Hypertonic- the water moves out of the cell
Hypotonic- the water moves into the cell
Isotonic- no water movement
Answer:
Which type of selection tends to increase genetic variation? A. Disruptive selection B. Directional selection C. Stabilizing selection
The Answer is option A (Disruptive selection)
Explanation:
Selection can either shift the mean value of a trait, reduce the trait's variation, or increase its variation.
Genetic variation which allows natural selection to increase or decrease frequency of alleles already in the population is a source of phenotypic variation as it refers to differences in all the hereditary information of members of the same species.
Disruptive Selection is important in maintaining variation and initiating speciation as it Increases Variation by favoring alleles corresponding to more extreme phenotypes. But for it to occur, the mean phenotype has to experience the lowest fitness. Disruptive selection affects the frequency distributions of alleles and genotypes within a population.
Disruptive selection is based on the variance of a trait in a population as it increases genetic variance by equalizing the frequencies of existing alleles at polymorphic loci (a genetic loci with two or more alleles). Disruptive selection maintains and may even increase variation in natural populations by favoring extreme phenotypes, individuals with extreme values for a trait have greater reproductive success than individuals with intermediate values.
As most microbes reproduce asexually, "species" are defined by differences in their DNA sequences. when the genome of soil microbe a is analyzed, long stretches of genes from multiple species of other soil microbial species are discovered. This indicates that the microbes present in the soil underwent transformation and transfection. Transformation, shown in the image, is the process of the prokaryotic nucleus taking up the foreign DNA from other microbes present in the environment. Tranfection is like transformation but for the eukaryotic cells.
In the lytic cycle, a virus that has invaded and entered a cell takes over the cell's replication mechanism. The virus makes viral DNA and viral proteins.
The virus then lyses (breaks open) the cell membrane, allowing the newly produced viruses to leave the now disintergrated host cell to infect other new cells.
The lytic cycle is considered the main method of viral replication. It is even more common than the lysogenic cycle. It has helped scientists understand better how the immune system responds to pathogens.
