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124 Cards in this Set
- Front
- Back
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Carolous Linneus
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Swedish naturalist, binomial nomenclature and believed species were changing
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Lamarck
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one species could give rise to another, but the characteristics acquired during one animal’s life is not passed on directly to offspring
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George Curvier
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wanted to explain fossils and successive groups of fossils
-Antediluvian: before the flood -Catastrophism: there are periodic episodes of extinctions and creations |
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Charles Lyell
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publishes “Principles of Geology”, and believed earth’s history has gone through gradual change over a long period of time
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Charles Darwin’s 2 observations
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Extinct animals resemble living ones in the same region
…Geographic variation, overall similarity (common ancestor), superficial differences (adaptations to local conditions) |
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Darwin’s ideas of evolution
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Evolution = decent with modification (earth changes, so animals and plants change to adapt)
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Darwin Natural Selection
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sexual reproduction produces variation, the better suited offspring produce more offspring than others, over generations this results in a new species. There is a “Struggle for Survival”, the “Elimination of the unfit” and “Differential reproduction”
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Artificial Selection
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selective breeding to benefit a breeder’s desires and produces varieties of domestic animals. This is compared to natural selection, where nature controls which animals breed.
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Thomas Malthus
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believed that sometimes there can be more offspring produced, than there are resources to live on. Populations experience periodic elimination due to disease, war and famine
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Micro Evolution
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small changes in gene frequencies over a short period of time
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Macro Evolution
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large changes in gene frequencies, over longer periods of time, allowing the appearance of new species, as well as the extinction of others
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Gregor Mendel
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inherit Genes and Alleles from each parent, dominant genes are expressed
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MACRO EVO – how do new species appear?...
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Stasis: Lineage shows no change
Extinction Anagenesis: Gradual evolution within lineage Cladogenesis: Splitting |
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Caldogenesis (how does splitting of species happen)?...
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Allopatric model: species are isolated geographically Sympatric: species live in same area but use different resources
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Uniformitarianism assumes…
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the same natural laws and processes that operate in the universe now, have always operated in the universe in the past and apply everywhere in the universe. "The present is the key to the past".
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Polymorphism…
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having multiple alleles of a gene within a population, usually expressing different phenotypes
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Homozygous…
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An organism is homozygous for a particular gene when identical alleles of the gene are present on both homologous chromosomes.
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Heterozygous…
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An organism is heterozygous for a particular gene when two different alleles occupy the gene's position on the homologous chromosomes.
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Locus…
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the position of a gene (or other significant sequence) on a chromosome
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Gene flow…
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is the transfer of alleles of genes from one population to another
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Genetic drift…
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the change in the relative frequency in which a gene variant (allele) occurs in a population due to random sampling and chance: The alleles in offspring are a random sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces. A population's allele frequency is the fraction of the gene copies that share a particular form.
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Founder Effect…
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the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population
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DNA…
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is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information.
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Mutation…
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changes in the DNA sequence of a cell's genome and are caused by radiation, viruses, transposons and mutagenic chemicals, as well as errors that occur during meiosis or DNA replication
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Population genetics…
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the study of the allele frequency distribution and change under the influence of the four evolutionary processes: natural selection,genetic drift, mutation and gene flow. It also takes account of population subdivision and population structure in space. It attempts to explain such phenomena as adaptation and speciation.
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Convergent evolution…
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describes the acquisition of the same biological trait in unrelated lineages.
