Heredity and Evolution Test - 23

• Species are those which are capable of interbreeding among themselves and can exchange genes. These are closely related. 
• The offspring produced as a result of interbreeding will be fertile in nature.
• Gene flow occurs between the populations of a species. 
• For example, gene flow can occur within plant species, when pollen is carried by bees or blown by the wind from one population of flowering plants to another of the same species. 
• Members of the two different species cannot interbreed and produce fertile offspring. Thus, each species is reproductively isolated from every other species.
  
• Genetic variation is the presence of differences in sequences of genes between individual organisms of a species.
  

The correct statements are III and IV.  
III. Wings of birds and wings of insects are analogous organs as they have different structures but perform the same function.
IV. Wings of bird and forelimbs of horse are homologous organs as they have same structure but perform different functions. Thus, the correct option is C.

Mendel is widely considered a pioneer in the field of genetics. Mendel discovered the basic principles of heredity through experiments in his monastery's garden. His experiments showed that the inheritance of certain traits in pea plants follows particular patterns, subsequently becoming the foundation of modern genetics and leading to the study of heredity.

Solution

Correct answer is option A.

Explanation for correct option:

Gregor Mendel – now known as father of genetics is the person who introduced the idea of genes and inheritance.

He studied 7 traits in pea plants which were as follows.

i.          Plant height (tall/ dwarf)

ii.         Flower colour (purple/white)

iii.       Flower position (terminal /axial)

iv.        Seed colour (yellow/green)

v.         Seed shape (round/ wrinkled)

vi.        Pod colour (green/yellow)

vii.       Pod shape (inflated/ constricted)

 

The modification in the structure and function of the eye is mainly due to the evolutionary changes that occur with time. The primitive organism had a very simple structure of an eye. They were devoid of the ability to sense the light intensity, but later on, in mammals, eyes have photosensitive cells.

Horse is the living organism with oldest fossil history. The evolution of horse, a mammal of the family Equidae, occurred over a geologic time scale of 50 million years, transforming the small, dog-sized, forest-dwelling Eohippus into the modern horse. Some features of Eohippus showed its relativity to modern horse.

Analogous organs have similar functions but different origins. An example of an analogous trait would be the wings of insects, bats and birds that evolved independently diverging from an ancestor without wings. The wings of insects originate from the inner or outer surface of the insect’s body. Feathers of birds originate from their forelimbs, and the wings of bats originate from both the forelimb and the membranous skin of the abdomen.