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Vertebrate Classification:. Part A: Classification and Evolutionary Relationships. 1. Taxonomy - categorizing organisms into groups (taxa). 1. Organisms are grouped together based on similarities and differences amongst their:.
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Vertebrate Classification: Part A: Classification and Evolutionary Relationships
1. Taxonomy - categorizing organisms into groups (taxa) 1. Organisms are grouped together based on similarities anddifferences amongst their: a. Physical traits - structure (anatomy) and function (physiology) b. Biochemical composition - DNA (genes) and proteins 2. The taxa (groups) used to categorize organisms from general characteristics to more specific are: Kingdom Phylum Class Order Family Genus Species 3. An organism’s scientific name includes its Genus and Species names.
2. Kingdom and 3. Phylum This illustration shows the classification of the grizzly bear from kingdom to species. Vertebrates belong to Kingdom Animalia: multicellular, eukaryotic (cells with organelles), consumers. Vertebrates belong to Phylum Chordata: have nerve chord. There are 5 groups of Vertebrates we will study, including Mammalia (shown here) Note: as the groups go from more general to more specific, the number of organisms in each group decreases. Figure 15-5, Miller-Levine, Biology
Taxonomy and the Evolution of Vertebrates This phylogenetic tree shows one hypothesis of the evolutionary relationships among vertebrates & approximately when important traits appeared. Each organism’s taxonomic classification reflects these relationships. Note important evolutionary advancemnets (circled). Figure 36-2, Miller-Levine, Biology
Part B: Comparing Form & Function Among Vertebrate Classes Fish Birds Reptiles Mammals Amphibians
1. Body Temperature Control (Metabolism) Ectotherms (“cold” blooded): Get heat from environment 1. Fish, Amphibians, Reptiles 2. Move less and move slower 3. Less need for insulation Important Evolutionary Advancement: Endothermy (in Birds and Mammals): Allowed for survival in a greater variety of environments. Endotherms (“warm”-blooded): Produce heat metabolically 1. Birds, Mammals 2. Move more, move faster 3. More need for insulation (feathers, fur)
2. Movement (Muscles, Skeleton) Vertebral column: Side to side movement. Fish, Amphibians, Reptiles Up and down movement. Birds, Mammals Limbs: Stick out sideways. Fish, Amphibians Point more directly down - hold more weight. Reptiles Point straight down. Birds, Mammals Important Evolutionary Advancement:Strong skeleton and 4 limbs (first evolved in Amphibians) allowed for better movement on land.
3. Feeding and Digestion Increasing complexity --> Important Evolutionary Advancement: Jaws (first evolved in Fishes). Allowed for greater food variety and size. Digestive system and other structures adapted to feeding habit of organism. Mammalian skulls
4. Respiration Important Evolutionary Advancement: Lungs (first evolved in Fishes, further developed in other vertebrates): Led to movement on to land. Fish: Gills (in most cases) High efficiency Low efficiency Anomaly:High complexity, air sacs Increasing complexity -->
5. Internal Transport (Circulation) Fish and Amphibians Circulation 2 chambers 3 chambers 4 heart chambers Heart Replies, Birds, Mammals Increasing complexity --> Important Evolutionary Advancements: Double-Loop circulation and additional heart chambers allow for more efficient circulation of oxygen-rich blood.
6. Excretion Important Evolutionary Advancements: Urea and uric acid are less toxic to the body and can be held internally on land. Pure ammonia waste requires organisms to stay in water to “flush”. Birds Mammals Reptiles Amphibs. Fish Some anomalies!
7. Response (Nervous System) Brains Increasing complexity --> Important Evolutionary Advancements: Folds and size of cerebrum allows for increased intelligence.
8. Reproduction Male and female organs (penis, vagina) Fish, Amphibian--> Reptiles, Birds-->MammalsExternal fertilization Internal Fertilization Ovoparous --> Ovoviviparous --> Viviparous(Eggs) (developed eggs with amnion) (amnion, live birth)Lots of anomalies: some fish give live birth, some mammals have eggs, etc. Fish, Amphibians Reptiles, Birds Mammals Important Evolutionary Advancement: Amniotic Eggs (first evolved in Reptiles): Eggs with yolk allowed for permanent movement on to land. Internal fertilization allowed for reproduction on land.
8. Reproduction (Development) Early embryonic development (all vertebrates very similar) Later embryonic development (more complex organisms gain complexity)