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8/19/2024 Biology Life on Earth with Physiology Twelfth Edition Chapter 1 An Introduction to Life on...

8/19/2024 Biology Life on Earth with Physiology Twelfth Edition Chapter 1 An Introduction to Life on Earth In collaboration with NIH, NCBI and other search engine ! Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Case Study: The Boundaries of Life Eb ola is on e o f many d ise ases caused by vir uses – Victims of E bola exper ience a wid e var iety of symptoms – Eb ola is typ ica lly fatal While viruses have so me thing s in commo n with th e org anisms they in fe ct, sci entists d isa gree ab out whethe r they a re livi ng orga nisms or not Vir us are no n-living, acellula r, canno t repr oduce on th eir own, n eed a specifi c living host to infect and survive within a host cell… Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Case Study: The Boundaries of Life Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1  8/19/2024 Viruses of bacteria and archaea typically undergo one of two replication cycles: the lytic or the lysogenic cycle Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved The non-human living inside of you ! These corn specimens helped Barbara McClintock make her Nobel Prize-winning discovery of transposons. They are now kept in CSHL’s library. Refer: Cold Spring Harbor Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Chapter 1 At a Glance 1.1 What Is L ife ? 1.2 What Is E vo lution? 1.3 How Do Scien tists Study Life ? 1.4 What Is S cie nce? Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 2  8/19/2024 1.1 What Is Life? Biology is the stu dy of life Organism s share common characteristi cs tha t, taken together , define life: – Active ly maintain or ganized comple xity – Acqui re and use ma te rials a nd ener gy – Se nse a nd respond to stimuli – Gro w – Repro duce – Evolve Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.1 What Is Life? Org anisms active ly maintain or ganized comple xity – Org anisms are mad e o f cells, th e basic un its of life ▪ Cells are se para ted from the ir sur round ings by a pla sma membran e Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.1 What Is Life? Cells fall in to two main gr oups – Eukaryotic cells con tai n a varie ty of organelles, stru cture s th at carry out a differen t fu nction s ▪ On e o rgane lle is the nuc le us, which contains the cell’s ma in gene tic ma ter ial - DNA ▪ Mitoch ondr ia a nd chlorop last – extrachromosoal DNA ▪ Including ri bosomes ! – Prokaryotic cells l ack orga nelle s and la cks nu cle us, but has cyto plasm, DNA a nd ribosomes Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 3  8/19/2024 Figure 1-1 The Cell is the Smallest Unit of Life Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.1 What Is Life? All org anisms with proka ry otic cells a re unice llular – They exi st a s a single cell Org anisms with eukaryotic cells ma y be unice llular or multic ellula r ▪ They exi st a s a collecti on of at least two cells Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved unicellular Diatoms group of cyanobacteria phytoplankton Saccharomyces (Chroococcales) cerevisiae unicellular fungal cells Ma la ria l pa rasi te - Pl asmo di um Paramecium (unicellular amoebas have long, skinny “false feet” called ciliate protozoa) pseudopodia Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 4  8/19/2024 Figure 1-2 Properties of Life Water flea Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.1 What Is Life? Org anisms acqui re and use ma te rials a nd ener gy – Org anisms use ene rgy continu ously – En ergy i s obtaine d by org anisms in two ways: – photosy nthes is and consumption – Imp ortant materia ls (mine rals, water, othe r simple chemical build ing blocks) a re a cq uired from air, water, soil, b odies of other living thing s Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Figure 1-3 The Flow of Energy and the Recycling of Non-living Nutrients Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 5  8/19/2024 1.1 What Is Life? Living thing s continuo usl y use energ y to ma inta in ve ry specific intern al con ditions – The abili ty o f an org anism to maintain its interna l enviro nment is ca lled hom eostas is Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Figure 1-4 Organisms Maintain Relatively Constant Internal