2 BiogeographyComparative Anatomy“homologous” structures, similarFossil record – similar structures, carbon dating – evolutionTheories of EvolutionCatastrophism – large environmental disaster things changeLamarck’sInheritance of acquired – characteristics (organism changed in it’s lifetime – could pass those changes to offspring)
3 FIGURE 14-3 Types of fossils Any part or trace of an organism that is preserved in rock or sediments is a fossil.
4 FIGURE 14-4 Fossils of extinct organisms Fossils provide strong support for the idea that today's organisms were not created all at once, but arose over time by the process of evolution. If all species were created simultaneously, we would not expect (a) trilobites to be found in older rock layers than (b) seed ferns, which in turn would not be found deeper than (c) dinosaurs, such as Allosaurus. Trilobites became extinct about 230 million years ago, seed ferns about 150 million years ago, and dinosaurs 65 million years ago.
5 Figure 14-10 Embryological stages reveal evolutionary relationships The early embryonic stages of a (a) lemur, (b) pig, and (c) human show strikingly similar anatomical features.
6 Wallace – “survival of the fittest” evolution Darwin – father of evolution 1858Biological diversity – gene pool – there is always diversity within a speciesFitness – traits best suited for survivalNatural selection – survival of the fittest, best traits will be passed onArtificial selection – man selected, domesticationAdaptation – allows for survivalStructural – anatomyBehavioral – courtship, hibernationPhysiological – how the body works
7 FIGURE 14-5 Darwin's finches, residents of the Galapagos Islands Each species specializes in eating a different type of food and has a beak of characteristic size and shape, because natural selection has favored the individuals best suited to exploit each food source efficiently. Aside from the differences in their beaks, the finches are quite similar.
8 Evidence for evolution Radiometric dating – carbon 14 dating, radioactive substances break down in half lives – decayFossils – imprints of structures within rockComparative morphology and embryology – development prior to birthHomologous features – similar structures, similar embryological development,Ex. bat and bird wings2. Analogous features – similar functions develop differentlyEx. bat wings and butterfly wings3. Vestigial structures: present, no longer needed
9 FIGURE 14-7 Homologous structures Despite wide differences in function, the forelimbs of all these animals contain the same set of bones, inherited through evolution from a common ancestor. The different colors of the bones highlight the correspondences among the various species.
10 Figure 14-9a Analogous structures Convergent evolution can produce outwardly similar structures that differ anatomically. The wings of (a) insects and (b) birds and the sleek, streamlined shapes of (c) seals and (d) penguins are examples of such analogous structures.
11 Figure 14-9b Analogous structures Convergent evolution can produce outwardly similar structures that differ anatomically. The wings of (a) insects and (b) birds and the sleek, streamlined shapes of (c) seals and (d) penguins are examples of such analogous structures.
12 Figure 14-12 Variation in a population of snails Although these snails are all members of the same population, no two are exactly alike.
13 Figure 14-13b Dog diversity illustrates artificial selection A comparison of (a) the ancestral dog (the gray wolf, Canis lupus) and (b) various breeds of modern dogs. Artificial selection by humans has caused a great divergence in size and shape of dogs in only a few thousand years.
14 Figure 14-14 Guppies evolve to become more colorful in predator-free environments Male guppies (top) are more brightly colored than females (bottom). Some male guppies are more colorful than others. In some environments, brighter males are naturally selected; in other environments, duller males are selected.
15 Experimental evidence – peppered moths, 2 variations white and grayTrees with birch (lighter bark)And lichen – more white moths1860’s coal soot killed lichen trees darken more gray moths1900’s less soot lichen back lighter bark- more white moths
17 Five agents in microevolution Change in frequency of alleles – how genetic information changes, which traits show up more oftenFive agents in microevolutionMutation – change in genetic code, lethal, neutral, beneficialGene flow – beneficial traits will be passed from generation to generation – one population to anotherGenetic drift – chance alteration of genesFounder effect – species in new environment will favor certain genesBottleneck – cheetah – severe reduction in population small population limited gene pool, greater chance for genetic disordersInbreeding – homozygous limited gene pool, greater chance for genetic disorders
18 FIGURE 15-7a Population bottlenecks reduce variation (a) A population bottleneck may drastically reduce genetic and phenotypic variation because the few organisms that survive may carry similar sets of alleles.
