Post on 03-Jan-2016
Comparative Vertebrate AnatomyHypothesizing 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
AIRPLANESPACE
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
MovementFISH
AMPHIBIANS
REPTILES
BIRDS MAMMALS
Dinosaurs?
Dinosaurs?
Vertebrate Cladogram