What is a pyramid of biomass?

55. What is a pyramid of biomass?
Biomass is the amount of living material present in an ecosystem, measured both as fresh weight or dry weight. In the case of a terrestrial ecosystem, the maximum biomass is with the producers. The biomass goes on decreasing with successive trophic levels. The pyramid of biomass in a terrestrial ecosystem becomes upright, ,but in an aquatic ecosystem, it is mostly inverted.
56. Write notes on pyramid of energy.
Producers have the maximum energy. Energy becomes progressively less at successive trophic levels. The amount of energy entering each successive trophic ievel gradually decreases as there is always loss of energy in the previous level. The pyramid of energy expresses the rate of food production.
57. Briefly explain ecological efficiencies.
Ecological efficiencies indicate the efficiency with which organisms exploit their food resources and convert the food into biomass which is made available to the next higher trophic level. The important efficiency measures for an ecosystem are (a) photosynthetic efficiency (b) net production efficiency (c) assimilation efficiency and (d) ecological efficiency.

66. What are the major biomes?
The regional biotic unit with climax vegetation is generally called a biome. Major biomes are (1) Forest biome (2) Grassland or Savanna biome and (3) Desert biome. Major forest biomes in India are (a) Tropical rain forest biome (b) Tropical deciduous forest biome (c) Temperate broad - leaved forest biome and (d) Temperate needle-leaf or coniferous forest biome.
Grassland ecosystems have treeless herbaceous plant cover. Desert biomes experience *longed moisture scarcity.
67. What are the characteristic features of temperate broad-leaved forests?
Here forests occur between 1500 to 2400 m altitude. Oak is the predominapt species. These plants are evergreen. Trees reach- 25-30m height with dense canopy. It is characterised with least developed herbaceous cover. Epiphytic flora is rich in oak forest. Annual rain fall is 10-25 cm.

Long Answer type Questions

73. What are the fundamental trophic levels? Describe the general make - up of each
The two fundamental trophic levels are producers and consumers.
(1) Producers (Autotrophs): Green plants are the producers in an ecosystem. Photosynthetic bacteria are also producers. These organisms convert light energy into chemical energy which is stored in glucose molecule. CO2 is absorbed and 02 is liberated as a result of this process. These organisms provide food for the rest.
(2) Consumers (Heterotrophs): They are members which consume the food synthesized by the producers. All living animals are thought to be consumers. Consumers may be of the following types.
(a) Primary consumers:- They include herbivores which depend upon green plants (First order). eg. cow, goat, rabbit, deer etc.
(b) Secondary consumers (Second order)- are carnivo. rous which eat the herbivores.
(c) Tertiary consumers are carnivorus animals which eai other carnivores. eg. Snakes eat fish, frog etc.
(d) Top consumers are carnivores of an ecosystem which are not killed and eaten by other animals.
eg. lion, vultures etc.