Some dinosaurs had feathers although they could not fly,but birds have feathers that help them to fly. In the context of evolution,this means that:

$A$ pea plant with blue colour flower denoted by $BB$ is cross-bred with a pea plant with white flower denoted by $ww$.
$(a)$ What is the expected colour of the flowers in their $F_{1}$ progeny?
$(b)$ What will be the percentage of plants bearing white flower in $F_{2}$ generation,when the flowers of $F_{1}$ plants were selfed?
$(c)$ State the expected ratio of the genotypes $BB$ and $Bw$ in the $F_{2}$ progeny.

All the variations in a species do not have equal chances of survival. Why?

$(a)$ What is geographical isolation?
$(b)$ Illustrate the formation of a species with the help of an example where individuals become very different from each other and are no longer capable of reproduction among themselves.

What is the cause of the differences found among individuals of the same species?

Exchange of genetic material takes place in