The most plausible hypothesis is: Tropical regions generally have more available water and higher levels of solar radiation. They also have very high rates of immigration and very low rates of extinction.
explanation:
Water is essential for an abundance of life, and sunlight is the means by which the whole food chain receives energy. Plants convert the sunlight into food, herbivores eat them, and other animals eat herbivores.
Hope this helps, and muchas luck on your biology.
Answer:
Selection is a directional process that leads to an increase or a decrease in the frequency of genes or genotypes. Selection is the process that increases the frequencies of plant resistance alleles in natural ecosystems through coevolution, and it is the process that increases the frequencies of virulence alleles in agricultural ecosystems during boom and bust cycles.
Selection occurs in response to a specific environmental factor. It is a central topic of population and evolutionary biology. The consequence of natural selection on the genetic structure and evolution of organisms is complicated. Natural selection can decrease the genetic variation in populations of organisms by selecting for or against a specific gene or gene combination (leading to directional selection). It can increase the genetic variation in populations by selecting for or against several genes or gene combinations (leading to disruptive selection or balancing selection). Natural selection might lead to speciation through the accumulation of adaptive genetic differences among reproductively isolated populations. Selection can also prevent speciation by homogenizing the population genetic structure across all locations.
Selection in plant pathology is mainly considered in the framework of gene-for-gene coevolution. Plant pathologists often think in terms of Van der Plank and his concept of "stabilizing selection" that would operate against pathogen strains with unnecessary virulence. As we will see shortly, Van der Plank used the wrong term, as he was actually referring to directional selection against unneeded virulence alleles.
Answer:
Four conditions are needed for natural selection to occur: reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population.
Answer/Explanation:
In humans, we breathe in oxygen via the respiratory system. The oxygen enters the lungs. The air sacs in the lungs - the alveoli - are the site of gas exchange in the lungs and are where the circulatory and respiratory systems interact.
The alveoli take in the oxygen, where it diffuses into the capillaries (circulatory system). Blood, which passes through the capillaries takes this oxygen to all the cells in the body. Oxygen binds to haemoglobin in red blood cells, which transport it around the body.
Additionally, blood also transports carbon dioxide back to the alveoli of the lungs, where it diffuses into the lungs and is expelled when we breathe out
