Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

Since the origin of life on the earth, there were five episodes of mass extinction of species.

1. How is the 'Sixth Extinction', presently in progress, different from the previous episodes?
2. Who is mainly responsible for the 'Sixth Extinction'?
3. List any four points that can help to overcome this disaster.

Draw the sketches of a zoospore and a conidium. Mention two dissimilarities between them and at least one feature common to both the structures.

Explain the process of parturition.

Why the ratio in pleiotropy is 2:1? Explain it with example.

Fertilisation is essential for production of seed, but in some angiosperms, seeds develop without fertilisation.
Give an example of an angiosperm that produces seeds without fertilisation. Name the process.

Given reasons : Usually crustose lichens form a pioneer species.

If implementation of better techniques and new strategies are required to provide more efficient care and assistance to people, then why is there a statutory ban on amniocentesis? Write the use of this technique and give reason to justify.

How do homologous organs represent divergent evolution? Explain with the help of a suitable example.

There are many animals that have become extinct in the wild but continue to be maintained in Zoological parks.

1. What type of biodiversity conservation is observed in this case?
2. Explain any other two ways which help in this type of conservation.