Exam questions topic 7

• Scientists found base sequence of dna of whales Use information about base sequence to estimate the size of a whale population by using mark release recapture explain why

  1. Recording dna is like marking an animal
  2. Find identical base sequence which would show the animals been caught before
• Explain advantage for different niches

  Less comoetition for resources
• Student concluded that a decrease in acidity caused an increase in the number of water beetle species evaluate this conclusion (3)

  1. Correlation doesn’t mean causation
  2. Other abiotic : biotic factors
  3. Variation in number of nettle species at same particular ph or same number of nettle species at different ph
  4. Large sample

  
• Explain how the presence of fish in a lake can cause increase in beetle species

  Fish eat beetle predators
• Explain how high nitrate concentration increases the growth of algae (2)

  - more DNA and proteins

  - more cell division / more number of cells formed
• Describe how the reduced oxygen concentration of the water will change the composition of the community in the river(2)

  - lowest species diversity/ number of species

  - species tolerant to low oxygen thrive
•  suggest one advantage of leaving a strip of background between the hedge draw and field (2)

  
  

  

  - provides habitat for beneficial insects

  - insect pests predators to survive

  - conserve common weed plants

  - weeds are producers in food chains