Biology Today Chapter 1 PDF

Introduction: Chapter Biology Today 1 Biology All Around Us: Biology & Society An Innate Passion for Life Biology surrounds us & affects us The Scientific Study of Life Biology is the scientific study of life The Process of Science Science is an approach to understa...

Introduction: Chapter Biology Today 1 Biology All Around Us: Biology & Society An Innate Passion for Life Biology surrounds us & affects us The Scientific Study of Life Biology is the scientific study of life The Process of Science Science is an approach to understanding the natural world that is based on inquiry: The Process of Science The drive to understand our world is manifest in two main scientific approaches: Discovery science Hypothesis-driven science Most scientists practice a combination of these two forms of inquiry Discovery Science Science seeks natural causes for natural phenomena This limits science to the study of structures & processes that we can verifiably observe & measure directly or indirectly with tools & technology, such as microscopes Discovery Science Recorded observations are called data, & scientific inquiry is based on data This dependence on verifiable data Discovery Science Verifiable observations & measurements are the data of discovery science – the what? Charles Darwin’s descriptions of the diverse plants & animals he observed in South America Hypothesis-Driven Science The observations of discovery science motivate us to ask questions & seek explanations – the why? As a process of inquiry, the scientific method consists of a series of steps that provide a guideline for scientific investigations  Experiment does not support Revise. hypothesis. Observation Question Hypothesis Prediction Experiment The remote What’s The With new Replace doesn’t wrong? batteries batteries, it batteries. work. are dead. will work. Experiment supports hypothesis; make more predictions and test. Figure 1.3 Hypothesis-Driven Science Most modern scientific investigations are hypothesis-driven science A hypothesis is a tentative answer to a question or a proposed explanation for a set of observations Hypothesis-Driven Science Once a hypothesis is formed, we can make predictions about what results are expected if that hypothesis is correct Theories in Science Accumulating facts is not the 1° goal of science Facts are verifiable observations & repeatable experimental results & the prerequisites of science Theories in Science Advances in science are theories that tie together a number of observations that previously seemed unrelated Theories in Science People like Isaac Newton, Charles Darwin, & Albert Einstein stand out in science because their theories had such broad explanatory power Theories in Science What is a scientific theory, & how is it different from a hypothesis? A theory is a comprehensive explanation supported by extensive evidence, & is general enough to spin off many new testable hypotheses Theories in Science For example, these are hypotheses: 1. “White fur is an adaptation that helps polar bears survive in an Arctic habitat” 2. “The bone structure in a hummingbird’s wings is an evolutionary adaptation that provides an advantage in gathering nectar from flowers” In contrast, the following theory ties together those seemingly unrelated hypotheses: Theories in Science Theories only become widely accepted by scientists if they are supported by extensive evidence & have not been contradicted by any scientific data The Nature of Life What is life? The phenomenon of life defies a simple definition The Properties of Life There are seven (7) properties & processes associated with life: Order, Regulation, Growth & development, Energy processing, The Properties of Life There are seven (7) properties & processes associated with life: Response to the environment, Reproduction, & Evolution Life in Its Diverse Forms The diversity of known life – all the species that have been identified & named – includes at least 290,000 plants, 52,000 vertebrates, & Life in Its Diverse Forms Estimates of the total number of species range from 10 million to more than 100 million Grouping Species: The Basic Concept Biology groups diverse organisms according to similarities A species – a group of organisms that live in the same place & have the potential to interbreed to produce healthy offspring Grouping Species: The Basic Concept We can sort groups into broader categories, such as rodents (which include squirrels) & insects (which include butterflies) Taxonomy – branch of biology that names & classifies species; arrangement of species into a hierarchy of broader & broader groups The Three Domains of Life The three domains of life are 1. Bacteria, 2. Archaea, 3. Eukarya The Three Domains of Life The Domain Eukarya has three divisions called kingdoms: 1. Kingdom Plantae, 2. Kingdom Fungi, & 