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Random change in gene/allelic frequency ...

Random change in gene/allelic frequency occurring by chance but not under the control of natural selection is called

A

Genetic drift

B

Natural selection

C

Isolation

D

Adaptive radiation

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The correct Answer is:
A
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Small populations are prone to change in allelic frequencies which decrease genetic variability, this is explained by:

For a spontaneous reaction, the free energy change must be negative. DeltaG=DeltaH-TDeltaS is the enthalpy change during the reaction. T is absolute temperature, and AS is the change in entropy during the reaction. Consider a reaction such as the formation ofan oxide . M+O_(2) MO Dloxygen is used wp in the course of this reaction. Gases have a more random structure (less ordered) than liquid or solids consequently gases have a higher entropy than liquids and solids, in this reaction (entropy or randomness) decreases, hence is negative. Thus, the temperature is raised the DeltaS becomes more negative. Since, TDeltaS is subtracted in the equation, then SG becomes less negative. Thus, the free energy changes increases with the increase in temperature. The free energy changes that occur when one mole of common reactant in this case dioxygen) is we may e plotted graphically against temperature for a number of reactions of metals to their oxides. The following plot is called an Ellingham diagram for metal oxide. Understanding of Ellingham diagram is extremely important for the efficient extraction of metals. Free energy change of Hg and Mg for the convertion to oxides the slope of DeltaG . T has been changed above the boiling points of the given metal because

Knowledge Check

  • Variations in gene frequecies within populations can occur by chance rather than by natural selection. This is referred to as :

    A
    Genetic flow
    B
    Genetic drift
    C
    Random mating
    D
    Genetics load

  • Changes in GnRH pulse frequency in females is controlled by circulating levels of

    A
    estrogen and inhibin
    B
    progesterone only
    C
    progesterone and inhibin
    D
    estrogen and progesterone

  • Two identical sonometer wires have a fundamental frequency of 400 vibrations per second when kept under the same tension. What fractional increase in the tension of one wire would cause an occurance of 8 beats per second when both wires vibrate together

    A
    0.02
    B
    0.03
    C
    0.01
    D
    0.04

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    For a spontaneous reaction, the free energy change must be negative. DeltaG=DeltaH-TDeltaS is the enthalpy change during the reaction. T is absolute temperature, and AS is the change in entropy during the reaction. Consider a reaction such as the formation ofan oxide . M+O_(2) MO Dloxygen is used wp in the course of this reaction. Gases have a more random structure (less ordered) than liquid or solids consequently gases have a higher entropy than liquids and solids, in this reaction (entropy or randomness) decreases, hence is negative. Thus, the temperature is raised the DeltaS becomes more negative. Since, TDeltaS is subtracted in the equation, then SG becomes less negative. Thus, the free energy changes increases with the increase in temperature. The free energy changes that occur when one mole of common reactant in this case dioxygen) is we may e plotted graphically against temperature for a number of reactions of metals to their oxides. The following plot is called an Ellingham diagram for metal oxide. Understanding of Ellingham diagram is extremely important for the efficient extraction of metals. As per the Ellingham diagram of oxides which of the following conclusion is true?

    For a spontaneous reaction, the free energy change must be negative. DeltaG=DeltaH-TDelaS is the enthalpy change during the reaction. T is absolute temperature, and AS is the change in entropy during the reaction. Consider a reaction such as the formation ofan oxide . M+O_(2) MO Dloxygen is used wp in the course of this reaction. Gases have a more random structure (less ordered) than liquid or solids consequently gases have a higher entropy than liquids and solids, in this reaction (entropy or randomness) decreases, hence is negative. Thus, the temperature is raised the DeltaS becomes more negative. Since, TDeltaS is subtracted in the equation, then SG becomes less negative. Thus, the free energy changes increases with the increase in temperature. The free energy changes that occur when one mole of common reactant in this case dioxygen) is we may e plotted graphically against temperature for a number of reactions of metals to their oxides. The following plot is called an Ellingham diagram for metal oxide. Understanding of Ellingham diagram is extremely important for the efficient extraction of metals. For the conversion of Ca(s) to CaO(s) which of the following represent the DeltaG vs T :

