(a)State the second law of thermodynamics.
(ii) Use the second law of thermodynamics to explain the flow of energy across different trophic levels in a food chain.
(b) (I) State three factors that can likely limit the size of human populations.
(ii) Outline two ways each by which humans can overcome the factors named in (b)(i).
Explanation
(a)(i) Second law of thermodynamics: This states that when there is conversion of energy from one form to another; there is always a loss/ decreases; in the amount of useful energy.
(ii) Flow of energy across different levels in a food chain
- Transfer of energy between trophic levels
- Is not 100% completely efficient
- Successive levels have less energy
- And support fewer organisms
- Primary producers/green plants have the highest energy
- When herbivores/ primary consumers feed on primary producers
- The energy level is reduced
- When carnivores/secondary consumers feed on herbivores
- The energy level is further reduced
- Part of the energy is lost as heat at each trophic level
- Not all parts of the preceding organisms are eaten by the predator/organism at the next trophic level; Energy is lost in the process of respiration/feeding/movement/metabolic active
(b)(i) Factors that can limit human populations: –
- Famine / scarcity of food
- diseases/epidemics
- increased mortality/death rate by wars /natural disasters emigration
- increase mortality – reduced natality/birth rate.
(b)(ii) Ways of overcoming the factors:
- Famine: – Availability of food (through improved farming techniques)
- Mechanized farming
- improved storage facilities
- Use of fertilizers/agro chemicals
- Genetic engineering
- Improved planting materials/seeds/stems etc.
- Improved finance
Diseases:
- Health care
- Immunization
- Preventive drugs
- Improved diet
- Good sanitation.
Wars:
- Improved/enhanced communication/dialogue
- Mediation.
- Prohibition of illegal firearms
- Good governance Natural disasters
- study of the environment
- promote environmental friendly activities
- preservation of natural habitats
- Accurate and prompt forecast of disaster
Increased Mortality/death rate:
- Provision of balanced/good diet
- Good Medicare
- Adequate security
- Peaceful resolution of conflicts/prevention of wars
- Effective management of disaster
Emigration: –
- Provide adequate food/shelter
- Improved health/environment/sanitation
- Urbanization/development
- Reduced natality/Birth rate
- Apply birth control methods
- Legislation against abortion
- Education/ awareness against sexual transmitted diseases (STD’s):