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DETERMINING THE BASES OF LIFE AGRISCIENCE AND TECHNOLOGY Modified by Georgia Agricultural Education Curriculum Office July, 2002 August 2008 CHARACTERISTICS OF AN ORGANISM • • • • • August 2008 Chemically and structurally unique Need energy Have a life span Are capable of growth and reproduction Respond to their environment PROTOPLASM • Only form of matter in which life exists • Made up of water and proteins • Chemical activity in protoplasm determines the kind of life and nature of the organism • Example: When a farmer applies fertilizer to a plant he is helping protoplasm carry out more chemical activity. August 2008 PHOTOSYNTHESIS • Plants have the capacity to manufacture their food through photosynthesis. • Food is broken down into energy that is used to support life processes. • Animals depend on plants as sources of food. August 2008 FIVE STAGES OF LIFE • BEGINNING: Varies between species • GROWTH : Occurs when an organism is young and immature • MATURITY: When the organism is fully developed • DECLINE : Loses its ability to maintain itself • DEATH : Protoplasm ceases to carry out chemical activity August 2008 LIFE IS CLASSIFIED AS LIVING AND NONLIVING • LIVING • PLANTS • ANIMALS August 2008 • • • • • • NONLIVING CLAY IRON ORE LIMESTONE ROCK COAL OIL ORGANISMS RESPOND TO THEIR ENVIRONMENT • RICE : Needs warm climate and requires lots of water • BANANAS : Requires tropical climate • WHEAT : Winter wheat is cold tolerant; can be planted in the fall • TROUT: Need cold fresh water • BEEF CATTLE : Some breeds suited for warm or cold climates August 2008 LIFE PROCESSES OF ORGANISMS • Getting and using food • Growth and Repair • Secretion • Movement • Sensation • Circulation • Reproduction • Respiration August 2008 PARTS OF A PLANT CELL • CELL MEMBRANE : Surrounds the cell and controls the movement of materials into and out of the cell. • NUCLEUS : Controls the cell activity (contains the chromosomes and DNA) • CYTOPLASM: Thick solution that flows in a cell (contains organelles) August 2008 CELL SPECALIZATION • Involves differences in cells so the cells can perform unique activities for the organism • TISSUES: Groups of cells that are alike in activity and structure; muscle, skin, nerves and bones are examples. • ORGANS : Collection of tissues that work together to perform certain function ; heart, lungs, stomach and liver are examples August 2008 CELL SPECIALIZATION CONT. • ORGAN SYSTEMS : Made up of several organs which work together to perform an activity; digestive system is made up of the mouth, stomach, small intestine, large intestine and others. • Found in complex animal organisms August 2008 HEREDITY • IS THE PASSING OF THE TRAITS OF PARENTS TO OFFSPRING • Asexual reproduction - offspring is identical to the parent (involves only one parent) • Example: plants produced by cuttings • Sexual reproduction - offspring exhibits traits of both parents; variations occur • Example: milk production in cattle August 2008 GENETICS • THE STUDY OF HEREDITY IN PLANTS AND ANIMALS • STUDY GENE COMBINATIONS / RESULTED IN GENE ENGINEERING • STUDY CELL DIVISION / RESULTED IN NEW VARIETIES OF CROPS AND IMPROVED NUTRIENTS FOR PLANTS AND ANIMALS August 2008 APPROACHES USED TO IMPROVE ORGANISMS • CONTROLLED BREEDING : Involves breeding plants or animals to achieve certain characteristics in the offspring. • Examples are cattle that grow faster or wheat varieties that produce more yields August 2008 METHODS OF CONTROLLED BREEDING • SELECTION : Selecting desirable traits in parents to pass on to offspring • INBREEDING : Involves breeding offsping of the same parents to each other ; used in plants and animals. • HYBRIDIZATION : Involves the crossing of two different but closely related plants or animals ; hybrid corn and hybrid striped bass are examples August 2008 THE OTHER APPROACH USED TO IMPROVE ORGANISMS • GENETIC MANIPULATION : Involves an artificial means of producing desirable traits in plants and animals. • Example would be the “Flavor Saver Tomato” (gene identified causing rotting processing inserted backwards increases shelf life of tomatoes) August 2008