Question

Many heterotrophic organisms live on one and the same plant. Observe one such plant in your neighbourhood and find out about the heterotrophs that depend upon it for their food. Observe and make notes about other organisms that use these heterotrophs as their food.

Answer 1

1. Cuscuta: Plant Parasite
   1. Existence on the plant:
      • Cuscuta is an obligate parasite.
      • It cannot produce its own food, so it grows by twining around the trunk of the host plant.
      • It sucks the sap from the plant’s veins.
   2. Effects on the plant:
      • The plant becomes weak and its growth is stunted.
      • Sometimes the plant dries up completely and dies.
   3. Use of Cuscuta by other organisms:
      • Some insects and fungi use cuscutaas food.
      • For example, certain types of insects live on cuscuta, which consume it.
2. Aphids: Insect Parasite
   1. Existence on the plant:
      • The aphids are found on the underside of the leaves and suck the sap of the plant.
      • They are very small and are found in large numbers on shrubs, fruit trees, and flowering plants.
   2. Effects on the plant:
      • The leaves of the plant dry up and turn yellow.
      • The natural immune system of the plant is reduced.
   3. Use of aphids by other organisms:
      • The ladybird beetle feeds on the aphids.
      • Some birds, such as sparrows and butterflies, eat the larvae.
3. Rust Fungus: Fungal Parasite
   1. Existence on plants:
      • Rust is a fungal parasitoid that grows on the leaves, trunk, and fruits of plants.
      • It penetrates the plant cells and absorbs nutrients.
   2. Effects on plants:
      • Red or brown spots appear on the leaves of the plant.
      • The plant gradually becomes weak, and its productivity decreases.
   3. Use of rust by other organisms:
      • Some types of fungi-eating microorganisms and insects feed on rust.
      • Some specific microorganisms (Bacteria and Fungi) are useful in controlling rust.