19 Nonrandom mating(sexual selection) – given member of a population is not equally likely to mate with any other given member “fittest”Natural selectionAdaptations – traits best suited for survival are passed onFitness – best adaptive traitsGalapagos finches – Darwin – 13 finches – common ancestor, beak size and shape – and Grant’s study – evolution can quickly occur
21 Three modes Stabilizing selection – “average” most common Directional selection – “change in the environment” shift to one extreme or the otherDisruptive selection – splits population into 2 groups
22 FIGURE 15-13 Three ways that selection affects a population over time A graphical illustration of three ways natural and/or sexual selection, acting on a normal distribution of phenotypes, can affect a population over time. In all graphs, the beige areas represent individuals that are selected against•that is, they do not reproduce as successfully as do the individuals in the purple range.
23 FIGURE 15-10 A compromise between opposing pressures (a) A male giraffe with a long neck is at a definite advantage in combat to establish dominance. (b) But a giraffe's long neck forces it to assume an extremely awkward and vulnerable position when drinking. Thus, drinking and male-male contests place opposing evolutionary pressures on neck length.
25 Species – interbreeding populations which produce viable offspring II. Reproductive isolating mechanisms – keeps species separatePrezygotic – prevents sperm from fertilizing eggMechanical – not physically compatibleBehavioral – “behaviors” are different, courtship song displays3. Temporal – breed at different times4. Gamete – egg and sperm cannot fuse5. Ecological – different habitats
27 FIGURE 16-4 Ecological isolation This female fig wasp is carrying fertilized eggs from a mating that took place within a fig. She will find another fig of the same species, enter it through a pore, lay eggs, and die. Her offspring will hatch, develop, and mate within the fig. Because each species of fig wasp reproduces only in its own particular fig species, each wasp species is reproductively isolated.
28 FIGURE 16-5 Temporal isolation Bishop pines, such as these, and Monterey pines coexist in nature. In the laboratory they produce fertile hybrids. In the wild, however, they do not interbreed, because they release pollen at different times of the year.
29 FIGURE 16-6 Behavioral isolation The mate-attraction display of a male greater bird of paradise includes distinctive posture, movements, plumage, and vocalizations that do not resemble those of other bird-of-paradise species.
30 FIGURE 16-7 Mechanical isolation (a) The shells of different snail species may coil in different directions. Among the three closely related species shown, two have shells that coil left and one has a shell that coils right. (b) Two snails with matching coils can mate, but (c) snails of different species with mismatched coiling cannot mate because the mismatch keeps their genitals (arrow) apart.
31 B. PostzygoticHybrids – offspring may not survive or be sterile
32 Table 16-1 Mechanisms of Reproductive Isolation
33 III. Mechanisms of speciation Allopatric speciation – “of other countries”1.species separated by geography change over time Darwin’s finchesColonization – 1 group of finches 13 species new island, the fittest surviveGenetic divergence – over time species change due to adapting to new environmentReproductive isolation – gene pool is separated from original gene pool – changes occur over timeCompetition – fittest for environment survive to breed those characteristics to offspringFurther speciation – original species new species
34 Chapter 16 OpenerThe saola, unknown to science until 1992, is one of a number of previously undiscovered species recently found in the mountains of Vietnam. The area's distinctive assemblage of species probably arose during a past period of geographic isolation.
35 FIGURE 16-3 Geographical isolation To determine if these two squirrels are members of different species, we must know if they are "actually or potentially interbreeding." Unfortunately, it is hard to tell, because (a) the Kaibab squirrel lives only on the north rim of the Grand Canyon and (b) the Abert squirrel lives only on the south rim. The two populations are geographically isolated but still quite similar. Have they diverged enough since their separation to become reproductively isolated? Because they remain geographically isolated, we cannot say for sure.
36 Sympatric speciation – absence of geologic separation, fruit flies, hawthornes, apples ????Parapatric speciation – next to small population on the fringe of a habitat can form it’s own breeding group
37 FIGURE 16-12 Adaptive radiation About 30 species of silversword plants inhabit the Hawaiian Islands. These species are found nowhere else, and all of them descended from a single ancestral population within a few million years. This adaptive radiation has led to a collection of closely related species of diverse form and appearance, with an array of adaptations for exploiting the many different habitats in Hawaii, from warm, moist rain forests to cool, barren volcanic mountaintops.
