Adaptations

[|bird beaks]

[|adaptations]

[|This is an incredible adaptations webquest!!!]

A. An adaptation is an __INHERITED__ characteristic or set of characteristics which improves the chances of survival of an organism. A complex adaptation evolves over a long period of time. Some inherited characteristics have no apparent adaptive value. Examples of adaptations: [| desert animals] [|desert plants] [|arctic animals] [|arctic plants] [|bird beaks] [|land plants vs aquatic plants] [|prairie plants] [|epiphytes] B. Types of adaptations: 1. **__Morphological__**- those which involve the structures of organisms, or their anatomy. (Most obvious form). (examples: structures of human foot, beaks of birds or hooves of horses). Morphological adaptations are important in food-getting. 2. **__Physiological__**- those which involve the various physical and chemical needs of organisms, including biochemical characteristics. (examples: various enzymes needed for digestion, clotting of blood or muscular contraction). 3. **__Behavioral__**- those which involve reactions to the environment. (example: migration of birds, courtship behaviors, hiding and storing nuts by squirrels, and tracking abilities of hunting dogs.) C. Any one adaptation depends upon all other adaptations. The behavioral adaptation of bird migration, for example, not only depends upon nervous coordination, but also upon morphological adaptations such as feathers, lightweight bones, and strong muscles.
 * ADAPTATIONS**

D. Adaptations involving deception and camouflage are widespread in nature: 1. **__Camouflage__**- a kind of "disguise" to blend with the environment. a. **__cryptic coloration__**- when the organism's color matches the color of his environment. This enables the organism to hide in his environment. An example of this is the peppered moth, which can be either black or white. The white moth matches the bark of the tree, whereas, the black moth matches the bark of the tree when it is covered with soot from industrial pollution. Another example is the stripes on tigers which break up the general body outline of the animal when he is amongst the weeds so that another animal may not see the tiger approaching. [|katydid] b. **__shape__**- Some animals "hide" by means of their shape. For example, many insects resemble the twigs of plants; pipefishes can resemble the algae among which they live by swimming in an upright position. [|walking stick;] [|noctuid caterpillar;] c. **__mimicry__**- In nature, sometimes a tasty organism has a color pattern similar to that of a distasteful organism. The origin of a mimic's coloration pattern is genetic. By random chance, variations occur which cause one group of organisms (the mimics) to resemble another group (the models). Those organisms which possess the variation are less likely to be eaten. Therefore, they will survive to reproduce offspring with the same variation. Eventually, through continued change and natural selection, the mimic gains a close resemblance to the model. Furthermore, mimicry does not have to be total mimicry. Any little change which improves the chances of survival and reproduction can be selected by natural selection. An example of this is the robber fly, who is the mimic of the bumblebee. The two nsects are not closely related, but their similarity in coloration deceives possible predators. Consequently, predators gnore the mimic just as they do the model. Note: Below, the Monarch butterfly (model) is on the left, and the Viceroy (mimic) is on the right. 2. **__Warning coloration__**- This involves a display of bright colors and patterns. These color patterns announce rather than conceal the presence of animals. For example, the yellow and black stripes of a bumblebee are recognizable to possible predators. See examples below: E. **__Industrial Melanism__**, otherwise known as the Evolution of the Peppered Moth. Evolution and adaptation do not always require extremely long periods of time. In England a rapid evolution of the peppered moth has been occurring for the last 100 years. In the middle of the nineteenth century almost all of the peppered moths in England were light in color. Black moths possessing a pigment called melanin were rare. Originally the tree trunks were very light in color. As a result, the moths blended with their environment. Birds which fed upon peppered moths had difficulty locating light-colored moths. However, dark moths were easily seen. As the industrialization in England increased, the tree trunks became covered with soot and smoke. Eventually they turned black. Then the mutant, black forms of the peppered moth, had a distinct advantage. When the black moths rested on the soot covered tree trunks they were invisible to the birds. Light-colored moths, however, became easy prey. During the last 100 years, the gene pool has evolved to such an extent that over 90% of the peppered moths are black. This particular phenomenon is called industrial melanism.

This story of industrial melanism is important for two reasons: A. It shows that evolution is truly an interaction of organism and environment. B. It points out that evolution and natural selection operate on the basis of genetic change within a population.