QUESTIONS & ANSWERS
1. Define reproduction. Mention its significance.

Ans. Reproduction is defined as a biological process in which an organism gives rise to young ones similar to itself. Reproduction enables the continuity of species, generation after generation. Genetic variation is created and inherited during reproduction.

2.Morphologically and genetically similar individuals are called……………… Ans. Clones

3.The size of the crows and parrots are not very different but their lifespan show a wide difference. Justify your answer.

Ans. Life span of organisms are not necessarily correlated with their size.
4.Name the asexual reproductive structures of the following organisms(a) Penicillium (b) Sponge (c) Hydra (d)Algae

Ans. (a) Conidia (b) Gemmules (c) Buds (d) Zoospores

5. Why vegetative reproduction is also considered as a type of asexual reproduction?

Ans. In vegetative reproduction there is no formation & fusion of gametes . A single parent is involved in vegetative reproduction and offsprings formed are genetically identical. So vegetative reproduction is considered as asexual reproduction.
6.Offsprings formed due to sexual reproduction have better chances of survival . Why?

Ans. Offsprings formed by sexual reproduction are heterozygous. They show hybrid vigour and genetic variation. So the range of tolerance increases.

7.Differentiate between monocarpic and polycarpic plants.

Ans. Monocarpic plants flower only once in their life time. Eg:- rice,wheat etc. Polycarpic plants flower every year or season after attaining certain maturity. Eg- Jackfruit,Mango

8. Mention the type of cell division occurs during gamete formation in haploid and diploid organisms.

Ans. In haploid organisms mitosis occurs and in diploid organisms meiosis occurs.

9. Explain the cyclical changes occurs in primate mammals and non-primate mammals.

Ans. In non-primate mammals oestrus cycle occurs . This cycle consist of a short period of oestrous or heat followed by a passive period. During heat period the female has very high blood level of oestrogens and develops a strong sex heat. During this period the female received the male for copulation.In primate mammals menstrual cycle occurs . Menstruation occurs at the end of cycle

10. Name the following

(a) Animals which possess both male and female reproductive organs.(b) A plant bearing male and female flowers.(c) Process of formation of male and female gamete.(d) Formation of new organism without fertilisation.

Ans (a) Hermaphrodites (b) Monoecious (c) Gametogenesis (d) Parthenogenesis

11. Which plant is known as “Terror of Bengal”. Why it is called so.? 

Ans. Eichhornia or water hyacinth is known as terror of Bengal.Water hyacinth propagates vegetatively and quickly spread all over the water body in a short span of time. It causes depletion of oxygen in the water ultimately results in death of fishes and other water animals. 

12. Name the vegetative propagules of following plants.

(a) Ginger (b) Bryophyllum (c) Potato(d) water hyacinth (e)Agave (f) centella

Ans. (a) Rhizome (b) Leaf buds (c) Tuber(d) Offset (e) Bulbil (f) Runner

13. Define external fertilisation. Mention its disadvantages.

Ans. The fusion of gametes occurs outside the body of organism is called external fertilisation.Disadvantages;- It requires a medium for fusion of gametes. The young ones are often exposed to the predators and no parental care

14. Why are offsprings of oviparous animals at a greater risk as compared to offsprings of viviparous animals?

Ans. In viviparous animals the young ones develops inside the body of female organisms, as a result, the young ones gets better protection and nourishment for proper development. In oviparous animals fertilisation and the devlopment of zygote takes place outside the body of the female parent. In this the fertilised eggs and offspring remain vulnerable to predators threatening their survival upto adulthood.

15.Describe the post fertilisation changes in a flower.

Ans. The post fertilisation changes in a flower are:- Zygote develops into embryo. Ovule develops into fruit. Ovary develops a thick wall called pericarp.. Sepals, petals and stamen fall off.