General Biology II

1
General Biology II

• Discussion Session 10

2
Body temperatures

• Cold-blooded
• V.
• Warm-blooded

3
Body temperatures

• Ectothermic
• Heterothermic
• v.
• Endothermic
• Homeothermic

4
Life as an ectotherm
5
Dermal chromatophore unit
Xanthophore
Iridophore with guanine crystals
Melanophore
6
Temperature regulation
7
Variation in termperatures

• Heterothermic ectotherm
• Typical reptile
• v.
• Homeothermic ectotherm
• Large animals that live in stable temperature
  environments

8
Variation in termperatures

• Homeothermic endotherm
• Typical bird or mammal
• v.
• Heterothermic endotherm
• Species that exhibit torpor or hibernation

9
Heterothermic endotherms
10
Heterothermic endotherms
During active flight and feeding, hummingbirds
can have a heart rate of 500 beats per minute.
During overnight torpor, that can drop to 50 bpm.
11
Heterothermic endotherms