Download Important Evolutionary Advancement

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:
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
Reptiles
Birds
Mammals
Amphibians
1. Body Temperature Control (Metabolism)
Ectotherms (“cold” blooded): Get heat from environment
1. Fish, Amphibians, Reptiles
2. Move less and move slower
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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)
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2. Movement (Muscles, Skeleton)
Vertebral column:
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Side to side movement. Fish, Amphibians, Reptiles
Up and down movement. Birds, Mammals
Limbs:
Stick out sideways. Fish, Amphibians
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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 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 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)
Low efficiency
High efficiency
Anomaly:
High complexity,
air sacs
5. Internal Transport (Circulation)
Fish and Amphibians
Circulation
2 chambers
3 chambers
4 heart chambers
Heart
Replies, Birds, Mammals
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
Reptiles
Mammals
Amphibs.
Fish
Some anomalies!
7. Response (Nervous System)
Brains
Important Evolutionary Advancements: Folds and size of cerebrum allows for
increased intelligence.
8. Reproduction
Male and
female
organs
(penis,
vagina)
Fish, Amphibian-->
External fertilization
Fish, Amphibians
Ovoparous -->
Reptiles, Birds --> Mammals
Internal Fertilization
Reptiles, Birds
Ovoviviparous -->
Mammals
Viviparous
(Eggs)
(developed eggs with amnion) (amnion, live birth)
Lots of anomalies: some fish give live birth, some mammals have eggs, etc.
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)