BIOL 111 Lecture Notes - Lecture 4: Cladistics
Document Summary
18 phylogenetic trees based on the idea that all living things have diverged from a common ancestor used to describe relatedness between organisms. Characteristics used for comparison and grouping are chosen for evolutionary significance morphological similarities. Homolog us structures may vary in form a function but have a common ancestral origin ; best source of information for phylogenetic relationships. An ologies structures similar function but different origins i no common ancestry common ancestry should be the basis for inferring relationships cladistics organizing organisms in groups based on common ancestry. To clade an ancestral species a its evolutionary descendants identify clades compare an ingroup with an out group ingroup : species that is being analyzed. Be outgroup : species that diverged before the lineage that contains the groups being studied developmental similarities distantly relatedness organisms look similar in early development stages the sooner differences emerge , the more distantly relatedness molecular similarities. Dna addresses the heart of evolutionary relationships.
