Ecological communities consist of all interacting organisms in a region as well as their environment. These organisms compete for and partition resources, prey or graze on each other, or live in symbiosis. Some organisms, like plants, can produce their own nutrients from sunlight and air (autotrophic), while others (heterotrophs) have to gain energy by consuming another organism. The food chain ranks organisms by their predator-prey relationships, and food webs enlarge these chains to encompass multiple predatory routes. Communities must be able to adapt to disturbances, but those of long duration, large areal coverage, or high frequency and intensity can be devastating, while intermediate disturbances promote biodiversity by providing many ecological niches. The loss of a keystone species can result in the collapse of the food web in that area.
consists of all of the organisms in an area that interact with one
another, and their environment. Interactions that occur within a
community include competition, predation and symbiotic
an interaction involving two species competing for the same limited
one species eating another and may include true predation as well as
relationship is one in which organisms of two or more species live
in direct contact. Parasitism is a symbiotic relationship between
different species in which one organism benefits at the expense of
Mutualism is a
symbiotic relationship in which both species benefit.
a symbiotic relationship in which one species benefits, and there is
no effect on the other.
structure of an ecosystem describes the energy-obtaining sequence
within a community. A linear sequence of a single species at each
trophic level is also known as a food chain. In an ecosystem there
are numerous food chains each interlaced with each other into a food
of a community after a destructive event occurs through the process
of ecological succession.
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.