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

Pattern of growth, P A TTERN OF GROWTH - 1 .       ISOMETRIC - ...

P A TTERN OF GROWTH - 1 .       ISOMETRIC - In it an organ grows at the same rate as the rest of body. External form of body is not changed. eg. fish, locust. 2 .

Show coding for stimulus intensity, Q. Show Coding for stimulus intensity? ...

Q. Show Coding for stimulus intensity? Coding for stimulus intensity: If AP's are all-or-none responses that do not vary in amplitude, how does the NS distinguish between stim

Define the characteristics that are seen in rickets, Define the characteris...

Define the characteristics that are seen in Rickets? The following characteristics are seen in fully developed cases of rickets: 1) In case of young infants, delayed closure

Spring overturn - overturn, Spring overturn - Overturn In spring and e...

Spring overturn - Overturn In spring and early summer season the increased solar radiation melts the ice cover, which, as it attains a temperature of 4° Celsius, becomes dense

What do you understand by arthropodization, What do you understand by Arthr...

What do you understand by Arthropodization? Many of the traits that we consider unique to the Arthropoda may not be independent traits. Instead, they may be the consequence of

Types of ribosomes, TYPE S OF RIBOSOMES Ribosomes are of two types: - ...

TYPE S OF RIBOSOMES Ribosomes are of two types: - 1 . Procaryotic Ribosomes - 70 s = Occur in cytoplasm of prokaryotes, and also in mitochondria, and Chloroplast o

Respiration, difference between the respiration occurs in lower and higher ...

difference between the respiration occurs in lower and higher organisms

How to produce organic material from inorganic substances, What are the pro...

What are the processes that autotrophic beings use to produce organic material from inorganic substances? Autotrophic beings make organic material by photosynthesis or by chemo

What is polysaccharides, What is Polysaccharides? Polysaccharides:  M...

What is Polysaccharides? Polysaccharides:  Many monosaccharide subunits can be joined to form long, complex polysaccharide molecules. These complex sugars are often used to s

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