Question

-:Plz Help:-Really Urgent☑️

Important Question With Answers From The Chapter "Reproduction In Organisms" [1 & 2 & 3 Marks]
[From The Topic Mentioned In Image]
[Notes Will Be Accepted]
【7 Points】

❌❎No Spamming❎❌

Answer 1

hello dear brother...!!!

1) Importance of Reproduction :

• continuity of species : reproduction maintains the continuity of species

•population organisation : reproduction maintains population of the young, adult and the aged person

•variation : reproduction introduces variation in the organism, the useful variations are essential for adaptation and evolution.

• life : life exist on earth due to reproduction in organism.

2) Basic Features of reproduction :

• All modes of reproduction have some common basic features,
a) synthesis of RNA
b) Replication of DNA
c) Cell division
d) Growth of cells
e) Formation of reproductive units
f) Formation of new individuals from reproductive units.

3) Types of reproduction :

•The mode of reproduction depends upon the structural complexity, habitat of the organism and physiology of the organism.

the major two types are :
a) Asexual reproduction
b) sexual reproduction .

4) Asexual reproduction :
•when the offspring are produced by a single parent without the involvement of genetic fusion, the reproduction is called asexual reproduction.

•offspring that are produced by this process are exact copies of their parent. such genetically and morphologically similar individuals is termed as CLONES.

5)vegetative reproduction of plants :
•vegetative propagation (vegetative reproduction) is the formation of new plants from vegetative units or propagules such as buds, tubers, rhizomes.. etc.

•this method produces a large number of population of clones in short period of time. it preserves purity, resistance. vegetative reproduction are of two types a) natural b) horticulture.

6)Micropopagation:
•tissue culture by plant is called micropropagation. This method includes propagation of plants by culturing the cells, tissue and organ which is called tissue culture.

•The undifferentiated mass of cells are called callus. this method helps in obtaining virus free plants .

7)Sexual reproduction :
•the process of development of new individual through the formation and fusion of gametes. Sexual reproduction is also called AMPHIMIXIS

•The sexual reproduction involves four process : a) gametogenesis b) zygote fertilization c) repeated mitotic divisions d) development of the embryo

8)Parthenogenisis :
•The development of an egg (ovum) into a complete individual without fertilization is known as parthrnogenisis.

•there are two types of parthenogenesis :
a) natural parthenogenesis
b) artificial parthenogenesis.

9)Phases of life cycle :
a) Juvenile phase / vegetative phase :
• it is the pre -reproductive phase in the life cycle of individual. the period of growth between the birth of an individual up-to reproductive maturity.

b) Reproductive phase :
• The organism has the capability to reproduce in this phase. Reproductive organs develop and mature during this period.

c) Senescent phase :
• It begins at the end of the reproductive phase senescence is the last phase of life span. it ultimately leads to death.

10)Events of sexual reproduction :

a) Pre - fertilization events :
•gametogenesis • gamete transfer

•gametogenesis refers to the process of formation of two types of gamete - male and female

•Two types of gamete must be brought together for fertilization. mostly male gamete is motile (movable) and female gamete is non motile.

b) Fertilization :

•the fusion of gametes, the process called syngamy results in the formation of diploid zygote. the complete process is called fertilization.

•this fertilization may be internal fertilization or external fertilization.

c) Post - fertilization :
•events that takes after the formation of zygote are called post fertilization events.

•diploid zygote formation, development of zygote.

•embroyogenesis, this refers to the process of development of embryo from the zygote this process undergo cell division and cell differentiation.

•animals are categorised into oviparous and viviparous .

•zygote develops into embryo, ovule into seeds, ovary into fruit and pericarp is formed which is the protective layer (function).

________________________________

hope it is useful to you...!!!!

Answer 2

Heya !!


