Ch1 Slides.pptx

Chapter 1 Evolution, the Themes of Biology, and Scientific Inquiry © 2017 Pearson Education, Inc. Objectives 1. You will d...

Chapter 1 Evolution, the Themes of Biology, and Scientific Inquiry © 2017 Pearson Education, Inc. Objectives 1. You will describe what makes a good hypothesis and understand the components of an experiment/data (The Scientific Method). 2. You will identify the 3 domains of life and know the evolutionary history behind them. 3. You will memorize the levels of biological organization and their emergent properties. 4. You will describe key differences between eukaryotic and prokaryotic cells. 5. You will define genome, genomics, proteome, proteomics, producers, consumers Observation and testing Sir Francis Bacon hypotheses (1561–1626) is credited with (The Scientific Method) being the first to define the scientific method. (credit: Paul van Somer)  The word science is derived from Latin and means “to know”  Scientists make observations, forming logical hypotheses, and testing them The Scientific Method Questions That Can and Cannot Be Addressed by Science  A hypothesis must be testable  Based on previous observations and assumptions (Deductive reasoning)  A prediction that can be tested false or not false (can never be proven true)  Supernatural and religious explanations are outside the bounds of science  An experiment is a scientific test, carried out under controlled conditions Exploration and Observation (Experiment)  Recorded observations are called data  Qualitative data often take the form of recorded descriptions (but this is still good data)  Quantitative data are expressed as numerical measurement, organized into tables and graphs  Controlled experiment- designed to compare an experimental group  Independent variable-factor being manipulated  Dependent variable-factor being measured Exploration and Observation  Data is analyzed and conclusions are made (Inductive reasoning)  Results are communicated through publications, online media, etc. Exploration and Observation  Repeating specific observations can lead to important generalizations  Replicating data is good but not required for a good hypothesis  Generalizations can lead to theories  More general in scope than a hypothesis (specific to your original question)  Supported by a large body of evidence in comparison to a hypothesis Building on the Work of Others  Scientists check each other’s claims by performing similar experiments  If experimental results are not repeatable, the original claim will have to be revised  It is not unusual for different scientists to work on the same research question  Scientists cooperate by sharing data about model organisms (for example, the fruit fly Drosophila melanogaster) The Scientific Method Experiment to test spontaneous generation versus germ hypothesis The Three Domains of Life  All living organisms are currently divided into three domains, named Bacteria, Archaea, and Eukarya  The prokaryotes include the domains Bacteria and Archaea  Domain Eukarya includes all eukaryotic organisms  Domain Eukarya includes the protists and three kingdom  Plants, Fungi, Animals The Three Domains of Life This phylogenetic tree was constructed by microbiologist Carl Woese using data obtained from sequencing ribosomal RNA genes. The tree shows the separation of living organisms into three domains: Bacteria, Archaea, and Eukarya. Bacteria and Archaea are prokaryotes, single-celled organisms lacking intracellular organelles. (credit: Eric Gaba; NASA Astrobiology Institute) Charles Darwin and the Theory of Natural Selection  Charles Darwin published On the Origin of Species by Means of Natural Selection in 1859  Darwin made a few observations:  Traits vary and are heritable  Species showed evidence of “descent with modification” from common ancestors  Species are generally adapted to their environments  “Natural selection” is the mechanism behind descent with modification Evolution accounts for the unity and diversity of life  Evolution-the concept that living organisms are modified descendants of common ancestors  Descent with modification  Figures 1.1 and 1.2  (Figure 1.1): (Archaea): ©Power and Syred/Science Source; (Bacteria): ©Alfred Pasieka/SPL/ Science Source; (Figure 1.2): (Protista): Source: Dr. Stan Erlandsen and Dr. Dennis Feely/CDC; (Fungi): ©Russell Illig/Getty Images; (Plantae): ©Iconotec/Glow Images; (Animalia): ©Alan and Sandy Carey/Getty Images  Each of the six kingdoms are profoundly different from the others Properties of Life and Homeostasis New Properties Emerge at Successive Levels of Biological Organization  Life can be studied at different levels, from molecules to the entire living planet  This enormous range can be divided into different levels of biological organization Exploring Levels of Biological Organization The Cell: An Organism’s Basic Unit of Structure and Function  The Cell Theory was developed in the 1800s  States that all living organisms are made of cells  The cell is the smallest unit of organization that can perform all activities required for life  All cells are enclosed by a membrane that regulates passage of materials between the cell and its environment (also allows the cell to interact with its environment) Contrasting Eukaryotic and Prokaryotic Cells in Size and Complexity The Cell: An Organism’s Basic Unit of Structure and Function  A eukaryotic cell has membrane-enclosed organelles, the largest of which is usually the nucleus  Multicellular organisms  By comparison, a prokaryotic cell is simpler and usually smaller and does not contain a nucleus or other membrane- enclosed organelles  Single cell organisms Life’s Processes Involve the Expression and Transmission of Genetic Information  Within cells, structures called chromosomes contain genetic material in the form of DNA (deoxyribonucleic acid)  The genetic information encoded by DNA directs the development of an organism  For example, a gene contains the information of a protein  The process of going from DNA to protein is referred to as gene expression  Genes are the units of inheritance DNA: The Genetic Material  Each DNA molecule is made up of two long chains arranged in a double helix  Information is saved in four kinds of chemical building blocks called nucleotides and abbreviated A, G, C, and T DNA double helix Genomics: Large-Scale Analysis of DNA Sequences  An organism’s genome is its entire “library” of genetic instructions  Genomics is the study of sets of genes in one or more species  The entire set of proteins expressed by a given cell, tissue, or organ is called a proteome  Proteomics is the study of whole sets of proteins and their properties Life Requires the Transfer and Transformation of Energy and Matter  The input of energy from the sun make life possible  Sunlight converted to chemical energy by plants and other photosynthetic organisms (producers) is passed along to consumers  Consumers are organisms that feed on other organisms or their remains From Molecules to Ecosystems, Interactions Are Important in Biological Systems  Interactions between the components of the system ensure smooth integration of all the parts  This holds true equally well for components of an ecosystem and the molecules in a cell  Many biological processes can self-regulate through a mechanism called feedback Molecules: Interactions Within Organisms  In feedback regulation, the output, or product of a process, regulates the process  The most common form of regulation in living organisms is negative feedback, in which the response reduces the initial stimulus  A less common form of regulation is positive feedback, in which an end product speeds up its own production Structure and Function  At each level of the biological hierarchy we find a correlation between structure and function  Analyzing a biological structure gives us clues about what it does and how it works  Conversely, knowing the function of something provides insight into its structure and organization Example  Receptor on human cell for insulin known  Find similar molecule in a worm  Might conclude this molecule functions the same in the worm