What is the difference between an invertebrate and a vertebrate animal?
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Transcript of What is the difference between an invertebrate and a vertebrate animal?
What is the difference between an invertebrate and a
vertebrate animal?
Invertebrates do not have a backbone
• Examples: jellyfish, earthworm, grasshopper, butterfly, octopus, crab
Vertebrates are chordates• Characteristics of chordates (all present at some point
during development) Notochord – flexible, supporting structure. The notochord
becomes the backbone in vertebrate chordates. Dorsal hollow nerve cord (spinal cord) Post-anal tail – a tail that is posterior to the anus Pharyngeal pouches (gill slits)
Nonvertebrate chordates
Jawless fishes
Cartilaginous fishes
Bony fishes
Amphibians
Reptiles
Birds
Mammals
A Cladogram of Chordates
Evolutionary Patterns
• Adaptive radiation or divergent evolution – evolutionary lines become less similar
• Convergent evolution – unrelated organisms become more similar
Body Temperature Control
• Ectotherms obtain heat from the environment and rely on behavior to regulate body temperature (fish, amphibian, reptile)
• Endotherms generate heat through metabolic activity and rely on physiological mechanisms to regulate body temperature (birds, mammals)
Bo
dy
Tem
per
atu
re (
°C)
Environmental Temperature (°C)
Trends in Vertebrate Evolution• As you move from fish to mammals, organ
systems become more complex• The heads of vertebrates show many adaptations
for feeding (mouthparts, snouts and tongues)
Esophagus
Stomach
Intestine
Liver
Gallbladder
Pancreas
Cloaca
Crop
Gizzard
Cecum
Rectum
Shark Salamander Lizard Pigeon Cow
Digestive Systems of Vertebrates
Salamander Lizard PigeonPrimate
Nostrils, mouth, and throat
Trachea
Lung
Air sac
Respiratory Systems of Vertebrates
Double-Loop Circulatory SystemSingle-LoopCirculatory System
FISHES MOST REPTILES BIRDS &
MAMMALS
Circulatory Systems of Vertebrates
Right atrium
Left atrium
Complete division
Heart
Domestic pigeon
Left ventricle
Right ventricle
Section 32-1
Right atrium
Left atrium
Complete division
Left ventricle
Right ventricle
Excretory Systems
• Fish and aquatic amphibians excrete ammonia through gills
• Birds and reptiles excrete uric acid through kidneys
• Mammals, land amphibians and cartilaginous fish excrete urea through kidneys
Nervous system
• The complexity of the cerebrum and cerebellum increases from fish to mammals
Movement
• Fish, snakes and salamanders move by wiggling side to side; limbs stick out to side
Movement
• Reptiles (lizards, crocodiles) have limbs bent under body, movement still side to side
• Mammals and birds have limbs directly under body; movement involves the backbone flexing up and down
Reproduction
• Sexual
• Fertilization is external in water for fish and amphibians
• Fertilization is internal on land for reptiles, birds and mammals
• Development of the egg is related to the habitat (oviparous, ovoviviparous or viviparous)