Describe the inter-relationship between productivity, gross primary productivity and net productivity.
The rate of biomass production per unit area, over a time period by plant during photosynthesis is called productivity. * It is expressed in (kcal m–2)yr–1 or g/m2 / yr or g m–2 y –1.* The amount of biomass or organic matter produced per unit area over a time period in plants during photosynthesis is called primary production.
It is commonly observed that parents feel embarrassed to discuss freely with their adolescent children about sexuality and reproduction. The result of this parental inhibition is that the children go astray sometimes.
(a) Explain the reasons that you feel are behind such embarrassment amongst some parents to freely discuss such issues with their growing children.
(b) By taking one example of a local plant and animal, how would you help these parents to overcome such inhibitions about reproduction and sexuality ?
(a) Compare, giving reasons, the J-shaped and S-shaped models of population growth of a species.
(b) Explain ‘fitness of a species’’ as mentioned by Darwin.
(a) When a seed of an orange is squeezed, many embryos, instead of one are observed. Explain how it is possible.
(b) Are these embryos genetically similar or different ? Comment.
Write the different components of a lac-operon in E. coli. Explain its expression while in an ’open’ state.
(a) Organisms may be conformers or regulators. Explain this statement and give one example of each.
(b) Why are there more conformers than regulators in the animal world ?