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Reproductive isolation…
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are the collection of mechanisms, behaviors and physiological processes that prevent the members of two different species that cross or mate from producing offspring, or which ensure that any offspring that may be produced is not fertile. These barriers maintain the integrity of a species over time
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Allopatric speciation…
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organisms that are closely related sister species, whose ranges are entirely separate, so that they do not occur in any one place together
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Sympatric speciation…
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organisms that are closely related sister species, whose ranges overlap or are even identical, so that they occur together at least in some places
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Speciation…
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the evolutionary process by which new biological species arise
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Stasis…
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a period of little or no evolutionary change in a species
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Anagenesis… aka "phyletic change,"
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is the evolution of species involving an entire population rather than a branching event, as in cladogenesis
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Cladogenesis…
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an evolutionary splitting event in which each branch and its smaller branches forms a "clade", an evolutionary mechanism and a process of adaptive evolution that leads to the development of a greater variety of sister organisms
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Punctuated Equilbibrium…
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a theory which proposes that most sexually reproducing species will experience little evolutionary change for most of their geological history (in an extended state called stasis)
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Isolating mechanisms…
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serve to prevent breeding between species. Reproductive isolation of populations is established. It is particularly important to the biological species concept, as species are defined by reproductive isolation
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Mate recognition…
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serves to prevent breeding between species. Reproductive isolation of populations is established. It is particularly important to the biological species concept, as species are defined by reproductive isolation.
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Turnover-Pulse Hypothesis…
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gauges the rate of survival and adaptations within species. The theory's key factors are based on the sequence of species in the paleontology of related genera, and environmental aspects in adaptation, survival and extinction.
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Particulate Inheritance…
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is a set of primary tenets relating to the transmission of hereditary characteristics from parent organisms to their offspring
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Diagnesis…
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describes all changes that occur to bones and teeth during fossilization
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Tempo of Macroevolution: special cases
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1. Adaptive radiation: sudden appearance of many closely related species
2. Mass extinction: global events prune the diversity of life; ex: the K-T Boundary, 65 Ma (end of dinosaurs?) in which mammals survived and proliferated, primates part of adaptive radiation |
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All species are a combination of:
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1. primitive traits: adaptations to past conditions, evolutionary history
2. derived traits: adaptations to present characteristics |
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Primate characteristics:
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1. primitive body plan: one bone in upper limb, two bones in lower limb, 5 digits in hands and feet (pentadactyly)
2. Dental Formula homodant: all teeth in jaw are alike, no precise occlusion (reptiles, 325 Ma) heterodant: teeth in different position in jaw, have different shapes and functions, teeth occlude (mammals, 200 Ma) |
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Dental formula in primates: incisors, canines, premolars, molars
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3. Grasping hand and foot: opposable thumb, all others except humans can use feet too
4. Reliance on sense of sight: stereoscopic and color vision, large visual cortex of brain, orbit of eye completely enclosed in bone 5. Little reliance on sense of smell: small muzzle, small olfactory bulb of brain 6. K Selected: • Robert MacArthur, E.O. Wilson, “The Theory of Island Biology,” 1967 • K selected: few offspring, large investment in each • r selected: many offspring, little investment in each |
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Apes (12 Ma possibly, subgroup of primates)
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• gorillas, chimps, orangutans, bonobos, humans
• Special about apes: • large body size • long life span • long birth interval (time between births) • altricial young: offspring helpless at births (opposite is precocial) • upright posture (trunk held erect, only hominids are bipedal) • large brain • short muzzle • increased reliance on vision • no tail |
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Primate locomotion
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• nearly all live in tropics
• about 150 species worldwide • nearly all are arboreal (live in trees) • grasping hand and foot (grab onto branches) • stereoscopic vision: depth perception (in leaping) • color vision: many eat fruit, can see ripe vs. unripe • larger primates spend more time on ground, even in forest • knuckle walking: chimps and gorillas, less mobile elbow and wrist • modern humans: ‘obligate’ bipeds |
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Primate diet
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all primates are omnivores and generalists with exception of colobus (leaf-eater)
eat a variety of food, seasonal variation |
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Jarmen/Bell Principle
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...quality and amount of food determined by body size
• small animals need less food, but the smaller the animal, the higher the metabolic rate, so higher quality food needed and must be processed fast, short gut • large animals need large quantities of food, but have lower metabolic rates, so food can be lower in quality. slower, longer processing gut |
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5 Basic ingredients of food:
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1. protein
2. carbs 3. oil 4. water 5. cellulose (fiber) |
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Food ranked from high quality to low quality:
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insects -> tree gums -> fruit -> leaves -> stems and bark
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Meat: a wild card
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1. high in food value
2. risky to obtain 3. unpredictable seasonality: food varies with season (fruits ripen, animals migrate) |
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Teeth and Diet
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• incisors: food preparation (taking a bite)
• premolars/molars: food processing • canines: food prep, killing a meal, defense and display (bigger in males) |
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“Cheek teeth” (ms and Pms)
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• bunodont: low crowned, fruit eating, omnivore ex: horse)
• hypsodont: high crowned, grass or leaf eating (ex: bear, human) • lophodant or selenodont: complex cusps, grass or leaf eating |
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Fossil:
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sign of animals or plant’s interaction with environment (ex: footprints, burrows)
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artifact:
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any object made or modified by hominins (ex: stone tools, first appeared ~2.6 Ma)
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context of artifact or fossil:
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circumstances of life (environment), gives meaning to artifact or fossil- how did object get here?