Conditions Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Maintenance Copyright of blood glucose © 2020 Pearson Education, levels Inc. A ll Rights Reserved 6  8/19/2024 1.1 What Is Life? Org anisms sense and respo nd to sti mu li – An ima ls use specialized cells to detect an d r espond to stimul i such as lig ht, te mp erature, so und, gravity, touch, an d che mica ls – Pla nts, fung i, and un icellula r o rganisms re sp ond to stimul i a s well Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Figure 1-5 Bending Toward the Light - Phototropis m - Ph oto receptors - On e p rotein, called phytochrome B - chloro phyll a and b Touch Me Not - Thigmotropism - Mechano receptors - condu ct cal ciu m ion s and an ions - Turgo r p ressu re cause wate r to move out o f th e cells Venus flytrap Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Chemotactic bacterial motility across Copyright © different 2020 Pearson Education,environments. Inc. A ll Rights Reserved 7  8/19/2024 1.1 What Is Life? Org anisms gro w – At some time i n its li fe, every or ganism grows ▪ Ba cteria gro w by enlar ging their cells, then dividin g to r eprod uce ▪ An ima ls an d p lants gro w by increasing the numbe rs of cell s in th eir bodi es via ce ll d ivi sio n – Gro wth may b e a ccompa nied by developm ent, in which a growing org anism b ecomes more comple x Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.1 What Is Life? Org anisms rep rodu ce – Org anisms rep rodu ce by dividing in ha lf, p rodu cin g seeds, o r b earing li ve young Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Figure 1-6 Organisms Reproduce Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 8  8/19/2024 - Asexual rep roduction - mostly ta ke s place in pro kar yo tes - The specific ce ll org anell es in eukar yotes, i.e., mitoch ondr ia a nd chloro plasts, a lso divide by bina ry fission. Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Meiosis is a process that creates genetic diversity Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 9  8/19/2024 1.1 What Is Life? Deoxyribonuc le ic acid (D NA) is p resent in e ver y cells and is passed on to de scen dants – Sp eci fic seg ments of DNA called genes are the basic uni ts o f her edity Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Figure 1-7 DNA Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Which living organisms follow this ? Central dog ma - is a theory stating that gen etic information flows on ly in one dire ction , fr om DNA, to RNA, to pro tein , or RNA d irectl y to pro tei n. Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 10  8/19/2024 1.1 What Is Life? Org anisms evolve – All living or ganisms de scen ded fr om an a nci ent common ancesto r – Today’s diverse forms of life have arisen throug h a pro ce ss of descent with modification kn own a s evolution Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.2 What Is Evolution? The scie ntific the ory of evolution states tha t all org anisms are re lated by common ancestry and ha ve chan ged over time – The th eory wa s fo rmulated by n aturalists Charle s Darwin and Al fre d Russell Wallace in the mi d-180 0s ▪ It is supp orted by a vast amoun t of evid ence – Simila riti es are foun d a mong diffe rent types o f org anisms as a r esu lt of common an ce stry Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Figure 1-8 Chimpanzees and People are Closely Related Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 11  8/19/2024 1.2 What Is Evolution? Natural selection ca uses evolu tio n – Natural selec tion occurs whe n some ind ivi duals in a pop ulation po ssess traits that h elp th em survive and rep roduce more succe ssfully than othe rs that la ck those tra its Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Finch beaks Pla nt toxins​ Darker frogs Gir affe necks Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.2 What Is Evolution? In p opula tio ns of organ isms, traits can vary – This vari atio n is ofte n d ue to mutat ions, chan ges in gen es caused by DNA-copying err ors or da mage to DNA Mutations can be categorized based on their effe cts on fitn ess: Be neficia l: Increase fitn ess Deleterio us: Decrease fitn ess Neutral: Not affe cted by selection becau se their effe cts are too small Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 12  8/19/2024 1.2 What Is Evolution? Natural