BIO 201 Lecture Notes - Lecture 4: Cryogenian, Bilateria, Paraphyly
Document Summary
Taxonomy and phylogeny of animals chapter 4. Animal classification: organized into groups by similarities, morphological/anatomical, physiological, reproductive, organized by relationships, similar to family trees. Taxonomy and phylogeny: humans have a tendency to categorize, organize and sort, aristotle was among the first to classify animals based on similarities, criteria: where they hung out, air, water, ground. Organizing diversity: various features used to group organisms together, different (cid:862)filing(cid:863) systems used to organize these groups until 1758. Cladistics: evolutionary relationships are illustrated in the form of a branching tree (cladogram) where nodes represent a common ancestor, characters on branches represent shared derived characters. Important terminology: monophyletic group: group that contains the ancestor of a group and all descendants (taxa and clades are monophyletic groups, taxon: group that contains the ancestor of a group and all descendants. Cladograms are made of a number of nested clades: sister groups: taxa that share a common ancestor and are the closest relatives to one another.
