This lecture covers early stages of evolution, from abiogenesis and Miller and Ureys experiments to the Cambrian Explosion as well as the theories of gradualism and punctuated equilibrium. Adaptive radiation of organisms can take place to fill niches in the environment, while patterns like convergent, divergent, and co-evolution can take place in different environments. These changes can be tracked by looking at biological species, a group of interbreeding organisms that can produce viable, fertile offspring. Different species are reproductively isolated, either prezygotively or post-zygotically. Speciation can occur via allopatric speciation (geographic isolation), genetic drift, and sympatric speciation (especially in plants, like polyploidy and autopolyploidy), habit isolation, temporal isolation, or sexual selection.
Gradualism describes evolution
as a slow steady series of changes, eventually culminating in a new
Punctuated equilibrium refers
to a pattern of evolution characterized by long periods of stasis,
punctuated by periods of rapid change.
Adaptive radiation is the
development of new species through evolution of an ancestral species
to fill niches in the environment.
Divergent evolution refers to
the evolution of a group of organisms in a different direction than
that of other members of their species.
In convergent evolution,
unrelated species evolve to have similar characteristics. The result
may be analogous structures such as the wings of birds and those of
A species is a group of
organisms that can interbreed and produce offspring which are viable
Allopatric Speciation is
speciation that occurs following the geographic isolation of
populations from each other.
Sympatric speciation occurs
among populations without a geographic barrier. Populations may
undergo sympatric speciation due to polyploidy, habitat isolation or
Speciation and Patterns of Evolution
Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.
The book and CD package include two full length practice exams that are presented with all questions answered and explained. The author also presents detailed reviews of all test topics and includes multiple-choice and free-response questions with answers at the end of each topic's chapter.
This book includes a review of the AP Biology exam format and scoring, proven strategies for answering multiple-choice questions, and hints for tackling the essay questions. The practice tests include answers and explanations and there is also proven test-taking strategies for both the multiple choice and essay parts.