Question

(a) Name the scientist who gave the laws of inheritance.
(b) Name an animal in which individuals can change sex. What does this indicate?

Answer 1

Hint: Mendel's first law is the law of dominance which say a cross between two organisms pure for any pair of contrasting characters, the character which appears in the first generation is called dominant and the one which is suppressed is called recessive and second is the law of segregation which is also known as the law of purity of gametes. Some animals can change their gender due to some unfavourable conditions. in the gender of this organism is not defined by birth.

Complete answer:Gregor Mendel (1822-1884) is called the father of genetics. He analysed hybridisation of garden pea over seven years and proposed laws of inheritance.
Reasons for Mendel's success:
His experiments had huge sampling sizes, which gave greater probability to the data that he collected.
Mendel examined the inheritance of individual traits at a time. (others considered the organisms as a whole) after establishing the genetic behaviour of a single trait, Mendel studied two traits together.
Mendel carried out his experiment to the F2 and F3 generation.
Mendel selected garden pea plant, an annual plant which has bisexual flowers and have seven pairs of contrasting characters. Each trait is influenced by two alleles of a single gene.
Coming to the second part of the question, in total there are six animals, where they can change their gender. Firstly, butterflies belong to arthropods. The other is common reed frog, yellow-bellied water snake, banana slug, forest mushroom corrals, shutter shock fish etc. this indicates sequential hermaphroditism.

Note: Unfortunately, Mendel's piece of work remained unattended for several years until 1990. Mendel's work was rediscovered by three different persons from three various places of Europe, while working independently on heredity in plants. These were Hugo DeVries of Holland, Von Tschammer of Austria and Karl Corners of Germany. Hermaphroditism is a phenomenon where an organism can produce male germ cells or female germ cells by their choice, such organisms are called hermaphrodites.