Reproduction, The Survival Instinct

By | June 7, 2021

 All living organisms have an instinct to measure their own lives so survive through their generations. This survival instinct is helped by the tactic of reproduction.

Living things take birth, age and die. Before death all individuals give birth to the offsprings (children) to continue their race. birthing to offspring, which are the identical as parents, is assumed as reproduction. Reproduction is one of the foremost important characteristics of life.

Reproduction is that the creation of latest lifetime of its own kind.

Reproduction is crucial for the survival of organisms. A species will disappear from the face of the globe if it doesn’t reproduce. Reproduction takes place in both, the plants and thus the animals.

 MODES OF REPRODUCTION

There are two modes of reproduction:

(a) agamogenesis, and

(b) reproduction.

 ASEXUAL REPRODUCTION

In the process of agamogenesis, one parent gives rises to new individuals. Both, plants and animals reproduce asexually. Reproduction takes place in several ways. as an example by:

*binary fission as in bacteria, amoeba,

*budding as in yeast and hydra,

*fragmentation as in spirogyra,

*spore formation as in moulds, mosses and ferns, and

vegetative propagation as in plants with tubers, bulbs, suckers, runners, bud bearing leaves (bryophyllum), cuttings and other vegetative parts of a plant body.

SEXUAL REPRODUCTION IN FLOWERING PLANTS

Flowers are the reproductive parts of a spermatophyte. Stamen in flower are the male sex organs. Each stamen bears fine dusty pollens or microspores in their anthers. Pollens are transferred to the stigma of the carpel by the strategy of pollination. Carpel or pistil during a awfully flower is that the female organ. Carpel bears one or many ovules. Each ovule bears an gamete or the famale gamete. Pollen on reaching the stigma germinates producing a plant part and two male gametes. The plant part grows towards the ovule to enter it. one amongst the 2 male gametes from the natural object enters the ovule to unite with the feminine gamete, the gamete. The union of the male gamete with the gamete (female gamete) is understood as fertilization.

 the merchandise of fusion of male and feminine gamete (fertilization) is termed oospore or zygote. The zygote develops and convert into an embryo (the baby plant) which remains within the seed. On germination the baby plant from the seed grows resolute form, an adult plant.

In the process of amphimixis sex cells (gametes) are formed, which generally come from two parents, one male and also the other female. Male and feminine gametes unite on fertilization forming zygote. Zygote develops and convert into an embryo growing into a baby.

SEXUAL REPRODUCTION IN ANIMALS

Look around and observe for the young ones from different animals. Kitten, puppy, chick and calf are type of the common young ones from different animals. have you ever ever ever ever wondered on how the babies are born? have you ever ever ever ever seen the young ones of frog and butterfly? Do they provide the impression of being like their parents? allow us to now determine about the approaching of babies.

Oviparous and Viviparous Animals

All animals lay eggs while some animals give birth to young ones, Insects, frogs, snakes, turtles and birds lay eggs. Young ones start from the eggs. Cat, dog,Jackal, man and elephant give birth to young ones. The animals which lay their own eggs are called oviparous animals. The animals which give birth to child are called viviparous animals.

REPRODUCTION IN OVIPAROUS

All laying animals are called oviparous animals. Insects, worms, frog and fish are oviparous animals. we’ve already Moth learnt about the life cycle during variety of the animals. We may recapitulate the life cycle of the silkworm: In silkworm male and feminine are separate. the feminine lays the eggs. Before laying, these eggs are fertilized within the body of the mother(female) with the sperms from father (male), and thus the eggs laid are literally zygotes.

Fertilization in insects is internal

The fertilized eggs create to larvae (also called caterpillars), pupa then adult.

Eggs → Larva → Pupa → Adult.

(zygotes)

Reproduction and life cycle during a butterfly and mosquito is that the identical. Study the stages within the life cycle of a mosquito within the image given below.

 Reproduction in Toads and Frogs

Toads and frogs are common found near a pond during early rains. Late within the season or the start of winter male frog which is smaller and dark climbs on the rear of an infinite and fair female. the feminine is fat along with her belly filled with eggs. Both, male and feminine frogs swim around in an exceedingly pond for sometime then they’re available near the shore where the feminine starts laying eggs (ova). because the large mass of eggs emerge from the body of the feminine, the male sheds sperms over them. Sperms swim to the eggs. One sperm fuses with one egg (ovum). Fusion of a sperm with an egg is termed fertilization. Product of fertilization is zygote. Fertilization in frog takes place in water. Fertilization in frog is external fertilization which is happened outside the body of the mother.

The fertilized eggs from frog are enclosed in thick jelly. the whole mass of zygotes in an exceedingly very jelly is thought as spawn.
There are three distinct stages within the event of a frog from zygote to adult. The stages of frog are eggs (zygotes), larva (tadpole) and adult. The tadpole stage in frog is a mid stage from aquatic to land habitat. Tadpole has gills for breathing in the water and finned tail to swim in the water. Adult frog has lungs for inhaling air.

In fish also, fertilization is done externally and it takes place in water.

METAMORPHOSIS, Young Ones to Adults

From the life cycles of a silkworm moth, butterfly, mosquito and frog we learn that the young one coming out of the egg (Zygote) has to pass through certain stages of development before growing into an adult. In insects the stages are egg, larva, pupa, adult. In frog the stages are egg, tadpole (larva), tailed tadpole, adult. The changes taking place during the development of an animal is called metamorphosis.

REPRODUCTION IN BIRDS, HEN

Hen and cock represent the birds.

Now, we will learn about the development of a chick from an egg in hen. Chick or chickens come from hen. Hen is an oviparous animal. It lays eggs. The eggs are fertilized internally before laying. In case cocks imale heni are not around, the eggs laid by a hen are not fertilized.

Development of Fertilized Eggs in Hen:

 CLONING, baby from a Body Cell

Cloning is the forming of a baby from “body cell” and not ovum (egg) and that too without fertilization.

In the process of cloning, egg from a sheep ‘A’ is taken out and its nucleus is replaced with a nucleus from a body cell from another sheep ‘B’. The cell thus produced, with the nucleus from the body cell of ‘B’ is implanted into the womb of sheep ‘A’ where it develops into a normal baby sheep.

The baby sheep thus born is found to be exactly similar to the sheep ‘8’, the source of the nucleus in the developing embryo. The baby is termed “CLONE” and the process is “cloning”. The clone has no similarities with the sheep in whose womb it developed.

Cloning experiment was performed in Roslin Institute in Edinburg, Scotland.

 Dolly was bom from the ovum from ‘A’ but with the nucleus from a body cell from ‘B’. The foetus developed in the womb of ‘A’ but Dolly was found identical to ‘B’ and it did not show any character of ‘A’.
 Dolly was bom from the ovum from ‘A’ but with the nucleus from a body cell from ‘B’. The foetus developed in the womb of ‘A’ but Dolly was found identical to ‘B’ and it did not show any character of ‘A’.

Dolly was born on 5th July, 1996 and died on 14 February, 2003 due to lung disease. Dolly lived as usual life and produced babies of her own through normal sexual way.

An Organism Produced Vegetatively (from a body cell) is a Clone.

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