Sexual Reproduction in Flowering Plants — BIOLOGY STD 12 Science — Question

Somatic chromosome number is 40. What shall be the chromosome number in the cells of seminiferous tubules?

Name the type of curve that characterizes most populations growing in favourable environment. Define carrying capacity.

Answer the following questions:
Would Western Ghats ecosystems be less functional if one of its tree frog species is lost forever? Substantiate your answer in the light of hypothesis proposed by Paul Ehrlich.

Name the important mammary gland secretions that help in resistance of the new born baby.

Given below is a list of autotrophs and heterotrophs. With your knowledge about food chain, establish various linkages between the organisms on the principle of ‘eating and being eaten’. What is this inter-linkage established known as?
Algae, hydrilla, grasshopper, rat, squirrel, crow, maize plant, deer, rabbit, lizard, wolf, snake, peacock, phytoplankton, crustaceans, whale, tiger, lion, sparrow, duck, crane, cockroach, spider, toad, fish, leopard, elephant, goat, Nymphaea, Spirogyra.

Discuss about the major programs that the Ministry of Environment and Forests, Government of India, has initiated for saving major Indian rivers from pollution.

Draw a schematic transverse section of a mature anther of an angiosperm. Label its epidermis, middle layers, tapetum, endothecium, sporogenous tissue and the connective.

Rearrange Ramapithecus, Australopithecus and Homo habilis in the order of their evolution on the Earth. Comment on their evolutionary characteristics.

Name the blank spaces a, b, c and d given in the following table:

Type of microbe	Name	Commercial product
Bacterium	a	Lactic acid
Fungus	b	Cyclosporin A
c	Monascus purpureus	Statins
Fungus	Penicillium notatum	d