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Types of rocks
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1. Volcanic: derived from molten crust (ex: lava)
2. Sedimentary: composed of particles of other rocks (ex: sandstones) 3. Metamorphic: sedimentary rocks transformed by ear or pressure (ex: marble) |
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Kinds of volcanic rock
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1. magma: underground
2. lava: extruded at surface 3. ash: exploded into air (tephra or tuff, pyroclastic flow) |
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Volcanic ash (tuff, tephra):
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• records single instant in time
• dateable by K?Ar and Ar/Ar • each eruption has a unique composition (geochemical “fingerprint”) • can cover huge area • excellent for correlating among sites |
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Pyroclastic flow: ex: Mt. Vesuvius, Pompeii, 79 AD, “Plinian” Eruption
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• cloud of ash and gas
• exploded high into atmosphere • saturated with water, column collapses under its own weight • flows downhill at high speed, very destructive, seals underlying layers |
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Sedimentary Rocks: classified by:
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1. Depositional Environment (where and how deposited):
a. marine sedimentary rocks: deposited in the sea b. lacustrine sedimentary rocks: deposited in lakes c. fluvial (alluvial): deposited by flowing water in a river d. Eolian: deposited by the wine (ex: dunes, loess) 2. Particle size a. Ranked fine (small) to course (big): mudstone/shale (clay)->sandstone (sand)->conglomerate (pebbles, cobbles, boulders) b. particle size in sedimentary rocks reflects how much energy there is in the sedimentary environment (how much energy is required to transport particles) c. Fine particle= low energy; course particles= high energy |
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1. mudstone, shale:
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small particles, low energy environment, slowly flowing water
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2. sandstone:
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higher energy environment, more rapidly flowing water
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3. conglomerate:
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high energy deposition, rapidly flowing water
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low energy sedimentary environments better for study of fossils:
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• preserve more information
• fossils less likely to be broken • fossils less likely to be moved far from where animals lived and died |
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Water transport and sediment particle size determined by:
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1. volume of water
2. speed of flow 3. influenced by slope |
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Dating methods:
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1. Relative: order of events
2. “Absolute” age in years, amount of elapsed time, chronometric, always have range of error |
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Superposition:
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Nicholas Steno (1638-1686), “Father of stratigraphy”
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Stratigraphy:
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study, description of rock layers (strata)
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Steno’s law of superposition:
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oldest layers at bottom, youngest at top
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Relative: correlation among sites:
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1. Lithostratigraphic correlation: strata correlated on basis of rock type
2. Biostratigraphic correlation: strata correlated on basis of fossils they contain |
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Dating methods:
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most chronometric methods are radiometric or isotopic methods based on decay of radioactive isotopes
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Chronometric dating:
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• radioactive isotopes present in rocks, organisms
• emit particles, decay into another isotopes • decay happens at known rate |
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To date:
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1. measure amount of radioactive isotope left (parent)
2. Measure amount of decay product (daughter) 3. Ratio parent/daughter= time since clock set |
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Potassium/Argon (K/Ar)
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• Used on volcanic rocks
• clock set at time of eruption • works on rocks older than 200 Ka |
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Argon/Argon (Ar/Ar)
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• Refinement of K/Ar
• works on volcanic rocks of any age |
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Radiocarbon (14C)
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• used on organic material
• clock set when organism dies • date things younger than 40 Ka |
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Dates
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• Dates always have range of uncertainty (+/-)
• Few methods date fossils directly • most methods date rocks: must know geology • date is usually time range (min & max)= “bracketing” dates |
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How bones become fossils
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• Fossilization process limits what parts get preserved, what we can know about past
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Requirements
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1. animals must have lived and died in area
2. animals must get buried without disturbance (rare) |
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Charles Darwin (1809-1882)
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Mechanism of evolution is natural selection OR differential reproduction
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Gregor Mendel (1822-1884)
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Requires variation- how is variation maintained?
“particulate of nature” |
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James Watson and Frances Crick- structure of DNA molecule
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• Structure of DNA ‘double helix’ : strands wrapped around each other joined by Hydrogen bonds between each base pair
• gene: codes for a trait, may be a single base pair, or longer stretch of DNA • anatomy and behavior of chimps is very similar to humans |
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How similar are they?
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Molecular biology: establishes evolutionary relationships of living animals
Vince Sarich, Rebecca Cann: DNA hybridization, overall differences |
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DNA hybridization
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• Step 1: extract DNA from human and chimp (blood, saliva, tissue, hair, etc.)
• Step 2: snip fragments of human and chimp DNA, heat up, determine melting temperature- when 2 strands “unzip” and hydrogen bonds let go • Step 3: put strands of human and chimp DNA in petri dish- cool off, allow hybrid strands to form • Step 4: heat up hybrid strand, determine melting temp. if hybrid strand is not a perfect match then melting temp is lower (takes less energy to break H bonds) melting temp: 86 degrees C |
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Difference in melting temp= overall difference in DNA (# of different base pairs)
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• 86 degrees C in chimp DNA or human DNA
• -83.6 degrees C chimp-human hybrid DNA • 2.4 degrees = 2.87% difference • ->humans and chimps share ~97-98% of DNA |
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DNA hybridization results
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• human-chimp-gorilla ‘trichotonomy’ -> 28 % difference
• human-gibbon-> 4.6 % difference • human-orang. -> 3.5 % difference • hybridization alone can’t solve human-chimp-gorilla relationship |
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DNA sequencing
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• human genome project took 13 years to complete, in 2000 ‘sketch’ published, 2001 complete version was publishes
• genome= total DNA in an organism • gene sequencing: many different methods • DNA strands cut into fragments; fragments are compared to each other OR to known sequence differences based on molecular weight |
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High Throughput Methods
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Jonathon Rothberg: founder of 454- human neanderthal genome project collaborator
whole genome sequencer- Roche- 454 Life Science (Branford, CT) |
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Chimp Genome project
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• Initial sequence in 2005, took 5 years
• biomedical forensic evolutionary applications • Chimp DNA sequencing and analysis consortium • 63 scientists |
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Precisely how are humans and chimps different?
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Amount of difference depends on what part of the genome is observed (coding vs. non-coding regions, rapidly vs. slowly evolving regions)
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How similar are they?
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• Direct comparison: 99% identical
• If include insertions and deletions: 94% identical • Differences between human and rat: 1/60 • between rat and mouse: 1/10 |
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Why do chimps and humans look so different?
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• Genes that are different may have important functions
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• Gene regulation:
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• M.C. King and A. Wilson: evolution at 2 levels in humans and chimps (1975)
• order that genes are activated during life of an organism • genetic code: coding portion of genome • codon: 3 base pairs (bp) • instructs for production of one amino acid |
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Redundancy of code: 64 possible base pairs (4 x 4 x 4)
20 amino acids |
• different base pairs can code for same amino acid
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Mutation: spontaneous change in genetic material, introduces novelty
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• Chromosome mutation: affects whole stretches of DNA, usually has negative consequences
• Point mutation: change in single base pair or codon |
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“Neutral Mutation Effect” Motoo Kimura (1968)
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• many mutations are silent, neutral, no apparent effect on organism
• Silent point mutations: change in genotype, not in phenotype • Molecular clock: genetic differences can show how recently 2 species shared a common ancestor • Wilson: molecular difference between pairs or species proportional to the time of their separation • Species if a breeding population: new mutations will spread throughout population • When population splits (cladogenesis): reproductive barrier |
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Mutations are random events- how can random events measure time?
