Organisms and Populations — BIOLOGY STD 12 Science — Question

Explain: Microbes are omnipresent.

What is entomophily? Describe the features of entomophilous flowers.

Banana crop is cultivated by farmers without sowing of seeds. Explain how the plant is propagated.

Angiosperms bearing unisexual flowers are said to be either monoecious or dioecious. Explain with the help of one example each.

The immune system of a person is suppressed. In the ELISA test, he was found positive to a pathogen.

1. Name the disease the patient is suffering from.
2. Write the full name of the causative organism.
3. Which cells of the body are affected by the pathogen.

Identify the statements as correct/ incorrect and give proper justification for your answer.

1. Zygote is the link between two generations.
2. Zygote is a single cell.
3. In organisms with haplontic life cycle, zygote divides by meiosis to form haploid spores.
4. In organisms with haplontic life cycle, zygote divides by mitosis to form haploid spores.

In the pie chart (a) and (b) drawn below to show the global animal diversity, which group of animals would you name and write on the areas shaded back in (a) and (b). In which kind of habitat would you find these groups of animals?

Condoms are the most popular contraceptive devices, used by human males. Give reasons.

Micropropagation is a method of producing new plants in a short duration using plant tissue culture.

A true breeding tall plant is crossed with a true breeding dwarf plant. F, progeny is 100% tall and F, has tall : dwarf in the ratio 3 : 1.

1. Explain why F, shows only one type of parental phenotype.
2. Name the patterns of inheritance in which the ratio deviates from above. Also mention the deviated phenotypic ratio.