Biology homework (evolution)

Biology
Tutor: None Selected Time limit: 1 Day

As a result of human activity (such as logging), large forests are becoming fragmented into several smaller forests.

a)      How might the increasing isolation of population in these forests influence their evolution?

b)      How might the fragmentation affect the evolution of a large mammal, like a moose, compared to a small invertebrate, like a worm?

Please explain it clearly so I can understand it properly. 

May 24th, 2015

a. Evolution occurs when there are changes in the frequencies of alleles within a population of interbreeding organisms; for example, the allele for black color in a population of moths becoming more common. So if the resources of a forest are breaking up, and group of a species of plant or animal is naturally selected by the environment, and those surviving species interbreed and evolution would be affected that way. Small horned moose might be naturally selected over small horned moose. A worm that survives in warm soil might be naturally selected over a worm that survives in cold soil.

b.I imagine it would have less effect on a moose. Moose can move over considerable distances, so populations in different small forests would be able to interbreed.

Worms don't move as far and so are dependent on many smaller sub-populations interbreeding, like a chain. If the chain is broken, they will have trouble simply "jumping over" that hole, since they simply don't move that far.

I.e. let's say two forested areas (and their populations) are separated by a mile of inhospitable, barren land. A moose can walk a mile easily, but a worm is unlikely to crawl that far. So, this zone creates a barrier for the worm, but not for the moose.

May 24th, 2015

I understand part B, but i still don't get part A. I have read the same answer for part A online but it wasnt any help to me. Could you please explain it in your own words. 

May 24th, 2015

rate me 5 star.....................ok i do

May 24th, 2015
solation means that organisms of the same species are separated, and happens when there is something between the organisms that they can't cross. Organisms become isolated as a result of environmental change. The cause of isolation can be gradual, like when mountains or deserts form, or continents split apart. It can also be quick, such as organisms being blown to different places by a storm or tsunami (tidal waves).

When organisms become isolated the two groups are also not able to reproduce together, so variations and mutations that occur in one group are not necessarily found in the other group. The longer the groups are isolated, the more different they are. They eventually become different species. Moreover, if there is a change in the environment of one group it does not necessarily occur in the environment of the other. So they will evolve and adapt differently.

The finches and other organisms that Darwin found on the Galapagos Islands are examples that demonstrate the effect that environmental change and isolation can have on a species.


May 24th, 2015

i hope now it wil be easy for you................

May 24th, 2015

Yes thank you!

May 24th, 2015

welcome rate me 5 star...............................

May 24th, 2015

are u there?


May 24th, 2015

ya dont worry, i rated you already :P

May 24th, 2015

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