Introduction To Biology PDF

INTRODUCTION TO BIOLOGY Copyright Cmassengale Copyright Cmassengale *  BIOLOGY – THE STUDY OF LIFE Life arose more than 3.5 billion years ago First organisms (living things) were single celled Only life on Earth for millions of years Organisms changed over time (evolved)...

INTRODUCTION TO BIOLOGY Copyright Cmassengale Copyright Cmassengale *  BIOLOGY – THE STUDY OF LIFE Life arose more than 3.5 billion years ago First organisms (living things) were single celled Only life on Earth for millions of years Organisms changed over time (evolved) Copyright Cmassengale Copyright Cmassengale * New organisms arose from older kinds Today there are millions of species They inhabit almost every region of Earth today Copyright Cmassengale Copyright Cmassengale *  Early Beliefs About the Origin of Life Theories about the origins of life are as ancient as human culture. The Theory of Spontaneous Idea: Generation / Proposed by Aristotle in Abiogenesis Concept: the 4th century, a belief small organisms are that last until 17th spontaneously generated century. from nonliving matter  BIOGENESIS As time passes by, scientists questioned this idea with an opposing concept. A belief that life originates from preexisting life. Experiments to prove Biogenesis Studies to prove BIOGENESIS FRANCESCO REDI (1668) Italian physician who experimented on fresh meat in jars Disprove the theory of spontaneous generation, concluded that life arose from living matter, such as maggots from eggs  In the first jar, with the meat sealed inside by a stopper, maggots did not appear on the meat; in the second jar, covered with mesh, maggots also did not appear on the meat; but in the third jar, without a cover, maggots did appear on the meat and developed into flies. Studies on Spontaneous Generation JOHN NEEDHAM (1748) Using his microscope, an English experimenter and priest, John Needham, noticed that broths made from meat were teeming with microorganisms, so he put it to his own test.  Needham heated the broth, let it sit covered for several days, then observed microorganisms in the fluid. In Needham’s mind, this finding suggested that the lifeless broth had given rise to life. But another scientist, an Italian named Lazzaro Spallanzani, thought that Needham must have done something wrong. Perhaps, he hadn’t heated the broth to a high enough temperature or for a long enough time. Studies to prove BIOGENESIS LAZZARO SPALLANZANI (1767) He boiled broth in two bottles, left one bottle open and one closed, and found that new microorganisms appeared only in the open bottle. His conclusion: the microorganisms entered the bottle through the air; they were not generated spontaneously in the broth  Spallanzani performed Needham's experiment, but also tested a bottle of broth that was closed after boiling. He found no microorganisms grew in the closed bottle. Experiments seeming to prove or disprove spontaneous generation of life went on for another century. Because of the difference between closed and open vessels, arguments focused on the possibility that spontaneous generation of life might require fresh air. Thus, lack of air in Spallanzani’s closed bottle could have been a factor confusing the results. 19th Century Advancement LOUIS PASTEUR (1861) He designed flasks with long, specially curved, swanlike necks and boiled the sugar solution with yeasts in it. The flasks were open to allow air to enter but there’s no organism developed in the mixture. Microorganism settled on the bottom of the curved neck of the flask and could not reach the mixture.  Then he cut the neck of the flask, and after two days, was teeming with microorganisms because they can easily enter it. The solution in Pasteur’s special flasks did not become infested with microorganisms despite being exposed to fresh air. This suggests that new bacteria appear only when they are produced by existing bacteria. And so, after a run of centuries, the hypothesis of spontaneous generation was finally laid to rest. CURRENT Beliefs About the Origin of Life  Current Beliefs Divine Spontaneous Panspermia Creation Origin  DIVINE CREATION Oldest belief that life came from a divine being Supernatural power than naturalistic means Creationism – the belief that life arose from nothing but the power of divine being SPONTANEOUS ORIGIN Simple molecules combined to form complex ones Energy – ligthing, geothermal, electric sparks PRIMORDIAL SOUP – organic broth on Earth’s early surface Panspermia Swedish scientist Svante Arrhenius Life arose outside Earth and life forms were transported from another planet to seed life on Earth A meteor or cosmic dust may have carried to Earth significant amounts of organic molecules, which started the evolution of life.  Despite the influx of information, the question about how life began on Earth remain unanswered because there is no account on what happened 4.5 billion years ago. THEMES OF BIOLOGY Cell structure and function Stability and homeostasis Reproduction and inheritance Evolution Interdependence of organisms Matter, energy, and organization Copyright Cmassengale Copyright Cmassengale * CELL STRUCTURE AND FUNCTION Cell basic unit of life All organisms are made of and develop from cells Some composed of only a single cell (unicellular) which is usually identical to parent Copyright Cmassengale Copyright Cmassengale * CELLS Most organisms are composed of many cells (multicellular) Cells are different (undergo differentiation) Cells are small Cells are highly organized Copyright Cmassengale Copyright Cmassengale * Cells contain specialized structures (organelles) that carry out the cell’s life processes Many different kinds of cells exist All cells surrounded by a plasma membrane Contain a set of instructions called DNA (genetic information) Copyright Cmassengale Copyright Cmassengale *  STABILITY AND HOMEOSTASIS Organisms must Maintain