CorrectionKey=B DO NOT EDIT--Changes mustbemadethrough “File info” 8 Unit 1:Introducing Biology from insects. (LM;magnification 700 these leaf hairsthat protect aleaf Figure 2.1 adaptation evolution homeostasis ecosystem system DNA metabolism cell organism VOCABULARY in specialized structures the maintenance ofhomeostasis of internal feedback mechanismsin whole system; 11Adescribe therole levels to each other andto the biological systems andrelate the the levels oforganization in occur amongsystems...; 10Canalyze 10A describe theinteractions that of diversity inandamongspecies; adaptation andto thedevelopment relationship ofnatural selection to 7E analyze andevaluate the synthesis ofnew molecules; transport ofmolecules, and homeostasis, energy conversions, cellular processes, including 4Binvestigate andexplain

1.2 Cells can work together 10C, 11A 4B, 7E, 10A, , suchas Unifying ThemesofBiology 3 ) fields ofbiology. All organisms share certain characteristics. these themes,orconcepts, can helpyou to connect thedifferent areas ofbiology. time, even intopics that mightseem to becompletely unrelated. Understanding biology, you see will something similar. That is,some concepts come uptimeafter computer desktop. Inboth cases, that themeshows upover andover again. In the musicat ofyour thestart favorite show orthecolors TV and organization ofa What doyou thinkaboutwhenyou hear theterm theme?Maybe you thinkabout Connect to Your World Key C

of functions the of life, just as you do. Larger organisms day that you every see forms of life Asingle-celled, or on unicellular, Earth. organism out carries all of life. In microscopic, fact, organisms single-celled are most the common An An Cells nonliving. show They some, but not of all, characteristics the of living things. Forperfect. example, into fall amiddlerange viruses living between and categories of living and nonliving are constructed by humans, and are they not characteristics,certain but an definition actual of life is not simple. Why? The MAI MAIN

oncept Evolution explains anddiversity theunity oflife. Organisms mustmaintain homeostasis to survive indiverse environments. Structure are andfunction related inbiology. levelsAll oflife have systems ofrelated parts. organismsAll share certain characteristics. organism N ID All organismsAll are made up of one or more cells. A ID E E A AS

is any individual living organisms thing. All share on Earth Unifying themesconnect concepts from many source of chemical energy. Some organisms, such as plants, chemicals from environment their to make own their ferrets to ferns, chemical use energy. Some organisms use change or to do work. living All things, from to bacteria out lifecarry processes. is ability the Energy to cause a Need for energy plete organism. information. Together, cells make you specialized acom- digestive juices, and your brain cells interpret sensory muscle cells contract and relax, your stomach cells secrete have functions, as shown specialized in isms. Different of types cells inamulticellular organism are made of many cells and are multicellular called organ-

10c All organismsAll asource need of to energy cell Figure 2.1 is basic unit the . Your

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(cr) ©David Fleetham/Bluegreen All levels oflife have systems ofrelated parts. Summarize

valves, arteries, and veins form asystem inyour circulatory system. body—the way that so to has cell do its the energy work. Moving up alevel, muscle, heart muscleheart cell, for example, chemicals and processes interact inaprecise to cells that only seen with can amicroscope, be to biosphere. the In just one car’s characteristics come from arrangement the and interaction of its parts. group of related that parts interact to form awhole. any Like other system, a to reproduce. to development allows organisms to mature and gain ability the cals—DNA and ribonucleic acid (RNA). The process of isms, from to people, bacteria are by carried same the chemi- instructions the cases, for growth and development of organ- combining genetic the information from two parents. In both way do you have aworking car. Acar is asystem. A of thatOnly all parts when the make up acar are put together correct inthe you have acomplete of set caryou parts, might not have afunctioning car. aboutThink separate the of parts acar—tires, engine, seats, and on. so Even if isms, such as gold-specs the jawfish in that is identical to cell. original the Many multicellular organ- divides into cells have new two cells. Both genetic information eating other organisms. In organisms, all is important energy for chemicals that later used can be as asource of energy. Animals obtain by energy and absorb from some bacteria, energy sunlightalgae, and store some of it in KLEE-ihk), orKLEE-ihk), deoxyribonucleic (dee- called acid mation that determines inherited characteristics is amolecule In organisms, all genetic the material that contains infor the reproduce, pass genetic their they material to offspring. their to produce individuals, new or reproduce. When organisms Reproduction anddevelopment that you know as mushrooms. ample, plants grow toward light. light need Some fungi to form structures the shade your organisms eyes. Other respond also to changes inlight. For ex- behavior might change. also You might put on sunglasses or raise your hand to One of your body’s responses is to contract pupils the of your eyes. Your respond to light you when leave adimly lit room and go into bright sunlight. stimuli,called to which organisms must respond. about Think how you Light, temperature,survive. and touch are just afew of physical the factors, Response to environment or of all chemical the processes that build up or break down materials. MAI Systems inbiology, exist on scales all from that molecules cannot seen, be Single-celled organisms can reproduce one when cell N ID

