Wednesday, November 21, 2007

Theme 2: EVOLUTION

Theme 2: EVOLUTION
Description: Biological change of organisms that occurs over time. Which is driven by the process of natural selection. Evolution accounts for the diversity of life on Earth.
Clarification: You would post here examples of evolutionary change in populations of organisms that we have been able to observe or have evidence of.

4 comments:

saad said...

Convergent Evolution: Natural selection has favored parallel evolutionary adaptations in similar environments. Different geographical locations have groups of plants and animals with simialr appearances even though they are distantly related. Marsupials and Placentals have had simialr adaptations. even though they live on different continents. They also occupy the same niches except in different ecological communties. This shows parallel evolution.

JacK said...

An evolutionary change is seen in Vestigial Structures.These are features that apparently serve no function in an organism but are derived from an evolutionary past. Although vestigial structures are no longer usefulthey can be used to better understand ancestral species. This can be seen in the eyes of cave-dwelling salamanders and fish that are completely blind.

saad said...

Theory of Endosymbiosis: The evolution of Eukaryotes began with single celled organisms engulfing bacteria and not digesting them. A mututalistic relationship occurs as the bacteria receive protection and the cells receive energy. The mitochondria today are believed to have originated from bacteria, and chloroplasts are believed to have originated from photosynthetic bacteria. Evidence shows that that mitochondia and chloroplasts resemble bacterial structures, they have their own DNA, and they move and reproduce freely in the cell unlike other organelles.

Shannah S. said...

Bacterial Evolution. Bacteria are able to mutate and evolutionize rapidly. The results of their ease of adaptation have allowed them to remain on the earth for 3 billion years. Their rapid evolutionary change can result in resistance to antibiotics as well.