Question

Given below are certain situations. Analyse each and describe its possible impact:
(i) A population of bacteria living in temperate waters whose temperature increased by global warming.
(ii) The sperm encounters the egg when it reaches the oviduct in human females.
(iii) Self pollination does not occur in a flower that contains only pistil.
(iv) Egg does not get fertilised in a human female.
(v) When the seed is placed under appropriate condition of water and air in the soil?

Hint:

Each biological situation has specific impacts: (i) Temperature affects bacterial growth; (ii) Sperm-egg encounter leads to fertilization; (iii) Pistil-only flowers need cross pollination; (iv) Unfertilized egg causes menstruation; (v) Suitable conditions trigger seed germination.

Answer 1

Analysis of the Given Situations and Their Possible Impact:

(i) A population of bacteria living in temperate waters whose temperature increased due to global warming:

An increase in temperature due to global warming can significantly affect bacterial populations. Since bacteria are highly sensitive to environmental changes, a rise in temperature may:

– Increase their rate of metabolism and reproduction if the temperature remains within their tolerance range.
– Lead to rapid multiplication and possible imbalance in the aquatic ecosystem.
– If the temperature exceeds their tolerance limit, it may cause death or migration of bacteria.
– Affect the food chain and disturb ecological balance.

Thus, global warming may either increase bacterial growth or disrupt the ecosystem depending on the extent of temperature rise.

(ii) The sperm encounters the egg when it reaches the oviduct in human females:

When the sperm meets the egg in the oviduct (fallopian tube), fertilization occurs.

– The male and female gametes fuse to form a zygote.
– The zygote begins cell division and develops into an embryo.
– The embryo moves to the uterus and implants in the uterine wall.
– This results in pregnancy.

Therefore, the encounter of sperm and egg leads to fertilization and possible development of a new individual.

(iii) Self pollination does not occur in a flower that contains only pistil:

A flower that contains only pistil (female reproductive part) is called a pistillate or female flower.

– Since it lacks stamens (male reproductive parts), it cannot produce pollen.
– Therefore, self-pollination is not possible.
– It depends on cross-pollination for fertilization.
– This promotes genetic variation.

Thus, absence of male parts prevents self-pollination.

(iv) Egg does not get fertilised in a human female:

If fertilization does not occur:

– The egg degenerates.
– The thickened uterine lining breaks down.
– Menstruation occurs.
– No pregnancy takes place.

This is a normal part of the menstrual cycle.

(v) When the seed is placed under appropriate condition of water and air in the soil:

When a seed receives proper conditions such as water, oxygen (air), and suitable temperature:

– The seed absorbs water (imbibition).
– Metabolic activities begin.
– The seed coat breaks.
– The radicle (root) emerges first.
– Germination occurs and a new plant starts growing.

Conclusion:
Each situation leads to specific biological consequences such as ecosystem changes, fertilization, prevention of self-pollination, menstruation, or seed germination depending on the environmental or physiological condition.