6 B. Darwin’s Influences 1. Lamarck (early 1800s) i. Believed thatanimalschange overtime-contrary topopularbelief!At least he sees that organisms change- gets a bad rapIf you cut a mouse tail off children will still have tail- not changing the genesCharacteristics gained after birth – cannot be passed on through reproductionii. Inheritance of Acquired Characteristics:characteristics can be gained through use and passed on to offspring
7 Kayan “giraffe” womenMountains between Burma and Thailand. Kayan women“Giraffe women”Part of Kayan beauty culture
8 Traits Must be Genetic to Pass On! You cannot “ force” yourself to have a characteristicsExample #1: You cannot force yourself to belactose tolerantExample #2: Bacteria CANNOT acquireresistance to antibioticsNote: New traits cannot be created during yourlifetimeOnly genes can be passed on
9 2. LyellHISTORY OF THE EARTH CALENDER is 4.5 Billion years oldThe other idea was that Earth itself is less than 10,000Lyell proposed that gradual and observable geologic processes such as erosion could explain the physical features of today's Earth.thousands or millions of yearsPreviously, idea was that Earth itself is less than 10,000 years oldProposed that gradual and observable geologic processes such as erosion could explain the physical features of today's Earth taking place over thousands or millions of years
10 i. Earth 4.5 billion years old 3.5 billion years first life (single celled)Earth 4.5 billion years old3.5 billion years first life ( single celled)
11 C. Fossils: found on Darwin’s trip. Shows earth is old – there is enough time for descent with modification to occurShows earth is old – there is enough time for descent with modification to occur
12 II. Darwin’s FinchesA. Biogeography- geographic distribution of life formsGalapagos Islands- Volcanic islands off the coast of South America1. Species were slightly different than the ones on the mainlandC. Finches- different beaks depending on the food availablei. Cactus-eating finch:more point beakii. Insect-eating finch: sharp ( trees)iii. Types of seedsD. All descended from one mainland FinchDESCENT WITH MODIFICATION from aCOMMON ANCESTOR
20 The Galápagos tortoise or Galápagos giant tortoise the largest living species of tortoise and 10th-heaviest living reptile, reaching weights of over 400 kg (880 lb) and lengths of over 1.8 meters (5.9 ft). shell size and shape vary between populations- humidity, dryness ectThe Galápagos tortoise or Galápagos giant tortoise the largest living species of tortoise and 10th-heaviest living reptile, reaching weights of over 400 kg (880 lb) and lengths of over 1.8 meters (5.9 ft). Shell size and shape vary between populations- humidity, dryness etc.
28 III. Natural Selection Definition: mechanism for evolutionary change Components:Inherited variations:Mutations- changes in DNAMeiosisStruggle for existenceAdaptations (traits that help an organism be more suited to the environment) increase survival and reproductive successReproduction- Genes for adaptations increase in each generation – (Fitness- reproductive success)LACKS DIRECTION – if environment change- not going towards a “BEST”Extinction- previous adaptations are no longer suitable to changed environment
29 IV. Artificial Selection Breeder choices which traits to perpetuate ( dogs descended from wolves)Canis familiaris comes from canis lupis domesticated 14, 000 years agoNatural selection would never have selected dogs with long ears ( ear infetions)Breeder choices which traits to perpetuate (dogs descended from wolves).Canis familiaris comes from Canis lupis domesticated 14,000 years ago.
34 8 million years ago humans chimpanzees : dozen human-like species called hominids The modern form of Homo sapiens first appeared about 100,000 years ago.This species is distinguished by large brain size, mouth not as protruding. Begin with bipedal ancestor- skulls begin when humans began to walk on two feet
35 Lucy, after the Beatles song "Lucy in the Sky with Diamonds", which was being played loudly and repeatedly on a tape recorder in the camp.
36 “Lucy”3.2 million year old hominid fossilAustralopithecus afarensisSignificant because skeleton shows evidence of small skull capacity like that of apes and of upright bipedal posture like humans
37 B. BiogeographyA mammal of an order (Marsupialia) whose members are born incompletely developed and are typically carried and suckled
38 C. Anatomical Evidence1. Homologous Structure: Structures that are similar because they are inherited from a common ancestor
39 C. Anatomical Evidence2. Analogous Structures: features are similar in function but not in structure. They do not derive from a recent common ancestor but in response to a similar environment.
41 C. Anatomical Evidence3. Vestigial structures: no longer have function. occur because organism inherit anatomy from their ancestors.Examples: Some snakes have small hindlimbsHumans: Appendix, wisdom teeth, tail bone
42 THE APPENDIX VESTIGIAL STRUCTURE we can’t digest cellulose (in leaves, barks of treesVESTIGIAL STRUCTURE