CHAPTER 1 INTRODUCTION: THEMES IN THE STUDY OF LIFE

Overview: Inquiring About the World of Life  Evolution - process of change that has transformed life on Earth  Biology - scientific study of life  Life defies a simple, one-sentence definition  is recognized by what living things do Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Order Evolutionary adaptation Response to the environment Reproduction Growth and development Energy processing Regulation Fig. 1-3

Concept 1.1: Themes connect the concepts of biology  Biology consists of more than memorizing factual details  Themes help to organize biological information Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Evolution, the Overarching Theme of Biology  Evolution makes sense of all we know about living organisms  are modified descendants of common ancestors  share the same genetic code Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Theme: New properties emerge at each level in the biological hierarchy  Life is studied at different levels  molecules  living planet  divided into different levels of biological organization Biosphere  ecosystems  communities  populations  organism  organs & systems  tissues  cells  organelles  molecules  atoms Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig. 1-4 The biosphere Communities Populations Organisms Ecosystems Organs and organ systems Cells Cell Organelles Atoms Molecules Tissues 10 µm 1 µm 50 µm

Emergent Properties  Emergent properties result from the arrangement and interaction of parts within a system  All parts come together in an exact way for new properties to emerge Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Power and Limitations of Reductionism  Reductionism – reducing complex systems to simpler parts, makes them easier to study  Biology must balance reductionism with the study of emergent properties  Realize that something broken down may no longer function as intended Dissected animal Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Systems Biology  A system is a combo of components that function together  Systems biology constructs models for the changing behavior of bio systems  The systems approach poses questions such as:  How does a drug for blood pressure affect other organs?  How does increasing CO 2 alter the biosphere? Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Theme: Organisms interact with their environments, exchanging matter and energy  Every organism interacts with its environment  both biotic and a biotic factors  Organisms and environment are affected by the interactions between them Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Ecosystem Dynamics  Major processes in ecosystem interactons include:  Cycling of nutrients material acquired by plants eventually returns to the soil  Flow of energy – enter as light leaves as heat Sunlight  producers  consumers Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig. 1-5 Sunlight Ecosystem Heat Cycling of chemical nutrients Producers (plants and other photosynthetic organisms) Chemical energy Consumers (such as animals)

Energy Conversion  Work requires a source of energy, which can be stored in different forms  light, chemical, kinetic, or thermal  Energy exchange between organism and environment involves energy transformations  Solar energy  chemical  kinetic energy Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Theme: Structure and function are correlated at all levels of biological organization  Structure and function of living organisms are closely related  a leaf is thin and flat, maximizing the capture of light by chloroplasts  bird bones, light and sturdy, allow for flight Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Theme: Cells are an organism’s basic units of structure and function  cell - lowest level of organization that can perform all activities required for life  Are enclosed by a membrane  Use DNA as their genetic information  cell division is the basis of all reproduction, growth, and repair of multicellular organisms Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

 eukaryotic cell - membrane-enclosed organelles, including the nucleus  Plant, fungi, animals  prokaryotic cell – simpler, smaller, and does not have nucleus or other membrane-enclosed organelles  Bacteria and archaea Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

1 µm Organelles Nucleus (contains DNA) Cytoplasm Membrane DNA (no nucleus) Membrane Eukaryotic cell Prokaryotic cell Fig. 1-8

Theme: The continuity of life is based on heritable information in the form of DNA  Chromosomes contain genetic material - DNA (deoxyribonucleic acid)  DNA makes up genes  Genes - units of inheritance contain info that parents transfer to offspring Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

DNA Structure and Function  A chromosome is one long DNA molecule with hundreds or thousands of genes  DNA controls the development and maintenance of organisms Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Nuclei containing DNA Sperm cell Egg cell Fertilized egg with DNA from both parents Embryo’s cells with copies of inherited DNA Offspring with traits inherited from both parents Fig. 1-9

 DNA molecule is two long chains arranged in a double helix  Each link in the chain is one of four nucleotides  Adenine – A  Guanine - G  Cytosine - C  Thymine - T Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig Nucleus DNA Cell Nucleotide (a) DNA double helix(b) Single strand of DNA

 Genes control protein production indirectly  DNA  into RNA  protein  genome is an organisms entire set of genetic instructions Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Systems Biology at the Levels of Cells and Molecules  Genomes have been sequenced using DNA- sequencing machines  knowledge of an organisms genes and proteins can be studied using a systems approach  Allows for understanding of disease and development of pharmaceutical treatments Understand cell cycle to understand cancer, leads to better treatment options Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

 Advances in systems biology at the cellular and molecular level depend on  “High-throughput” technology, which yields enormous amounts of data  Bioinformatics - use of computational tools to process a large volume of data  Interdisciplinary research teams Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings