Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Life Cycle: The series of changes that a living organism passes through from the beginning of its life until its death is called its life cycle.
Metamorphosis: A biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. For a frog, this is the transition from an aquatic tadpole to a terrestrial adult.
Stage 1: Egg (Spawn) - Adult female frogs lay hundreds of eggs in water, usually in floating clumps called 'frogspawn'. The jelly-like coating protects the embryos.
Stage 2: Tadpole - After hatching, the organism is called a tadpole. It lives entirely in water, has a tail for swimming, and breathes through external gills, absorbing dissolved oxygen () from the water.
Stage 3: Froglet - As the tadpole grows, it develops hind legs, then front legs. Its tail begins to shrink through a process of cell reabsorption. It starts developing lungs for breathing air.
Stage 4: Adult Frog - The tail is completely absorbed. The frog now breathes using lungs and its moist skin. It can live on land but stays near water to keep its skin moist and for reproduction.
Characteristics of Living Things in Frogs: Like all living creatures, frogs exhibit growth, movement, response to stimuli, and reproduction (symbolized by the cycle itself).
📐Formulae
💡Examples
Problem 1:
Identify the primary respiratory organ in a tadpole versus an adult frog.
Solution:
Tadpole: Gills; Adult Frog: Lungs and Moist Skin.
Explanation:
During metamorphosis, the frog undergoes internal changes where gills are replaced by lungs to facilitate breathing atmospheric oxygen ().
Problem 2:
A scientist observes a frog-like creature with four legs and a small, stubby tail. In which stage of the life cycle is this creature?
Solution:
The creature is in the Froglet stage.
Explanation:
The presence of legs combined with a remaining (shrinking) tail is the defining physical characteristic of a froglet transitioning into an adult frog.
Problem 3:
Why must frog eggs be laid in water or very moist environments?
Solution:
To prevent desiccation (drying out) and provide a medium for external fertilization.
Explanation:
Unlike reptile or bird eggs, frog eggs do not have a hard shell; they are surrounded by a permeable jelly-like substance that requires water to maintain its structure and protect the embryo.