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.
The dermal tissue system protects the soft tissues of plants and handles interactions with the plants' surroundings. The epidermis is a dermal tissue that is usually a single layer of cells comprising the younger parts of a plant. It conceals a waxy layer named the cuticle that inhibits water loss. Plant parts that become woody no longer have dermal tissue as their outer layer because it is followed by periderm or cork. Just as our own covering assists to defend our bodies, the dermal layer of a plant has the same function.
b, this is because a consumer, is something that consumes something, and the clam consumes the energy and nutrients when it filters the particles in from the water. Because it consumes these, it is a consumer for that reason. So, the answer is b. Hope this helps!!!
An amino acid is an organic molecule that is made up of a basic amino group (−NH2), an acidic carboxyl group (−COOH), and an organic R group (or side chain) that is unique to each amino acid.
