ZOO510 Final Term MCQs and Questions 2019

MUHAMMAD IMRAN

ZOO510 - Economic Zoology

Q1. Mode of action of pesticide and pest resistance. (10 marks)

Mode of action: how they work to control the pest

• Systemic pesticides are absorbed through tissues and transported elsewhere where the pest encounters it through feeding • Used on plants or livestock
• Contact pesticides must come in direct contact with the target pest

Pesticides vary in how they work to actually control the pest. We call this the mode of action

• how they kill or control the pest.

Some pesticides are systemic and actually move through animal or plant tissues and the pest encounters it when feeding on the animal or plant.

Other pesticides work by contact action like battery acid on your pants. You must make sure that you apply the material so that it comes into direct contact with the pest.

Selectivity: what range of pests they affect

• Non-selective – kills all related pests – for example some herbicides kill all green plant that gets a sufficient dose
• Selective – kills only certain weeds, insects, plant pathogens – for example other herbicides only kill broadleaf weeds not grasses

Pesticides also vary in their selectivity or how many different pest species they target.

Some affect all related organisms equally and are called non-selective. A good example is glyphosate, the active ingredient in Roundup Original. Glyphosate is non-selective when applied to green plants. ANY green plant that gets a sufficient dose will die whether it’s a broadleaf or a grass plant.

In contrast, a selective pesticide only kills a small group of related organisms and does not harm others. The herbicide 2,4-D is a good example. It only kills broadleaf plants and does not harm grass plants when applied according to label directions.

Persistence: how long they remain active in the environment

• Residual pesticides – remain active for weeks, months, years – for example herbicides used around road guard rails
• Non-residual – inactivated immediately or within a few days – for example – some herbicides do not remain active in the soil once applied

Persistence is the term used for how long a pesticide remains present in the environment. DDT, which is no longer used, was a very persistent insecticide that’s still found in the environment today. Many of the new products break down in a matter of hours or a few weeks. There are some persistent materials on the market today; we call them residual insecticides and herbicides and use them where we want long-term control.

Applications of residual herbicides are made to rights-of-ways so repeated applications are not required throughout the year.

Non-residual materials are also available, they break down very quickly.

Q2. Source of protein. (3 marks)

Sources of Protein

6 common sources

1. Soybean Meal
2. Cotton Seed Meal
3. Fish Meal
4. Tankage
5. Skim Milk
6. Alfalfa

Q3. Difference between hygene quality and milk. (3 marks)

Hygiene and Milk Quality

Dirty milk (containing dirt, bacteria or antibiotics) can cause serious problems when processing. Dirty milk is caused by unhygienic milking machines or poor milk filters. Antibiotics are found in milk as residues from treatments to cows for mastitis. When milk is found to be not up to standard, it may be rejected by the creamery or bought at a lower price.

Q4. Milk composition . (5 marks)

Milk used for bottling or drinking must by law contain 3.6% fat and 8.5% SNF. Creameries buy milk in many different ways – sometimes at a flat rate per kg. Sometimes, however, it may be by percentage butterfat or protein. Milk composition varies also amongst different breeds. The milk of the Jersey cow has the highest butterfat and SNF content of any cow. Also the composition of milk varies during milking. The milk at the start may only contain 1% fat, while the milk at the end (“The Stripping”) may contain 10% fat.

Q5. Bubonic plague . (5 marks)

14th Century Europe: mysterious scourge kills millions Centuries later it was found that rat fleas became infected with disease-causing bacteria Fleas sought other warm-blooded hosts (humans) when rat numbers declined Plague is currently managed monitoring for plague and reducing the number of rodent-hosts for fleas

Do you remember anything from your history lessons about Black Plague in Europe? During the 14th Century there were Plague outbreaks, millions of people died, and at the time it wasn’t understood why. Centuries later, it was discovered that Plague was a bacterial disease and it was spread by fleas found in rodent populations. Besides biting rats, infected fleas would bite humans and other mammals. Bubonic plague is still present in some rodent populations today, even here in the United States. But with rodent management and plague monitoring, only a few people a year are infected with plague.

Q6. Bio accumulation . (2 marks)

Bioaccumulation: when a chemical accumulates in animal fat (historical fact) Bioaccumulation is the gradual accumulation of substances, such as pesticides, or other chemicals in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost by catabolism and excretion.

Q7. Monogastric and polygastric . (2 marks)

A monogastric organism has a simple single-chambered stomach, compared with a ruminant organism, like a cow, goat, or sheep, which has a four-chambered complex stomach. Monogastric (simple stomach) Pig, Dog, Human