Why is climate change, in it's beginning stages, a positive feedback loop? Why will it one day become a negative feedback loop?
Climate change is presently a positive feedback loop due to it's tendency to speed itself up. For example, polar ice caps reflect large amounts of solar radiation due to them being white - a characteristic known as albedo. However, as they melt, less solar radiation is reflected, causing an increase in the rate of global warming. However, once humans are no longer able to survive on the Earth and must either migrate or perish, the decreased output of carbon dioxide an opportunity for ecosystem growth will revitalize the planet and bring it's temperature's back to a sustainable form.
What type of vertical gene transfer might occur if a bacterium was infected by a lytic virus?
If the bacterium's own DNA was encapsulated by the forming viral capsules, generalized (and possibly specialized) transduction may occur. Transduction is the movement of genetic material between two bacteria cells as a result of viral infection, incorrect viral replication, then re-infection of a new bacterium by the incorrectly formed virus.
When trying to test two populations' similarities in categorical response to a survey or treatment, which type of statistical test would be most appropriate?
A chi square test for homogeneity would be appropriate, as the chi square test for homogeneity allows a statistician to discern the statistically significant differences in the categorical variables between two populations.