You are watching: Does natural selection act on phenotype or genotype
NATURAL selection acts on one organism"s features (phenotype), not straight on that is alleles (genotype). Natural selection favors a details physical characteristics or behavioral characteristic end another.
The GENE POOL consists of all the gene that are present in a population, consisting of all the various alleles for each gene.
ALLELE FREQUENCY is the variety of times an allele occurs in a gene pool, compared to the total number of alleles in that pool for the very same gene. (Ex: how numerous time red hair allele shows up in gene pool contrasted to all the hair color alleles (red, brown, blond, black)
Evolution, in hereditary terms, involves a readjust in the frequency the alleles in a population over time.
Populations evolve...not individuals. Natural selection operates ~ above individuals, but the transforms it cause in allele frequency show up in the populace as a whole.
Three resources of genetic VARIATION:1) Mutations2) genetic recombination in sexual reproduction3) Lateral gene transfer
MUTATIONS are transforms in the genetic material of a cell. Part mutations space within the gene and others space on the chromosome. Mutations are considered valuable if they aid an organism"s capability to endure or reproduce. Most mutations are neutral--have no influence on survive or reproduction. Mutations matter only if they space passed down from generation to generation--making mutations a resource of hereditary variation.
Most differences are brought about by genetic RECOMBINATIONS during sexual reproduction--not mutations. Chromosomes space recombined during meiosis--including CROSSING-OVER--swapping DNA lengths. These recombinations present variation right into the gene pool.
LATERAL GENE transport is as soon as individual biology swap genes--this is certain popular in single-cell organism (bacteria). These carry leads to genetic variation and often time creates various strands that bacteria, etc.
Why does sexual reproduction provide more opportunities for hereditary variation 보다 asexual reproduction?
In sex-related reproduction, the genetic material of TWO various organisms come with each other to kind a DAUGHTER organism. Two different parent organisms carry out for much more allele choice for the offspring. Additionally, much more mutations and also recombinations can take place on the genes and chromosomes of the offspring. And also lastly, sexual reproduction typically occurs in multi-cellular organisms the have much more genes and also chromosomes to vary than single-cell organisms.
A POLYGENIC characteristics is a trait regulated by 2 or much more genes. Most of these gene have much more than 2 alleles.Example: Height
Because much more polygenic characteristics involve lot of genes and each gene has multiple alleles because that a single trait, climate there is will more comprehensive range the phenotypes--characteristics. Single-gene traits have a narrower range of phenotypes together they have actually fewer alleles come express under traits.
Natural selection on single-gene traits have the right to lead to transforms in allele frequencies and, thus, to changes in phenotype frequencies. If a mutation occurs developing a different color organism than if it help the organism endure or reproduce then the organism will live come reproduce and also pass this mutation on to its offspring.
When properties are managed by an ext than one gene then the results of natural selection are more complex. Natural choice affects the fitness the phenotypes (physical traits) and also causes three types of selection:1) directional selection2) stabilizing selection3) disruptive selection
When individuals at one finish of the spectrum are more fit 보다 others then the phenotype shifts toward the DIRECTION the the more successful offspring that room surviving to reproduce and also pass your traits onto offspring.
When many of the people are fit climate the traits perform not waver to much out native the mass of the group. The phenotypes room STABLE with tiny variation.
When individuals at both external ends that the spectrum room fit climate DISRUPTION occurs and also often times 2 phenotypes will emerge--representing both end of the spectrum.
GENETIC DRIFT is when people carrying a particular allele leave much more descendants 보다 other people leave--just by chance. End time, there are much more of this alleles in the population"s hereditary pool.
The BOTTLENECK effect is a readjust in allele frequency because of dramatic palliation in the size of the population. This bottleneck sharply reduces genetic diversity.
Genetic drift can additionally occur as soon as a brand-new group of people colonize a new community. The little FOUNDING team becomes the entire population. This Founder effect is when allele frequency changes due to the fact that a brand-new group forms.
GENETIC EQUILIBRIUM occurs when a populace is not evolving and the allele frequency in the gene pool does not change.
No. Hypothetically, a population of sexually reproducing organisms could remain in genetic equilibrium.
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This rule states: allele frequencies in a population should remain continuous unless one or more factors reason the frequency to change.