Heredity And Evolution Test - 2

Following are the two methods to know the age of fossils:

(i) Relative method: On digging the earth, the fossils, which are found closer to the earth's surface are more recent than the fossils found from the deeper layers of the earth.
(ii) By detecting the ratio of different isotopes of the same element in the fossils

Certain variations give some individuals of a population, an advantage when competition among the members is high. Eventually, individuals with these variations would be present in larger numbers and would produce offspring that will make a greater percentage of the total. This is the basic essence of natural selection.

Genetic drift is related to the size of the population. It operates when the population size is small. Therefore, accidents in small populations can change the frequency of some genes in an advantage. This is the essence of genetic drift.

Animals like snails can change their sex during their life. Snails are hermaphrodite, i.e. organisms which possess both male and female sex organs during their life.

TTRR represents homozygous and dominant condition for T and R allele. Others either represent heterozygous or recessive condition.

From the options given, crossing of hybrid parents will result in the formation of plants having dominant trait and recessive trait. The gametes formed by crossing Pp x Pp will be: PP (purple), Pp (purple), Pp (purple) and pp (red).

Piercing of ear is limited to the cells of ear and do not affect the DNA. Also, it is not inherited because it is not carried by reproductive cells. On the contrary, traits of hair colour, eye colour and nose shape are contained in the DNA of reproductive cells and are expressed by proteins, which pass into the next generation.

Speciation means formation of new species from already existing species. This occurs due to gradual accumulation of changes over hundreds of generations. Since changes in the genetic makeup do not occur in asexual reproduction, the chances of speciation are reduced to almost nil for individuals reproducing by asexual methods.

The traits of different individuals of the same species differ from each other. This occurs due to small changes in the genetic makeup that occur during DNA copying or recombination during sexual reproduction. These differences are called variations, and evolution is a result of variations occurring over generations.

On the other hand, inheritance and heredity are opposite of variation because they refer to the transmission of traits from one generation to another.