What is amphimixis? - Biology

Short Note

What is amphimixis?



Amphimixis (amphi=both; mixis=mixing): It involves the mixing or fusion of genetic material of male and female gametes. The offsprings produced are not identical to parents. They show genetic variation.

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2012-2013 (October)



Which mode of reproduction gives rise to variation?

Give the importance of variation in survival of species.

Complete the following table to get the differences between asexual and sexual reproduction:

Characteristics Asexual Reproduction Sexual Reproduction
Number of parents involved ........................... ..............................
Type of cells involved Somatic cells Germ cells
Type of cell division ............................ Meiosis and mitosis

What is meant by sexual reproduction?

Name two main processes of sexual reproduction

List six specific characteristics of sexual reproduction.

What are chromosomes?

What is the effect of DNA copying, which is not perfectly accurate, on the reproduction process? How does the amount of DNA remain constant though each new generation is a combination of DNA copies of two individuals?

Describe the process of fertilization in human beings.

Choose the most appropriate answer.

Internal fertilization occurs

Choose the most appropriate answer.

The number of nuclei present in a zygote is

Indicate whether the following statements are True (T) or False (F).

Oviparous animals give birth to young ones. ( )

Indicate whether the following statement is True (T) or False (F).

Each sperm is a single cell. ( )

Indicate whether the following statement is True (T) or False (F).
A new human individual develops from a cell called gamete. ( )

Indicate whether the following statement is True (T) or False (F).

A zygote is formed as a result of fertilization. ( )

Indicate whether the following statement is True (T) or False (F).
An embryo is made up of a single cell. ( )

Give two differences between a zygote and a foetus.

Differentiate between internal fertilization and external fertilization.

List any four steps involved in sexual reproduction .

Give reason for the following:

The parents and off-springs of organisms reproducing sexually have the same number of chromosomes.

The advantage that internal fertilisation has over external fertilisation is that in internal fertilisation :
(a) new off-springs are exactly like the parent
(b) production of large numbers of gametes is unnecessary
(c) copulation and fusion of gametes is passive
(d) fewer individuals are produced

The figure given alongside shows the human male reproductive organs. Which structures make sperms and seminal fluid?
(a) V makes sperms and X makes seminal fluid
(b) W makes sperms and Y makes seminal fluid
(c) X makes sperms and W makes seminal fluid
(d) Y makes sperms and V makes seminal fluid

Characters that are transmitted from parents to offspring during sexual reproduction show :
(a) only similarities with parents
(b) only variations with parents
(c) both similarities and variations with parents
(d) neither similarities nor variations with parents

The number of chromosomes in parents and offsprings of a particular species remains constant due to :
(a) doubling of chromosomes after zygote formation
(b) halving of chromosomes during gamete formation
(c) doubling of chromosomes after gamete formation
(d) halving of chromosomes after gamete formation

Distinguish between the following pair of terms:

Sexual reproduction and asexual reproduction.

Define the term Fetilization.

Define the term  Implantation.

What is the function of uterus?

Define the term Metamorphosis.

Mention the common method of reproduction in Amoeba.

Mention the common method of reproduction in Hydra.

Mention the common method of reproduction in Flatworm.

Mention the common method of reproduction in Start fish.

Name the organ involved in the following:

Fertilisation of ovum by tile sperm.

Name the organ involved in the following:

Passing of sperms from a man to a woman.

Explain why variations are observed in the offsprings of sexually reproducing organisms?

Sketch and label the diagram showing self- and cross-pollination.

In the sexual mode of reproduction, greater diversities are generated.

Answer in one sentence.

Outline the path of sperm upto the urethra.

Answer in one sentence.

Which glands contribute fluids to the semen?

Answer in one sentence.

Name the endocrine glands involved in maintaining the sex characteristics of males.

Answer in one sentence.

Enlist the external genital organs in the female.

Explain the histological structure of testis.

Answer the following question.

Which is the function of male accessory glands?

Long answer question.

Describe female reproductive system of human.

What is atresia with respect to ovary in human females?

Give an account of external genitalia in human females.

Identify the labels from the given diagram.

Which are the components of pollination?

Animals which give birth to young ones directly are named as ______.

What are the different stages of sexual reproduction?

Which organs/glands produce eggs and sperms?

In an ovule, meiosis occurs in ______

Due to presence of which of the following chemical component, pollen grains can remain well preserved in fossil?

Testosterone is produced by ____________.

Which of the following is the male accessory gland?

Identify the INCORRECT statement.

Match column -1 with column - II and select the correct option.

  Column - I   Column - II
1. Seminal vesicles a. Membranous urethra
2. Scrotum b. Thermoregulatory
3. Tunica vaginalis c. Fibro muscular pouches
4. Cowper's gland d. Peritoneal covering

______ is the first stage of sexual reproduction.

______ fertilisation takes place in frogs and fish.

The zygote divides repeatedly into a group of cells, which develops into different tissues and organs constituting a full body. This structure is known as ______.

Animals in which an embryo develops outside the body are called ______ animals.

______ lay thousands and sometimes millions of small, soft eggs in water.

The eggshell protects the ______ from the outer environment.

In ______ animals, the development of the embryo takes place inside the body.

Name the two ways by which fertilisation in animals takes place.

What is external fertilisation?

Which is a better mode of reproduction, sexual or asexual? Why?


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