Reproduction, Biology

REPRODUCTION -

  • It is not only production of new ones to increases its number but a means for the survival of a population on earth.
  • Main aim is "survival and continuation or race".
  • If there is no reproduction, species will become extinct just after one generation.
  • Reproduction is mainly of 2 types -

S .No.

Asexual

 

Se x ua l

1

W ithout reproduc tive organs

Reprodutive organs present

2

No formation of gametes

Formation of gametes

3

Uniparental

Uni or biparental

4

Meiosis absent

Meiosis present

5

Offsprings are genetically similar to parents

Different

6

No variation

Variation occur

7

Possibility of extinction is increased

Evolution occur

  • Animal may be unisexual or diocious (male & female are separate) and bisexual or monocious (male & female in same animal).
  • Unisexual are - insects, aschahelminthes & vertebrates.
  • Bisexuals are hydra, earthworm & platyhelminthes.
  • Fertilization may internal (inside body) e.g. sponges, platyhelminthes, aschahelminthes, arthropoda, reptiles, birds, mammals or external (outside body) e.g. coelenterata, earthworm, some pisces & amphibia.
  • Fertilization may be self (in same animal), e.g. tapeworm and crossed e.g. bisexual (protandrous e.g. hydra, earthworm, progynous e.g. sponges) & all unisexual animals.
  • Protandrous means testes mature first.
  • Progynous means ovary mature first.
Posted Date: 10/8/2012 5:44:11 AM | Location : United States







Related Discussions:- Reproduction, Assignment Help, Ask Question on Reproduction, Get Answer, Expert's Help, Reproduction Discussions

Write discussion on Reproduction
Your posts are moderated
Related Questions
An ideal EIA system would: (i)     Apply to all projects that are expected to have significant environmental effects and address all impacts that are expected to occur due to t

Define Goals of National and International Requirement Estimates and RDAs? One of the goals of the RDAs has been reiterated through this unit. They serve as the guidelines for

Is water a polar or a non-polar molecule? What is the consequence of that characteristic for the function of water as solvent? Water is made of two atoms of hydrogen attached b

Q. What is the cyclosporin? How are fungi related to this substance? Cyclosporin is a drug discovered in the 1970's that revolutionized organ transplantation in Medicine, It is

Q What are the constituent elements of the blood? The blood is made of a liquid and a cellular part the fluid part is called as plasma and in it there are several substances li

Airway Management To improved ventilation, suctioning, IPPB, Ultrasonic mist therapy and postural drainage with clapping and vibrating are all employed to halt the progress o

Explain the Compartments of Body Water? Within the body, water is found in two major compartments. These are: - The intracellular compartment (inside the cell) - The extr

Write a short note on muscular system? The muscular system provides mobility and support to the body. There are three types of muscle tissue: skeletal, smooth, and cardiac. Th

What is the root cap? The root cap is a protective structure located in the tip of the growing root. It protects the meristematic tissue of the root forming a cap that surround

Q. What are the pentoses? What are the vital roles of pentoses in DNA and RNA molecules? Pentoses are carbohydrates whole of five carbons. The DNA molecule is made of a sequ