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by: Ezequiel Orn


Marketplace > University of Texas at Austin > Biology > BIO 311D > INTRODUCTORY BIOLOGY II
Ezequiel Orn
GPA 3.89

Zaiming Zhao

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Zaiming Zhao
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This 14 page Class Notes was uploaded by Ezequiel Orn on Sunday September 6, 2015. The Class Notes belongs to BIO 311D at University of Texas at Austin taught by Zaiming Zhao in Fall. Since its upload, it has received 14 views. For similar materials see /class/181722/bio-311d-university-of-texas-at-austin in Biology at University of Texas at Austin.




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Date Created: 09/06/15
Meiosis is the basis of sexual reproduction Synapsis The pairing of homologous chromosomes Crossing over otherwise known of Chiasmata Key Concepts 0 Sexual reproduction dominates the life cycle of nearly all animals 0 Contributors to variation in traits among offspring Crossing Over random segregation and random fertilization Asexual Reproduction 0 Form of reproduction of a hydra Sexual Reproduction 0 Panda turtles humans Roles of Meiosis in life Cycle start Adults2n Meiosis in testes and wmm39 n Va ovaries spermn and eggn fusion to quot quot gta39vqu form zygote2n Mitosis differentiation mnnsis I39lllferamla onv V amwm gtd bi and growth2n Juvenile2n more mitosis Sn VWWW QHJ differentiation and growth Adults minis If In haploid gametes the n23 ovum and V f mismms I I wmw sperm In diplOid n46 zygote 12mm egg m1 dimed The Process of Meiosis 0 DNA replication occurs in interphase prior to meiosis I 0 Prophase90 chromosomes condense homologous chromosomes pair to form tetrads 0 Crossing over occurs between the homologues 0 Metaphase Chromosomes line up at the equator of cell in a random order 0 Anaphase homologues separate sister chromatids remain together random SegregationIndependent Assortment 0 Telophase Chromosomes remain condensed No DNA replication between meiosis I and Meiosis II Meiosis is similar to Mitosis Stages of Meiotic cell division MHomologous New I Mummu mamas ch romo 5 one s 5 ep ara te m Wmm mmw mmm mws o In Meiosis II Sister pm mmmpm chromatids Separate Conwmcm HomMogous an kmcloehm cnmmasomes separMe Nuolcav chicmalm envclapc mm a mum mam m pmumq s mm Curum M g kgrgj WW mamquot murmummumam mm 22quotquotquot HWE39 ZET quot 1Wquot EJ K TJL mm 71 m39smt h msmwmww ra mmquot numbaby Eukaryotes lelde by mltosls or melosls whlle prokaryotes lelde by blhar flssloh chromosome 7 1 DNA with a protelh attached Cells with a dlplold humber cohtalh two of each klhd of chromosomes m melosls slster chromatlds are separated and four haplold o a w H n m n s of Inhe ltan Genes a Lvhlts of lhformatloh about lhherlt d alts ach has a lar locatloh on a partlcular chromosome fuhctloh uhlt al a M Not all tralts are cle r11 domlhaht or recesslve but can be part 1 haht a lall domlhaht or cosdoml he l cus a the locatloh for a speclflc gene on a speclflc type Alleles a cer alh molecular form of a gene one of alterhatlve form of a partlcular gene s Truesareedlhg a produce offs a h certa prlhg cohslstehtly ldehtlcal to the lh deflned characters after gene Hetrozmous a carrylhg two dlfferent alleles of a glveh gene Domlhaht 7 allele that expresses ltself Recessive an allele that is masked Genotype an organism s allelic genetic makeup Phenotype the outward appearance or expression of an organism Generation key P parental Fl offspring of the parental generation Fg Offspring of the F1 Reasons for studying peas 1 small easy and inexpensive 2 short generation time 3 many varieties of pure lines available which were true breeding 4 obtain large numbers for mathematical analysis of the data Seven traits studied 1 smooth vs Wrinkled 2 green vs Yellow 3 Purple vs White flower 4 Tall vs Dwarf 5 inflated vs Constricted pod 6 yellow vs Green pod 7 axial vs Terminal Punnett Square a way to predict the genotypes and phenotypes of offspring in specific crosses Mendel s First Law law of Segregation Each gamete receives only one of each parent s pair of genes for each trait When a sperm fertilizes an egg the resulting offspring receives one allele from the father and one from the mother Independent Assortment Second Law The alleles for one trait may distributed to the gametes independently of the alleles for the other traits produces four equally likely allele combinations during meiosis 933l dihybrid Incomplete dominance Snap Dragons heterozygous phenotype is intermediate between two parents Both make proteins but one makes more than the other Co dominance Human Blood Type the Gene is located on chromosome 9 BloodType A B antibodies antibodies B A antibodies ABnone O A and B Polygenic Inheritance When alleles at more than one locus contribute to the same trait EX Skin Color Human Height Pedigree analysis Pedigree tracing is a dominant trait widow s peak Pedigree tracing a recessive trait attached earlobes Recessive inherited diseases Q sickle cell anemia one amino acid changes in hemoglobin molecule where molecules tend to cluster together and block the capillary vessels normalSS diseasess carriersSs Q In Africa 45 of certain population have the genotype Ss bc the heterozygous are resistant to Malaria a deadly disease Q Pleiotropic effects one gene has multiple phenotypic effects 4Cystic Fibrosis most common lethal genetic disease in the US Normal heterozygous parents have a 25 chance of having child with cystic fibrosis 0 Dominant inherited diseases Achondroplasia ll0000 One type of dwarfism caused by dominant gene heterozygous Huntington disorder no symptoms untilo the carrie is about 35 to 45 years old located on Chromosome 4 0 New tools for genetic testing More Genetics 0 Sex Determination O O lX O system roaches and grasshoppers males have no sex chromosome 22 2Z W system birds some fish and insects sex determined by eggs 76 3Haploidl6 diploid32 System bees and ants females from fertilized eggs males have no father Sex organ development 0 XY Embryo 8 wks found by the SRY gene on the Y chromosome regulates many other genes Sex linkage Only one recessive gene can get expressed A son receives his X chromosome from his mother and can pass it on only to his daughters For this reason there is a tendency to skip a generation 0 Hemo hilia disease in which the blood does not clot normally recessive on x chromosome and red green color blind X linked Recessive InheritancezHemophilia A Color Blindness Duchenne Muscular dystrophy DMD most common muscular disease progressive weakening of muscles i thickened but weak calves sway back posture ichairriden by age 12 usually dead by the age of 20 Often mild mental retardation Incurable but treatment may delay the deformity of joints Gene located on the x chromosome Genetic screening can test mother carriers for the gene High mutation rate of DMD gene is cause of about 13 of the cases Y linked inheritance 39 Common among the populations of India but is rare in other populations 39 Hairy ear rims is said to be cause by a y linked gene Changes in chromosome structure Deletion when a gene is completely deleted by a mutation J J J Duplication when genes are repeated twice or more times Inversion when genes are reversed Reciprocal translocation when two chromosomes come close enough to switch genes with one another Changes in Chromosome Number Abnormal Humannumber 2n46 Men 22 pairs of autosomes and KY Women22 pairs of autosomes and XX Barr bodies every extra X produces a Barr body in the nucleus women have 1 barr body men have none aneu loid or 01 loid Q Klinefelter syndrome 22 pairs of autosomes XXY Q Turner syndrome 22 pairs of autosomes X Q Speck syndrome 22 pairs of autosomes XYY Q Trisomy Down syndrome 3 21 Q Trisomy X 22 pairs of autosome XXX 00 Triploidy XXY and xxx Population Genetics gt V V V V V39V Individuals of a population have the same number and kinds of genes In populations genes exist in different forms Microevolution changes have occurred in a population s alleles frequency Allele frequencies can change through mutations gene flow genetic drift nonrandom mating and natural selection Population Is a localized group of individuals that are capable of interbreeding and producing fertile offspring Polymorphism traits come in two or more distinct forms Gene Flow pool of genetic resources that in theory is shared by all members of the population Hardx Weinberg Theorem The frequencies of alleles in the gene pool will remain constant unless acted by other agents 4L 4L Theoretical state in which a population is not evolving Only if there is no mutation The population is very large Isolated from other populations There is no selection Random mating Five causes of Microevolution O O O Mutations Gene flow Emigration and alleles Genetic Drift Changes in due to chance Nonrandom mating immigration of individuals flow of the gene pool of a small population 0 Natural selection gsteEs causes changes in gene freguencies of a population lThere is genetically based variation in a population from random mutation 2Some individuals are more fit a certain environment with certain genetic based traits have greater reproductive success than others 3Individuals with phenotypes that are better adapted to the environment pass more copies of their alleles into next generation 4As a result there is a change in allele frequency overtime microevolution 0 Natural selection does not cause genetic changes in individuals 0 Natural selection befalls individuals but evolution occurs in populations 0 Only natural selection generally leads to an accumulation of favorable adaptations in a population Darwinian Changes 0 An outcome of differences in survival and reproduction among individuals Genetic Drift Describes how allele frequencies can fluctuate unpredictably from one generation to the next Tends to reduce genetic variation The Bottleneck Effect i A sudden change in the environment may drastically reduce the size of a population 4The gene pool may no longer be reflective of the original population s gene pool Reduces individual variation and adaptability Understanding the bottleneck effect can increase the understanding of how human activity affects other species Gene Flow gt Causes a population to gain or lose alleles gt Results from the movement of fertile individuals or gametes gt Tends to reduce differences between populations over time Genetic Variation and Natural Selection Natural Selection 0 Natural selection is the primary mechanism of adaptive evolution 0 