3. Kingdom Animalia Domain Eukarya These kingdoms are distinguished partly by how they obtain food Plants produce their own food by photosynthesis Fungi are mostly decomposers, digesting dead organisms Animals obtain food by consuming other organisms The Three Domains of Life Eukaryotes that do not fit into the other three kingdoms are grouped into the protists group Most protists are single-celled; like the microscopic amoebas Major Themes in Biology Five (5) unifying themes occur throughout our investigation of biology: Evolution, Structure/Function, Information Flow, Energy Transformations, Interconnections within Systems 1. Evolution What do a tree, a mushroom, & a human have in common? What can account for this combination of unity & diversity in life? 1. Evolution Evolution is the fundamental principle of life & the core theme that unifies all of biology The theory of evolution by natural selection, described by Charles Darwin more than 150 years ago, is the one idea that makes sense of everything we know about living organisms 1. Evolution Life evolves Each species is one twig of a branching tree of life extending back in time through ancestral species more & more remote The Darwinian View of Life The evolutionary view of life – In 1859 Charles Darwin published On the Origin of Species by Means of Natural Selection The Darwinian View of Life Darwin developed two main points: Species living today descended from a succession of ancestral species in what Darwin called “descent with modification,” capturing the duality of life’s 1. unity (descent) & 2. diversity (modification) The Darwinian View of Life In the struggle for existence, those individuals with heritable traits best suited to the local environment are more likely to survive & leave the greatest number of offspring The environment “selects” only certain heritable traits The Darwinian View of Life A classic example involves the finches of the Galápagos Islands The Darwinian View of Life Antibiotic resistance in bacteria evolves in response to the overuse of antibiotics (e.g., dairy & cattle farms) Some bacteria will vary in their susceptibility to the antibiotics The Darwinian View of Life Surviving bacteria → offspring with the survival trait Over many bacterial generations → evolution of antibiotic-resistant bacteria Observing Artificial Selection Artificial selection – purposeful breeding of domesticated plants & animals by humans Observing Artificial Selection All these vegetables have a common ancestor in one species of wild mustard 2. Structure/Function: The Relationship of Structure to Function Within biological systems, structure & function are related, with each providing insight into the other 2. Structure/Function: The Relationship of Structure to Function The structure of your lungs correlates with function Small branches → millions of tiny sacs for gas exchange 3. Information Flow For life’s functions to proceed properly, information must be stored, transmitted, & used Every cell in your body was formed when a previous cell transmitted info to it (i.e., DNA) 3. Information Flow Info flows from generation to generation, passed down encoded in molecules of DNA All cells use DNA as genes, the units of inheritance that transmit info from parent to offspring 4. Energy Transformations: Pathways That Transform Energy and Matter Various cellular activities are work, such as growth & movement → work requires energy (E) Life is made possible by the input of E (from the sun), & 4. Energy Transformations: Pathways That Transform Energy and Matter Plants & other photosynthetic organisms (“producers”) capture E & convert it into food (i.e., chemical energy) 4. Energy Transformations: Pathways That Transform Energy and Matter Chemical E is passed through “consumers” that use the chemical E 4. Energy Transformations: Pathways That Transform Energy and Matter Everything in the universe is composed of matter 5. Interconnections within Biological Systems The study of life extends from the microscopic scale of the molecules & cells of organisms to the global scale of the entire living planet 5. Interconnections within Biological Systems The biosphere – all life & places where life exits on Earth including the lower atmosphere Ecosystems 5. Interconnections within Biological Systems Communities – all organisms in a ecosystem Populations – groups of individuals species in an ecosystem Organisms 5. Interconnections within Biological Systems Organ systems & organs – organs within individuals Tissues – groups of cells that perform a specific function Cells 5. Interconnections within Biological Systems Organelles – functional components of cells that perform specific functions Molecules & atoms 5. Interconnections within Biological Systems At each new level, novel properties emerge that are absent from the preceding one