Questions and Answers

[Diagrams are to be drawn as per NCERT textbook illustrations.]

A typical flower of Solanaceae (e.g., Solanum nigrum) is described as: Actinomorphic, bisexual, pentamerous; calyx 5, united; corolla 5, united; androecium 5, epipetalous; gynoecium bicarpellary, syncarpous, ovary superior, axile placentation. Floral formula: ⚥ K(5) C(5) A5 G(2). [Floral diagram to be drawn as per NCERT guidelines.]

The types of placentation are: Marginal, where ovules are arranged along the margin of the ovary, as in pea; Axile, where ovules are placed on a central axis, as in tomato; Parietal, where ovules develop on the inner wall of the ovary, as in mustard; Free central, where ovules are borne on a central column not connected by septa, as in Dianthus; Basal, where a single ovule is attached at the base of the ovary, as in sunflower.

• Ans: Flowering plants (angiosperms) have flowers as their reproductive unit.
Angiosperms reproduce sexually through flowers.
• Flowers are usually modified stems with condensed axes. There are four concentric
lobes on a flower.
• Calyxes, corollas, androecium, and gynoecium make up the four whorls of the flower,
from outside to inside. • On flowers, the androecium represents the male reproductive whorl and the gynoecium
represents the female reproductive whorl.
• An example of a bisexual flower is one with both androecium and gynoecium, while a
unisexual flower only has gynoecium.
• There is usually a distinct corolla and calyx, but they can be fused (called perianth).
All four parts of a flower are known as a complete flower.

Ans: Flowering plants (angiosperms) have flowers as their reproductive unit.
Angiosperms reproduce sexually through flowers.
• Flowers are usually modified stems with condensed axes. There are four concentric
lobes on a flower.
• Calyxes, corollas, androecium, and gynoecium make up the four whorls of the flower,
from outside to inside. • On flowers, the androecium represents the male reproductive whorl and the gynoecium
represents the female reproductive whorl.
• An example of a bisexual flower is one with both androecium and gynoecium, while a
unisexual flower only has gynoecium.
• There is usually a distinct corolla and calyx, but they can be fused (called perianth).
All four parts of a flower are known as a complete flower. A. Calyx: The calyx is made up of sepals in the outer whorl of the flower. At the buds
stage, they serve as a protective covering. An open flower’s sepals are known as
polysepalous, whereas flowers with fusions of sepals are known as gamosepalous.
In addition to being photosynthetic, sepals are also green in color. B. Corolla: The flower whorl is the part of the flower that lies toward the inner side of
the calyx. Individual petals of the corolla are brightly colored and help attract
insects for pollination. The condition in which the petals are fused is called
gamosepalous, and the condition with free petals is known as polypetalous.
C. An androecium or stamen is a yellow or red shaped male reproductive organ. A
filament and a bilobed anther constitute the filament. Anthers bilobeds produce
pollen grain and undergo meiosis. One connective connects the two anther lobes.
D. The gynoecium represents the female reproductive branch of a flower. A female
ovary is present in the body. An ovary is connected to the stigma via a long tube
(called a style).
Numerous ovules form an attachment to the placenta at the ovary.

A flower is described as epigynous, perigynous, or epigynous depending on the position
of its calyx, corolla and androecium (relative to the ovary). Hypogynous flowers possess an
ovary positioned at the top of the thalamus while other floral parts sit below. The ovary is
located on the rim of the thalamus in perigynous flowers, while in China roses, mustards, etc.,
the ovary is situated toward the middle. Plum, rose, peach, etc., are examples of ovary half
inferiors. The thalamus surrounds the ovary in epigynous flowers and forms a fusion with its
wall. Above the ovary, there is another group of floral parts. In the flowers of guava and
cucumber, the ovary is considered inferior.

Segmentation in the body is first observed in which of the following: (a) Platyhelminthes (b) Aschelminthes (c) Annelida (d) Arthropoda

Distinguish between intracellular and extracellular digestion.

How useful is the study of the nature of body cavity and coelom in the classification of animals?

Could the number of eggs or young ones produced by an oviparous and viviparous mother be equal? Why?