very stable internal conditions - HOMEOSTASIS Temperature, water content, chemical content, etc. must be maintained Copyright Cmassengale Copyright Cmassengale *  REPRODUCTION AND INHERITANCE All organisms produce new organisms like themselves REPRODUCE Organisms transmit hereditary information to their offspring INHERITANCE Copyright Cmassengale Copyright Cmassengale *  DNA Genetic Information in all cells Deoxyribonucleic Acid DNA contains instructions for traits GENES Make the structures and complex chemicals necessary for life PROTEINS DNA in every body cell (SOMATIC CELLS) is exactly alike Copyright Cmassengale Copyright Cmassengale *  SEXUAL REPRODUCTION Hereditary information from two different organisms of the same species are combined Egg and sperm → zygote (fertilized egg) Zygote contains hereditary information from both parents Copyright Cmassengale Copyright Cmassengale *  ASEXUAL REPRODUCTION Hereditary information from one, usually unicellular, organism that divides Resulting cells contain identical hereditary information Genetic information from single parent Copyright Cmassengale Copyright Cmassengale *  EVOLUTION Populations of organisms change (evolve) over generations (time) Explains how many different kinds of organisms came into existence SPECIES Explains how modern organisms are related to past organisms Copyright Cmassengale Copyright Cmassengale * Explains why organisms look and behave the way they do Provides a basis for exploring the relationships among different groups of organisms Copyright Cmassengale Copyright Cmassengale *  NATURAL SELECTION Natural selection is the driving force in evolution Organisms that have certain favorable traits are better able to successfully reproduce than organisms that lack these traits Copyright Cmassengale Copyright Cmassengale *  NATURAL SELECTION Survival of organisms with favorable traits cause a gradual change in populations over many generations Also Called “Survival of the Fittest” Copyright Cmassengale Copyright Cmassengale *  INTERDEPENDENCE OF ORGANISMS Interaction of organisms with one another and with their environment ECOLOGY Insects depend and flowers DEPEND on each other for food & pollination COEVOLUTION Copyright Cmassengale Copyright Cmassengale *  All organisms need substances such as nutrients, water, and gases from the environment The stability of the environment depends on the healthy functioning of organisms in that environment Copyright Cmassengale Copyright Cmassengale *  MATTER, ENERGY AND ORGANIZATION Living things are highly organized Require a constant supply of energy to maintain their orderly state Copyright Cmassengale Copyright Cmassengale *  ENERGY ALL energy comes from the SUN (directly or indirectly) Photosynthesis is the process by which some organisms capture the energy from the sun (solar) and transform it into energy (chemical) that can be used by living things Copyright Cmassengale Copyright Cmassengale *  AUTOTROPHS Organisms that make their own food are called autotrophs Phototrophs – use solar energy (photosynthesis) to get energy Convert H O and CO into sugar and O2 2 2 Chemotrophs – use different chemical processes to get energy Copyright Cmassengale Copyright Cmassengale *  HETEROTROPHS Organisms that must take in food to meet their energy needs are called heterotrophs Consume autotrophs (herbivores), other heterotrophs (carnivores) or both (omnivores) for their energy needs Complex chemicals are broken down and reassembled into chemicals and structures needed by organisms Copyright Cmassengale Copyright Cmassengale * Characteristics of Life Copyright Cmassengale Copyright Cmassengale * Cells All living things are composed of cells In multicellular organisms, many are specialized to perform specific functions Cells are always very small The size of multi-celled organisms depends on the number of cells NOT their size Copyright Cmassengale Copyright Cmassengale * Organization Organized at both the molecular and cellular levels Take in substances from the environment and organize them in complex ways Specific cell structures (organelles) carry out particular functions Copyright Cmassengale Copyright Cmassengale * In multicellular organisms, cells and groups of cells (tissues) are organized by their function Cells → tissues Tissues → organs Organs → systems Systems → ORGANISM Copyright Cmassengale Copyright Cmassengale *  Energy Use Use energy in a process called metabolism Sum of all chemical processes Require energy to maintain their molecular and cellular organization, grow and reproduce Copyright Cmassengale Copyright Cmassengale * Homeostasis Maintain stable internal conditions Temperature, pH, etc. Copyright Cmassengale Copyright Cmassengale *  Growth Grow occurs as the result of cell division and cell enlargement Cell division is the formation of two cells from a preexisting cell New cells enlarge as they mature When a cell grows to a size where its surface area isn’t big enough for its volume, the cell divides Copyright Cmassengale Copyright Cmassengale * Development The process by which an adult organism arise is called development Repeated cell divisions and cell differentiation Copyright Cmassengale Copyright Cmassengale *  Reproduction All species have the ability to reproduce Not essential to survival of individual but is essential for continuation of a species Copyright Cmassengale Copyright Cmassengale * Responsiveness Respond to stimuli in the external environment Detect and respond to changes in light, heat, sound and chemical and mechanical contact Coordinates it’s responses Copyright Cmassengale Copyright Cmassengale *  Evolve Ability to adapt to their environment through the process of evolution Favorable characteristics are selected for and passed on to offspring Called adaptations Driven by natural selection or “survival of the fittest” Copyright Cmassengale Copyright Cmassengale *