Question

3. Write differences between-
a)
Internal fertilisation and external fertilisation
b) Sperm and ovum
d) Sexual and asexual reproduction
c) Embryo and foetus​

Answer 1

Answer:

[tex][/tex] Write the differences between -

a) Internal fertilisation and external fertilisation

Internal fertilisation:

1. Syngamy of gametes occurs inside the female body after insemination through copulation.
2. Observed in birds, mammals, birds occurring in terrestrial plants and animals, also in some of the aquatic entities. This is observed in three ways – ovoviviparity(eggs retained in the female body, hatched when fully developed, oviparity(egg-laying), viviparity(offsprings develop within the female body).
3. Observes in plants such as bryophytes, pteridophytes.
4. Fusion of gametes within the body of the female.
5. Gemates are lesser is released and deposited inside the body of the female.
6. Gametes involved only male gametes are discharged into the female genital tract.

External fertilisation:

1. Syngamy of gametes outside the female body/outer environment, notably in water bodies.
2. Observed in few vertebrates, sea urchins, fish, aquatic invertebrates, almost all amphibians. Deposition of sperms and eggs by males and females in open surroundings is known as spawning.
3. Broadcast fertilization – used when sperms swim through the water uniting with eggs to fertilize.
4. Union of the gametes in an external environment(Water bodies).
5. Gametes are multiple gametes(both male and female) released into the external environment.
6. Gametes involved in both female and male gametes are discharged into the external surroundings.

b) Sperm and ovum

Sperm:

1. Sperm is the male gamete.
2. Motility - Motile (flagella).
3. The smallest cell in the human body.
4. Mitochondria - Centrally located.
5. Cytoplasm - Present in very small amounts.
6. Nucleoplasm - Absent.
7. Contains X or Y chromosomes.
8. Centrioles - Present.
9. Produces in the testes.
10. Segmented into head, neck, middle and tail.

Ovum:

1. Ovum is the female gamete.
2. Motility - Non-motile.
3. The largest cell in the human body.
4. Mitochondria - Scattered in the cytoplasm.
5. Cytoplasm - Present in large amounts.
6. Nucleoplasm - Present (called germinal vesicle).
7. Contains only X chromosomes.
8. Centrioles - Absent.
9. Produced in the ovary.
10. No such external segmentation.

c) Sexual reproduction and Asexual reproduction

Sexual reproduction:

1. Occurs almost in all types of multicellular organisms including humans, animals, and higher plants.
2. It is usually bi-parental.
3. Gametes are formed.
4. Germ cells of parents are involved.
5. Fertilization takes place.
6. Presence of fully developed reproductive organs.
7. Both meiosis and mitosis type of cell division occurs.
8. The progenies will be genetically different from the parents.
9. Characteristics of both parents are inherited.
10. The genetic material undergoes intermixing from both parents to form a new set of genetic material.
11. Syngamy, external fertilization, and conjugation are different types of sexual reproduction.
12. Has evolutionary significance in the population.

Asexual reproduction:

1. Occurs in prokaryotic microorganisms and in some eukaryotic unicellular and multicellular organisms, lower invertebrates and plants.
2. It is uniparental.
3. Gametes are not formed.
4. Somatic cells of parents are involved.
5. No fertilization occurs.
6. No involvement of reproductive organs.
7. Only mitosis type of cell division occurs.
8. The progeny and the parent are genetically identical.
9. Characteristics of only one parent are inherited.
10. The genes and genetic material are just multiplied and passed on to new organisms from the parent.
11. Bacterial fission, fragmentation, spore formation, budding of hydra are different types of asexual reproduction.
12. No evolutionary significance.

d) Embryo and foetus

Embryo:

1. The term embryo is from Latin work “embryum” which means “that which grows”.
2. Embryo is multicellular.
3. The process of formation of embryo is known as embryogenesis.
4. In medical terms, embryo is known as diploid eukaryote.

