These fluctuations may also affect the predators that feed on these prey items, such as wolves, foxes and owls. These predators must either find an alternate source of prey or risk starvation and death. Ecological Succession. When changes to either abiotic or biotic factors affect an entire ecosystem, ecological succession occurs.
A temporary decrease in blood flow to the brain results in unconsciousness, or fainting. Many disorders, some of them serious, can cause this.
Not that any of you have this, but I have fainting spells and occasionally black-out or near fainting spells, and the most likely suspects for me are POTS (postural orthostatic tachycardia syndrome) and/or neurocardiogenic syncope (NCS, also know as neurally mediated hypotension or vaso vagal syncope).