Science : Ch 09 – Heredity and Evolution

Inheritance from the previous generation provides both a common body design and subtle changes in it due to inaccuracies during DNA copying. However, greater diversity will be generated if sexual reproduction is involved

The Foremost attribute are always supreme. Tallness is a dominant trait as a single copy of ‘T’ is enough to make the plant tall, while two copies have to be ‘t’ for the plant to be short.

The maleness of a child is determined by the presence of the Y chromo-some in the zygote inherited from the father.

Radish and carrot represent the correct homologous structures because both have similar design or structure, though both are of different species.

The two versions of a trait which are brought in by the male and female gametes are situated on copies of the same chromosome. Each parent contributes one copy of the gene for a particular trait.

The wings of an insect and a bird have distinct structures but they carry out the same function of fying. Therefore, they are analogous organs

Asexual reproduction will not result in variation as there are no gametes involved. Movement of individuals from one habitat to another will not afect the DNA.

The pair of sex chromosomes is odd as it is not a perfect pair. Women have a perfect pair of sex chromosomes, both called XX while men have a mismatched pair in which one is a normal sized X and the other is a short one called Y.

The tendril of a pea plant and the phylloclade of Opuntia are homologous structures, as they are modifed stems but serve diferent functions in diferent plants.