Answer:
Date and latitude interact to determine photoperiod, the daily period of daylight. This interaction has important implications for latitudinal migrants for whom daylight may be a resource or for whom photoperiod regulates annual transitions in life‐history stages (i.e. birds).
Using an established formula, we developed user‐interactive, animated models that enable the visualization of how latitude and date determine photoperiod for latitudinal migrants. We also calculated the photoperiodic schedules for a broad range of hypothetical migratory programmes and real migratory programmes newly available through the proliferation of citizen‐science data. This enabled us to infer the limitations some migratory programmes place on mechanisms for photoperiodic regulation of annual breeding.
In the vast majority of cases, the act of migrating elevates annual daylight exposure. This raises the hypothesis that daylight availability selects for latitudinal migration, potentially contributing to its evolution in animals such as diurnal birds with limited time during the spring and summer to feed young. However, photoperiodic mechanisms regulating annual cycles could constrain the evolution of such migrations, depending on how they affect photoperiodic schedules. Most migratory programmes are consistent with known mechanisms of avian photoperiodism, but the range of feasible mechanisms declines for transequatorial migrants, which experience semi‐annual, 180°‐phase‐shifts in their photoperiodic cycles.
Understanding photoperiodic constraints on migration are particularly important in this age of changing latitudinal distributions and phenologies driven by climate change.
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<span>proton gradient</span> establishment
Chemiosmosis is the process that allows the diffusion of a
molecule or an atom through the membrane. Also, it is the movement of ions
across semipermeable membrane down their electrochemical gradients. In chloroplast,
chemiosmotic coupling is an important factor in ATP production through proton
gradient establishment.
Chromosomes have hereditary function that are capable of self-duplication and they have thread-like structures seen inside the nucleus of plant and animal. In plants, they go through a cycle called alteration of generation that has multicellular stages. One is sporophyte that is a diploid, and the other is gametophyte with a haploid.
Moreover, spores are produce through meiosis so it go through a process of chromosome reduction in order to create a haploid spores. While, gametes undergo mitosis and the structure is already a haploid, which means that the number of chromosomes will not change in order to produce haploid. In this case, the plant have both spores and gametes and the similarities is that, they are both singles celled and a haploid. Therefore, the number of the chromosome in the gametophyte generation is also 32.
Answer:
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