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9 0 / 2 1 / 5 115/12/09 15:57:33 Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. a person who studies plants and animals by by and animals who studies plants a person , 4 8

4 8 i . 7 8 4 2 Structural adaptations involve shape, size, color, and other physical features; Structural adaptations involve shape, size, color, length of a Galápagos tortoise species’ neck is an example of this type of the adaptation. If a variation benefited a tortoise, allowing it to compete for food better than If a variation benefited a tortoise, reproduced more, and passed on its other tortoises, the tortoise lived longer, variations to its offspring. Darwin knew that food is a(n) limiting resource, so members of a species that live so members of Darwin a(n) limiting resource, knew that food is in the same area compete for food. 9 8 _ t u A(n) adaptation is a characteristic of a species that enables the species to surviveA(n) adaptation is a characteristic of a species that enables the in its environment. Scientists classify adaptations into three categories. a. Natural selection is the process by which populations of organisms with variations with variations Natural selection is the process by which populations of organisms and compete better, that help them survive in their environments live longer, reproduce more than populations that do not have the variations. a. b. differences, called variations. that variations in populations know about genes, but he realized Darwin didn’t species of Galápagos tortoises and other could help explain how the different organisms evolved. the species of tortoise that lived on an island with lots of short grass had short tortoise that lived on an island with lots of short grass had short species of the necks. Darwin tortoises shared a common ancestor that came to thought all the Galápagos years ago. one of the islands millions of Darwin species, members of the same species each have slight knew that in any Darwin was a relationship between each species and the food noticed that there the island it lived on. of sources on an island with tall cacti had long necks; The species of tortoise that lived Darwin not the first to develop a theory was his theory of evolution, but is the one by evidence today. best supported that live on each of the Galápagos mockingbird, and finch The type of tortoise, different; DarwinIslands was slightly some varieties were later figured out that species. to be classified as different different enough Charles DarwinCharles was a(n) naturalist observing them. O s n A _ F Adaptations Darwin’s Theory Darwin’s Charles DarwinCharles R The and Environment Change Over Time C _ 1. 2. 6. 5. 3. 4. 1. 2. 2. 3. 1. 7 T4 C. B. Lesson 2: Theory of Evolution by Natural Selection Natural by Theory of Evolution 2: Lesson A. Lesson Outline for Teaching Outline for Lesson 8 0 _ 2 8 0 _ 4 1 2 CC214_082_087_CRF_AnsOut_892487.i84 84 CC214_082_087_CRF_AnsOut_892487.i85 85 2 1 4 _ 0 8 2 _ 0 8 7 _ C R

F Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. _ A n s O u t The Environment and Change Over Time Time Over Change Environmentand The this happened,thespeciesmightevolveintoanewspecies. andreproduceinthechangedenvironment.If adaptations thatallowedthemtosurvive become extinctunlessoffspringofthatpopulationdevelopedvariationsleadingtonew should explainthatasignificantchangeintheenvironmentcouldcausespeciesto claws, whichhelpitcaptureaparticularprey. Afterdescribinganadaptation,students insect’s coloration,whichhelpsithideinaparticularenvironment;mammal’s orbird’s Possible answers:abird’s beak,whichhelpsitgetaparticularfood;mammal’s oran what mighthappentoeachspeciesifitsenvironmentchangedinasignificantway. orknowabouthave.Explain Describe someadaptationsthatcommonanimalsyouobserve Discussion Question D. Lesson continued Outline _ 8 4. 3. 2. 1. 5. 4. 3. 9 2

4 Artificial Selection 8 7 . i 8 5

Selective breedingistheoforganismsfordesiredcharacteristics. environments. adaptations and,therefore,eventuallycloselymatchEarth’s changing Darwin’s ofevolutionbynaturalselectionpredicts thatspecieswilldevelop theory that cannotadapttosuchchangeswillbecomeextinct. The livingandthenonlivingpartsofenvironmentarealwayschanging;species An adaptationinwhichonespeciesresemblesanotheriscalledmimicry. environment iscalledcamouflage. A structuraladaptationthataidsmembersofaspeciesinblendingwiththeir c. b. Artificial selectionexplainsandsupportsDarwin’s theory. b. a. realizedthatnaturalselectionandselectivebreedingaresimilarprocesses. Darwin 8 5 example ofthistypeadaptation. expandingbloodvesselsthatcoolajackrabbit’sbiochemistry; bloodisan Functional adaptationsinvolveinternalbodysystemsthataffectorganisms’ example ofthistypeadaptation. Behavioral adaptationsinvolvethewayorganismsact;huntingatnightisan For this reason, Darwin calledselective breedingartificialselection. For thisreason,Darwin breeding, humanscausethechangesinspecies. In naturalselection,naturecausesthechangesinspecies;selective 115/12/09 15:57:34 T5 5 / 1 2 / 0 9

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