Answer:
A species of lizard is found on the eastern and western sides of part of a mountain range. On both sides, individual populations are small. On the western side, individual populations are relatively close together and males move extensively among populations to breed. On the eastern side, however, populations are farther apart and males seldom move among more than one or two adjacent populations to breed. If you were to study the genetic diversity of western and eastern populations, which pattern would you expect to find?
Each western population would be genetically diverse, although the allele frequencies might differ from one population to the next. Eastern populations would be less diverse, and some populations will have only a limited number of the total alleles available in the species.
Explanation:
Renal autoregulation is the ability of the kidneys to maintain a relatively constant GFR or glomerulofiltration rate despite fluctuating blood pressure. Autoregulation is a remarkable property of multiunit smooth muscles of small arteries and arterioles to respond to changes in internal and external pressure. The blood vessels in the human body react by contracting whenever the blood pressure is elevated and by expanding when the blood pressure is reduced. On the other hand, if there is an elevation or reduction of the external interstitial pressure, it results in dilation and contraction, respectively. The lowest autoregulating pressure is about 60 mmHg. By a further reduction in perfusion pressure, RBF is sharply reduced.
Kidneys are the important organs of the excretory system involved in the removing of nitrogenous wastes from the body. Apart from this, they are involved in maintaining the acid-base balance, electrolytes and thus contibuting in homeostatis of the body.
The structural and functional unit of a kidney is called a nephron. Glomeruli of the nephrons are involved in the process of filtering the waste products and excess of fluids from the blood. This process is called the glomerular filtration. GFR or the glomerular filtration rate is the rate at which the fluids are filtered from the glomerulus of the nephron. A constant GFR is very essential for the healthy functioning of kidneys. Any change in the arterial pressure can injury the nephrons of the kidney. Hence a constant GFR despite of changes in the blood pressure is maintained by a process called the renal autoregulation.
Renal autoregulation together with the tubuloglomerular feedback help in maintaining a constant GFR inspite of changes in the sodium chloride levels in the urinary filtrate. An elevated level of sodium, results in constriction of the afferent arteriole, decreasing renin secretion and thus, lowering the GRF. Any decrease in sodium levels stimulates more renin production, constricts the efferent arteriole and increases the GRF.
Thus, renal autoregulation is the ability of the kidneys to maintain a constant GRF rate despite changes in the blood pressure.
Answer:
Adaptive radiation occurs within a single lineage
Explanation:
Adaptive radiation generally occurs when an organism enters a new area and different traits affect its survival. An adaptive radiation is a burst of evolution, creating several new species out of a single parent species, which simply means that adaptive radiation occurs when a single lineage produces many descendant species. Adaptive radiation is considered to be a rapid process, where adaptation from a recent common ancestor takes place in a short period of time (with respect to geological time, of course).
Adaptive Radiation refers to the process causing a rapid rate of speciation, within a single lineage, particularly when a single species invades various diverse environments. This process leads to multiple new species evolving from a single ancestral species. An established example illustrating this concept is Darwin's study of finches on the Galapagos Islands.
The correct statement about adaptive radiation is that it occurs within a single lineage. Adaptive radiation is a process that prompt multiple speciation events in a relatively short time, particularly when a single species invades different and diverse environments. Each of these invasions results in adaptational and evolutionary changes, leading to multiple new species originating from a single ancestral species.
For instance, Charles Darwin's study of finches on the Galapagos Islands is a classic example of adaptive radiation. The different beak shapes evolved over time in response to the different food sources available on the separate islands within the archipelago.