    For a spontaneous reaction, the free energy change must be negative. DeltaG=DeltaH-TDeltaS is the enthalpy change during the reaction. T is absolute temperature, and AS is the change in entropy during the reaction. Consider a reaction such as the formation ofan oxide . M+O_(2) MO Dloxygen is used wp in the course of this reaction. Gases have a more random structure (less ordered) than liquid or solids consequently gases have a higher entropy than liquids and solids, in this reaction (entropy or randomness) decreases, hence is negative. Thus, the temperature is raised the DeltaS becomes more negative. Since, TDeltaS is subtracted in the equation, then SG becomes less negative. Thus, the free energy changes increases with the increase in temperature. The free energy changes that occur when one mole of common reactant in this case dioxygen) is we may e plotted graphically against temperature for a number of reactions of metals to their oxides. The following plot is called an Ellingham diagram for metal oxide. Understanding of Ellingham diagram is extremely important for the efficient extraction of metals. Which of the following elements can be prepared by heating the oxide above 400^(@)C ?

    observe the below diagram showing variation in beetle population and its impact. Let us consider a group of eweleve beetles. They live in bushes on green leaves. Their population will grow by sexual reproduction. So they were able to generate variations in population. Let us assume crows eat these red beetles. If the crows eat more Red beeles, their population is slowly reduced. let us disuss the above 3 different situations in detail. A. Situation-1 : in this situation a colour variation arises during reproduction. So that there appears one beetle that is green n colour instead of red moreover this green coloured beetle passes it's colur to it's offspring (Progeny ). So that all its progeny are green. Crows cannot see the green coloured beetles on green leaves of the bushes and therefore crows cannot eat them. But crows can see the red beetles and eat them As a result there are more and more gren beetles than red ones which decrease in their number . the variation of colour in beetle green gave a survival advantage to green beetles' than red beetles. in other word it was naturaly selected. We can see that the natural selection was exerted by the crows. The more crows there are, the more red beetles would be eaten and the more number of green beetles in the population would be. thus the natural selection is directing evolution in the beetle population. it results in adaptation in the beetle population to fit in their envirnment better. Let us think of another situation. Situation-2: In this situation a colour variation occurs again in its progeny during reproducation but now it results in blue colour beetles instead of red colour beetle. this blue colour beetle can pass its colour to its progeny. So that all its progeny are blue. crows can see blue coloured beetles on the green leaves of the bushes and the red ones as well. And therefore crows can eat both red and blue coloured beetles. In this case there is no survival advantage for blue coloured beetles as we have seen in case of green coloured beetles What happens initially in the population, there are a few blue beetles, butmost are red. Imagine at this point an elephant comes by and stamps on the bushes where the beetles live. this kills most of the beetles. By chance the few beetles survived are mostly blue. Again the beetle population slowly increases. But in the beetle population most of them are in blue colour. Thus sometimes accidents may also result in changes in certain characters of the population. Characters as we know are governed by genes. Thus there is change in the frequency of genes in small populations. this is known as genetic drift, which provides diversity in the population. Situation-3: In this case beetles population is increasing, but suddently bushes were affected by a lant disease in which leaf material were destroyed or in which leaves are affected by this beetles got les food material. So beetles are poorly nourished. So the weight of beetles decrease but no changes take place in their genetic material (DNA). After a few years the plant diseases are eliminated. Bushes are healthy with plenty of leaves. (Q) What do you think will be conditin of the beetles?

    In a population, which is in Hardy-Weinberg equilibrium, the recessive allelic frequency is 0.8, in a population of 1300. Find out the number of dominant individuals in that population, if the gene in reference has only two alleles.

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