BISC160 Chapter 1.docx

7 Pages

Biological Science
Course Code
BISC 160
Dr.Beckie Symula

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Chapter 1 8/22/2012 1:55:00 PM 1.1 What is biology? Living organisms: o Consist of one or more cells o Contain genetic information o Use genetic info to reproduce o Are genetically related and have evolved o Can convert molecules obtained from their environment into new biological molecules o Can extract energy from the environment and use it to do biological work o Can regulate their internal environment  Discovery of cells; microscope: Hans and Zaccharias Janssen 1590, Antony van Leeuwenhoek of Holland and Robert Hooke of England in 1600s  Hooked named the “cell”  Schleidan and Schwann, plant and animal tissues, cell theory: o Cells are the basic structural and physiological units of all living organisms o Cells are both distinct entities and building blocks of more complex organisms  Pasteur proved that life must be present in order for new life to be generated  Modern Cell theory: All cells come from preexisting cells All cells are similar in chemical composition Most of the chemical reactions of life occur in aqueous solution within cells Complete sets of genetic information are replicated and passed on during cell division Viruses lack cellular structure but remain dependent on cellular organisms  Evolution: change in the genetic makeup of biological populations through tie o Charles Darwin 1859 Origin of Species o Natural selection: differential survival and reproduction among individuals in a population o All living organisms evolve from a common ancestor o Species: a group of organisms that can produce viable and fertile offspring with one another o Adaptations: structural, physiological, or behavioral traits that enhance an organism’s chances or survival and reproduction in environment o Sexual selection: selection due to mate choice o Genetic drift: the random fluctuation of gene frequencies in a population due to chance events  Cells use nutrients to supply energy and to build new structures o Nutrients supply the organism with energy and raw materials for carrying out biochemical reactions o Building=synthesis o Metabolism: the sum of all the chemical transformations and other work done in all the cells of an organism  Living organisms regulate their internal environment o Cells are bathed in extracellular fluids, from which they receive nutrients and into which they excrete waste products o atommoleculecelltissueorgansystemorganismpo pulationcommunityecosystembiosphere  Population: a group of individuals of the same species that interact with one another  Community: populations of all the species that live and interact in the same area  Ecosystem: Communities together with their abiotic environment o Arctic tundra, coral reef, tropical rainforest  Knowledge about how animals develop has come from work on sea urchins, frogs, chickens, roundowrms, and fruit flies.  Discovery of a major gene controlling skin color came from work on zebrafish Summary 1.1: Living organisms are made of (or depend on) cells, are related by common descent and evolve, contain genetic information and use it to reproduce, extract energy from their environment and use it to do biological work, synthesize complex molecules to construct biological structures, regulate their internal environment, and interact with one another. 1.2 How is all life on earth related?  Fossil record: the preserved remains of organisms that lived in the distant past  Molecular methods for comparing genomes are enabling biologists to more accurately establish the degrees of a relationship between living organisms and to use that info to interpret the fossil record  Life arose from non-life via chemical evolution o Earth is 4.5 and 4.6 billion years old o 600 million years before life happened o Biologists say that complex biological molecules first arose through random physical association of chemicals in that environment  Cellular structure evolved in the common ancestor of life o Fatlike molecules (not soluble in water and form membranous films) when agitated form vesicles, which could have enveloped biological molecules o Membrane formation led to the ab
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