Chapter 411. Form, Function, and Adaptationa. Adaptations-heritable traits that allow individuals to survive-and reproduce in certain environment better than individuals who lack those traitsb. Natural Selection-occurs when individuals w. certain alleles leave more offspring-than individuals w. diff. alleles2. Role of Fitness Trade-Offs Draw 41.1a. Human spine descended from animals that walked on four legs-not adapted well for upright=results: back painb. trade-offs-inescapable compromises between traitsc. There is trade-off between number and size of eggs-clutch size-number of eggs laid by femaled. In species of lizards, it is not possible for a female-to produce large numbers of large eggs-this is example of a trade offe. results of experiment showed that survival increases as egg mass increases-so larger offspring survive much better than smaller offspring3. Adaptation and Acclimationa. Acclimatization-phenotypic change in an individual in response -to short term changes in the environmentb. Adaptation-genetic change in a population-in response to natural selection exerted by the environmentc. Tibetans who live in high altitude, low oxygen levels-have an allele that increased ability of hemoglobin to hold O2.1. How Structure Correlates with Functiona. a structure's size, shape, or composition correlates w. its functionb. Example of Natural selection: during years of drought, birds w. deep beaks-are more able to survive in order to crack open large fruits-in wet years those w. small beaks can pick off small seedsc. If mutant allele provides advantage to organisms, they will -reproduce more offspring than others and frequency of that allele will increase2. Structure-Function Relationships at Molecular Levela. Cell structure is important for its function-cells that make or secrete hormones or digestive enzymes-are packed w. Rough ER and Golgib. Shape of cell can also correlate w. its function-Cells that transport materials into or out of the body-often have very large plasma membranes to accommodate the membrane channels and such3. Tissues Are Groups of Similar Cells That Function as a Unita. Multicellular-body contains distinct types of cells specialized for diff. functionsb. Tissue-group of similar cells that function as a unitc. As inidvidual develops, embryonic tissue makes 4 adult tissue types-Connective tissue, nervous tissue, muscle tissue, epithelial tissue4. Connective Tissuea. consists of cells loosely arranged in a liquid, jelly-like, or solid matrixb. each type secretes distinct type of extra-cellular matrix-nature of matrix determines nature of the connective tissue5. Types of Connective Tissue1. Loose Connective Tissue: Has array of fibrous proteins in a soft matrix and- serves as packing material bet. organs or padding under skin-Adipose tissue is a loose connective tissue made of cells dominated by-fat droplets and a loose matrix of fibers and fluid2. Dense connective tissue: found in tendons and ligaments-that connect muscles, bones, and organsa. matrix in tendons and ligaments dominated by the tough collagen fibers3. Supportive connective tissue: has a firm extracellular matrix- bone and cartilage are connective tissues-that provide structural support or the vertebrate body-and protective enclosures for the brain and components of nervous system4. Fluid Connective Tissue: consists of cells surrounded by a liquid extra-cellular matrix-blood contains variety of cell types and has specialized extracellular matrix called plasma6. Nervous Tissuea. Consists of nerve cells called neurons and supporting cells-neurons transmit electrical signals b. supporting cells regulate ion concentration around neurons-and supply neurons w. nutrients or provide supportc. Neurons have2 types of projections from the cell body where the nucleus is located-dendrites: highly branched, relatively short process-axons: relatively long structures7. Muscle Tissuea. Skeletal tissue: attaches to the bones of the skeleton and exerts-force on them when it contracts-responsible for most body movements-controls swallowing and consists of long cells called muscle fibersb. Cardiac muscle: makes up walls of the heart and is responsible-for pumping blood throughout the body-Unlike skeletal muscle cardiac muscle cells made direct end-end contact-like this way cells send electrical signals to each other during a heart beatc. Smooth Muscle: cells tapered at each end and form a muscle tissue-that lines the walls of the digestive tract and the blood vessels-Responsible for expelling fetus at birth8. 3 Distinctions about muscle cells and tissuesa. There are voluntary muscles and involuntary muscles-involuntary muscles move in response to unconscious electrical signalsb. muscle cells may have one or many nuclei-skeletal muscle cells and come cardiac muscle cells are multi-nucleatec. Some cells and tissues have a banded or striated appearance-skeletal and cardiac muscle are striated; smooth muscle is unstriated9. Epithelial Tissue-Also Called Epitheliaa. Covers the outside of the body, lines surfaces of organs and forms glands-gland: group of cells that secrete specific molecules or solutionsb. Epithelia regulate transfer of heat bet. interior + exterior of structures-as well as transfer of water, nutrients, and other substancesc. Often epithelial cells are joined by structures that hold them together-such as tight junctions and desmosomesd. Apical side of epithelia faces away from tissue, toward the environment-basolateral faces interior of animal and connects to connective tissues-this connection made by layer of fibers called the basal laminae. Short lived bec. they are exposed to harsh conditions10. Organs and Organ Systems Draw 41.7a. Organ system -consists of groups of tissues and organs-that work together to perform one or more functionsb. Each system accomplishes a specific task req. for survival-and reproduction and each works in conjunction w. other systems1. How Body Size Affects Animal Physiologya. Laws of physics affect anatomy and physiology of a living machine-force of gravity limits how large an animal can be and still move efficientlyb. body size affects how animals function-large animals take longer to mature, reproduce more slowly, and live longerc. juveniles and adults of same species face diff. challenges -simply bec. their body sizes are different2. Surface Area/Volume Relationships: Theorya. As a cube gets bigger, its surface area increases -much more slowly than its volume (or
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