GENERAL BIOLOGY 101 Chapter 1 Scientific Process Three Basic Themes 1 2 Evolution populations of organisms have evolved through time from earlier forms of life Information transfer info must be transmitted within organisms and among organisms and organisms must be able to recieve info from their environment 3 Energy Transfer all life processes require a continuous input of energy Characteristics of Life cells basic unit of life unicellular and multicellular organisms surrounding environment every cell is enveloped by a protective plasma membrane that separates it from the chaea two fundamentally different types of cells prokaryotic cells are exclusive to bacteria and to microscopic organisms called ar are structurally simpler do not have a nucleus or other membrane enclosed organelles eukaryotic cells all other organisms typically contain a variety of organelles en closed by membrane including a nucleus which houses DNA all form of life respond to stimuli physical or chemical changes in their internal or ex ternal environment cilla tiny hairlike extensions of the cell and flagella longer structures sessile organisms can still have cilla or flagella that beat rhythmically to bring them food and oxygen in the surrounding water asexual reproduction reproducing by splitting in half to form two new cells simple organisms sexual reproduction in most plants and animals carried out by the fusion of an egg and a sperm cell to form a fertilized egg reductionism learning about a structure by studying its parts however the whole is more than the sum of its parts each level have emergent properties characteristics not found at lower levels populations of organisms have emergent properties such as population density age structure and birth and death rates the individuals that make up a population do not have these characteristics organisms have several levels of organization atom molecule macromolecule organelle cell organ organ system organism pop ulation community ecosystem biosphere Information Transfer info is transmitted by chemical and electrical signals genes control the development and functioning of every organism the DNA that makes up the genes contains the recipe for making all the proteins required by the organism proteins are large molecules important in determining the structure and functioning of cells and tissues cells use proteins and many other types of molecules to communicate with one another in a multicellular organism cells produce chemical compounds such as hormones that signal other cells the mechanisms involved in cell signaling ofter involve complex biochemical processes The Energy of Life all energy transformations and chemical processes that occur within an organism are re ferred to as its metabolism Energy is necessary to carry on the metabolic activities essential for growth repair and maintenance during cellular respiration cells capture energy released by nutrient molecules through a series of carefully regulated chemical reactions the cell can use this energy to do work there is a one way flow of energy through ecosystems organisms can neither create en ergy nor use it with complete efficiency during every energy transaction some energy dis perses into the environment as heat and is no longer available to the organism plants algae and certain bacteria are producers or autotrophs that produce their own food from simple raw materials most of these organisms use sunlight as an energy source and carry on photosynthe sis the process during which producers synthesize complex molecules such as glucose from carbon dioxide and water oxygen is produced as a byproduct of photosynthesis animals are consumers or heterotrophs organisms that depend on producers for primary consumers eat producers where as secondary consumers eat primary food energy and oxygen consumers consumers obtain energy by breaking down sugars and other food molecues originally produced during photosynthesis most bacteria and fungi are decomposers heterotrophs that obtain nutrients by break ing down nonliving organic material such as wastes dead leaves and branches and the bodies of dead organisms Chapter 1 Evolution the process by which populations of organisms change over time evolutionary theory has become the most important unifying concept of biology evolution involves passing genes for new traits from one generation to another leading to differences inpopulations systematics is the field of biology that studies the diversity of organisms and their taxonomy is a subspecialty of systematics the science of naming and classifying or evolutionary relationships ganisms species is the group of organisms with similar structure function and behavior members of a population contribute to a common gene pool all the genes present in a population closely related species are grouped together in the next broader category the genus binomial system of nomenclature each species is assigned a two part name the first part is the genus and the second is the species genus is capitalized species is not classification domain kingdom phylum subphylum class order family genus species Tree of Life stood clade group of organisms with a common ancestor tree of life family tree showing proposed evolutionary relationships among organisms cladogram a branching diagram that depicts the tree of life as it is currently under Prokaryotes assigned two domains bacteria and archaea each with corresponding king dom Eukaryotes domain eukarya kingdoms protists plantae animalia fungi protists unicellular colonial or simple multicellular organisms that have a eukaryotic cell organization idea that protists were the first eukaryotes to evolve primarialy aquatic organisms diverse plantae complex multicellular organisms adapted to carry out photosynthesis characteristic plant features include the cuticle stomata etc fungi composed of the yeasts mildews molds and mushrooms do not photosynthesize obtain nutrients by secreting digestive enzymes into food and then absorbing the predigested food animalia made up of multicellular organisms that obtain their nutrients by eating other organisms Chapter 4 Cell Structure the organization of cells and their small size allows them to maintain homeostasis an appropriate internal environment anisms to function they must work continuously to maintain the internal conditions that enable their mech in order to maintain this the contents must be separated from the external environment the plasma membrane is a