Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings The Characteristics of Life and Overview of
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Introduction to Biology: Brown pelicans –Are part of the web of life in their environment
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings The brown pelicans’ proximity to humans –Has meant trouble for the species The brown pelicans’ connection to the environment –Sets the stage for the study of biology
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings THE SCOPE OF BIOLOGY Life’s levels of organization define the scope of biology Life’s structural hierarchy –Defines the scope of biology, the scientific study of life Biosphere Ecosystem Florida coast Community All organisms on the Florida coast Population Group of brown pelicans Organism Brown pelican Organ system Nervous system Organ Brain Tissue Nervous tissue Cell Nerve cell Organelle Nucleus Molecule DNA Atom Nucleus Brain Spinal cord Nerve
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings An ecosystem consists of all the organisms living in a par ticular area –As well as the nonliving environmental components All the living organisms in an ecosystem –Make up a community
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings A population –Consists of a localized group of individuals of a species An individual living entity –Is an organism
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings The hierarchy continues downward with –Organ systems –Organs –Tissues –Cells –Organelles –Molecules
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Living organisms and their environments form interconnecting webs Ecosystems are characterized by the cycling of chemical nutrients from the atmosphere and soil –To producers to consumers to decomposers and back to the environment
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Energy flows one-way through an ecosystem –From the sun to producers to consumers and exits as heat Sun Air CO 2 O2O2 H2OH2O Chemical energy Inflow of light energy Loss of heat energy Producers Cycling of Chemical nutrients Consumers Decomposers Soil Ecosystem
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Cells are the structural and functional units of life A cell –Is the basic unit of life
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Eukaryotic cells –Contain membrane-enclosed organelles, including a DNA-containing nucleus Prokaryotic cells –Lack such organelles Nucleus (contains DNA) Eukar yotic cell Prokar yotic cell DNA (no nucleus) Organelles 25,000
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings EVOLUTION, UNITY, AND DIVERSITY The unity of life: All forms of life have common features DNA is the genetic information –For constructing the molecules that make up cells and organisms
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Each species’ genetic instructions –Are coded in the sequences of the four building blocks making up DNA’s two helically coiled chains A C T A T A C C G T A G T A
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings All organisms share a common set of features –Made of one or more cells –Displays organization –Grows and develops
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings –Reproduces –Responds to stimuli –Requires energy –Maintains homeostasis –Adaptations evolve over time
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings The diversity of life can be arranged into three domains Organisms are grouped (classified) –Into the prokaryotic domains Bacteria and Archaea and the eukaryotic domain Eukarya
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings SEM 25,000 Domains Bacteria and Archaea SEM 3,250
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Domain Eukarya includes –Protists (protozoans and algae, falling into multiple kingdoms) –The kingdoms Fungi, Plantae, and Animalia 275 Protists (multiple kingdoms) Kingdom Fungi Kingdom Animalia Kingdom Plantae
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Evolution explains the unity and diversity of life Charles Dar win –Synthesized the theory of evolution by natural selection
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Populations with varied inherited traits Elimination of individuals with certain traits Reproduction of survivors Natural selection is an editing mechanism –That occurs when populations or organisms, having inherited variations, are exposed to environmental factors that favor the reproductive success of some individuals over others
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings All organisms have adaptations –That have evolved by means of natural selection Killer whale Pangolin
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings THE PROCESS OF SCIENCE Scientists use two main approaches to learn about nature Science –Is a way of knowing –Seeks natural causes for natural phenomena
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Discovery Science In discovery science –Scientists describe some aspect of the world and use inductive reasoning to draw general conclusions
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Hypothesis-Based Science In hypothesis-based science –Scientists attempt to explain obser vations by testing hypotheses
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings With hypothesis-based science, we pose and test hypotheses Hypothesis-based science involves –Obser vations, questions, hypotheses as tentative answers to questions –Deductions leading to predictions, and then tests of predictions to see if a hypothesis is falsifiable
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings A Case Study from Ever yday Life Deductive reasoning is used in testing hypotheses as follows –If a hypothesis is correct, and we test it, then we can expect a par ticular outcome Observations Question Hypothesis # 1: Dead batteries Hypothesis # 2: Burnt-out bulb Prediction: Replacing batteries will fix problem Prediction: Replacing bulb will fix problem Test prediction Test falsifies hypothesis Test does not falsify hypothesis
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings A Case Study of Hypothesis-Based Science In experiments designed to test hypotheses –The use of control groups and experimental groups helps to control variables Percent of total attacks on artificial snakes % 17% 16% 84% Artificial king snakes Artificial brown snakes Coral snakes absent Coral snakes present Figure 1.8BFigure 1.8C
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Biology is connected to many impor tant issues in our lives –Environmental problems and solutions –Genetic engineering –Medicine
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Many technological advances –Stem from scientific research The science-technology-society relationship –Is an impor tant aspect of a biology course