38 Evolutionary changeA. Vestigial structures: present, no longer neededCoevolution –symbiotic relationships “mimicry”C. Comparative biochemistry –chemical makeup, horseshoe crab,blood chemistry same as spidersD. Genetics – DNAV. Extinction: death of the last of a speciesA. Habitat destructionB. Competition
39 SYSTEMATICS: SEEKING ORDER AMIDST DIVERSITY CHAPTER 18SYSTEMATICS:SEEKING ORDER AMIDST DIVERSITY
40 I. TaxonomyLinnaeus – father of taxonomy, classification system based on homologous structuresBinomial nomenclature2 term naming systemGenus species – identification systemHomo sapiens, Felis tigris, Felis leo
41 FIGURE 18-1 Three species of bluebird Despite their obvious similarity, these three species of bluebird—from left to right, the eastern bluebird (Sialia sialis), the western bluebird (Sialia mexicana), and the mountain bluebird (Sialia currucoides)—remain distinct because they do not interbreed.eastern bluebird (Sialia sialis), the western bluebird (Sialia mexicana), and the mountain bluebird (Sialia currucoides)—remain distinct because they do not interbreed.
42 1. Archaea- ancient bacteria prokaryotes C.Domains1. Archaea- ancient bacteria prokaryotes2. Bacteria- modern bacteria prokaryotes3. Eukarya- eukaryotes divided into Animal, Plant, Protist and Fungi KingdomsD. KingdomsAnimal – heterotrophs, multicellular, eukaryotePlant – autotrophs – multicellular, eukaryoteProtist – heterotrophs & autotrophs, unicellular, eukaryoteFungi – heterotrophs, plant like, multi cellular, eukaryoteMonera – bacteria and viruses, prokaryotesD DomainsArchaea- ancient bacteria prokaryotesBacteria- modern bacteria prokaryotesEukarya- eukaryotes divided into Animal, Plant, Protist and Fungi Kingdoms
43 Table 18-1 Classification of Selected Organisms, Reflecting Their Degree of Relatedness
44 FIGURE 18-3 Human and chimp chromosomes are similar Chromosomes from different species can be compared by means of banding patterns that are revealed by staining. The comparison illustrated here, between human chromosomes (left member of each pair; H) and chimpanzee chromosomes (C), reveals that the two species are genetically very similar. In fact, the entire genomes of both species have been sequenced and are 96% identical. The numbering system shown is that used for human chromosomes; note that human chromosome 2 corresponds to a combination of two chimp chromosomes.
45 Taxonomic system Humans 1. Kingdom Animalia2. Phylum Chordata “notochord”3. Class Mammalia “hair, mammary glands,give birth to live young4. Order Primate “binocular vision, opposable thumb”5. Family Hominidae “walk upright”6. Genus Homo “man-like”7. Species sapien modern dayE. Taxonomic Key – systematic way to identify organisms using structures
46 How Many Species Exist?Biodiversity is the total number of species in an ecosystemBetween 7,000 and 10,000 new species are identified annually, mostly in the tropicsTropical rain forests are believed to be home to two-thirds of the world’s existing species, most of which have yet to be namedBecause 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 survivalFIGURE 18-7 The black-faced lion tamarinResearchers 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 FIGURE 17-12 Representative primates 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.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 visionGrasping handsEnlarged brain (facilitated hand-eye coordination and complex social interactions)
50 Oldest Hominid Fossils Hominids include humans and extinct humanlike primatesThe oldest known hominid fossils are between 6 and 7 million years oldSahelanthropus tchadensis lived more than 6 million years agoExhibits human-like and ape-like characteristics
51 FIGURE The earliest hominidThis nearly complete skull of Sahelanthropus tchadensis, which is more than 6 million years old, is the oldest hominid fossil yet found.
52 Oldest Hominid Fossils Ardipithecus ramidus and Orrorin tugenensis lived between 4 million and 6 million years agoKnowledge of these earliest hominids is limited - few specimens have been foundThe first well-known hominid line, the australopithecines, arose about 4 million years ago
53 FIGURE 17-14 A possible evolutionary tree for humans This hypothetical family tree shows facial reconstructions of representative specimens. Although many paleontologists consider this to be the most likely human family tree, there are several alternative interpretations of the known hominid fossils. Fossils of the earliest hominids are scarce and fragmentary, so the evolutionary relationship of these species to later hominids remains unknown.
