Diurnal species

Humans are a diurnal species, which means that we are active in the day and asleep at night. Indeed, day-... 

If the model for the oscillator is correct. Per and Cry expression will define solar/ circadian time, driving the activity—rest cycle rather than just being a passive reflection of the activity cycle. Therefore, their expression patterns should exhibit the same phase in the SCN of nocturnal and diurnal species. This is confirmed by examination of Per expression in the SCN of the diurnally active ground squirrel, Spermophilus (Mrosovsky et al 2001). The rhythm of Per1 and Per2 expression in... 

Table 2. Typical Average Diurnal Concentrations of Molecular Species in Nonpolluted Ambient Air ...

Additional information on essential oil variation in C. monspeliensis comes from a study by Angelopoulou et al. (2002) who were interested in diurnal and seasonal patterns. Significant differences were noted during both time periods. It would be of interest to learn what effects cultivation in a common garden enviromnent would have on oil expression in these species. 

It is most probable that sleep and waking stem from an inherent cycle of neuronal activity that can be influenced dramatically by changes in sensory stimulation. This is demonstrable not only in humans and laboratory animals, but also in invertebrates. Thus, while we cannot be sure that other animals sleep in the same way that we do, they do show a circadian cycle of motor activity. In some (nocturnal) species, such as the rat, this activity is actually highest during darkness. Even aplysia, the sea hare, has such a rhythm but this is more like that of humans in being maximally active during daylight (diurnal). 

Pollen allelopathy can find utilization in field cultivations that could contain pollen of allelopathic crops or weeds. Pollen allelopathy could be an effective method for annual weed control that reproduce, at least in part, via wind pollination and flower concurrently with the allelopathic species. The effects of allelopathy should result in the loss of genetic variation and so in reduction of reproductive ability, but some plants are probably able to detoxify the pollen allelochemicals (Murphy and Aarssen 1995a, b). Murphy and Aarssen (1989) suggested possible delaying of weed flowering at later, less favorable times of the season or diurnal period, so decrease in weed pressure. However, infestation by perennial weeds can worsen due to compensation of pollen allelopathy through increase in the formation of rhizomes. 

Figure 3.2 Diurnal changes in pH and concentrations of carbonate species in the flood-water in a ricefield (Mikkelsen et al., 1978). Reproduced by permission of Soil Sci. Soc. Am.

Figure 3.3 Calculated diurnal changes in the pH and concentrations of carbonate species in ricefield floodwater for sinusoidally varying [H2CO3 ] with (a) [Aik] = lOmM, (b) [Aik] = 0.5 mM. The free CO2 concentrations are in mgL to be consistent with Figure 3.2...

The vapor pressure of volatile compounds, measured in atmospheres (or millimeters of mercury), varies with temperature. For example, the vapor pressure of acetone increases from 200 to 400 mmHg with a temperature rise from +20 to +40 °C, and that of w-heptane from 100 to 400 mmHg with a temperature change from +40 to +80 °C (e.g. Adams et ah, 1970). The half-lives of several acetates decreased by two- to fourfold when the temperature was raised from 20 to 30 °C (McDonough etal., 1989). In temperate latitudes, temperatures can vary from about 40 to 0 °C within 24 hours. Therefore, it is important to know the vapor pressure of a given compound for the ambient temperatures under which a particular animal species operates. Diurnal and nocturnal animals may have selected different signal compounds (or mixtures). Do polar and tropical species differ in their choice of compounds for communication. Have cold-climate... 

France raptors liver Diurnal, 11 species Nocturnal, 5 species Lead-contaminated... 

As you can see, the amount of sleep a particular species needs is not directly proportional to obvious things like its size, number of legs, or whether or not it is nocturnal or diurnal. So, why does a bat need 20 hours of sleep while a giraffe only 2 Your guess is as good as any. 

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