Thermoregulation in vertebrates presentation

Thermoregulation in vertebrates

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THERMOREGULATION IN
VERTEBRATES
Name : Rounak Mukherjee
Subject : Zoology
Semester : 3
Reg.No: 20103003209
Session :
BIDHAN CHANDRA COLLEGE

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•Animals divided into two main
categories:
Pikilotherms:(cold blooded)
change their body temp.
According to environment e.g. fishes , amphibians
and reptiles.
Homeotherms: (warm blooded) maintain
their body temp. e.g. birds and mammals .

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MODERN CLASSIFICATION OF ANIMALS
▪Ectotherms: take heat from outside e.g.fish
amphibians and reptiles also invertebrates
▪Endotherms: take heat from inside e.g.
mammals birds and fishes .
▪Heterotherms: Take heat from inside but
change body temp. e.g. bird, humming bird

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▪Cold blooded but ectotherms as well .
▪Core body temp. close to environment.
▪2 types of thermoregulation.
a)Behavioral thermoregulation.
b)Physiological thermoregulation.
BEHAVIORAL THERMOREGULATION
➢Occurs when it seeks out areas of water with higher or lower temp.
➢Move from surface to downward or reverse . E.g., Juveniles of the bear lake sculpin
lives in bottom(5°c in day time ) eat food and move to the surface at night (14°c) to
digest their stored food.

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B. PHYSIOLOGICAL THERMOREGULATION
➢Occurs in only a few species,all of which are marine and swim
constantly
➢Controls its core body temp. by means of internal physiological and
metabolic activities
➢Network of blood capillaries (rete mirabile ) b/w swimming red
muscles, act as heat exchanger.
➢Heat from muscle transported to blood .
➢Oxygen-depleted blood is sent to gills .

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THERMOREGULATION IN AMPHIBIANS
➢Are ectotherms
➢Face daily and seasonal changes
➢Produce little heat from metabolism and lose it rapidly.
➢Show behavioral adaptation
➢Have moist skin which helps in evaporative cooling in warm temp.
➢To get moist ,live in shady areas mostly .

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THERMOREGULATION IN REPTILES
➢Have dry skin , reduce water loss
➢Have extensible rib cage,provides efficient ventilation.
➢Conserve body heat into the center of body
➢Increase heat production in response to hormones thyroxin and
epinephrine.
➢Tortoises and land turtles can cool themselves through salivating
and frothing at the mouth.

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THERMOREGULATION IN BIRDS
➢Are endothermic .
➢Regulate their body temp.
➢Don’t have sweat gland lose heat from gular pouches present in throat .
➢Their fluttering increase evaporation from respiratory system
➢In some spp., feathers provide insulation.
➢Downy type feather trap air next to body to prevent body heat loss.
➢Aquatic species have “rete mirabile” process in their legs and feet.

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THERMOREGULATION IN MAMMALS
➢Mammals in cooler regions have exchange vessels in their
ears,nose,legs and tails .
➢In warmer regions,get rid of heat by sweating .
➢In aquatic climates thick layer of insulating fat “Blubber”.

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Heat production in Birdsand Mammals
▪Can generate heat by
1.Muscle contraction
2.ATPase pump enzymes
3.Oxidation of fatty acids in brown fats
4.Basal metabolic rate.