6. (a) (i) To what phylum do insects belong? (ii) Describe a role insects can play in crop production - Leaving Cert Agricultural Science - Question 6 - 2009

Insects play several crucial roles in crop production, primarily in pollination. They facilitate the fertilization of flowering plants by transferring pollen, which is essential for the production of fruits and seeds. Additionally, some insects act as biological control agents, managing pest populations naturally, thus minimizing the need for chemical pesticides.

1. Habitat changing: Modern agricultural practices often involve the conversion of diverse habitats into monocultures, which decreases biodiversity and reduces insect populations.
2. Indiscriminate pesticide use: The widespread application of pesticides can be toxic to non-target insect species, leading to significant declines in their populations.

The stages in the life-cycle of an insect that undergoes complete metamorphosis are:

1. Egg
2. Larva
3. Pupa
4. Adult (imago).

Incomplete metamorphosis refers to a type of life cycle in which the insect develops through three stages: egg, nymph, and adult. In this process, the nymph hatches from the egg and resembles a smaller version of the adult, gradually growing and molting into its adult form without a distinct pupal stage.