Biology Chapter 40 I

Biology Chapter 40 I - Chapter 40 Basic Principles of...

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Chapter 40 Basic Principles of Animal Form and Function Overview: Diverse Forms, Common Challenges Analyzing the hawk moth’s proboscis gives clues about what it does and how it functions. ° Anatomy is the study of the structure of an organism. ° Physiology is the study of the functions an organism performs. ° Natural selection can fit structure to function by selecting, over many generations, the best of the available variations in a population. The concept of bioenergetics—how organisms obtain, process, and use energy resources—is a connecting theme in the comparative study of animals. Concept 40.1 Physical laws and the environment constrain animal size and shape Body size and shape affect interactions with the environment. An animal’s size and shape have a direct effect on how the animal exchanges energy and materials with its surroundings. Exchange with the environment occurs as dissolved substances diffuse and are transported across the plasma membranes between the cells and their aqueous surroundings. Multicellular animals are composed of microscopic cells, each with its own plasma membrane that acts as a loading and unloading platform for a modest volume of cytoplasm. Most animals are more complex and are made up of compact masses of cells, producing outer surfaces that are relatively small compared to the animal’s volume. ° Most organisms have extensively folded or branched internal surfaces specialized for exchange with the environment. ° The circulatory system shuttles material among all the exchange surfaces within the animal. ° A specialized outer covering can protect against predators; large muscles can enable rapid movement; and internal digestive organs can break down food gradually, controlling the release of stored energy. Concept 40.2 Animal form and function are correlated at all levels of organization Animals are multicellular organisms with their specialized cells grouped into tissues. In most animals, combinations of various tissues make up functional units called organs, and groups of organs work together as organ systems. Tissues are groups of cells with a common structure and function. ° Different types of tissues have different structures that are suited to their functions. ° A tissue may be held together by a sticky extracellular matrix that coats the cells or weaves them together in a fabric of fibers. Tissues are classified into four main categories: epithelial tissue, connective tissue, nervous tissue, and muscle tissue. Occurring in sheets of tightly packed cells, epithelial tissue covers the outside of the body and lines organs and cavities within the body. ° The cells of an epithelium are closely joined and in many epithelia, the cells are riveted together by tight junctions. ° The epithelium functions as a barrier protecting against mechanical injury, invasive
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This note was uploaded on 11/04/2010 for the course BIO 107 taught by Professor Abott during the Fall '09 term at UConn.

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Biology Chapter 40 I - Chapter 40 Basic Principles of...

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