor)- solving an approach by “shaving away” unnecessary complications Chapter 26 Protobiont- Aggregates of abiotically produced molecules surrounded by a membrane or membrane-like structure Ribozyme- RNA, which plays a central role in protein synthesis, can also carry out a number of enzyme-like catalytic functions Can make complementary copies of short pieces of RNA o Must be supplied with nucleotide building blocks Endosymbiosis- Protobionts self-replicating RNA and DNA to create eukaryotes and ultimately multicellular eukaryotes Precambrian Era: All marine, aquatic Eukaryotes evolve- 2 B.Y.A Multicellular eukaryotes evolved 800-700 M.Y.A 650-550 M.Y.A. see simple multicellular organism First invertebrates 550 M.Y.A Cambrian Era: 542-488 M.Y.A. Sudden in crease in diversity of many animal phyla
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Test 2 Review - Test 2 Review Chapter 25 Phylogenetics...

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