W6: Vertebrate Physiology (Homeostasis & Phenotypic Plasticity) [Dr. Matt] Flashcards
Responses of animals to environmental changes: what are the changes that animals would need to respond to? (3)
- Acute (short-term) changes in individuals.
- Chronic (long-term) changes in individuals.
- Evolutionary changes in population traits via NS.
Response of animals to acute changes?
Homeostasis.
Response of animals to chronic changes?
Phenotypic plasticity.
Responses of animals to evolutionary changes?
Genetic adaptation (over generations).
Homeostasis?
= processes to maintain fairly stable conditions in the body.
Phenotypic plasticity?
= the ability of a genotype to produce multiple phenotypes.
Egs of Phenotypic plasticity? (2)
- Acclimatisation.
- Acclimation.
Strategies of responding to the external environment? (3)
- Regulation.
- Conformity.
- Mixed conformity & regulation.
Regulation?
= when an animal’s internal environment is held constant when its external environment changes.
Conformity?
= when an animal’s internal environment varies so that it matches the external environment.
Mixed conformity & regulation?
= when an animal’s internal environment either remains constant or varies to match the external environment for different conditions.
Eg of Mixed conformity & regulation?
Salmon.
Explain the Salmon eg? (2)
- These salmon are temperature conformers, as their internal environment matches the temperature of the water that they are in (river or ocean water).
- These salmon are also blood concentration regulators, as their internal environment remains constant irrespective of the salt concentration of the water.
Types of feedback systems? (2)
- Negative feedback.
- Positive feedback.
Negative feedback attributes? (5)
- Regulatory processes that maintain homeostasis.
- Sensors continuously sample controlled variables (eg, temperature, pH).
- Deviations from setpoints stimulate immediate corrective measure.
- Respond using physiological, biochemical, behavioural or other mechanisms.
- Opposes deviation to bring the variable back to the setpoint.
Egs of negative feedback systems? (3)
- Regulation of blood glucose levels.
- Regulation of CO2 levels.
- Regulation to changing temperatures.
Regulation of blood glucose levels? (11)
1) If the blood glucose level rises:
- Beta cells in pancreas secrete insulin into the blood.
- Body cells take up glucose.
- Liver takes up glucose & stores it as glycogen.
- Blood glucose level declines.
- Homeostasis.
2) If the blood glucose level declines:
- Alpha cells in the pancreas secrete glucagon.
- Liver breaks down glucagon & releases glucose.
- Blood glucose level rises.
- Homeostasis.
Regulation of CO2 levels? (11)
- Physical activity increases.
- Cellular respiration increases.
- CO2 production increases.
- Medulla oblongata stimulated.
- Impulses sent to the heart & lungs.
- Heart rate increases.
- Blood with CO2 brought faster to the lungs.
- Breathing rate increases.
- CO2 exhaled more rapidly.
- CO2 level drops.
- Normal CO2 level.
Regulation to changing temperatures? (14)
1) Brain signals to skin via nerves that it’s Too cold (low temperatures):
- Vasoconstriction, shivering & MR rising.
- Response = heat conservation/production.
- Blood temperature rises.
- “Homeostasis”.
2) Brain signals to skin via nerves that it’s Too hot (high temperatures):
- Vasodilation & sweating.
- Response: heat dissipation.
- Blood temperature drops.
- Homeostasis.
Positive feedback attributes? (3)
- Amplifies changes, not stabilises.
- Accelerates processes & initiates changes.
- Less common in homeostasis.