Tuesday, September 25, 2007

Were it all started: The origin of species!!!

Hello everyone. Well the point of todays class and the main point that Ms.Foglia was tying to make was how and why species diverged from each other. There are two ways: Pre-Reproduction and Post-Reproduction.

First and foremost, What is meant by the word species??? that is the question...
Species is a population where the organisms are able to interbreed and produce offspring that will be able to survive and reproduce. The organisms must be reproductively compatible which means they are able to mate with each other.

OK well thats said huh? So whats next... PRE-Reproduction and how it causes species to diverse. WooHoo

There are 6 different barriers that may be obstacles and may prevent mating or inability to fertilize if mating occurs. Here they are:

Geographic Isolation: There is a physical barrier that does not allow the species to inter mate. The species will occur in different areas.

Ecological Isolation: Species occur in the same area but occupy different habitats. This means that the seldom if never meet.

Temporal(Time) Isolation: Species breed during either different times of the day, different seasons, or different years. This means that the species cannot mate.

Behavioral Isolation: Unique behavior patterns isolate species. If an organism doesn't recognize the calls, dances, songs, etc. then they do not mate.

Mechanical Isolation: Morphological differences can prevent successful mating.

Gametic Isolation: The sperm of one species may not be able to fertilize the egg of another species.


The three post-reproduction barriers, which prevent hybrid offspring from developing into survivable fertile adult, are a)reduced hybrid viability b)reduced hybrid fertility c)hybrid breakdown.

Reduced Hybrid Viability- The hybrid would be very fragile. The genes of the different parents will interact and impair the hybrids development.

Reduced Hybrid Fertility-
The hybrids will survive and live a full life but they are unable to produce offspring. Probably because the number in chromosomes may differ in the parents and cause the hybrid to have abnormal gametes.

Hybrid Breakdown-
hybrids could be fertile and viable in the first generation but when they mate offspring are feeble and sterile.

Well folks thats all there is. See you all in class tomorrow or i should say today cause its already 12:12am.


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Hey guys just check out this link i think the banana thing is cute. You'll get it once you see it.

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