Evolution Test - 76

• The Hardy-Weinberg equilibrium is a principle stating that the genetic variation in a population will remain constant from one generation to the next in the absence of disturbing factors.
• For instance, mutations disrupt the equilibrium of allele frequencies by introducing new alleles into a population. 
• There are five basic Hardy-Weinberg assumptions: no mutation, random mating, no gene flow, infinite population size, and no selection.
• Hence, Hardy-Weinberg equilibrium is known to be affected by gene flow, genetic drift, mutation, genetic recombination, and natural selection.

So, the correct answer is 'Natural selection'.

The geological time scale is used to understand the history and evolution of life by showing the relationship of events that have occurred during the history of the earth. G.Arduino is the geologist who first gave classification in geological time scale

The Hardy-Weinberg equation is expressed as p² + 2pq + q² = 1, where p is the frequency of the "A" allele and q is the frequency of the "a" allele in the population. In the equation, p² represents the frequency of the homozygous genotype AA, q² represents the frequency of the homozygous genotype aa, and 2pq represents the frequency of the heterozygous genotype Aa. In addition, the sum of the allele frequencies for all the alleles at the locus must be 1, so p + q = 1. So if the frequency of an allele A is 0.7, then the frequency of allele a is 0.3. Therefore according to formula: (0.7)² + 2Aa + (0.3)² = 1 

0.49 + 0.9 + 2Aa = 1

Aa = 0.42 (2Aa represents genotype frequency of genotype Aa). Hence option B is correct.

The RNA world hypothesis proposes that self-replicating ribonucleic acid (RNA) molecules were precursors to all current life on Earth. It is generally accepted that current life on Earth descends from an RNA world, although RNA-based life may not have been the first life to exist.
RNA stores genetic information like DNA, and catalyzes chemical reactions like an enzyme protein. It may, therefore, have played a major step in the evolution of cellular life. The RNA world would have eventually been replaced by the DNA, RNA and protein world of today, likely through an intermediate stage of ribonucleoprotein enzymes such as the ribosome and ribozymes, since proteins large enough to self-fold and have useful activities would only have come about after RNA was available to catalyze peptide ligation or amino acid polymerization. DNA is thought to have taken over the role of data storage due to its increased stability, while proteins, through a greater variety of monomers (amino acids), replaced RNA's role in specialized biocatalysis.
The RNA world hypothesis is supported by many independent lines of evidence, such as the observations that RNA is central to the translation process and that small RNAs can catalyze all of the chemical group and information transfers required for life. The structure of the ribosome has been called as the "smoking gun," as it showed that the ribosome is a ribozyme, with a central core of RNA and no amino acid side chains within 18 angstroms of the active site where peptide bond formation is catalyzed.
So, Most biologists think that RNA was the first genetic material because, the existence of ribozymes suggests that early cells could have used RNA to catalyze chemical reactions and transfer information. So, Biologists believe that the current DNA RNA protein system is the result of a long period of evolution because evidence indicates that RNA preceded DNA as the genetic material. Thus, option C is correct and other options are wrong.

• According to the Hardy Weinberg law, the allele and genotype frequencies in a population remain constant in the absence of factors responsible for evolution. It states that the sum of all genotype frequencies can be represented as the binomial expansion of the square of the sum of p and q. 
• This sum is equal to one. -$$(p + q)^2$$ = $$p^2$$ + $$2pq$$ + $$q^2$$ = $$1$$. 
• Here, "p" is the frequency of the dominant allele, and q is the frequency of the recessive allele. The "2pq" in the equation shows the frequency of heterozygotes in the population. 
• In the question, the frequency of dominant homozygous individuals $$p$$$$^{2}$$= $$49%$$ or $$0.49$$. 

Hardy Weinberg Law states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences. The conditions which are favorable for this law are: large population size, no migration, no mutation, random mating and random reproductive success. 

The heterotrophic hypothesis, also known as the Haldane-Oparin hypothesis after two scientists who independently proposed it, posits that life (organic molecules) could have formed from inorganic molecules. In other words, life could have formed without requiring a 'divine nudge' and without having to come from another planet. Much research has been conducted to explain how life could spontaneously form. The general theme is that components of earth's atmosphere could form into complex organic molecules, which could then assemble into more complex groupings, which eventually would become life. The heterotroph hypothesis assumes that a very simple organism evolved slowly from non-living matter and this occurred in the primitive environmental conditions.
Spontaneous generation, the hypothetical process by which living organisms develop from nonliving matter. It assumed that spontaneous generation was a continuous process that could happen even today. Thus, option D is correct.

• Genetic drift is the random change in the frequency of alleles in a population due to chance events causing unequal participation of individuals in producing succeeding generations. 
• Genetic drift can be a principal force in the evolution of some populations; it is especially associated with populations of small size.
• The alleles in the offspring are a sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces.

The Hardy-Weinberg equilibrium can be disturbed by a number of forces, including mutations, natural selection, nonrandom mating, genetic drift, and gene flow. For instance, mutations disrupt the equilibrium of allele frequencies by introducing new alleles into a population. Similarly, natural selection and nonrandom mating disrupt the Hardy-Weinberg equilibrium, because they result in changes in gene frequencies. This occurs because certain alleles help or harm the reproductive success of the organisms, that carry them. Another factor that can upset this equilibrium is genetic drift, which occurs when allele frequencies grow higher or lower by chance and typically takes place in small populations. Gene flow, which occurs when breeding between two populations transfers new alleles into a population, can also alter the Hardy-Weinberg equilibrium.

Cromagnon man was an excellent tool maker and a very fine artist as they drew various pictures on the walls in their caves. They were first to domesticate dogs. Also, they were religious. They showed many features which depicted that they were civilized and able to learn new activities.
Thus, the correct answer is option A