Homeostasis Flashcards
What is Shelford’s Law of Intelligence?
For an organism to succeed in a given environment, each of a complex set of conditions must remain within the tolerance of that organism or it will fail to thrive
What are Endotherms?
they are able to generate enough heat to elevate their own temperature to a high an stable level
e.g. birds and mammals
Explain thermal radiation
energy travels from place to place via electromagnetic waves.
What is convection?
the flow of heat by the mass movement of an intervening fluid
Explain conduction
the direct flow of heat between bodies in contact
What is an Ectotherm?
the heat is conducted away as fast as it is produced, and many behaviorally select areas of more favorable temperature,
e.g. basking in the sun or staying in the shade
Why is temperature regulation important?
biochemical activities are sensitive to temperature because enzyme have an optimum temperature so cold temperatures wouldn’t allow the reaction to be fast enough to maintain activity and reproduction in the organism but too high a temperature and the enzyme could become denatured or destroyed.
What is the definition of Homeostasis?
relative constancy of the internal fluid environment
Name the two most common regulatory systems and how they regulate
- The nervous system regulates by sending nerve impulses.
2. The endocrine system does it by secreting hormones.
What is a negative feedback system?
It reverses a change in a controlled condition
e.g. the sequence of events ends with the negation of the original stimulus.
Explain how ADH increases renal tubular absorption of water.
water deprivation increases osmolarityof the plasma which activates hypothalmic osmoreceptors to release ADH. This causes an increase in membrane permeability to water which permits back diffusion of solute free water, resulting in more concentrated urine.
What is the connection between ADH and blood pressure?
When blood volume pressure decreases, ADH secretion is stimulated.
What is hypovolemia?
an abnormal decrease in the volume of blood plasma
If an organism (e.g. salmon) migrates from sea to spawn in freshwater, what are they called?
anadromous
What is the difference between hypotonic and hypertonic osmoregulators?
Hypotonic - need to obtain/retain water
Hypertonic - need to excrete excess water
