CBSE Questions for Class 10 Biology Heredity And Evolution Quiz 1 - MCQExams.com

• F$$_1$$ generation is the first filial generation. 
• It means these are the offspring that belong to the first generation after a cross between the male and female parents.

• An allele is one of the two, or more, forms of a given gene variant that is located at a specific position on a specific chromosome. 
• In nature, alleles can be inherited as dominant, recessive, or codominant alleles. For example, in pea plants, the gene for plant height has two alleles - one for tall trait and the other for the dwarf trait; the gene for seed shape has one allele for the round shape of the seed and the other one for wrinkled shape of the seed.

• So, the correct answer is option A. 
  

• The male sex gametes possess X and Y chromosomes, and the female sex gametes possess two X chromosomes. 
• The sex of the child depends on the gamete of the male which fuses with the female. If the X gamete fuses, the zygote formed has the XX chromosomes which form a girl child whereas, the male child is formed by the zygote with the XY chromosome content. 

Heredity can be defined as the transmission of various genetic characteristics from the parents to their offspring. These characteristics include the colour of the eyes, the hairstyle, the shape of the face, nose, etc. The similarity between parents’ physical features and their children’s physical features is marked by heredity inherent traits.
Therefore, the correct answer is option A.

• The branch of biology that deals with heredity and variation is genetics. Gregor Mendel is the father of genetics.
• Reproduction (or procreation or breeding) is the biological process by which "new individual organisms" are produced from their "parents". Reproduction is a fundamental feature of all known life forms; each individual organism exists as the result of reproduction.
• Sericulture is the production of silk and the rearing of silkworms for this purpose.
• Evolution is the change in the heritable traits of biological populations over successive generations.

• Seven characters found in garden pea plants were selected by Mendel for his experiment. 
• They were seed shape, seed colour, flower colour, pod shape, pod colour, flower position, and stem height. 
• For the experiments, Mendel selected a set of two contrasting traits for each of these characters. 

• A genotype is the genetic makeup/constitution of a cell of an organism.
• A phenotype is an external appearance caused by the presence of a particular genotype.
• A trait indicates the specific characteristic of an individual. 
• An allele is a variant form of a gene.

• Mendel's laws of inheritance explain well about heredity and are thus applicable only in the case of sexual reproduction.
• According to Mendel's laws of inheritance:-
  
• Law of independent assortment - Allele pairs separate independently during the formation of gametes.
• Law of dominance - Some alleles are dominant while some others are recessive. An organism with at least one dominant allele will express the dominant character.
• Law of segregation - Alleles for a trait separate when gametes are formed.
  Hence, the correct answer is option B.