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The common wild oat (Avena fatua) is described as a noxious weed - Leaving Cert Agricultural Science - Question 3 - 2013
Question 3
The common wild oat (Avena fatua) is described as a noxious weed. (i) Give three reasons why this weed is considered noxious. (ii) Name two other noxious weeds. T... show full transcript
Worked Solution & Example Answer:The common wild oat (Avena fatua) is described as a noxious weed - Leaving Cert Agricultural Science - Question 3 - 2013
Step 1
Give three reasons why this weed is considered noxious.
Answer
- Contaminates Cereal Seeds: Wild oats contaminate crops sown for seed, making them unsuitable for their intended purpose.
- Hosts for Pests and Diseases: The wild oat serves as a host for pests such as the cereal eelworm and diseases like Barley Yellow Dwarf Virus, leading to lower crop yields.
- Invasive Nature: Avena fatua competes aggressively with other crops, decreasing agricultural productivity.
Step 2
Step 3
Give two reasons for the decline in the cultivation of Avena sativa.
Answer
- Decrease in Horse Population: With fewer horses requiring oats for feed, the demand for Avena sativa has diminished.
- Greater Demand for Barley: Farmers have shifted towards barley cultivation, which has a higher economic value compared to oats.
Step 4
Step 5
List three differences between complete and incomplete insect metamorphosis.
Answer
- Stage Distinction: In complete metamorphosis, the insect undergoes distinct stages: egg, larva, pupa, and adult. In incomplete metamorphosis, the stages include egg, nymph, and adult, where nymphs resemble smaller adults.
- Developmental Changes: Complete metamorphosis involves significant physiological changes during the pupal stage, while incomplete metamorphosis shows gradual changes.
- Examples: Complete metamorphosis is seen in butterflies, while insects like grasshoppers exhibit incomplete metamorphosis.
Step 6