Charles Darwin developed the idea of evolution by natural selection
“Any trait that helps an organism survive and reproduce under a given set of environmental conditions is said to have adaptive value. For example, a rabbit’s ability to blend in with its surroundings may allow it to escape capture by a fox” (BRLE)
Adaptive radiation is a process in which organisms diversify rapidly into a multitude of new forms. This may happen when a change in the environment makes new resources available, or creates new challenges. (Wikipedia)
The below is from http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_25
The process is relatively simple but often misunderstood.
Download this series of graphics
If you have variation, differential reproduction, and heredity, you will have evolution by natural selection as an outcome. It is as simple as that.
Sources of variation:
1. Mutations – random mistakes in DNA when cells divide
2. Crossing over during meiosis (during production of eggs and sperm)
Results of genetic variation
The degree of kinship between organisms or species can be estimated from the similarity of their DNA sequences; this similarity often closely matches organisms’ or species’ classification based on anatomical similarities.
The graphic above shows that:
All of these primates had a common ancestor, the ancestral primate.
The human and chimpanzee have the closest evolutionary relationship as their DNA is the most similar
Bats, dolphins, and many forms of mammals, all use adaptations of the same original five-fingered animal hand.
Charles Darwin discovered adaptive radiation occurring in finches, on the Galapagos Islands.
Here is a color graphic summarizing how one species of finch radiated over time to become many.
Here is the same information, as presented on a New York Regent’s exam.
Are all of these changes successful?
Extinction is shown on a tree of life, when a line comes to an end, without any branches.
BRLE = Prentice Hall Brief Review The Living Environment (Pearson)