open ended questions for the exam

Question 1

chemical and biological control of pests and weeds

Answer 1

CHEMICAL
- herbicides; systemic (roots to phloem all through plant); selective (kill certain plants; broad leaf)
- pesticides - systemic; absorbed by roots; kill the insects on the plant when they eat the plant
- fungicides - prevent fungal disease
BIOLOGICAL
- natural predators, parasites, diseases
- integrated pest management - mixture of chemical, biological and cultural control

Question 2

ANIMAL WELFARE

Answer 2

COSTS AND BENEFITS - ETHICS
- intensive - costs: low price and low quality of life. benefits: less land required and less labour intensive. not ethical.
- free range - costs: more land required and more labour intensive. benefits: higher price and better quality of life. ethical.
INDICATORS OF POOR WELFARE
- stereotypy: repetitive movement
- misdirected behaviour: normal behaviour done to extremes
- failure of sexual or parental behaviour
- altered levels of activity: sleepiness, hyperaggression

Question 3

metabolic pathways, types of metabolic reactions, protein embedded

Answer 3

• metabolic pathways can be reversible, irreversible, and can follow alternative routes.
• metabolic pathways are enzyme controlled
• methabolic reactions can be catabolic (release energy, breakdown large molecules) or anabolic (require energy, build up large molecules)
• the proteins embedded in the membrane can be enzymes (speed up chemical reactions), pumps (active transport) or pores (allow diffusion/ osmosis (passive transport)

Question 4

regulators and thermoregulation

Answer 4

REGULATORS
- manintain internal environment regardless of external environment
- use metabolism to control internal environment
- can use a wide range of ecological niches
- high metabolic costs
THERMOREGULATION
- controlled by negative feedback
- control centre = hypothalamus
- COLD: shivering(muscle contraction generates heat); hair erector muscles(trapping/insulating air); increased metabolic rate(generates heat); vasoconstriction(decreased blood flow to the skin = less heat loss)
- HOT: sweating(water evaporates, cooling skin); lowered metabolic rate(less heat generated); vasodilation(increased blood flow to skin, more heat loss)