Hear the different songs of three lacewing flies in this interactive activity. These songs are an example of a reproductive barrier that can lead to speciation; the differences among the songs determine mate choice and result in reproductive isolation between the different populations.Also included is a table summarizing the different kinds of isolating mechanisms.ear the different songs of three lacewing flies in this interactive activity. These songs are an example of a reproductive barrier that can lead to speciation; the differences among the songs determine mate choice and result in reproductive isolation between the different populations.
Sometimes, a black eye can occur after cosmetic surgery to the face, such as a facelift or a nose operation. The area around the eye turns bluish or purple because tiny blood vessels under the skin burst and blood leaks out into surrounding soft tissue.
Pupil. The visible black center of the eye is the pupil. The pupil works like the aperture or opening of a camera to regulate the amount of light entering the eye. In bright light, the pupil closes down to limit how much light comes into the eye. In dim light the pupil opens up and becomes visibly larger. This allows the eye to receive more light.