What is Sampling in Archaeology

What is Sampling in Archaeology Sampling is the practical, ethical method of dealing with large amounts of data to be investigated. In archaeology, it is not always prudent or possible to excavate all of a particular site  or survey all of a particular area. Excavating a site is expensive and labor-intensive and it is a rare archaeological budget that allows that. Secondly, under most circumstances, it is considered ethical to leave a portion of a site or deposit unexcavated, assuming that improved research techniques will be invented in the future. In those cases, the archaeologist must design an excavation or survey sampling strategy that will obtain enough information to allow reasonable interpretations of a site or area, while avoiding complete excavation. Scientific sampling needs to carefully consider how to obtain a thorough, objective sample that will represent the entire site or area. To do that, you need your sample to be both representative and random. Representative sampling requires that you first assemble a description of all the pieces of the puzzle that you expect to examine, and then select a subset of each of those pieces to study. For example, if you plan to survey a particular valley, you might first plot out all the kinds of physical locations that occur in the valley (floodplain, upland, terrace, etc.) and then plan to survey the same acreage in each location type, or the same percentage of area in each location type. Random sampling is also an important component: you need to understand all parts of a site or deposit, not just the ones where you might find the most intact or the most artifact-rich areas. Archaeologists often use a random number generator to select areas to study without bias. Sources See the Sampling in Archaeology Bibliography.

The Basics of Mammalian Temperature Regulation

The Basics of Mammalian Temperature Regulation Do you find it surprising that reindeer, which spend much of their time standing in snow, dont get cold feet? Or that dolphins, whose thin flippers are gliding constantly through cool water, still manage to pursue very active lifestyles? A special circulatory adaptation known as countercurrent heat exchange enables both of these animals to maintain the appropriate body temperature in their extremities, and this is only one of the many clever adaptations mammals have evolved over the last hundred million years to help them to deal with variable temperatures. Mammals Are Endothermic All mammals are endothermic- that is, they maintain and regulate their own body temperature, no matter the external conditions. (Cold-blooded vertebrates, like snakes and turtles, are ectothermic.) Living in widespread environments around the world, mammals face daily and seasonal fluctuations in temperatures and some- for example, those indigenous to harsh arctic or tropical habitats- have to deal with extreme cold or heat. To maintain their correct internal body temperature, mammals must have a way to produce and conserve body heat in colder temperatures, as well as dissipate excess body heat in warmer temperatures. The mechanisms mammals have for producing heat include cellular metabolism, circulatory adaptations,  and plain, old-fashioned shivering. Cellular metabolism is the chemical process that constantly occurs within cells, by which organic molecules are broken down and harvested for their internal energy; this process releases heat and warms the body. Circulatory adaptations, such as the countercurrent heat exchange mentioned above, transfer heat from the core of the animals body (its heart and lungs) to its periphery via specially designed networks of blood vessels. Shivering, which youve probably done some of yourself, is easiest to explain: this crude process generates heat by the rapid contraction and shaking of muscles.   If An Animal Gets Too Warm What if an animal is too warm, rather than too cold? In temperate and tropical climates, excess body heat can accumulate quickly and cause life-threatening problems. One of natures solutions is to place blood circulation very near the surface of the skin, which helps to release heat into the environment. Another is the moisture produced by sweat glands or respiratory surfaces, which evaporates in comparatively dryer air and cools the animal down. Unfortunately, evaporative cooling is less effective in dry climates, where water is rare and water loss can be a real problem. In such situations, mammals, like reptiles, often seek protection from the sun during the hotter daylight hours and resume their activity at night. The evolution of warm-blooded metabolisms in mammals wasnt a straightforward affair, as witness the fact that many dinosaurs were apparently warm-blooded, some contemporary mammals (including a species of goat) actually have something akin to cold-blooded metabolisms, and even one type of fish generates its own internal body heat.