Foetus:

1. It is the stage of the embryo which nearly resembles a human being.
2. It is a multicellular structure.
3. Produced after the processes of cell division and cell labour division.
4. In Foetus well-described body parts are present.

Answer 2

ANSWER

Write the differences between -

a) Internal fertilisation and external fertilisation

Internal fertilisation:

1. Syngamy of gametes occurs inside the female body after insemination through copulation.
2. Observed in birds, mammals, birds occurring in terrestrial plants and animals, also in some of the aquatic entities. This is observed in three ways – ovoviviparity(eggs retained in the female body, hatched when fully developed, oviparity(egg-laying), viviparity(offsprings develop within the female body).
3. Observes in plants such as bryophytes, pteridophytes.
4. Fusion of gametes within the body of the female.
5. Gemates are lesser is released and deposited inside the body of the female.
6. Gametes involved only male gametes are discharged into the female genital tract.

External fertilisation:

1. Syngamy of gametes outside the female body/outer environment, notably in water bodies.
2. Observed in few vertebrates, sea urchins, fish, aquatic invertebrates, almost all amphibians. Deposition of sperms and eggs by males and females in open surroundings is known as spawning.
3. Broadcast fertilization – used when sperms swim through the water uniting with eggs to fertilize.
4. Union of the gametes in an external environment(Water bodies).
5. Gametes are multiple gametes(both male and female) released into the external environment.
6. Gametes involved in both female and male gametes are discharged into the external surroundings.

b) Sperm and ovum

Sperm:

• Sperm is the male gamete.
• Motility - Motile (flagella).
• The smallest cell in the human body.
• Mitochondria - Centrally located.
• Cytoplasm - Present in very small amounts.
• Nucleoplasm - Absent.
• Contains X or Y chromosomes.
• Centrioles - Present.
• Produces in the testes.
• Segmented into head, neck, middle and tail.

Ovum:

• Ovum is the female gamete.
• Motility - Non-motile.
• The largest cell in the human body.
• Mitochondria - Scattered in the cytoplasm.
• Cytoplasm - Present in large amounts.
• Nucleoplasm - Present (called germinal vesicle).
• Contains only X chromosomes.
• Centrioles - Absent.
• Produced in the ovary.
• No such external segmentation.

c) Sexual reproduction and Asexual reproduction

Sexual reproduction:

• Occurs almost in all types of multicellular organisms including humans, animals, and higher plants.
• It is usually bi-parental.
• Gametes are formed.
• Germ cells of parents are involved.
• Fertilization takes place.
• Presence of fully developed reproductive organs.
• Both meiosis and mitosis type of cell division occurs.
• The progenies will be genetically different from the parents.
• Characteristics of both parents are inherited.
• The genetic material undergoes intermixing from both parents to form a new set of genetic material.
• Syngamy, external fertilization, and conjugation are different types of sexual reproduction.
• Has evolutionary significance in the population.

Asexual reproduction:

• Occurs in prokaryotic microorganisms and in some eukaryotic unicellular and multicellular organisms, lower invertebrates and plants.
• It is uniparental.
• Gametes are not formed.
• Somatic cells of parents are involved.
• No fertilization occurs.
• No involvement of reproductive organs.
• Only mitosis type of cell division occurs.
• The progeny and the parent are genetically identical.
• Characteristics of only one parent are inherited.
• The genes and genetic material are just multiplied and passed on to new organisms from the parent.
• Bacterial fission, fragmentation, spore formation, budding of hydra are different types of asexual reproduction.
• No evolutionary significance.

.

d) Embryo and foetus

Embryo:

1. The term embryo is from Latin work “embryum” which means “that which grows”.

• Embryo is multicellular.
• The process of formation of embryo is known as embryogenesis.
• In medical terms, embryo is known as diploid eukaryote.

Foetus:

• It is the stage of the embryo which nearly resembles a human being.
• It is a multicellular structure.
• Produced after the processes of cell division and cell labour division.
• In Foetus well-described body parts are present.

Hope it will help