Sickle cell trait (genotype HbAS)
confers a high degree of resistance to severe and complicated malaria [1–4] yet the precise mechanism remains unknown.
Does the gene pool include only the beneficial traits in a population?
Terms in this set (20)
stabilizing, directional, and disruptive. The gene pool includes only the
beneficial
traits in a population. … This diagram represents the founder effect, that is, when a population moves into a new area and becomes reproductively isolated.
Which of the following is an example of balanced polymorphism?
Sickle Cell disease
is an autosomal recessive disorder that causes anemia, joint pain, a swollen spleen, and frequent, severe infections. It illustrates balanced polymorphism because carriers are resistant to malaria, an infection by the parasite Plasmodium falciparum that causes cycles of chills and fever.
What is another name for the evolutionary force called gene flow?
balanced polymorphism means that not all African Americans are heterozygous for the sickle cell trait. Another name for the evolutionary force called gene flow is: a. “
disruptive selection
.”
Which of the evolutionary forces will likely decrease variation between populations?
Which of the evolutionary forces is most likely to decrease variation between two populations?
Genetic drift
is the force of evolution that is most powerful when acting on very large populations. Reproductive isolation is key to the development of individual species.
What does balanced polymorphism mean?
A genetic polymorphism that is stable and is maintained in a population by natural selection
, because the heterozygotes for particular alleles have a higher adaptive value (i.e. fitness) than either homozygote. From: balanced polymorphism in A Dictionary of Ecology »
What is the concept of balanced polymorphism?
Definition. Balanced polymorphism or balancing selection is.
a phenomenon by which more than one morph
.
exists in the population at a stable frequency at a
.
given time
.
How does population size affect genetic drift?
Small populations tend to lose genetic diversity more quickly than large populations due
to stochastic sampling error
(i.e., genetic drift). This is because some versions of a gene can be lost due to random chance, and this is more likely to occur when populations are small.
What is founder effect give an example?
For example,
the Amish populations in the United States
exhibit founder effects because they have grown from a very few founders, have not recruited newcomers, and tend to marry within the community.
What are the two main sources of genetic variation?
Natural selection acts upon two major sources of genetic variation:
mutations and recombination of genes through sexual reproduction
.
What are the two types of gene flow?
Alternatively, gene flow can take place between two different species through
horizontal gene transfer
(HGT, also known as lateral gene transfer), such as gene transfer from bacteria or viruses to a higher organism, or gene transfer from an endosymbiont to the host.
What is gene flow example?
Gene flow is the movement of genes from one population to another population. Examples of this include
a bee carrying pollen from one flower population to another
, or a caribou from one herd mating with members of another herd.
What produces gene flow?
Gene flow is the movement of genes into or out of a population. Such movement may be due to
migration of individual organisms that reproduce in their new populations
, or to the movement of gametes (e.g., as a consequence of pollen transfer among plants).
What increases and decreases genetic variation?
Mutation, recombination, and gene flow
all act to increase the amount of variation in the genotypes of a given population. There are also forces at work that act to decrease this variability.
What increases genetic variation?
Gene duplication, mutation, or other processes can produce new genes and alleles
and increase genetic variation. New genetic variation can be created within generations in a population, so a population with rapid reproduction rates will probably have high genetic variation.
What increases early human chances of hunting?
To increase early humans’ chances of hunting success, hunting:
was conducted with lithic tools and cooperative strategies
. Archaeologists: study past human societies, focusing mostly on their material remains.
