What is metamorphosis?
The transformation from a fertilized egg to an adult.
Name the stages in the life cycle of a toad.
Egg, Zygote, Young Tadpole, External Gill Stage, Internal Gill Stage, Limb Stage, and Young Toad.
What hormone controls metamorphosis in toads?
Thyroxine.
What are the two types of metamorphosis in insects?
Complete and incomplete metamorphosis.
Describe complete metamorphosis.
Insects pass through four stages: egg → larva → pupa → adult.
What is incomplete metamorphosis?
Insects develop from an egg into a nymph, which resembles a small adult but lacks wings and sexual maturity.
List the stages in the life cycle of a housefly.
Egg, Larva, Pupal Stage, and Adult.
How does the cockroach life cycle differ from the housefly life cycle?
Cockroaches undergo incomplete metamorphosis, developing from an egg to a nymph and then an adult.
What are the main parts of a bird's egg?
Shell, membranes, albumen, yolk, and chalaza.
How are mammalian eggs different from bird eggs?
Mammalian eggs are microscopic and develop inside the mother's body.
What is oviparity?
A reproductive strategy where eggs are laid in the environment, and the embryo develops outside the mother’s body.
Define viviparity.
A reproductive strategy where embryos develop inside the mother’s body, nourished by a placenta.
What is ovoviviparity?
A reproductive strategy where eggs are retained inside the mother’s body without a placenta, and the young hatch inside before being born alive.
What role does the placenta play in mammals?
It connects the embryo to the mother for nutrient and oxygen exchange.
Name the embryonic membranes in mammals and their functions.
Amnion (cushions embryo), Chorion (oxygen absorption), Allantois (respiration and waste disposal).
What is the function of the umbilical cord?
It links the embryo to the placenta, transporting blood and nutrients.
What are the stages of the life cycle of a cockroach?
Egg, Nymph, and Adult.
What is the purpose of the yolk in vertebrate eggs?
It provides nutrients to the developing embryo.
Why are fish eggs enclosed in a case?
To provide nourishment for the embryo until it hatches.
Describe the shell of reptile eggs.
It is tough and leathery, allowing the egg to absorb water from the environment.
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