Can you all describe at least two ways in which reproductive isolation can produce new species?

I have to do a review for my high school Biology Class and this is one question that is really tripping me up. This question is under the section about evolution and I know what reproductive isolation is but i can't seem to come up with two different scenarios in which reproductive isolation can produce new species. The internet hasn't offered much help either. All input is appreciated!Can you all describe at least two ways in which reproductive isolation can produce new species?
hey Alex its john i got ya dawg


this comes straight from Mrs. logsdons notes


';Reproductive isolation can occur either by sperm and eggs no longer being compatible or if mating seasons fall at different times of the year. These two scenarios can potentially cause the evolution of a new species, or speciation.';


i can e-mail you her notes if you need them


oh and best answer me okay?Can you all describe at least two ways in which reproductive isolation can produce new species?
One way is that there will not be an adaptation component which will lead to a more basic species. One specific to the needs of its immediate and reproductive environment. (less diversity creates a counter evolution)





Another would be that the recessive trait genes, which would normally go unmanifested, will become more pronounced and will become the norm rather than rare genetic abnormalities. This can also lead to mutations.
Since we are talking about evolution there are lots of scenarios.





Ring species are one. This is where migration around a single obstacle can cause reproductive isolation. There are Larus Gulls that have over time migrated and caused speciation. Look up ';ring species'; and ';Larus Gulls';





On the simple side your teacher may just be looking for a flood that changes a rivers course separating two species, and continental drift which separated Australia from the rest of the globe causing separation before the separation of metatherian and Eutherain mammals. This is why Austraila has Kangaroos and not Deer as major grazing animals.





Or your teacher may want more specific detail of speciation. Tree frogs and river frogs have been kept from mating by location. Darwin looked at the birds on his trip and described differences in beaks which seemed to be better adapted for the flowers on a specific island.





To make a long story short, too late, animals that are separated by any distance are under different evolutionary pressures. Birds with a little longer beak may live longer because they get more nectar from the local flowers. Marsupial mammals may be killed by predators over time on one piece of land, but those predators do not migrate to another piece of land. Migration around an obstacle over a period of time may cause a spieces of bird to not recognize a slightly altered song from the same species and therefore not mate.





Sorry for all the information
I don't know if this is completely correct, but my best guess is A. A genetic mutation alters the offspring completely, leading to a change of species after several generations.


B. Envirement calls for a different trait that is selected by survival of certain offspring that have the helpful trait.
No.





Reproductive isolation, as on islands, can cause speciation events through genetic drift, mutation, and selection. In this scenario, a very limited number of ';founders'; colonize the island. Right from the get-go, they're not going to have all the alleles that the original population had.





Populations are subject to new alleles appearing via mutation; and the new island population will therefore gain new alleles that will not be found in the original population. Selection may favor some of these new alleles in the island environment. Some of these will be morphological changes; some behavioral. After a long period of time, the island population will have changed enough so that a member of the original mainland species would no longer appear to be sexually attractive, or would not respond appropriately to courtship cues.





This sort of scenario is the best explanation for the 700 species of fruit flies on the Hawaiian archipelago!
In order to create new species you need to prevent gene flow, i.e. stop parts of a population from interbreeding with another part.





1) Consider geography. If we take a population of animals and in the middle of the population add a mountain range the animal cannot cross. Over time the single population will become two distinct species because the two groups cannot interbreed. If the two groups could cross the mountain range then no speciation will occur.





2) Think sex. What makes one mate more preferable over another? A study by Lu, G. and L. Bernatchez in 1999 from the journal Evolution showed lake whitefish tend to choose mates based on size. That is larger fish bred with other large fish and normal size fish bred with other normal size fish. If this trend continues there will be two different sub-species for lake whitefish because each group will take on new characteristics over time.