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:
The most closely related are amphibians and reptiles.
The least related are amphibians and mammals
Explanation:
Amphibians broke off from reptiles, birds, and mammals around 260 millions years ago and next up are the reptiles which broke off around 225 million years ago. So they are the most closely related
Mammals are the last to break off, around 200 million years ago. So they are the least related to amphibians.
Answer:
there is a good and bad effect on the world, the positive reason being economically. smoking is a great money maker it was worth US$88 billion dollars in 2018. the negative reason is the pollution and what it does to the human body such as cancer
Explanation:
West Coast water temperatures are much lower than those along the East Coast. ... This means Atlantic waters travel to the U.S. East Coast from the south and are relatively warm compared with West Coast Pacific waters that arrive from the north out of the chilly Gulf of Alaska.
The air above the cold Benguela current and upwelling region along the west coast is relatively dry and cold, contributing to the dry climate of the west coast. Moist air from the warm Indian Ocean and Agulhas Current is frequently transported into eastern South Africa by easterly winds.
Explanation:
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