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I.Biogeography A.Comparative Anatomy 1.homologous structures, similar 2.Fossil record – similar structures, carbon dating – evolution II.Theories of Evolution.

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Presentation on theme: "I.Biogeography A.Comparative Anatomy 1.homologous structures, similar 2.Fossil record – similar structures, carbon dating – evolution II.Theories of Evolution."— Presentation transcript:

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2 I.Biogeography A.Comparative Anatomy 1.homologous structures, similar 2.Fossil record – similar structures, carbon dating – evolution II.Theories of Evolution A.Catastrophism – large environmental disaster things change B.Lamarcks 1.Inheritance of acquired – characteristics (organism changed in its lifetime – could pass those changes to offspring)

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6 C.Wallace – survival of the fittest evolution D.Darwin – father of evolution Biological diversity – gene pool – there is always diversity within a species 2.Fitness – traits best suited for survival 3.Natural selection – survival of the fittest, best traits will be passed on 4.Artificial selection – man selected, domestication 5.Adaptation – allows for survival a)Structural – anatomy b)Behavioral – courtship, hibernation c)Physiological – how the body works

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8 III.Evidence for evolution A.Radiometric dating – carbon 14 dating, radioactive substances break down in half lives – decay B.Fossils – imprints of structures within rock C.Comparative morphology and embryology – development prior to birth 1.Homologous features – similar structures, similar embryological development, Ex. bat and bird wings 2. Analogous features – similar functions develop differently Ex. bat wings and butterfly wings 3. Vestigial structures: present, no longer needed

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15 D.Experimental evidence – peppered moths, 2 variations white and gray Trees with birch (lighter bark) And lichen – more white moths 1860s coal soot killed lichen trees darken more gray moths 1900s less soot lichen back lighter bark- more white moths

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17 I.Change in frequency of alleles – how genetic information changes, which traits show up more often II.Five agents in microevolution A.Mutation – change in genetic code, lethal, neutral, beneficial B.Gene flow – beneficial traits will be passed from generation to generation – one population to another C.Genetic drift – chance alteration of genes 1.Founder effect – species in new environment will favor certain genes 2.Bottleneck – cheetah – severe reduction in population small population limited gene pool, greater chance for genetic disorders 3.Inbreeding – homozygous limited gene pool, greater chance for genetic disorders

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19 D.Nonrandom mating(sexual selection) – given member of a population is not equally likely to mate with any other given member fittest E.Natural selection 1.Adaptations – traits best suited for survival are passed on 2.Fitness – best adaptive traits 3.Galapagos finches – Darwin – 13 finches – common ancestor, beak size and shape – and Grants study – evolution can quickly occur

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21 1.Three modes a)Stabilizing selection – average most common b)Directional selection – change in the environment shift to one extreme or the other c)Disruptive selection – splits population into 2 groups

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25 I.Species – interbreeding populations which produce viable offspring II. Reproductive isolating mechanisms – keeps species separate A.Prezygotic – prevents sperm from fertilizing egg 1.Mechanical – not physically compatible 2.Behavioral – behaviors are different, courtship song displays 3. Temporal – breed at different times 4. Gamete – egg and sperm cannot fuse 5. Ecological – different habitats

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31 B. Postzygotic 1.Hybrids – offspring may not survive or be sterile

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33 III. Mechanisms of speciation A.Allopatric speciation – of other countries 1.species separated by geography change over time Darwins finches a)Colonization – 1 group of finches 13 species new island, the fittest survive b)Genetic divergence – over time species change due to adapting to new environment c)Reproductive isolation – gene pool is separated from original gene pool – changes occur over time d)Competition – fittest for environment survive to breed those characteristics to offspring e)Further speciation – original species new species

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36 B.Sympatric speciation – absence of geologic separation, fruit flies, hawthornes, apples C.????Parapatric speciation – next to small population on the fringe of a habitat can form its own breeding group

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38 IV.Evolutionary change A. Vestigial structures: present, no longer needed B.Coevolution – symbiotic relationships mimicry C. Comparative biochemistry – chemical makeup, horseshoe crab, blood chemistry same as spiders D. Genetics – DNA V. Extinction: death of the last of a species A. Habitat destruction B. Competition

39 CHAPTER 18 SYSTEMATICS: SEEKING ORDER AMIDST DIVERSITY

40 I. Taxonomy A.Linnaeus – father of taxonomy, classification system based on homologous structures B.Binomial nomenclature 1.2 term naming system 2.Genus species – identification system Homo sapiens, Felis tigris, Felis leo

41 eastern bluebird (Sialia sialis), the western bluebird (Sialia mexicana), and the mountain bluebird (Sialia currucoides)remain distinct because they do not interbreed.

42 C.Domains 1. Archaea- ancient bacteria prokaryotes 2. Bacteria- modern bacteria prokaryotes 3. Eukarya- eukaryotes divided into Animal, Plant, Protist and Fungi Kingdoms D. Kingdoms 1.Animal – heterotrophs, multicellular, eukaryote 2.Plant – autotrophs – multicellular, eukaryote 3.Protist – heterotrophs & autotrophs, unicellular, eukaryote 4.Fungi – heterotrophs, plant like, multi cellular, eukaryote 5.Monera – bacteria and viruses, prokaryotes

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45 D.Taxonomic systemHumans 1. KingdomAnimalia 2. PhylumChordatanotochord 3. ClassMammalia hair, mammary glands, give birth to live young 4. OrderPrimate binocular vision, opposable thumb 5. FamilyHominidae walk upright 6. GenusHomoman-like 7. Speciessapienmodern day E. Taxonomic Key – systematic way to identify organisms using structures

46 How Many Species Exist? Biodiversity is the total number of species in an ecosystem Between 7,000 and 10,000 new species are identified annually, mostly in the tropics Tropical rain forests are believed to be home to two- thirds of the worlds existing species, most of which have yet to be named Because tropical rain forests are being destroyed so rapidly, species may become extinct before we ever knew they existed

47 The black- faced lion tamarin Researchers estimate that no more than 260 individuals remain in the wild; captive breeding may be the black- faced lion tamarin's only hope for survival

48 The (a) tarsier, (b) lemur, and (c) liontail macaque monkey all have relatively flat faces, with forward-looking eyes providing binocular vision. All also have color vision and grasping hands. These features, retained from the earliest primates, are shared by humans

49 Primates Some of these adaptations were inherited by humans – Large, forward-facing eyes with overlapping fields of view (allowed accurate depth perception) – Color vision – Grasping hands – Enlarged brain (facilitated hand-eye coordination and complex social interactions)

50 Oldest Hominid Fossils Hominids include humans and extinct humanlike primates The oldest known hominid fossils are between 6 and 7 million years old Sahelanthropus tchadensis lived more than 6 million years ago Exhibits human-like and ape-like characteristics

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52 Oldest Hominid Fossils Ardipithecus ramidus and Orrorin tugenensis lived between 4 million and 6 million years ago Knowledge of these earliest hominids is limited - few specimens have been found The first well-known hominid line, the australopithecines, arose about 4 million years ago

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54 The Earliest Hominids The earliest australopithecines possessed knee joints that permitted bipedal (upright, two-legged) locomotion – 4 million year old fossilized footprints confirm that early australopithecines sometimes walked upright An upright stance was significant in the evolution of hominids because it freed their hands from use in walking

55 The Australopithecines Several species of Australopithecus have been identified from fossils Australopithecus anamensis Australopithecus afarensis – believed to have given rise to: – A. africanus – A. robustus – A. boisei All australopithecines were extinct by 1.2 million years ago

56 The Genus Homo The genus Homo diverged from the australopithecine line 2.5 million years ago

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58 The Genus Homo Homo habilis appeared 2.5 million years ago – Bodies and brains were larger than australopithicenes – Retained apelike long arms and short legs Homo ergaster appeared 2 million years ago Limb proportions were more like those of modern humans

59 The Genus Homo Homo ergaster is believed by many to be the common ancestor of: – H. erectus (first hominid species to leave Africa approximately 1.8 million years ago) – H. heidelbergensis Some migrated to Europe and gave rise to H. neanderthalensis Those remaining in Africa gave rise to H. sapiens (modern man)

60 Advances in Tool Technology Hominid evolution is closely tied to the development of tools Homo habilis produced fairly crude chopping tools that were unchipped on one end to hold in the hand

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62 Advances in Tool Technology Homo ergaster produced finer tools that were typically sharp all the way around the stone – Some of these may have been tied to spears

63 Advances in Tool Technology Homo neanderthalensis produced exceptionally fine tools with extremely sharp edges made by flaking off tiny bits of stone

64 The Neanderthals Neanderthals lived in Europe from 150,000 to 30,000 years ago They were heavily muscled, had brains slightly larger than modern humans, walked fully erect, and constructed finely crafted stone tools Neanderthals were once believed to be a variety of H. sapiens; however, molecular evidence indicates that Neanderthals are a separate species

65 Modern Humans Homo sapiens appeared in Africa about 160,000 years ago European and Middle Eastern H. sapiens appeared about 90,000 years ago and were known as Cro-Magnons

66 Cro-Magnons Cro-Magnons had domed heads, smooth brows, and prominent chins 30,000-year-old Cro-Magnon artifacts include: – Bone flutes – Ivory sculptures – Evidence of elaborate burial ceremonies Unlike their predecessors, Cro-Magnons created remarkable cave paintings that made use of sophisticated artistic techniques

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69 Cro-Magnons and Neanderthals Cro-Magnons coexisted with Neanderthals in Europe and the Middle East for as many as 50,000 years It is not known why the Neanderthals became extinct Two hypotheses have been proposed for the evolution of Homo sapiens African replacement hypothesis Multiregional origin hypothesis

70 African Replacement Hypothesis Members of the genus Homo made repeated long-distance migrations out of Africa beginning 1.8 million years ago H. sapiens emerged from Africa about 150,000 years ago and spread across the Near East, Europe, and Asia The dispersing H. sapiens populations replaced all other hominids

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72 Multiregional Origin Hypothesis H. erectus emerged from Africa 1.8 million years ago and spread across the Near East, Europe, and Asia Continued migrations and interbreeding occurred among widespread H. erectus populations Regional populations of H. erectus evolved into H. sapiens

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74 Large Brains Highly developed brains may have evolved in response to increasingly complex social interactions, such as the cooperative hunting of large game If the distribution of this group-hunted meat was best accomplished by individuals with large brains, then natural selection may have favored such individuals Characteristics made possible by a large brain Language Abstract thought Advanced culture

75 The Cultural Evolution of Humans The evolutionary success of humans is the result of cultural evolution and a series of technological revolutions – The development of tools – The agricultural revolution – The industrial revolution We may not be suited for our role as stewards of lifes continuity on Earth, but here we are. Stephen Jay Gould


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