Question

Phyllodes and cladodes are examples of?
A. Analogous organ
B. Homologous organ
C. Either analogous or homologous organ
D. Modified stem

Answer 1

Hint: A phylloclade is a modified stem responsible for photosynthesis. Melanoxylon is an example of a plant with phyllodes and cactus and Coccoloba has phylloclades. A phyllode is a modified leaf that bears an axillary bud while a Cladode is a modified green stem of limited growth which appears like leaves with spiny tips, e.g., Ruscus aceileuius, Asparagus, etc.

Complete answer: Phyllodes and cladodes are examples of an analogous organ. It is because both perform the function of photosynthesis but have a different origin. Cladode refers to a modified green stem of limited growth. It appears to be like leaves with spiny tips, e.g. Ruscus aceileuius, Asparagus. They may be seen in a cluster or singly in the axil of a scale leaf. On the other hand, phyllode is the modified leaf (petiole), it is aerial or a branch modification. It bears nodes and internodes at intervals e.g., Opuntia. Cladodes are also called cladophylls. Analogous organs are the contrary of homologous organs, which have similar functions but different origins. An example of an analogous trait is the wings of insects, bats and birds that evolved independently in each lineage individually after diverging from an ancestor without wings.
i. Homologous organs are distinguished as organs of different animals that retain a similar structure but differ in their functions. The structure of the two distinct animals resembles but the purpose of their organs varies.
ii. Stem modifications are modifications of the stem, vegetative buds and floral buds of plants growing in different conditions. They perform functions such as climbing, protection, synthesis of food and vegetative propagation.
Hence, the correct answer is option A.

Note: Leaves are often modified, like other organs for various functions other than photosynthesis. Example: tendrils of plants are leaves modified for support. In certain plants, the entire leaf is a tendril, and photosynthesis in these plants is delegated to leaflike structures called stipules at the base of each leaf.