Speciation, Biology

Assignment Help:

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.

Related Discussions:- Speciation

Explain the klebsiella - characteristics of bacteria, Explain the Klebsiell...

Explain the Klebsiella - Characteristics of Bacteria? It is gram negative, non-sporulating, non-motile and non-pigmented rod, which is commonly found in soil or water. It is th

What is exposure assessment, What is Exposure Assessment Exposure Asse...

What is Exposure Assessment Exposure Assessment :  The qualitative and quantitative evaluation  of the  degree  of  intake likely  to occur.

Cromngnon skull, Subsequently many such fossils were known from France, Ita...

Subsequently many such fossils were known from France, Italy and middle East. All such fossils exhibited reduced brow ridges, steep forehead, high rounded cranial vault, short face

Show appearance of food product, Q. Show Appearance of food product? Ap...

Q. Show Appearance of food product? Appearance can be judged by the eye. Appearance factors include such things as size, colour, uniformity, absence of any defect, shape, whole

Explain nutrient requirements during hypertension, Q. Explain nutrient requ...

Q. Explain nutrient requirements during hypertension? In order to meet the above objectives, we need to understand the nutrient requirements during hypertension. Let us start w

Development of endosperm, Development of Endosperm In a fertilized emb...

Development of Endosperm In a fertilized embryo sac, the primary endosperm nucleus is generally observed below the zygote. It divides, and further divisions of its products gi

Explain observations seen in thyphoid, Some observations seen in this fever...

Some observations seen in this fever are: 1.  Massive loss of  lean body mass or muscle due to tissue breakdown (250-500 g muscle tissue is lost/day) leading to excessive nitro

Pathogenesis of acute rheumatic fever, You have learnt about the epidemiolo...

You have learnt about the epidemiology, etiology and pathogenesis of acute rheumatic fever. Revised Jones criteria, which have major and minor criteria, are helping to diagnosis of

Indication of exchange transfusion, Indication of Exchange Transfusion ...

Indication of Exchange Transfusion i) Early exchange transfusion is indicated in the presence of hydrops and is often indicated by a history of previously severely aff

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd