Presentation is loading. Please wait.

Presentation is loading. Please wait.

Introduction: Themes in the Study of Life

Similar presentations


Presentation on theme: "Introduction: Themes in the Study of Life"— Presentation transcript:

1 Introduction: Themes in the Study of Life
Chapter 1 Introduction: Themes in the Study of Life

2 Word Roots -ell = small bio = life eu- = true
Organelle: small membrane-enclosed body with specialized function found in cytoplasm of eukaryotic cells eu- = true Eukaryotic cell: cell that has true nucleus pro- = before; karyo- = nucleus Prokaryotic cell: cell that has no nucleus bio = life Biology: study of life Biosphere: all environments on Earth inhabited by life; Bioinformatics: using information technology to extract useful information from large sets of biological data

3 Framework Outline broad scope of biology
Biology is collection of facts/concepts structured within theories and organizing principles Describe themes that unify study of life Recognizing common themes within biology helps to structure your knowledge Examine scientific construction of biological knowledge

4 Overview: Inquiring About the World of Life
Biology: scientific study of life Pose questions Seek science-based answers (scientific inquiry) Evolution: Process of change shaping life from its origin on Earth to today’s diversity Adaptations ensure survival by matching organisms to their environment Life’s basic characteristics is high degree of order Life defies simple, one-sentence definition Life is recognized by what living things do

5 Fig. 1-3 Some properties of life
Life evolves in response to interactions between organisms and environment (evolutionary adaptation) Organisms highly ordered, other characteristics of life emerge from this complex organization Organisms respond to stimuli from environment Organisms regulate internal environment to maintain steady state (homeostasis), even in face of fluctuating external environment Organisms reproduce; life comes from life (biogenesis) Organism take in/transform energy to do work (energy processing), including maintenance of ordered state Heritable programs stored in DNA direct species-specific pattern of growth and development

6 Concept 1.1: Themes help connect the concepts of biology
More than memorizing factual details Themes help organize biological information Evolution (biology’s core/organizing principle) Makes sense of everything we know about living organisms Organisms modified descendants of common ancestors Why traits can be shared by 2 organisms Account for differences when heritable changes occur Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

7 Study of life divided into different levels of biological organization
Fig. 1-4 Levels of Biological Organization Study of life divided into different levels of biological organization Biosphere: all environments on earth inhabited by life Cells: life’s fundamental unit of structure and function 10 µm Ecosystems: all living things/ nonliving in area Organs and organ systems Cell Organelles: various functional components of cell Communities: all organisms inhabiting particular ecosystem 1 µm Atoms Tissues: group of similar cells 50 µm Populations: all individuals of species living in specified area Molecules: chemical structure consisting of 2 or more atoms Organisms: individual living things

8 Emergent Properties result form arrangement and interaction of parts within system
All biological systems, from cells to ecosystems, are composed of parts that interact with each other Resulting interactions enable characteristics not found in individual parts alone Phenomenon called “emergent properties” (interactions among components at each level of biological organization lead to emergency of novel properties at next level/result from structural arrangement and interaction of parts) Gain broader perspective when integrate studies at one level to those with processes at other levels Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

9 Interactions between constituent parts of polymers, their order, their molecular orientation and their interactions with their environment define structure and function of polymer DNA molecule comprised of series of nucleotides linked together in various sequences forming polymer that carries hereditary material for cell Other polymers important to life include carbohydrates, lipids and proteins

10 The Power and Limitations of Reductionism
Reductionism (complex systems understood by studying simpler components) balanced w/study of emergent properties How parts of cells, organisms, and populations are functionally integrated Watson/Crick deduced role of DNA in inheritance by studying its molecular structure Limitations: cell dismantled to chemical ingredients no longer cell Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

11 Theme: Organisms interact with their environments, exchanging matter and energy
Organisms/their environments (water/ minerals from soil/CO2 from air; tree releases O2 to air/roots help form soil) affected by their interactions between them Dynamics of ecosystem include Cycling of chemical nutrients (materials acquired by plants return to soil) Flow of energy from sunlight to producers to consumers (energy exchange between organism and its environment often involves energy transformations; some energy converted to thermal energy and dissipated as heat to surroundings) (Energy flows through ecosystem, usually entering as light and exiting as heat) Work requires energy source Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

12 Theme: Structure and function are correlated at all levels of biological organization
Form fits function (how something works is correlated with its structure) Analyzing biological structure gives clues about what it does and how it works Leaf is thin and flat, maximizing capture of light by chloroplasts Knowing function of something provides insight into its construction Bird’s build/structures of its components makes flight possible Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

13 (a) Wings (aerodynamically efficient shape)
Fig. 1-6 For fits function (a) Wings (aerodynamically efficient shape) (b) Bones (honeycombed internal structure is strong but lightweight) Infoldings of membrane Mitochondrion Figure 1.6 Form fits function in a gull’s wing 100 µm 0.5 µm (d) Mitochondria (in flight muscles with extensive inner folding supply needed energy in small container) (c) Neurons (control flight muscles, have long extensions suited for communication with body)

14 Theme: Cells are an organism’s basic units of structure and function
Lowest level of organization that can perform all activities required for life All cells Are enclosed by membrane Use DNA as genetic information Ability of cells to divide is basis of all reproduction, growth, and repair of multicellular organisms Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

15 Though structurally different, both have many similarities, especially in chemical processes
Eukaryotic cell: Has membrane-enclosed organelles Plants/animals/fungi/all other forms Prokaryotic cell: Simpler/usually smaller No nucleus/other membrane-enclosed organelles Bacteria/Archaea Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

16 Theme: The continuity of life is based on heritable information in the form of DNA
DNA (heritable information of cell) is substance of genes (units of inheritance which transmit information from parents to offspring) Instructions for all complex structures/functions Genes located on chromosomes (long DNA molecules that replicate before cell division and provide identical copies to daughter cells) Control protein production indirectly (DNA transcribed into RNA/translated into protein) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

17 Genome: entire set of organism’s genetic instructions
Biological instructions for development and functioning of organisms coded in arrangement of 4 kinds of nucleotides in DNA molecule Most genes program cell’s production of proteins Almost all cellular actions involve one or more proteins Enzymes are proteins that catalyze cell’s chemical reactions Genome: entire set of organism’s genetic instructions Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

18 DNA Structure and Function
Each chromosome has one long DNA molecule with 100s/1000s of genes Controls development/ maintenance of organisms All forms of life use essentially same genetic code Particular nucleotide sequence provides same info to one organisms as it does to another Differences among organisms reflect differences in nucleotide sequences Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

19 Systems Biology at the Levels of Cells and Molecules
System: combination of components that function together Systems biology constructs models for dynamic behavior of whole biological systems using DNA-sequencing machines and predicts their responses as variables change Systems approach Integrates and inventories all known cell genes/proteins at cellular/molecular levels Investigate how each part behaves in relation to others in working system (all protein-protein interactions) Computers/specialized software pools all data into system network Systems approach poses questions such as How does a drug for blood pressure affect other organs? How does increasing CO2 alter biosphere? Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

20 Figure 1.12 A systems map of interactions among proteins in a cell
Outer membrane and cell surface Cytoplasm Map of 2,346 proteins (dots) and network of interactions (lines connecting dots) in fruit fly cell Used to predict how one change can ripple through cell’s molecular circuitry to cause other changes Nucleus

21 Advances in systems biology at cellular/molecular level depend on
“High-throughput” technology or mega-data-collection methods which analyzes biological systems and yields enormous amounts of data (uses automatic DNA-sequencing machines) Bioinformatics provides computing power, software, mathematical models to process and integrate data from large volume of data sets Interdisciplinary research teams from variety of fields (computer/math/engineers/scientists) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

22 Theme: Feedback mechanisms regulate biological systems
Regulatory mechanisms allow biological processes to self-regulate (ensure balance) by feedback Organisms obtain energy from fuels (cells break down molecules in series of closely regulated enzyme-catalyzed chemical reactions) When muscles need more energy, enzymes catalyze rapid breakdown of sugar molecules to release energy At rest, other enzymes store energy in complex sugars Common to life at all levels, from molecules to ecosystems Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

23 http://www. rattlerscience
Negative Feedback As more product accumulates, process that creates it slows, and less of product produced Stabilizing regulation ABC D: too much D causes AB to slow down Insulin signals cells to take up glucose so blood glucose levels go down ABC D: too little D causes AB to speed up If insulin too low, cells don’t take up glucose so blood glucose levels remain high Enzyme 1 Enzyme 2 Excess D blocks step Enzyme 3

24 Positive Feedback As more product accumulates, process that creates it speeds up, and more of product produced WXYZ: too much Z causes more of XY and then more YZ Blood clotting/labor/ fever Enzyme 4 Enzyme 5 Excess Z stimulates step Enzyme 6

25 Concept 1.2: The Core Theme: Evolution accounts for the unity and diversity of life
“Nothing in biology makes sense except in the light of evolution”—Theodosius Dobzhansky Evolution unifies biology at different scales of size throughout history of life on Earth Species change over time/their history described as branching tree of life that show ancestors/descendants Very similar species share common ancestor at recent branch point on phylogenetic tree Less closely related organisms share more ancient common ancestor All life connected/can be traced back to primeval prokaryotes that existed more than 3 billion years ago Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

26 Organizing the Diversity of Life Grouping Species: The Basic Idea
~1.8 million species identified/ named, thousands more identified each year Estimates range from 10-over 100 million Taxonomy: branch of biology that names and classifies species according to system of broader and broader groups Domains, followed by kingdoms, are broadest units of classification Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

27 The Three Domains of Life
Replaced old five-kingdom system Domain Bacteria/ Domain Archaea comprise prokaryotes Domain Eukarya includes all eukaryotic organisms (almost all multicellular) Protista being split into several kingdoms to better reflect evolutionary relationships (a) DOMAIN BACTERIA (b) DOMAIN ARCHAEA (c) DOMAIN EUKARYA Kingdom Plantae Protists Kingdom Fungi Kingdom Animalia Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

28 Unity in the Diversity of Life
Striking unity underlies diversity of life, and is evident in similarities between different kinds of organisms Universal genetic code uniting prokaryotes with eukaryotes Similar metabolic pathways (i.e., glycolysis) Similarities of cell structures among eukaryotes (flagella of protozoan/ mammalian sperm cells) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

29 Charles Darwin and the Theory of Natural Selection
Published On the Origin of Species by Means of Natural Selection in 1859 “Descent with modification” captured Duality of unity (in kinship among species descending from common ancestor) Diversity (in evolved modifications as species branched from common ancestors) Natural selection Mechanism behind “descent with modification” (evolutionary adaptation of populations in their environments) Though they have variation, each has liplike petal to help attract pollinators and provides landing platform for them Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

30 Darwin observed that Individuals in population have traits that vary
Many are heritable Individuals best suited to environment more likely to survive/reproduce/leave more surviving, fertile offspring Over time, more individuals in population have advantageous traits (natural selection) More offspring are produced than survive or environment can support Competition is inevitable Species generally suit their environment Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

31 Organisms’ adaptations to environments products of natural selection
Darwin proposed natural selection could cause ancestral species to give rise to two or more descendent species (Galápagos finches) Organisms’ adaptations to environments products of natural selection Natural selection doesn’t create adaptations Increases frequency of inherited variants that arise by chance When exposed to specific environmental pressures, certain inheritable variations favor reproductive success of some individuals over others Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

32 The Tree of Life Underlying “unity in diversity” seen in structures of related species (living/in fossil record) reflects inheritance of that structure from common ancestor (“descent with modification”) Their diversity results from natural selection acting over millions of generations in different environments Forelimb of bat/human/horse/whale flipper share common skeletal architecture Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

33 Cactus-flower-eaters
Fig Cumulative changes in population over long time spans could produce new species from ancestry one Green warbler finch Certhidea olivacea Warbler finches Insect-eaters COMMON ANCESTOR Gray warbler finch Certhidea fusca Seed-eater Sharp-beaked ground finch Geospiza difficilis Bud-eater Vegetarian finch Platyspiza crassirostris Mangrove finch Cactospiza heliobates Woodpecker finch Cactospiza pallida Tree finches Insect-eaters Population may be fragmented into several isolated populations in different environments What began as one species could gradually diversify into many species Each isolated population would adapt over many generations to different environmental problems Medium tree finch Camarhynchus pauper Large tree finch Camarhynchus psittacula Small tree finch Camarhynchus parvulus Large cactus ground finch Geospiza conirostris Figure 1.22 Descent with modification: adaptive radiation of finches on the Galápagos Islands Cactus-flower-eaters Cactus ground finch Geospiza scandens Ground finches Seed-eaters Small ground finch Geospiza fuliginosa Medium ground finch Geospiza fortis Large ground finch Geospiza magnirostris

34 Science: Latin “to know”
Concept 1.3: Scientists use two main forms of inquiry in their study of nature Science: Latin “to know” Seeks natural causes for natural phenomena Limited to study of structures/processes we can observe/measure, either directly/indirectly Involves inquiry: search for information/ explanation to answer questions about nature Discovery science Hypothesis-based science Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

35 Discovery Science Careful/verifiable observation and analysis of data
Scientists observe (senses/tools that extend senses) and describe some aspect of world (natural structures/ processes) and use inductive reasoning Based on Verifiable observation/measurements Analysis of data (recorded observations) Qualitative: descriptions Quantitative: recorded measurements (tables/graphs) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

36 Can lead to conclusions via Inductive Reasoning
Inductive Reasoning: inferences from set of specific observations to reach general conclusion Generalization formed by induction not necessarily hypotheses Reflect past experience (based on evidence) Repeat specific observations can lead to important generalizations Search for additional explanations via scientific method Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

37 Hypothesis-Based Science (Hypothetico-deductive science)/The Role of Hypotheses in Inquiry
Hypothesis: tentative explanation to well-framed question or explanation of observations and inductions Leads to predictions that can be tested by observation or experimentation Observation: Your flashlight doesn’t work Question: Why doesn’t your flashlight work? Hypothesis 1: The batteries are dead Hypothesis 2: The bulb is burnt out Both these hypotheses are testable (replace batteries/bulb) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

38 Deduction: The “If…Then” Logic of Hypothesis Based Science
Deductive reasoning: Uses general premises (inferences, hypothesis) to make specific predictions Used in testing hypothesis Logically follows if premises are true Predicts expected experimental results IF hypothesis is true Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

39 A Closer Look at Hypotheses in Scientific Inquiry
Must be testable and falsifiable Frame two or more alternative hypotheses/design experiments to falsify each candidate explanation Failure to falsify hypothesis does not prove that hypothesis Replace flashlight bulb, and it now works This supports hypothesis that bulb burnt out But does not prove it (perhaps first bulb was inserted incorrectly) Can be eliminated through falsification If repeated experiments consistently disprove predictions, then false If repeated experimentation supports deductions, may be true Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

40 The Myth of the Scientific Method
Myth Is idealized process of inquiry Hypothesis-based science based on “textbook” scientific method but rarely follows all ordered steps Discovery science has made important contributions with very little dependence on scientific method Not rigid procedure/requires evidence to logically solve problems Hypothesize (hypothetical explanations) Use deductive reasoning to predict results Controlled experiment Make observations Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

41 Designing Controlled Experiments
Experimentation/collection and analysis of scientific evidence (from experimental investigation/scientific observation/findings of others/historic reconstruction/archival records) at heart of biology Pose question  investigate and arrive at answers through experimentation and reasoning Justify selection of kind of data needed to answer question design experiment Identify needed controls (compares experimental group w/control group that ideally differ in one variable) Identify needed supplies and equipment

42 Misconception Develop or follow experimental protocol to collect data
Analyze data and draw conclusions from the results Describe limitations of experiment and conclusions Misconception Control experimental environment to keep everything constant except for one variable being tested (impossible) Instead, control groups used to cancel effects of unwanted variables, but not eliminate them Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

43 Limitations of Science
Science cannot address possibility of supernatural explanations because Hypotheses must be testable/falsifiable Observations/experimental results must be repeatable Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

44 Theories in Science Theory
Broader in scope/more comprehensive than hypothesis General, and can lead to new testable hypotheses Well-supported by large body of extensive and varied evidence Can be modified/rejected Widely accepted by scientific community Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

45 Model Building in Science
Models: representations of ideas, structures, and processes that help up understand natural and scientific phenomena/make predictions Diagrams Three-dimensional objects Computer programs Mathematical equations Test of good model is that it fits available data, incorporates new observations, and makes accurate prediction of new experiments Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

46 The Culture of Science Science is social activity characterized by both cooperation and competition Most scientists work in teams, which often include graduate and undergraduate students Good communication is important in order to share results through seminars, publications, and websites Political/cultural environment influences ways in which scientists approach their work Adherence to criteria of verifiable observations and hypotheses that are testable/falsifiable sets science apart for other ways of “knowing nature” Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

47 Science, Technology, and Society
Science and technology are interdependent (new scientific discoveries often depend on advances in technology) Goal of science: understand natural phenomena Generates new information that makes technological inventions possible Marked by “discoveries” Goal of technology: method or device that applies scientific knowledge for some specific purpose Extends ability to observe/measure Marked by “inventions” Ethical issues can arise from new technology, but have as much to do with politics, economics, and cultural values as with science and technology Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

48 You should now be able to:
Briefly describe the unifying themes that characterize the biological sciences Distinguish among the three domains of life, and the eukaryotic kingdoms Distinguish between the following pairs of terms: discovery science and hypothesis-based science, quantitative and qualitative data, inductive and deductive reasoning, science and technology Explain, in your own words, what is meant by “form fits funtion” Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings


Download ppt "Introduction: Themes in the Study of Life"

Similar presentations


Ads by Google