Q➡Why is reproduction essential for organisms?
Ans▶Reproduction is the ability of living organisms to produce a young one similar to itself. It ensures continuity of a species generation after generation. Reproduction introduces variation in the organisms. Useful variations are essential for adaptation and evolution. Therefore, it is essential for organisms.



Q➡ Which Is a better mode of reproduction: sexual or asexual? Why?
Ans▶Sexual reproduction is a better mode of reproduction than asexual mode because the former contributes to the evolution of the species by introducing variation in a population and occurs much more rapidly. Variation in a population occurs because of the fusion of male and female gametes (sexual reproduction) carrying different sets of chromosomes.

Q➡Why is the offspring formed by asexual reproduction referred to as clone?
Ans▶Asexual reproduction is a type of reproduction in which a single individual is capable of producing offspring. These offspring are not only genetically and morphologically similar to one another but also similar to their parent. Clone is the term given to individuals that are genetically and morphologically similar. Thus the offspring produced by asexual reproduction are called clones.

Q➡Distinguish between asexual and sexual reproduction. Why is vegetative reproduction also considered as a type of asexual reproduction?
Ans▶
Asexual reproduction :

◼It occurs only in invertebrates and lower chordates
◼ It's always uniparental
◼ Gametes are not formed
◼It involves only mitosis
◼ Daughter organisms are genetically identical to the parent
◼ Since there is no variation, so it doesn't contribute to evolution of the species

Sexual reproduction :

◼It occurs almost in all types of animals
◼It is usually biparental
◼Two types of gametes are formed
◼It involves both Meiosis and mitosis
◼ Daughter organisms genetically differ from their parents.
◼ Because of variations, it contributes to the evolution of species

In plants asexual reproduction is called vegetative reproduction because vegetative plant parts like rhizome, runner, s_ucker, tuber, bulb all are capable of producing off springs These parts give rise to daughter individuals without the involvement of two parents.


Q➡ Define:
(a)Juvenile phase
(b)Reproductive phase
(c)Senescent phase.
Ans▶(a)Juvenile phase : All organisms have to reach a certain stage of growth and maturity in their life before they can reproduce sexually. That period of growth is called juvenile phase. However, this phase is known as vegetative phase in plants. This phase is of different durations in different organisms.
(b)Reproductive phase: The end of juvenile/ vegetative phase marks the beginning of reproductive phase. During this phase, the organisms produce offspring. In higher plants, this phase can be easily seen when they come to flower but in animals, the juvenile phase is followed by morphological and physiological changes prior to active reproductive behaviour. The reproductive phase is also of variable period in different organisms like some plants, flower throughout the year while others show seasonal flowering. In animals like birds lay eggs seasonally “but when in captivity (as in poultry farms) can be made to lay eggs throughout the year. Placental female mammals, undergo cyclical changes in reproductive organs during this phase.
(c) Senescent phase: It begins from the end of the reproductive phase. During this phase of life span, there is progressive deterioration in the body (like slowing of metabolism, etc.). Old age ultimately leads to death.




Q➡ Differentiate between gametogenesis from embryogenesis.
Ans :
Gametogenesis :
◼It is the formation of male and female gametes...
◼ Gametes are haploid cells...
◼ Both mitotic and meiotic division take place...
Embryogenesis :

◼It is the formation of embryo from zygote ...
◼Embryo is a diploid cell...
◼Only mitotic division occur..




Q➡What is % bisexual flower? Collect five bisexual flowers from your neighbourhood and with the help of your teacher find out their common and scientific names.
Ans▶Flowers in which male and female sex organs (stamens and carpels) are borne on the same flowers are called bisexual flowers. You can observe following bisexual flowers in your kitchen and colony gardens :
(i)Brassica (sarson) – Brassica campestris
(ii)Onion – Allium cepa
(iii)Garden Pea (Edible pea) – Pisum sativum
(iv)Petunia – Petunia hybrida
(v)China rose (shoe flower) – Hibiscus rosa- sinensis.



Hope this helps you