Inheritance and Variation — BIOLOGY STD 12 Science — Question
Maharashtra BoardEnglish MediumSTD 12 ScienceBIOLOGYInheritance and Variation4 Marks
Question
Environmental sex determination
✓
Answer
Environmental sex determination is shown by lower organisms such as Bonellia viridis.
In this animal the environmental factors decide the sex of an offspring.
There is extreme sexual dimorphism in this worm. Female is about 10 cm long while male is tiny and parasitic in the reproductive parts of mature female.
If larva is reared in vicinity of mature female then it becomes a male. By settling on the proboscis of mature female, larva becomes parasitic, enters the female’s mouth and then takes permanent shelter in the female uterus. Such males then produce gametes and fertilize the eggs.
If larvae are drifted away from mature female or if they settle on the sea bottom, they develop into females. Thus determination of sex is due to environmental factors.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.