Types of Fertilisation
Types of Fertilisation
Internal Fertilisation and External Fertilisation
We have just studied that the fusion of a sperm with an egg is called fentilisation Now, the egg (or ovum) is made in the body of a female animal. So, the fertilisation of an egg by a sperm can take place either inside the body of the female animal or outside the body of female animal. This leads to two modes of fertilisation in animals : internal fertilisation, and extenal fertilisation.
The fertilisation which takes place inside the female body is called internal fertilisation. In internal fertilisation, the female animal's eggs are fertilised by sperms inside her body. In internal fertilisation, the male animal puts his sperms into the female animal's body And these sperms then fertilise the eggs inside her body. For example, a man puts his sperms inside a woman's body. These sperms then fertilise the egg inside the woman's body. This type of fertilisation in which the fusion of a male gamete (sperm and a female gamete (egg) occurs inside the body of the female animal, is called internal fertilisation. Internal fertilisation takes place in a very large number of animals such humans, cows, dogs, cats, tigers, lions, rabbits, deer, horse, birds (such as hen, sparrow crow, pigeon, etc.), reptiles (such as lizard, snake and crocodile, etc.), and insects (such as silk moth, housefly and butterfly, etc.). In all these animals, fertilisation occurs inside the body of the female animal.
The fertilisation which takes place outside the female body is called external fertilisation. In external fertilisation, the female animal's eggs are fertilised by sperm outside her body. In frogs and most fishes, the fertilisation of eggs occurs outside the female animal's hody. In extemal fertilisation, the male and female animals release their sperms and eggs in water where fertilisation takes place by collisions between sperms and eggs. For example, the males and females of frogs and fishes release their sperms and eggs in water in which they live. The sperms then collide with the eggs and fertilise them outside the body of female frog or fish. External fertilisation is very common in aquatic animals such as frog, fish and star fish, etc. In these animals, fertilisation takes place in water. We will now describe the external fertilisation in frogs in somewhat detail.
During spring season (or rainy season). frogs move to the water in ponds and slow- moving streams. When the male frog and female frog come together, the female frog lays hundreds of eggs in water (see Figure 4). Unlike the hen's eggs, frog's eggs are not covered by hard shells. The frog's eggs are very delicate. A layer of jelly holds the frog's eggs together and provides protection to the eggs. When the female frog lays hundreds of eggs, at the same time the male frog releases millions of sperms from its body (see Figure 4). The sperms swim randomly in water with the help of their long tails. When the sperms of frog come in contact with the eggs floating in water, then fertilisation takes place. This type of fertilisation in which the fusion of a male gamete (sperm) and a female gamete (egg) takes place ouside the body of the female animal, is called external fertilisation. Just like frogs, external fertilisation also takes place in fish. When the male Gish and female fish come together in water, the female fish lays hundreds of eggs in water and at the same time, the male fish releases millions of sperms in water. When the Sperms come in contact with eggs, the eggs get fertilised. In this way, a female fish's eggs are fertilised by sperms outside its body. This is also an example of external fertilisation.
We will now explain why the animals like frog and fish lay hundreds of eggs at a time (whereas a hen lays only one egg at a time). Though the animals like frog (and fish) which undergo external fertilisation, lay hundreds of eggs, all the eggs do not get fertilised and hence do not develop into new frogs (or fishes). This is because of the following reasons
(i) Frog (and fish) lay eggs and release sperms in water. Many of these eggs and sperms are carried away by the movement of water, wind or rainfall, and hence all the eggs do not get fertilised.
(ii) Many of the eggs of frogs (and fish) are eaten up by other animals which live in water.
(iii) Many of the larvae (young ones) of frog and fish which are hatched from the fertilised eggs are eaten up by other animals in water and fail to develop into adult frogs (or fish).
So, out of hundreds of eggs laid by the female frog (or female fish), only a few will survive to become adult frogs (or adult fish). Since many of the eggs of frogs and fish are carried away by moving water, wind or rain, and many are eaten up by other animals, therefore, the production of a large number of eggs is necessary to ensure the fertilisation of at least a few of them. Out of hundreds of eggs laid by female frog (or female fish) only a few get fertilised and their larvae survive to become adult frogs (or adult fish).
