Speciation, Biology

SPECIATION -

  • Origin of new species: An isolated population of a species independently develops different types of mutations.
  • The later accumulate in its gene pool. After several generations, the isolated population becomes genetically and reproductively different from others so as to constitute a new species.
  • The million of different species that exist today did not emerge by any single sequence of events but have come into existence by following types different paths of speciation.

1.       PHYLECTIC SPECIATION -

  • Darwin entitled his great book.
  • For Darwin, speciation was the simple, gradual accumulation of changes in a lineage throughout time, until the group was distinct enough to be considered a new species. This process is now called phyletic speciation.

2.       ALLOPATRIC SPECIATION -

  • It is considered as the most common type of speciation.
  • Allopatric speciation typically occurs when a physical barrier i. e., a mountain range, a river, or an oil pipeline, geographically separates a population from its parental population.
  • E.g., Different species of Darwin finches in the Galapagos Island.

3.       SYMPATRIC SPECIATION -

  • Sympatric speciation occurs in populations where individuals continue to live among one another, even though some type of biological difference, such as the time of the year when gonads mature, has divided the members into different reproductive groups.
  • The best accepted cases of sympatric speciation occur in plants as a result of polyploidy, an increase in the number of sets of chromosomes per cell occurs.

4.       PARAPATRIC SPECIATION -

  • Parapatric speciation is thought to occur in populations that lie adjacent to one another.
  • Gene pools diverge because the environment varies sufficiently in the different localities.
  • As a result, different traits are selected in each population.
Posted Date: 10/9/2012 1:50:55 AM | Location : United States







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

Write discussion on Speciation
Your posts are moderated
Related Questions
GIRDLES - (i ) PECTORAL GIRDLE - 4 bones. It is located on posterolateral part of upper region of the throax. It consists of scapula & clavicle. Scapula is placed

Development of Pollen in Cyperaceae In all members of the Cyperaceae out of the four nuclei formed after meiosis, only one functions, the others degenerate. The functional nuc

Define Risk assessment Risk  assessment  has  been  described  as  the process  of  organizing  information concerning a particular  risk in  a systematic way  so  that the dec

Explain the Formation of enzyme? Formation of enzyme: Vitamin D is essential for the formation of two enzymes -  alkaline phosphtase in the intestinal lining (involved in cal

Explain the Complications of Burns? Most minor burns are superficial and do not cause complications. However, deep second-degree and third-degree burns swell and take more time

Q. Investigation of Tricuspid stenosis by Echocardiography? Findings are subtle. One should carefully search for organic tricuspid valve involvement in all rheumatic heart dise

PO L YIN V AGIN A TIO N OR INGRESSION - This is found in discoblastula and periblastula. In it the blastomeres of the blastoderm divide and form new blastomeres wh

Define Metabolic Activity and Cell Constituents? Metabolic activity like amount of acid produced or CO 2 produced is directly proportional to the number of bacteria present, s

These views are obtained by placing the transducer in the suprasternal notch with the ridge pointing cephalad. The neck is extended during the suprasternal notch examination. Thi