Comparative Vertebrate Anatomy Hypothesizing Evolutionary Relationships

Kingdom Animalia Common Characteristics: Multicellular; eukaryotic; heterotrophs that ingest their food; lack cell walls; reproduce sexually Phylum Chordata Common Characteristics: Notochord, Pharyngeal Gill Slits, Dorsal Nerve Cord Subphylum Vertebrata Common Characteristics: Backbone (vertebral column), Endoskeleton, Brain and Skull Classes: Chrondrichthyes, Osteichthyes, Amphibia, Reptilia, Aves, Mammalia I. Vertebrate Classification (Review)

II. Evolutionary Relationships A. Organisms are classified using 2 main assumptions: 1.The more similar the genes and physical traits of two species are, the more closely related they are. 2.The similarities were inherited from a common ancestor. B.Predicting Evolutionary Relationships 1.Evolutionary relationships can be predicted using diagrams. Each diagram is a hypothesis of how groups of organisms are related to one another. a.Phylogenetic Trees - Hypothesize evolutionary relationships among organisms and predicts when important traits evolved. b.Cladograms - Hypothesize evolutionary relationships among organisms based on significant physical traits.

Figure 36-2, Miller- Levine, Biology Phylogenetic Tree

Cladograms Family tree that branches systematically at points (nodes) representing specific trait possessed by some groups, but not others.

Evolution of Individuals in the Workplace (Matt Groening, 1985)

Node: Specific trait or traits Organisms branching to right HAVE this trait. Organisms branching to left DO NOT have this trait. Branch: Name or Type of Organism III. How To Make a Cladogram Less Complex More Complex Primitive Traits Derived Traits

Example SLEIGH BIKE CAR AIRPLANE SPACE SHUTTLE modes of transportation wheels engine wings travels at 17,500 mph

Brain Case and Backbone; Endoskeleton; Dorsal Nerve Cord (primitive traits) 4 Limbs; Lungs; Double-Loop Circulatory System; Highly Complex Digestive System Amnion; Internal Fertilization Mammary Glands; Hair 4-Chambered Heart; Endothermy; Up and Down Movement FISH AMPHIBIANS REPTILES BIRDSMAMMALS Dinosaurs? Vertebrate Cladogram