Chapter 41 1 Form Function and Adaptation a Adaptations heritable traits that allow individuals to survive and reproduce in certain environment better than individuals who lack those traits b Natural Selection occurs when individuals w certain alleles leave more offspring than individuals w diff alleles 2 Role of Fitness Trade Offs Draw 41 1 a Human spine descended from animals that walked on four legs not adapted well for upright results back pain b trade offs inescapable compromises between traits c There is trade off between number and size of eggs clutch size number of eggs laid by female d In species of lizards it is not possible for a female to produce large numbers of large eggs this is example of a trade off e results of experiment showed that survival increases as egg mass increases so larger offspring survive much better than smaller offspring 3 Adaptation and Acclimation a Acclimatization phenotypic change in an individual in response to short term changes in the environment b Adaptation genetic change in a population in response to natural selection exerted by the environment c 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 Function a a structure s size shape or composition correlates w its function b 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 seeds c If mutant allele provides advantage to organisms they will reproduce more offspring than others and frequency of that allele will increase 2 Structure Function Relationships at Molecular Level a Cell structure is important for its function cells that make or secrete hormones or digestive enzymes are packed w Rough ER and Golgi b 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 such 3 Tissues Are Groups of Similar Cells That Function as a Unit a Multicellular body contains distinct types of cells specialized for diff functions b Tissue group of similar cells that function as a unit c As inidvidual develops embryonic tissue makes 4 adult tissue types Connective tissue nervous tissue muscle tissue epithelial tissue 4 Connective Tissue a consists of cells loosely arranged in a liquid jelly like or solid matrix b each type secretes distinct type of extra cellular matrix nature of matrix determines nature of the connective tissue 5 Types of Connective Tissue 1 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 fluid 2 Dense connective tissue found in tendons and ligaments that connect muscles bones and organs a matrix in tendons and ligaments dominated by the tough collagen fibers 3 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 system 4 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 plasma 6 Nervous Tissue a 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 support c Neurons have2 types of projections from the cell body where the nucleus is located dendrites highly branched relatively short process axons relatively long structures 7 Muscle Tissue a 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 fibers b 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 beat c 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 birth 8 3 Distinctions about muscle cells and tissues a There are voluntary muscles and involuntary muscles involuntary muscles move in response to unconscious electrical signals b muscle cells may have one or many nuclei skeletal muscle cells and come cardiac muscle cells are multi nucleate c Some cells and tissues have a banded or striated appearance skeletal and cardiac muscle are striated smooth muscle is unstriated 9 Epithelial Tissue Also Called Epithelia a Covers the outside of the body lines surfaces of organs and forms glands gland group of cells that secrete specific molecules or solutions b Epithelia regulate transfer of heat bet interior exterior of structures as well as transfer of water nutrients and other substances c Often epithelial cells are joined by structures that hold them together such as tight junctions and desmosomes d 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 lamina e Short lived bec they are exposed to harsh conditions 10 Organs and Organ Systems Draw 41 7 a Organ system consists of groups of tissues and organs that work together to perform one or more functions b Each system accomplishes a specific task req for survival and reproduction and each works in conjunction w other systems 1 How Body Size Affects Animal Physiology a Laws of physics affect anatomy and physiology of a living machine force of gravity limits how large an animal can be and still move efficiently b body size affects how animals function large animals take longer to mature reproduce more slowly and live longer c juveniles and adults of same species face diff challenges simply bec their body sizes are different 2 Surface Area Volume Relationships Theory a As a cube gets bigger its surface area increases much more slowly than its volume or mass same relationship holds for cells tissues organs and systems b
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