The term sperm competition can be used in two ways.

In the broad sense, it involves a large range of morphological, behavioural and physiological attributes, including courtship and copulation behavior (for example, a male that guards females to ensure that he’s the father).  

In the narrow sense, which is the focus of this article, sperm competition is used to denote the physiological processes occurring inside the female’s genital organs after multiple matings.

(For a brief review on the complexity of sperm selection, see Wigby and Chapman, 2004).

The world is changing. Climate change, deforestation, and much more, are all having an impact on our litlle planet. A question that follows this statement quite naturally, is 'Will the earth's organisms be able to adapt to the changing circumstances?'

Well, probably, some will, given enough time. But that might be a problem.

The world is changing fast. So the question should really be 'Will the earth's organisms be able to adapt to the changing circumstances fast enough?' 

By using two types of nanoparticles, drug delivery to tumors could be increased significantly. At the moment, several drug-delivering nanoparticles are already being used in clinical trials to combat tumors. A team at MIT decided to use two distinct particles, each with its own job, one to locate the tumor, and another one to deliver the drugs, all the while making use of the body’s own blood clotting system.

Climate change is very complex, and, consequentially, models predicting it need to take into account many different aspects, from wind patterns to plant and algal growth. One of the expected consequences of the changing climate is that some regions will be drier, while others will be subjected to higher rates of precipitation, which, up in the north, means more snow.