Extra questions (Reproduction in Plants) class 7

 Reproduction in Plants

(Extra questions)

Q.1. What is the importance of reproduction?

Ans. Biological process which involves production of new organism from existing species is called reproduction.

Importance:

*It ensures continuity of life on earth.

*It is essential for survival of species on earth and ensures their stability.

*Reproduction helps in maintaining a proper balance among various biotic constituents of ecosystem.

*It also facilitates evolution because variation comes through reproduction over several generations.

Q.2. What happens when bryophyllum falls on moist soil?

Ans. Bryophyllum (sprout leaf plant) has buds in the margins of leaves. If a leaf of this plant falls on a moist soil, leaf buds at its notches develop into new plants.

Q.3. What is the importance of notches (eyes) in a potato?

Ans. Potato tuber has depressions called "eyes" on its surface. These eyes have vegetative buds in them which germinate to produce a new potato plant. 

Q.4. What is the role of fruits in plants?

Ans. The role of fruit is to protect the seed inside and aid in its dispersal by different means.

Q.5. Why some fruits are brightly colored?

Ans. Fruits of some plants are brightly colored and emanate a detectable odour which attracts birds and animals to eat them and getting seed dispersed to other areas for germinating new plants.

Q.6. Differentiate between:

        a) budding and fragmentation

        b) unisexual and bisexual flowers

Ans. a)

Budding	Fragmentation
A type of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site.	A type of asexual reproduction in which the body of the parent organism breaks off into pieces that subsequently regenerate.
occurs in both unicellular and multicellular organism.	Occurs in multicellular organisms.
Produces a single daughter organism.	Produces several daughter organisms.
For example: Occurs in yeast.	For example: Occurs in spirogyra.

b)

Unisexual flower	Bisexual flower
It contains either male or female reproductive system.	It contains both male and female reproductive systems.
It is also known as incomplete flower.	It is also known as complete flower.
For example: Hibiscus	For example: Cucumber

Q.7. Seeds of pine trees are not enclosed in a fruit. How are they dispersed?

Ans. Pine trees have naked seeds. These plants do not have flowers. So, the seeds are not enclosed inside any specialized structure like the ovary seen in the other group of plants. Rather, the seeds develop on the surface of the reproductive structures of the plants.

They can be dispersed in multiple ways:

1) Animals eat pine seeds and spread them around by defecating them and letting them grow.

2) Sometimes if the pine seeds are in a windy environment, they can be blown around and spread.

3) Some are dispersed by water. Currents can carry seeds across oceans, lakes and rivers, and they end up on shores where they can grow.

4) There is manual dispersing, where humans plant pine seeds.

Q.8. Some fruits are seedless. Explain the reason.

Ans. Some fruits like banana, grapes etc do not have seed because fertilization does not take place in them. The process of producing or developing fruits without the process of pollination and fertilization is called parthenocarpy which can be natural or artificial. The plant growth hormones help the ovaries to mature without fertilization, which grows and produce fruit without the seeds.