AP Biology Animal System Review
Chapter 40: Animal Form and Function
Levels of Organization (i.e. tissues, organs)
Cells, tissues, organs, organ system, organism
Homeostasis-negative and positive feedback
Negative Feedback and Stability
The usual means of maintaining homeostasis is a general mechanism called a negative
body senses an internal change and activates mechanisms that reverse, or negate, that change.
An example of negative feedback is body temperature regulation. If blood temperature rises too high, this is
sensed by specialized neurons in the hypothalamus of the brain. They signal other nerve centers, which in
turn send signals to the blood vessels of the skin
Positive Feedback and Rapid Change
The counterpart to negative feedback is the positive feedback loop, a process in which the body senses a
change and activates mechanisms that accelerate or increase that change. This can also aid homeostasis, but
in many cases it produces the opposite effect and can be life-threatening.
An example of its beneficial effect is seen in blood clotting. Part of the complex biochemical pathway of
clotting is the production of an
that forms the matrix of the blood clot, but also speeds up the
production of still more thrombin.
Ectotherm vs. Endotherm
An ectotherm is an animal that warms itself primarily by obtaining heat from the environment, perhaps by
sunning itself. An endotherm is an animal that produces most of its own heat metabolically.
All birds and mammals are endotherms. More surprising, organisms such as tuna fish, skunk cabbages,
butterflies, honey bees, crocuses, and others regularly warm their bodies to an appreciable extent through
the use of metabolic heat.
Ectothermic animals include most fish, amphibians, and reptiles as well as most invertebrates. Many such
animals do, however, control body temperature through behavior.
Chapter 41: Animal Nutrition
3 main stages of food processing
4 main stages of food processing
Organs and their food-processing functions
-What are the organs?
-What are the functions of each organ?
-What are the enzymes that are the key players?
Chapter 42: Circulation and Gas Exchange
Open vs. Closed Circulatory System