On the islands of the Galapagos lives a group of birds called finches. There are 13 species in this group. These species have diverse ecologies--some eat seeds, some eat insects, some eat fruit, and some even eat cactus. Although the bodies of these species look fairly similar, their beaks are very different. That is because it is their beak that is adapted to these diverse ways of feeding (Figure 8.14).
The lining of the back of eye containing two types of photoreceptor cells - rods - sensitive to dim light and black and white - and cones - sensitive to colour. A small area called the fovea in the middle of the retina has many more cones than rods.
There are three types of survivorship curves. Type I curves depict individuals that have a high probability of surviving to adulthood. Type II curves depict individuals whose chance of survival is independent of age. Type III curves depict individuals that mostly die in the early stages of their life.