Because of its size and availability, Ascaris (Gr. askaris, intestinal worm) is usually selected as a type for study in zoology, as well as in experimental work. Thus it is probable that parasitologists know more about structure, physiology, and biochemistry of Ascaris than of any other nematode. This genus includes …

The hydrologic cycle, or water cycle, moves water from land and ocean to the atmosphere. Water from the oceans and land surfaces evaporates, changing state from liquid to vapor and entering the atmosphere. Total evaporation is about six times greater over oceans than land because oceans cover most of the …

Blistering summer heat waves can be deadly, with the elderly and the ill at greatest risk. However, in such weather, even healthy young people need to be careful, especially when it is both hot and humid. High humidity slows the evaporation of perspiration from our bodies, reducing its cooling effect. …

Approximately 25,000 species of Nematoda (nem-a-to´da) (Gr., nematos, thread) have been named, but many authorities now prefer Nemata for the name of this phylum. It has been estimated that if all species were known, the number might be nearer 500,000. They live in the sea, in freshwater, and in soil, …

Surface type (urban or rural), elevation, latitude, daily and annual insolation cycles, and location (maritime or continental) all can influence air temperatures. Now let’s put all these factors together and see how they affect world air temperature patterns. First, we need a quick explanation of air temperature maps. Figure shows …

Images of the Earth from space show that about half of our planet is blanketed in clouds. Clouds play a complicated role in temperature—both cooling and warming the Earth and atmosphere. In this chapter, we will look at one of the most familiar roles of clouds: producing precipitation. Clouds are …

In general, the air is cooler at higher altitudes. Most incoming solar radiation passes through the atmosphere and is absorbed by the Earth’s surface. The atmosphere is then warmed at the surface by latent and sensible heat flows. So it makes sense that, in general, air farther from the Earth’s …

On a hot day, rural environments will feel cooler than urban environments. In rural areas, water is taken up by plant roots; it then moves to the leaves and evaporates from leaf pores in a process called transpiration. This process cools leaf surfaces, which in turn cool nearby air. Evaporation …

This chapter focuses on air temperature —that is, the temperature of the air as observed at 1.2 m (4 ft) above the ground surface. Air temperature conditions many aspects of human life, from the clothing we wear to the fuel costs we pay. Air tem-perature and air tempera-ture cycles also …

The colligative effects of solutes in seawater (around 450 mM) depresses sea water freezing point to –1.9°C , while ordinary teleost blood (much more dilute) freezes at –0.4°C. So to avoid the blood and all tissues freezing solid, marine coldwater teleosts produce small anti-freeze proteins in the scales, skin, fins, …