SLOTHYS

• Modern phylogenetic techniques


  • Allow classifications of organisms (e.g. sloths) to be updated from earlier anatomical evidence
• Comparing amino acid sequences from the same protein produced by different sloths using DNA profiling


  More similarities = more closely related
• A mutation made the sloth hair more suitable for algae to colonise


  More algal growth helps newborn sloths survive by providing extra nutrients (e.g. nitrogen and phosphorus)
• Sloths with the advantageous hair allele

  More likely to survive, reproduce and pass alleles on to their offspring
• Over many generations


  Allele frequency increases in the population
• Calculating energy transfer efficiency

  1. Energy out (metabolic rate) = 162kJ/day/kg

  2. Energy in (leaf material) = 2000kJ/day/kg

  3. ETE = energy out/energy in x100 = 8.1%
• Low metabolic rate


  • Low rate of reaction/enzymes
  • Low rate of respiration -> less energy/ATP
• Low metabolic rate of the sloth

  Reduces the amount of virus found in their bloodstream
• Muscles of an olympic weightlifter vs a marathon runner

  • Endurance runners have more slow twitch fibres, more capillaries, more myoglobin, more mitochondria
  • Weightlifter has more fast twitch fibres, relies on anaerobic respiration for quick energy when oxygen supply is limited
• How enzymes in muscle cells could prevent the lactic acid from accumulating

  1. Enzymes could oxidise lactate to form pyruvate

  2. Pyruvate could enter the link reaction and be respired

  3. Pyruvate could be converted to glucose and used in respiration / glycolysis
• Method to calculate the biodiversity of different species

  1. Record the number of species on each sloth

  2. Record the number of individuals of each species

  3. Calculate the index of diversity for each sloth species

  4. The higher the index the greater the biodiversity
• Reasons why different moth species on the same sloth do not interbreed with each other

  • Sympatry of moth species that coexist become reproductively isolated due to one sloth not recognising courtship displays /pheromones
  • Different breeding times
  • Physically incompatible genitalia
  • Live on different parts of the sloth