Which of the following animal shows internal fertilisation ? | |||
| Right Option : D | |||
| View Explanation | |||
Which of the following are a type of fertilization ? | |||
| Right Option : C | |||
| View Explanation | |||
The type of fertilisation in which the fusion of a male gamete (sperm and a female gamete (egg) occurs inside the body of the female animal, is called ________________ fertilisation. | |||
| Right Option : B | |||
| View Explanation | |||
Students / Parents Reviews [20]
It has a great methodology. Students here can get analysis to their test quickly.We can learn easily through PPTs and the testing methods are good. We know that where we have to practice
Barkha Arora
10thMy experience with Abhyas Academy has been very good. When I was not in Abhyas whenever teacher ask questions I could not speak it confidently but when I came in Abhyas, my speaking skills developed and now I am the first one to give the answer of teachers question.
Upmanyu Sharma
7thMy experience with Abhyas is very good. I have learnt many things here like vedic maths and reasoning also. Teachers here first take our doubts and then there are assignments to verify our weak points.
Shivam Rana
7thMy experience with Abhyas academy is very good. I did not think that my every subject coming here will be so strong. The main thing is that the online tests had made me learn here more things.
Hiya Gupta
8thA marvelous experience with Abhyas. I am glad to share that my ward has achieved more than enough at the Ambala ABHYAS centre. Years have passed on and more and more he has gained. May the centre flourish and develop day by day by the grace of God.
Archit Segal
7thThe experience was nice. I studied here for three years and saw a tremendous change in myself. I started liking subjects like English and SST which earlier I ran from. Extra knowledge gave me confidence to overcome competitive exams. One of the best institutes for secondary education.
Aman Kumar Shrivastava
10thAbhyas Methodology is very good. It is based on according to student and each child manages accordingly to its properly. Methodology has improved the abilities of students to shine them in future.
Manish Kumar
10thAbhyas is an institute of high repute. Yogansh has taken admission last year. It creates abilities in child to prepare for competitive exams. Students are motivated by living prizes on basis of performance in Abhyas exams. He is satisfied with institute.
Yogansh Nyasi
7thThird consective year,my ward is in Abhyas with nice experience of admin and transport support.Educational standard of the institute recumbent at satisfactory level. One thing would live to bring in notice that last year study books was distributed after half of the session was over,though study ...
Ayan Ghosh
8thWe started with lot of hope that Abhyas will help in better understnding of complex topics of highers classes. we are not disappointed with the progress our child has made after attending Abhyas. Though need to mention that we expected a lot more. On a scale of 1-10, we would give may be 7.
Manya
8thI have spent a wonderful time in Abhyas academy. It has made my reasoning more apt, English more stronger and Maths an interesting subject for me. It has given me a habbit of self studying
Yatharthi Sharma
10thBeing a parent, I saw my daughter improvement in her studies by seeing a good result in all day to day compititive exam TMO, NSO, IEO etc and as well as studies. I have got a fruitful result from my daughter.
Prisha Gupta
8thIn terms of methodology I want to say that institute provides expert guidence and results oriented monitering supplements by requsite study material along with regular tests which help the students to improve their education skills.The techniques of providing education helps the students to asses...
Aman Kumar Shrivastava
10thAbhyas academy is great place to learn. I have learnt a lot here they have finished my fear of not answering.It has created a habit of self studying in me.The teachers here are very supportive and helpful. Earlier my maths and science was good but now it has been much better than before.
Barkha Arora
10thUsually we see institutes offering objective based learning which usually causes a lag behind in subjective examinations which is the pattern followed by schools. I think it is really a work of planning to make us students grab the advantages of modes of examination, Objective Subjective and Onli...
Anika Saxena
8thIt was good as the experience because as we had come here we had been improved in a such envirnment created here.Extra is taught which is beneficial for future.
Eshan Arora
8thMy experience was very good with Abhyas academy. I am studying here from 6th class and I am satisfied by its results in my life. I improved a lot here ahead of school syllabus.
Ayan Ghosh
8thIt was a good experience with Abhyas Academy. I even faced problems in starting but slowly and steadily overcomed. Especially reasoning classes helped me a lot.
Cheshta
10thAbhyas institute is one of the best coaching institute in the vicinity of Ambala cantt.The institute provides good and quality education to the students.The teachers are well experienced and are very helpful in solving the problems. The major advantages of the institute is extra classes for weak...
Shreya Shrivastava
8thAbout Abhyas metholodology the teachers are very nice and hardworking toward students.The Centre Head Mrs Anu Sethi is also a brilliant teacher.Abhyas has taught me how to overcome problems and has always taken my doubts and suppoeted me.
