Early mammals and ectothermy Flashcards
What are the advantages confered by an hard and soft palate?
Mammals could breath while chewing sucking milks and this indicates higher metabolic rates.
What are the characteristics of cynodont?
You have complete loss of lumbar ribs which result in increase in flexibility and is associated with the evolution of diagphram.
What are the features that distinguish mammalian from early mammals?
-Hairs on skin -Mammary glands
What are the three main sets of mammals?
-Monotremes (Prototheria) -Marsupial and Placental (Theria)
Describe the features of placental mammals:
-Locomotions doesn’t affect the lungs -They have less kinetic skulls but they have articulated jaws.
What is homeothermy?
Animals that are capable of maintaining constant body temperature
What is poikilothermic?
Animals whose internal temperature varies considerably
What are ectotherms?
Animals whose body temperature is determined by the environment, heat is conducted aways as fast as it’s produced.
What are endotherms?
Animals whose source of body heat is internal and produced through metabolism.
Describe thermoregulations in tuna and sharks:
They have retia, which are heated up by muscles in which they are embedded. Heat moves from warm blood to cold blood vessels.
Describe cuntercurrent heat exchange:
Heat is exchanged between hot and cold blood running in opposite direction.
Describe the two main reasons why gigantothermic is an effective way of thermoregulation:
-Bigger animals have a smaller surface to volume ratio, thus less heat is exchanged with the sorroundings. -Small sizes animals require a lot of energy to maintain their body heat per gram.
What are the three different types of endotherm based on their body temperature?
-Basoendotherm (30°C) -Mesoendotherm (35-38°C) -Supraendotherm
What are the two theories accounting for the evolutionary origin of endothermy?
1) It was a byproduct of high metabolic rates of aerobic animals. 2) It was a byproduct of the excessing production of material for feeding the youngs.
Describe the two ways of negative feedback that regulate body temperature?
Sensors on the skin feel the temperature of the environment and they send information to the hypothalamus that sense and regulate the blood temperature.