selection results in ada pta tio n – Adaptations are structur es, physiologi ca l pr ocesses, o r beh aviors that a id i n survival and re produ ction Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.2 What Is Evolution? Extinctio n e liminates spe cie s – If muta tio ns that a re adap tive do not occur , a ch angin g enviro nment may doom a sp ecies to ext inction, complete elimina tio n – Dinosau rs flourishe d for 100 milli on ye ars bu t went extinct because they d id n ot ad apt to ch angin g enviro nmental co nditions Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Figure 1-9 A Fossil from a Newly Discovered Dinosaur, Titanosaurus Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 13  8/19/2024 In Jur assic Park, the dino sau rs ar e g enetically modified to be fe ma le to p revent b reedi ng and control th e popul ati on. The park's ge neticists, includ ing Dr. Henry Wu, circumve nt the hor mo ne need ed fo r d inosaurs to be co me male. However, the pla n _ ____ ____ ____ ? Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Figure 1-10 Levels of Biological Organization Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.3 How Do Scientists Study Life? Life ca n be studie d at different levels – An at om is the smallest pa rticle of an elemen t th at retain s all th e prope rtie s of the ele ment – Atoms may co mb ine to form molecule s – Molecule s pro vid e b uildi ng blocks fo r e ach cell, which is the basic un it of l ife – Cells comb ine to form tissues Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 14  8/19/2024 1.3 How Do Scientists Study Life? Tissue s combine to for m organs, which can wo rk together as organ syst ems Multicellula r o rgani sms a re co mp osed of multiple org an systems Org anisms of the same sp ecies that live in a de fine d area form a population Inte ractin g popul ati ons make up a comm unity Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.3 How Do Scientists Study Life? A commu nity and its non living enviro nment form an ecosy stem – All the ecosystems of the Ea rth compose the biosphere Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Figure 1-11 The Domain s of Life Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 15  8/19/2024 1.3 How Do Scientists Study Life? Bio logists classify o rgani sms b ased on th eir evolutiona ry rela tio nships – Ea rth’ s diverse species a re placed into th ree major dom ains ▪ Ba cteria ▪ Archa ea ▪ Eu kar ya – Funda mental differe nces amon g cel l types Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.3 How Do Scientists Study Life? Cells structure distin guishes th e B acter ia, Ar cha ea, a nd Eu kar ya – Ba cteria an d A rchaea are p rokaryoti c – Eu kar ya are e uka ryoti c Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.3 How Do Scientists Study Life? Bio logists use the b inomial system to name org anisms – Bio logists use a binomial sy stem consistin g o f th e gen us an d the species to na me o rgani sms ▪ For example, the common wate r flea woul d h ave the sci entific name: Daphnia longis pina Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 16  8/19/2024 1.4 What Is Science? Sc ience can be defined a s systemati c inqu iry throu gh obser vation an d experimen t, in to all aspe cts of the physical universe Three pr inciples apply to science – Events h ave n atu ral ca uses – Laws do not chan ge over time or distance – Findin gs ar e “ val ue neutral” ; inde pend ent of bias Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.4 What Is Science? The scie ntific me tho d i s an importan t to ol of scie ntific inq uiry – This metho d con sists of six i nte rrelated ele ments ▪ Ob ser va tion ▪ Qu estion ▪ Hypothesis ▪ Pre dictio n ▪ Exper iment ▪ Conclusion Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.4 What Is Science? Scien tific in quiry begin s with a n obs ervation of a phe nomen on – Ob ser va tion , in tu rn, le ads to a que stion abo ut what was o bserved – Afte r studying ea rlier investi gations, thinking , recallin g prio r e xp erien ce , and ofte n con ve rsi ng wi th collea gues, a hypot he sis, a pro posed explan ati on, is for me d Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 17  8/19/2024 1.4 What Is Science? BALB/c is an albino, A pre diction, ba se d laboratory-bred on the hypothesis, is strain of the made house mouse dependent va ria