In ecology, a disturbance is a temporary change in environmental conditions that causes a pronounced change in an ecosystem.
Disturbances often act quickly and with great effect, to alter the physical structure or arrangement of biotic and abiotic elements.
Disturbance can also occur over a long period of time and can impact the biodiversity within an ecosystem.
Major ecological disturbances may include fires, flooding, storms, insect outbreaks and trampling.
Earthquakes, various types of volcanic eruptions, tsunami, firestorms, impact events, climate change, and the devastating effects of human impact on the environment (anthropogenic disturbances) such as clearcutting, forest clearing and the introduction of invasive species can be considered major disturbances.
Not only invasive species can have a profound effect on an ecosystem, but also naturally occurring species can cause disturbance by their behavior.
Disturbance forces can have profound immediate effects on ecosystems and can, accordingly, greatly alter the natural community. Because of these and the impacts on populations, disturbance determines the future shifts in dominance, various species successively becoming dominant as their life history characteristics, and associated life-forms, are exhibited over time.
Answer:
e. PhoU keeps PhoR bound to the phosphate transporter protein Pst
Explanation:
PhoU is a membrane protein known to regulate the transport of phosphate (Pi) between cellular compartments. It has been discovered that mutations in this protein cause lethality because the cell becomes incapable of controlling the intracellular levels of Pi, this being toxic for the cell. PhoR is a histidine kinase/phosphatase. When the Pi level is considered to be a limiting factor, PhoR autophosphorylates at a histidine residue and then donates its phosphoryl group to PhoB. On the other hand, when the Pi level is high, this protein removes the phosphoryl group from phospho-PhoB. Finally, the Pst is a signal transduction protein that acts as a transporter capable of switching its conformation during the transport of PI.
A. True, a galvanometer is a device used to measure electrical currents
