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Genetic drift is the spread of specific random variations throughout the gene pool in the absence of specific selection pressures. There's always random variation in the population, but there aren't always changes in the environment for the population to adapt to. So natural selection, in stead of moving the population towards adaptation, might select from that random variation to move 'sideways', as it were, to a state that's equally well-adapted to the environment as what came before, but different. As random variation may produce many variants that are, more or less, equally well-adapted to their environment, the direction of evolution that results is more or less random.
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What are the potential causes of micro evolution?
Potential causes of microevolution include mutations in DNA, gene flow between populations, genetic drift (random changes in gene frequency), natural selection (favoring certain traits), and changes in environmental conditions. These factors can lead to changes in allele frequencies within a population over time.
What factors change the allele frequency of a population?
Factors that can change the allele frequency of a population include natural selection, genetic drift, gene flow, mutations, and non-random mating. Natural selection favors certain alleles, genetic drift causes random changes, gene flow introduces new alleles, mutations create new variation, and non-random mating can lead to specific alleles being passed on more frequently.
What are the causes of microevolution?
The same as the causes of so called macroevolution. The change in allele frequency over time in a population of organisms. By mutation, natural selection, genetic drift and gene flow. I would rip to pieces about half of the biology text books of America over this constant misunderstanding of evolutionary theory they perpetrate.
What is the effect of a bottleneck on allele frequencies?
A bottleneck can reduce genetic diversity by decreasing the population size, leading to a loss of alleles. This can increase the likelihood of genetic drift and limit the ability of the population to adapt to changing environments. It can also increase the frequency of deleterious alleles due to random fluctuations in the small population.
How can evolution be defined and measured by the frequency of alleles in a gene pool?
It's not gene pools that have a frequency, but allelesthat have a frequency in the gene pool.Alleles are "rival" variants for the same gene. For instance, if hair colour is coded by one gene, then brown hair may be allele A for that gene, while blonde hair is allele B for the same gene.Imagine people as being packages of genes, each containing two full sets of genes (humans are diploid, so we contain two copies of genes in all our cells - but they may be two different alleles for the same gene). Now put the contents of all those people-packages together in one pool: that's your gene pool.The more people have some trait T, coded for by allele A of gene G, the higher the number of copies of allele A will be in the gene pool. That's what's called the allele frequency.
what causes changes in frequency?
There are three main mechanisms that can cause changes in allele frequency.These include natural selection, genetic drift, and gene flow.
What does natural selection cause in a population on a genetic level?
Natural selection causes changes in the frequency of certain genetic traits within a population over time. Traits that confer a survival or reproductive advantage are more likely to be passed on to the next generation, leading to an increase in those beneficial genetic traits in the population.
What are the potential causes of micro evolution?
Potential causes of microevolution include mutations in DNA, gene flow between populations, genetic drift (random changes in gene frequency), natural selection (favoring certain traits), and changes in environmental conditions. These factors can lead to changes in allele frequencies within a population over time.
A small founding population of a few hundred Europeans in North America had an unusually high frequency of an allele that causes polydactyly . What is an example of?
Genetic Drift
A small founding population of a few hundred Europeans in North America had an unusually high frequency of an allele that causes polydactyl What is this an example of?
Founder Effect
What factors change the allele frequency of a population?
Factors that can change the allele frequency of a population include natural selection, genetic drift, gene flow, mutations, and non-random mating. Natural selection favors certain alleles, genetic drift causes random changes, gene flow introduces new alleles, mutations create new variation, and non-random mating can lead to specific alleles being passed on more frequently.
What are the causes of microevolution?
The same as the causes of so called macroevolution. The change in allele frequency over time in a population of organisms. By mutation, natural selection, genetic drift and gene flow. I would rip to pieces about half of the biology text books of America over this constant misunderstanding of evolutionary theory they perpetrate.
A person can be tested for the allele that causes huntingtons disease because of that allele is different from that of a normal allele?
Because Huntington's is a genetic disorder and it is known what sequence in what region causes the disorder.
What causes an allele frequency to go up in one generation and back down in the next generation?
There are three basic reasons: 1. Natural Selection-- thr environment may have favored the allele in previous generations, but now disfavors it. 2. Genetic Drift-- in every finite population, the frequency of an allele will fluctuate due to chance. For example, the vast majority of sperm fail to fertlize any egg, so allels can be lost this way due to chance. Individuals carrying a copy or copies of an allele may die young due to random accidents, or may never find a mate. These basic chance events cause the frequencies of alleles to fluctuate, and the degree of frequency change depends upon the population size. The greater the population size, the smaller the change in frequency. 3. A combination of both.
A person can be tested for the allele that causes Tay-Sachs disease because the what of that allele is different from that of the normal allele?
The DNA sequence of the allele that causes Tay-Sachs disease is different from that of the normal allele. This difference in the DNA sequence allows for specific genetic tests to be conducted to identify the presence of the Tay-Sachs disease allele in individuals.
What causes genetic drift?
Genetic drift is caused by random sampling errors in a population's gene pool. These errors can occur during processes like genetic recombination, migration, or founder events, leading to changes in allele frequencies over generations. The smaller the population, the greater the impact of genetic drift.
Explain how the founder effect can cause a change in the frequency of alleles in a population?
Genetic variation, variation in alleles of genes, occurs both within and among populations. Genetic variation is important because it provides the "raw material" for natural selection.