E What characteristics are shared by all living things? by living all shared are characteristics What A DNA. 10 C All organismsAll must react to environment their to Members of must aspecies have ability the ry ahk-see- FIGURE 2.2, -boh-noo-

reproduce by system is an organized - metabolism,

in hismouth. unhatched eggs by holding them male gold-specs jawfish protects gies differ amongspecies.The Figure 2.2 Chapter inthe21stCentury 1:Biology

Reproductive strate- 9 CorrectionKey=B DO NOT EDIT--Changes mustbemadethrough “File info” 10 Figure 2.4 Figure 2.3 protection inreturn. eel’s mouthandgets food and Theshrimpcleansbenefit. the system inwhichboth organisms the cleaner shrimpare ofa parts magnifications: beetle 20 rough surfaces. (colored SEMs; to easily walk onboth smooth and pads onitstarsi (right)that allow it (below) hasspecialized prongs and Unit 1:Introducing Biology

The moray eeland The snoutbeetle 3 ; tarsus 100 3 ) Structure and function are related function and biology.Structure in

cals and then cause the chemicals to react with eachother. to with react chemicals the cause then and cals chemi proteinsThese to have to only certain them attach allow shapes that are protein that molecules make chemical processes possible inliving things. a tube that chemicals to allows pass specific into and out of acell. Enzymes extends through membrane, the or outer layer, of acell. It has astructure like differentvery structures and functions. Achannel is aprotein that molecule example, membrane channels and enzymes are proteins, both but have they your help teeth you eat, but different of have types teeth different functions. Thenteeth. you probably chew it mostly with your grinding molars. of All For example, you when eat, you probably bite into with your food sharp front What something inan does organism is directly related to its shape or form. perform that Structure function. and are function related also inliving things. isfunction directly related to its structure. No other of part car the can structure For function. of acargives aspecific part part the example, a tire’s aboutThink acar again. In acar, different have parts different structures. The MAI Structure and are function related at level the of chemicals incells. For N ID E A parts. An parts. system—anlogical ecosystem—that has living and nonliving can see in can see how interactions. chemicals brain inthe social affect across different system levels. For example, some scientists study an ecosystem. However, more and more biologists are working behavior inbirds might on focus predator–prey relationships in chemical interactions that place take inacell. Aperson studying example, aperson studying DNA might specific on focus very as an individual tree. or aforest. area, But small such an avery ecosystem be can also might about think alarge region, suchacoral reef, as adesert, physical environment. When you hear term ecosystem, the

4 Two organisms that interact asystem, be can as you also Often, different biologists study different systems. For b , 10 , ecosystem figure 2.3. C On alarger you scale, are of apart abio- is acommunity of organisms and their to carry oxygen.to Their carry structure allows smaller, disk shaped, and are specialized are different. very are They much messages cells to other blood cells. Red long extensions that allow to them send mation from have other also cells. They have many branches that receive infor in your brain process information. They structures. Forspecialized example, cells different functions that on depend their Different of have types cells also you you - -

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(cr) ©Andrew Syred/Photo Researchers, Inc.; (b) ©Fritz Polking/Peter Arnold, Inc. in diverse environments. to homeostasis survive maintain must Organisms Summarize Infer

and feel thirsty you when water? need Why(98.6°F)? do you shiver you when are cold, sweat you when are hot, ture is below but freezing, have still astable temperature body around 37°C get cold, too and move they into shadeget warm. too ifthey may put on ajacket. Reptiles sit on awarm rock insunlight ifthey regulate temperature their through behavior. If you feel cold, you body. temperaturebody above rises normal, different responses your cool shiver, and vessels blood near your skin’s constrict. surface If your return your temperature to normal. Your muscles cause you to temperaturebody drops below normal, systems inyour to act body computer the speed, set the tells up. car the to speed Similarly, ifyour computer the speed, set tells car the to slow down. If car the slows below thatsend information to acomputer. If to car the go begins faster than the controlA cruise system has sensors that monitor car’s the and then speed how acar’s control cruise keeps acar moving at aconstant speed. set tends to return that system to its state. original For example, about think feedback. In negative feedback, achange inasystem causes aresponse that homeostasis are often life threatening. sugar, acidity, and other conditions must controlled. be Breakdowns in within best function alimited range of conditions. Temperature, blood internal conditions inan organism. Homeostasis is important cells because in conditions inside organisms usually stay quite stable. How polar the bear does Temperature and other environmental conditions are always changing, but the is impossiblewall for you. in The beetle surfaces. Walking on such asurface as iceis more and up walking a difficult, example, your foot structure allows you easily on to walk rough, fairly level out your body. Of course, abrain cannot cell place the take of cell. ared blood tothem fit through vessels smallest even the blood to deliver oxygen through- function thanfunction your foot has, but for are both walking. specialized for on walking rough surfaces.The beetle’s tarsus has adifferent structure and have sharp prongs that can grip smooth surfaces,as or well as pads vertical soft MAI Figure 2.5