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• individual mutations are random, but total genome is so large that mutation rate is effectively uniform
• human genome is 3.2 billion base pairs (and >30,000 genes) |
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Genome acts like a clock- how do we set it?
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• need fossils to set the clock (to establish dates)
• Origin of primates ~ 65 Ma • Calibration ~ 12 Ma |
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Carl Linnaeus:
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humans= homo sapiens, common chimp= homo troglodytes (now Pan troglodytes)
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First Fossil Chimpanzee
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• Early hominins were chimp-like; assumption: common ancestor was probably chimp-like
• Hominins have changed a lot in the last 7 Ma- have chimps really stayed the same? |
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Why no fossil chimps (until now)?
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• Forest in Africa- poor preservation, few exposures, no dating
• Good fossil preservation in East African Rift Valley |
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Biogeographical separation?
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• Chimps-> forest; humans-> Savanna
• “Savanna Hypothesis” Origin of Bipedalism • “East Side Story” Coppens, 1994 • First bipeds lived in the forest |
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McBrearty Research:
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• Chimp fossil sites found in Rift Valley (not where they are supposed to be): Lake Baringo, Kapthurin Formation, Kenya
• This contradicts the Forest/Savanna idea • Chimp fossils: lake sediments; human fossils: stream sediments |
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Chimp dentation:
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Molars: low crown (bunodant), cusp pattern like pan, thin enamel (Different from humans who have very thick enamel). Very small compared to modern chimps, so may be an extinct species
Incisors: very thick at base, lingual tubercle (humans have no tubercle), thin enamel • Fossils now kept in the hominid vault in the National Museums of Kenya • So far, no bones have been found probably due to fossilization (teeth are the hardest substance and preserve better) |
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Kapthurin Formation:
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• Lake Sediments (lacustrine): saline, Alkaline-> lake has migrated across the landscape
• Tufa sediment (Fresh water spring) • Stream sediments (Fluvial) |
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From geology:
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• lake level is fluctuating
• sedimentary facies= different parts • Isochron= formed at the same time • Chimp fossils found on the shore of the lake • Tufas form where fresh and alkaline waters meet |
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Paleoenvironment of chimp site:
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• Fresh water: fish, turtles, crocodiles, hippos, elephant, buffalo, colobus monkey
• Waterbuck: eats leaves (trees around) • also may be open area nearby because: • Oryx (likes dry environment); lions (more numerous in open setting) |
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Turkwell River, Southwest Turkana
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1. Local= gallery forest
2. Regional= arid habitat 3. Time averaging? (How much times does site represent?) |
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Main message:
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• Habitats are changeable
• Both hominins and chimps are adaptable • Habitats of common ancestor not known yet • Forest vs. Savanna adaptation is probably not the reason for divergence of chimp and hominin linages • We still need to find a reason for divergence |
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The Jarman-Bell principle
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High quality, low quantity VS low quality, high quantity
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Lacustrian sediments are derived from...
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lakes
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Homodont and Heterodont
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HOMO - all the same teeth(reptiles)
HETERO - different teeth |
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Paleomagnetism
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magnets face north, but switch in irregular cycles
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Alapatric speciation
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due to geographic barrier
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Simpatric speciation
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due to reproductive barrier
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Mendel
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Recessive, dominant, co-dominant traits
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O18/O16...which is warmer period?
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16 (cold periods have more O18 than usual)
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Lineas created...
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binary system of classifying animals
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Homology
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trait shared from a common ancestor
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Old/New primate dental formula
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Old - 2 - 1 - 2 - 3
New- 2 - 1 - 3 - 3 New has an extra premolar |
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Genetic drift
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in a population, random events can kill off members of populations, and the overall genetic frequency can change
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taphonomy
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study of disturbance of strata
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3 types of mutations
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point, silent and chromosomal
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human primitive and derived traits
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primitive - 5 fingers
derived - hair, different molar pattern |
