Site Loader

Communities change a great deal over time especially after natural disasters like fire, flood, and even earthquakes.  These disturbed areas can be colonized by a variety of species.  These may be replaced  as yet other species come and grow there.  Primacy succession occurs when nothing exists in a particular area, like the lava from a volcano that forms land, and over time it grow something like mold or moss. This is secondary succession because it occurs where a disturbance has destroyed an existing community but left the soil intact.  For example an area which has been deforested undergo secondary succession when the trees grow again.  Succession is seen constantly whether in water or on land. It is the natural progression of the earth and it is a form of evolution.Question 9Salamanders which live in the water usually have an appearance of eel because they have different needs then those salamanders which live on or mostly on land.  The difference in appearance is an example of what Darwin call the survival of the fittest.  Aquatic Salamanders with an eel like body were better suited to survive in the water.  Therefore they were able to survive and reproduce.  Whereas, salamanders who had limbs died off and were not able to reproduce.MusselsEvolution usually takes a very long time to see.  This is why the mussels which have now become a nuisance in the Great Lakes is quite a find for scientists.  Mussels’ nature predators are crabs which have the ability to snap open the muscles and crab their shells.  This is an important predator prey relationship because it keeps the mussel population in check while feeding the crabs which actually act as food for humans in the regions.  The ideas of the food and energy chains are central to the concept of evolution and the maintenance of balance within a community and therefore within a ecosystem.  However, mussels have evolved quite rapidly an in the last 30 years scientists have been able to observe drastic changes in the muscles.  These changes are exactly what Darwin would have called survival of the fittest or natural selection.  Mussels with hard shells are now dominate in the mussel community.Why?  Because they are the only mussels to survive the attack of a crab.  Hardness of the shell is built into genetic code or DNA which means that only mussels with hard shells survive to mate, and reproduce.  This is because mussels with soft shells are eaten by the crab and are not able to produce offspring (because they are dead).  This is great for the mussel – happy as a clam because it can live freely now.  Of course this is a major issue for the crab, lake wildlife, and humans.  Mussels are now able to grow out of control without a natural predator.  In doing so they have devastated the water in which they live, sucking up resources and food that other animals needs to survive.  They are no longer prey for crabs which means that crabs must struggle for food and eat things they would not normally consume.  This causes the crab population to decrease and this also means that there is no crabs for human to catch which many humans use for money.;;

Post Author: admin


I'm Tamara!

Would you like to get a custom essay? How about receiving a customized one?

Check it out