BIOLOGY 3 Lecture Notes - Lecture 3: Ribosomal Rna, Cladistics, East Los Angeles College
Document Summary
Phylogenetics = the evolutionary development and history of a species or higher taxonomic grouping of organisms. Evolution of new organisms is driven by. Diversity- different individuals carry different variants of the same basic blue print. Mutations- the dna sequence can be changed due to single base changes, deletion/insertion of dna segments, etc. Speciation events lead to creation of different species. Speciation caused by physical separation into groups where different genetic variants become dominant. 1866 ernst haeckel created the first lebensbaum or tree of life . Until mid 1950"s phylogenies were constructed by experts based on their opinion (subjective criteria) Since then, focus has been on objective criteria for constructing phylogenetic trees (cladistics) thousands of articles in the last decades. Important for many aspects of biology: classification and understanding biological mechanism. Increasing use of phylogenetic trees in the biological sciences. Need to know what trees diagrams do and do not communicate. Provide an efficient structure for organizing biodiversity info.