ble – The pred iction is tested in a carefully desig ned experiment – A conclusion is rea ch ed reg ardin g the validity o f th e hypothesis Copyright © 2020 Pearson Education, Inc. Ainde ll Rights pendeReserved nt va ria ble 1.4 What Is Science? Exper iments incorp orate co ntro ls – Two types o f situ atio ns ar e e stabl ish ed ▪ Exper iments te st the h ypo th esi s th at a single facto r, or variable, is the cause of a n o bserved phe nomen on ▪ To guard ag ainst the effe cts of unnoticed variab les, exper ime nts usually include controls – These are sectio ns of the expe riment in which no variab le is chang ed Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved MORE EXA MP LES OF an ind epen dent var iable is a vari able that is ma nipul ate d o r chang ed by the scie ntist, while a dep ende nt varia ble is the variab le tha t is mea su red or observed in the experimen t. Plant growth The independent variable could be the amount of water given to a plant, and the dependent variable could be the plant's size, number of leaves, or whether it's dead. Exercise and weight loss The independent variable could be exercise, and the dependent variable could be the amount of weight lost. The scientist would need to keep other factors constant, such as diet, age, and sleep, during the experiment. Blood pressure The independent variable could be treatment level, and the dependent variable could be blood pressure. The scientist could collect data on blood pressure before and after treatment for participants over a period of time. Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 18  8/19/2024 1.4 What Is Science? Exper iments are no t always possible – In some cases, an experi me nt Drosophila m elanogaster would be theo retica lly po ssible but is impra ctical or unethical Caenorhabditi s e legans Or Yeast (Saccharomyces Arabidops is thaliana cerevisiae) Escherichia coli Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.4 What Is Science? Scien ce req uires repe ata bility an d communi ca tion – To ensure validity, resear ch ers pe rfo rm multiple rep eti tion s of a n exp eriment – Scien ce is u se less unl ess commu nicated Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Figure 1-12 Researchers Share their Results at a Scientific Meeting Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 19  8/19/2024 1.4 What Is Science? Scien tific theo ries h ave b een th orou ghly tested – A scientific theory is a ge nera l an d reliab le expla nation of impo rta nt natura l p heno me na ▪ It has been de ve loped throu gh exten si ve an d rep roducib le o bservations a nd experimen ts – A scie nti fic the ory is best de scribe d a s a natural law, a basic principle d erived fro m the stud y of n atu re tha t has never be en disproven by scien tific in quiry Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.4 What Is Science? Cell theory is a n e xa mp le of a scie nti fic the ory – All living or ganisms ar e compo se d o f cell(s) – An y limitatio ns to th is Theory ? – Is it ap plicable to all living th ings ? – What about unicellu lar bacte ria ? – What about unicellu lar fu ngi like yea st or ma larial par asite? Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 1.4 What Is Science? Scien ce is a h uman end eavor – Accidents, lucky gue sses, compe tition with o the r sci entists, and curio sity can contribu te to scientific advan ce s Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 20  8/19/2024 Figure 1-13 Penicillin Kills Bacteria Si r Ale xa nde r Fl em ing Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved Copyright This wor k is prote cte d by U nit ed State s c opy right la ws and is prov ide d s ole ly for the use of instr uctor s in te ac hing their cour se s and as se ssing student lea rning. Dis se mination or sa le of any pa rt of this wor k (including on the Wor ld Wide Web) will des troy the inte grity of the work a nd is not perm itted. The wor k and ma te rials fr om it should nev er be m ade a va ila ble to s tudents ex ce pt by ins truc tor s using the ac com pa nying te xt in their cla ss es. A ll re cipients of this work a re e xpe cte d to a bide by the se re st rictions and to honor the intended peda gogica l purpose s a nd the nee ds of ot he r instr uctors who re ly on the se m at eria ls. Copyright © 2020 Pearson Education, Inc. A ll Rights Reserved 21