part a: classification and evolutionary relationships vertebrate classification:

Part A: Classification and Evolutionary RelationshipsPart A: Classification and

Evolutionary Relationships

Vertebrate Classification:Vertebrate Classification:

1. Taxonomy - categorizing organisms into groups (taxa) 1. Taxonomy - categorizing organisms into groups (taxa)

1. Organisms are grouped together based on similarities and differences 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:

KingdomKingdomPhylumPhylum

ClassClassOrderOrder

FamilyFamilyGenusGenus

SpeciesSpecies3. An organism’s scientific name includes its Genus and Species names.

This illustration shows the classification of the grizzly bear from kingdom to species.

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

2. Kingdom and 3. Phylum2. Kingdom and 3. Phylum

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)

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

Part B: Comparing Form & Function Among Vertebrate Classes

Amphibians

BirdsReptilesFish

Mammals

1. Body Temperature Control (Metabolism)1. Body Temperature Control (Metabolism)

1. Fish, Amphibians, Reptiles

2. Move less and move slower

Endotherms (“warm”-blooded): Produce heat metabolically

1. Birds, Mammals

2. Move more, move faster3. More need for insulation (feathers, fur)

Ectotherms (“cold” blooded): Get heat from environment

3. Less need for insulation

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Important Evolutionary Advancement: Endothermy (in Birds and Mammals): Allowed for survival in a greater variety of environments.

2. Movement (Muscles, Skeleton)2. Movement (Muscles, Skeleton)

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

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Important Evolutionary Advancement: Strong skeleton and 4 limbs (first evolved in Amphibians) allowed for better movement on land.

3. Feeding and Digestion3. Feeding and Digestion

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 skullsMammalian skulls

4. Respiration4. Respiration

Anomaly: High complexity, air sacs

Fish: Gills (in most cases)

Low efficiencyHigh efficiency

Important Evolutionary Advancement: Lungs (first evolved in Fishes, further developed in other vertebrates): Led to movement on to land.

5. Internal Transport (Circulation)5. Internal Transport (Circulation)

Fish and Amphibians

Replies, Birds, Mammals

2 chambers3 chambers 4 heart chambers

Heart

Circulation

Important Evolutionary Advancements: Double-Loop circulation and additional heart chambers allow for more efficient circulation of oxygen-rich blood.

6. Excretion6. Excretion

Some anomalies!

Fish

Amphibs.

Birds

MammalsReptiles

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”.

7. Response (Nervous System)7. Response (Nervous System)

Brains

Important Evolutionary Advancements: Folds and size of cerebrum allows for increased intelligence.

8. Reproduction8. Reproduction

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

Male and female organs (penis, vagina)

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)8. Reproduction (Development)

Early embryonic

development

(all vertebrates

very similar)

Later embryonic

development

(more complex

organisms gain

complexity)