54 The Earliest HominidsThe earliest australopithecines possessed knee joints that permitted bipedal (upright, two-legged) locomotion4 million year old fossilized footprints confirm that early australopithecines sometimes walked uprightAn 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 fossilsAustralopithecus anamensisAustralopithecus afarensis – believed to have given rise to:A. africanusA. robustusA. boiseiAll australopithecines were extinct by 1.2 million years ago
56 The Genus HomoThe genus Homo diverged from the australopithecine line 2.5 million years ago
57 FIGURE 17-14 A possible evolutionary tree for humans This hypothetical family tree shows facial reconstructions of representative specimens. Although many paleontologists consider this to be the most likely human family tree, there are several alternative interpretations of the known hominid fossils. Fossils of the earliest hominids are scarce and fragmentary, so the evolutionary relationship of these species to later hominids remains unknown.
58 The Genus Homo Homo habilis appeared 2.5 million years ago Bodies and brains were larger than australopithicenesRetained apelike long arms and short legsHomo ergaster appeared 2 million years agoLimb proportions were more like those of modern humans
59 The Genus HomoHomo 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. heidelbergensisSome migrated to Europe and gave rise to H. neanderthalensisThose remaining in Africa gave rise to H. sapiens (modern man)
60 Advances in Tool Technology Hominid evolution is closely tied to the development of toolsHomo habilis produced fairly crude chopping tools that were unchipped on one end to hold in the hand
61 FIGURE 17-15 Representative hominid tools (a) Homo habilis produced only fairly crude chopping tools called hand axes, usually unchipped on one end to hold in the hand. (b) Homo ergaster manufactured much finer tools. The tools were typically sharp all the way around the stone; at least some of these blades were probably tied to spears rather than held in the hand. (c) Neanderthal tools were works of art, with extremely sharp edges made by flaking off tiny bits of stone. In comparing these weapons, note the progressive increase in the number of flakes taken off the blades and the corresponding decrease in flake size. Smaller, more numerous flakes produce a sharper blade and suggest more insight into toolmaking, more patience, finer control of hand movements, or perhaps all three.
62 Advances in Tool Technology Homo ergaster produced finer tools that were typically sharp all the way around the stoneSome 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 NeanderthalsNeanderthals lived in Europe from 150,000 to 30,000 years agoThey were heavily muscled, had brains slightly larger than modern humans, walked fully erect, and constructed finely crafted stone toolsNeanderthals 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-MagnonsCro-Magnons had domed heads, smooth brows, and prominent chins30,000-year-old Cro-Magnon artifacts include:Bone flutesIvory sculpturesEvidence of elaborate burial ceremoniesUnlike their predecessors, Cro-Magnons created remarkable cave paintings that made use of sophisticated artistic techniques
67 FIGURE 17-16 Paleolithic burial This 24,000-year-old grave shows evidence that Cro-Magnon people ritualistically buried their dead. The body was covered with a dye known as red ocher, then buried wearing a headdress made of snail shells and with a flint tool in its hand.
68 FIGURE 17-17 The art of Cro-Magnon people Cave paintings by Cro-Magnons have been remarkably preserved by the relatively constant underground conditions of a cave in Lascaux, France.
69 Cro-Magnons and Neanderthals Cro-Magnons coexisted with Neanderthals in Europe and the Middle East for as many as 50,000 yearsIt is not known why the Neanderthals became extinctTwo 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 agoH. sapiens emerged from Africa about 150,000 years ago and spread across the Near East, Europe, and AsiaThe dispersing H. sapiens populations replaced all other hominids
71 FIGURE 17-18a Competing hypotheses for the evolution of Homo sapiens (a) The "African replacement" hypothesis suggests that H. sapiens evolved in Africa, then migrated throughout the Near East, Europe, and Asia, displacing the other hominid species that were present in those regions.
72 “Multiregional Origin” Hypothesis H. erectus emerged from Africa 1.8 million years ago and spread across the Near East, Europe, and AsiaContinued migrations and interbreeding occurred among widespread H. erectus populationsRegional populations of H. erectus evolved into H. sapiens
73 FIGURE 17-18b Competing hypotheses for the evolution of Homo sapiens (b) The "multiregional" hypothesis suggests that populations of H. sapiens evolved in many regions simultaneously from the already widespread populations of H. erectus.
74 Large BrainsHighly developed brains may have evolved in response to increasingly complex social interactions, such as the cooperative hunting of large gameIf the distribution of this group-hunted meat was best accomplished by individuals with large brains, then natural selection may have favored such individualsCharacteristics made possible by a large brainLanguageAbstract thoughtAdvanced culture
75 The Cultural Evolution of Humans The evolutionary success of humans is the result of cultural evolution and a series of technological revolutionsThe development of toolsThe agricultural revolutionThe industrial revolution“We may not be suited for our role as stewards of life’s continuity on Earth, but here we are.”Stephen Jay Gould