Behavior involved is also inhomeostasis. For example, animals Homeostasis is usually maintained through aprocess negative called Structure and are function related also on level the of organism. the For Homeostasis Do you think heart muscle has the same structure as arm muscle? E muscle? arm as structure same the has muscle heart youDo think 10 N ID C

E What is homeostasis, and why is it important? important? it why is and homeostasis, is What A live Arctic? inthe How can outside people be tempera the when - (hoh 4B, 10A, 11A 10A, 4B, -mee-oh-STAY-sihs) is maintenance the of constant Figure 2.4 is different. Its tarsi, or feet,

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The polar bear can 3 )

11 CorrectionKey=B DO NOT EDIT--Changes mustbemadethrough “File info” 12 Unit 1:Introducing Biology (right), look like ofplants. parts insects, suchasthethornbug that look like insects, andsome some orchids (left) have flowers Figure 2.6 the Evolution unit. are described inmore detail in natural selection, andadaptation The processes ofevolution, Evolution CONNECT TO

Through evolution, E volution explains the unity and diversity and oflife.volution explains unity the

see andsee eat it. This adaptation allows thorn the bug and to survive reproduce. thorn bug’s appearance is an adaptation that makes predators less likely to orchidthe can pollinate flower, the helping orchid the to reproduce. The likelooks lures an insect to other it. that insects The insects are attracted to adapted inways that make resemble them other organisms. The orchid that ual organismsual and on is passed to future generations is an environment.particular An inherited trait that gives an advantage to individ- and survive reproducespecies more successfully than other individuals ina natural agenetic, selection, or inherited, trait helps some individuals of a One way evolution is through occurs natural of selection adaptations. In Adaptation Evolution and genetic comparisons of shows species, that evolution is continuing today. biosphere.the range Awide of evidence, scientific including fossil the record concept of evolution observations links from levels of all biology, from cells to a change genetic inthe makeup of asubgroup, or population, of The aspecies. evolve to point the at are which they different species. adaptations indifferent environments. The two populations may continue to adaptation. Two different populations of same might the species have different time, makeup the of apopulation changes more because individuals have the MAI Consider orchid the and thorn the bug in N ID is change the inliving things over time. More specifically, evolution is E A

7e igure 2.6. figure 2.6. Both organisms have have organisms Both adaptation. Over Over

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In different environments, however, you would find other orchid and insect species that have different adaptations. Adaptation in evolution is different from the common meaning of adapta- tion. For example, if you say that you are adapting to a new classroom or to a new town, you are not talking about evolution. Instead, you are talking about consciously getting used to something new. Evolutionary adaptations are changes in a species that occur over many generations due to environmental pressures, not through choices made by organisms. Evolution is simply a long-term response to the environment. The process does not necessarily lead to more complex organisms, and it does not have any special end point. Evolution continues today, and it will continue as long as life exists on Earth. Unity and Diversity Evolution is a unifying theme of biology because it accounts for both the diversity and the similarities, or the unity, of life. As you study biology, you will see time after time that organisms are related to one another. When you read about cells and genetics, you will see that all organisms have similar cell structures and chemical processes. These shared characteristics result from a common evolutionary descent. Humans and bacteria have much more in common than you may think. Both human and bacterial genetics are based on the same molecules—DNA and RNA. Both human and bacterial cells rely upon the same sources of energy, and they have similar cell structures. Both human and bacterial cells have membranes made mostly of fats that protect the inside of the cell from the environment outside the cell. Now think about the vast number of different types of organisms. All of the species alive now are the result of billions of years of evolution and adaptation to the environment. How? Natural selection of genetic traits can lead to the evolution of a new species. In the end, this genetic diversity is responsible for the diversity of life on Earth. Analyze How does evolution lead to both the diversity and the unity of life? 7E

Self-check Online HMDScience.com 1.2 Formative Assessment GO ONLINE Reviewing Main Ideas Critical thinking CONNECT TO 1. Describe a biological system. 4. Analyze How are structure and Cells 10c function related to adaptation? 7. Do you think homeostasis is 2. Why is homeostasis essential for 7e necessary at the level of a living things? 4b 5. Apply How is the process of natural single cell? Explain. 4b, 10A, 10c 3. What is the relationship between selection involved in evolution? adaptation and natural selection? 7e 7e 6. Apply Describe the relationship between cells and organisms. 10C

Chapter 1: Biology in the 21st Century 13