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What is A description of what a selection pressure is what selected for means and what selected against means?
Selection pressure is the environmental force that influences which individuals within a population are more likely to survive and reproduce. "Selected for" means traits that increase an organism's likelihood of survival and reproduction, while "selected against" means traits that decrease an organism's likelihood of survival and reproduction.
What else can I help you with?
What modes of selection leads to a reduction in variation but no change in the mean?
Stabilizing selection is the mode of selection that can lead to a reduction in variation without changing the mean of a trait. In this type of selection, extreme phenotypes are selected against, while intermediate phenotypes are favored, resulting in a narrower range of phenotypic variation but maintaining the same mean.
In selection individuals with both extreme forms of a trait are at a selective advantage?
There are three patterns of natural selection. 1) Disruptive selection: this is when the two extreme forms of a trait are selected for and intermediate forms are selected against. For example plants which can tolerate heavy metal ions are at an advantage on old spoil tips, whereas those which cannot tolerate these ions are at an advantage on uncontaminatied soil. 2) Stabilizing selection: this is when the intermediat forms are selected for and the extreme forms are selected against. A classic example is birth weight in humans. Babies which are much heavier or much lighter than average are more likely to die than average weight babies. 3) Directional selection:this is when one extreme is selected for and the other extreme is selected against. For example in Darwin's finches on the Galapagos Islands, during a drought larger birds with larger beaks are favoured over smaller birds with smaller beaks. See: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/Evolution.html http://www.evotutor.org/Selection/Sl5A.html
What is stabilizing selection and how does it impact the evolution of traits in biology?
Stabilizing selection is a type of natural selection that favors the average form of a trait in a population, while extremes are selected against. This leads to a reduction in genetic variation and can result in the preservation of a specific trait within a population. Over time, stabilizing selection can contribute to the evolution of traits by maintaining the status quo and preventing significant changes in the population's characteristics.
When stabilizing selection acts to elimination extremes at both ends of a range of phenotypes the frequencies of the intermediate phenotypes increase?
Yes, when stabilizing selection is acting, individuals with extreme phenotypes are selected against, leading to an increase in the frequencies of intermediate phenotypes within a population. This process helps to maintain the overall consistency of a particular trait or characteristic over successive generations by favoring individuals with traits closer to the population average.
Why must there be genetic variation in order for natural selection to occur?
Genetic variation is necessary for natural selection to occur because it provides different traits and characteristics within a population. These variations create diversity, allowing some individuals to have traits that are more advantageous for survival and reproduction in certain environments. Without genetic variation, there would be no differences in traits to be selected for or against, and natural selection would not be possible.
Is selection against the phenotype or phenotype?
smaller are selected for and larger are selected against
Which type of natural selection in which the mean characteristics of a population are preserved?
This type of natural selection is called stabilizing selection because the mean traits of the population are being selected for against the immediate environment.
What characteristics must population first have for nautral selection to occur?
Individuals are selected, but in the population of organisms there are many variations, some better at survival and reproduction than others, and against the immediate environment, what natural selection really is, these beneficial variations will be selected.
Does natural selection cause changes in the environment?
No, natural selection is the environment! The variant organism is selected against the immediate environment where it survives and reproduces better than it's conspecifics.
What is the 3 types of natural selection?
Stabilizing Selection-- The extremes are selected against.Example: height; mostly beings tend to the average height- not too many really short ones or really tall ones.Directional selection-- One extreme value is selected for.Example: speed; faster is always better so a population will tend to get faster over time.Disruptive selection-- The extremes are both selected for.This type of selection is not as common as the first two. Example: Prey-type animal with distinctive markings which the predators know will over time move away from the norm in both directions.
Which force of evolution makes a population more alike?
Stabilizing selection occurs when the extreme forms of some trait are selected against by natural selection. It is a force of natural selection which causes evolution (definition: change of allele frequency in a population divided by time).
What modes of selection leads to a reduction in variation but no change in the mean?
Stabilizing selection is the mode of selection that can lead to a reduction in variation without changing the mean of a trait. In this type of selection, extreme phenotypes are selected against, while intermediate phenotypes are favored, resulting in a narrower range of phenotypic variation but maintaining the same mean.
When two extreme phenotypes are selected in natural selection the intermediate phenotypes become?
The intermediate phenotypes tend to be selected against, resulting in stabilizing selection that favors the extreme phenotypes. This can lead to a reduction in genetic variation within the population, as individuals with intermediate traits are less likely to survive and reproduce.
What process selects against populations that are not fit to survive in their environment?
No process. The selection process selects variant individuals against the immediate environment. You seem to be talking about group selection which is not established biological consensus. Individuals are selected while populations evolve. Natural selection is for individuals and you need to get this concept down correctly. PS: Where do you people get these ill posed questions? Teachers?
In selection individuals with both extreme forms of a trait are at a selective advantage?
There are three patterns of natural selection. 1) Disruptive selection: this is when the two extreme forms of a trait are selected for and intermediate forms are selected against. For example plants which can tolerate heavy metal ions are at an advantage on old spoil tips, whereas those which cannot tolerate these ions are at an advantage on uncontaminatied soil. 2) Stabilizing selection: this is when the intermediat forms are selected for and the extreme forms are selected against. A classic example is birth weight in humans. Babies which are much heavier or much lighter than average are more likely to die than average weight babies. 3) Directional selection:this is when one extreme is selected for and the other extreme is selected against. For example in Darwin's finches on the Galapagos Islands, during a drought larger birds with larger beaks are favoured over smaller birds with smaller beaks. See: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/Evolution.html http://www.evotutor.org/Selection/Sl5A.html
Why must there be Variation in the population in order for natural selection?
Without the subtle differences on organisms phenotypes what would natural selection select from? All organisms in a population are variants and some survive and reproduce better than other against the background of the immediate environment and these are selected by that environmental pressure.
Which natural selection select against both extremes?
Stabilizing selection.