Natural Selection 0 Accumulates and maintains favorable genotypes in a population 0 Natural selection increases the frequencies of certain genotypes fitting organisms to their environment over generations How is genetic variation measured 0 Population geneticists measure genetic variation both at the level of Whole genes and at the molecular level of DNA Gene diversity neasures the average percent of loci that are heterozygous 0 Humans genetic variation 0 Gene diversity is about 14 in humans 0 Nucleotide diversity is only Ol 39 You are your neighbor have the same nucleotide at 999 out of every lOOO nucleotide sites in your DNA Directional Change in the Range of variation 0 Directional Selection 0 Shift in allele frequency in a consistent direction The Case of the P J Moths 0 Industrial Revolution 0 Soot on tress Camouflage of moths increases survival from predators 0 Directional selection from light colored to dark moths Directional Selection 0 Pesticide resistance 0 Pesticides kill susceptible insects resistant insects survive and reproduce if resistance has heritable basis it becomes more common with each generation 0 Antibiotic resistance 0 With directional selection allele frequencies tend to shift in response to directional changes in the environment Stabilizing Selection 0 Intermediate forms are favored and extremes are eliminated Alleles 0 That specify extreme forms are eliminated from a population Se39lert39inn Anzinltt or in Favor of 39F39Rtveme 1quot quot 0 Disruptive Selection 0 Both forms at extreme ends are favored 0 Intermediate forms are eliminated Descent with Modification Key Concepts 0 Evolutionary theories gave early scholars new ways to interpret the occurrences in the new world Today biological evolution is interpreted as heritable changes 0 Darwin and Wale explained evolution on the basis of Natural Selection 0 The traits that characterize a population can change over time Lamarck s Theogz of Evolution 0 Theory of Inheritance of Acquired Characteristic 0 Aristotle believed that each kind of organism was distinct from all the rest Charles Darwin 1809 1882 called evolution Descent with Modificationquot 0 Darwin Voyage of the Beagle 1831 o Darwin s Observations 39 Prevailing ideas about species they did not change or interbreed 39 Darwin s evidence for the change came from 0 His observations of living organisms 0 Geologic evidence and fossil record 0 Theories of population 0 Darwin s Mechanism of Evolution by Natural Selection 0 Selection consists of observations on four aspects of the natural world 39 Variation Variation among individuals means they individually have different abilities to obtain resources 39 Overproduction The reproductive ability of each species has the potential to cause its population increase 39 Limits on Population Growth Limited resources in the environment produces a struggle for existence 39 Differential Reproductive Success Selection pressures act upon individuals that compete for resources producing differential reproductive success 0 Individuals that have difficulty producing members of the next generation have their genes reduced and possibly subsequent populations 0 Factors that Influenced Darwin s Thinking 0 Geology As Earth has changed so did typed of fossil organisms in rock strata Population studies many organisms are produced only a few survive to reproduce 0 Artificial breeding experiments Humans select desirable traits in plants and animals so does nature 0 Darwin used pigeons to explain connections between evolution and variation traits Artificial Selection 0 In the process of artificial selection Humans have modified other species over many generations by selecting and breeding individuals that possess desired traits Natural Selection A MEChanism of Evolution 0 Darwin s explanation for species diversity 0 Nature selects organisms which have inheritable traits adaptations suited to their environment which allow them to survive to reproductive age 0 Survivors then breed and pass on these characteristics to their offspring Natural Selection 0 Selection can increase the frequency of a trait in a population 0 0 Environment may favor a trait over another 0 Alfred Wallace 0 Developed same theory as Darwin 0 The Origin of Species o 1859 Darwin 0 Evidence for the Theory of Evolution The Origin of Species 0 Darwin made two major points in his book 0 He presented evidence that the many species of organisms presently inhabiting the Earth are descendants of ancestral species 0 He proposed a mechanism for the evolutionary process natural selection 39 Descendants of these ancestors accumulated diverse modifications or adaptations that fit them to specific ways of life and habitats Fossils 0 The study of fossils helped to lay the groundwork for Darwin s idead 0 Fossils are remains or traces of organisms from the past 0 Usually found in sedimentary rock which appears in lavers or strata Homology similarity resulting from common ancestry 0 Anatomical Homologies homologous structures between organisms are anatomical resemblances that represent variations on a structural theme that ws present in a common ancestor Comparative Embryology 0 Reveals additional anatomical homologies not visible un adult organisms Vestigial Organs 0 Some of the most intriguing homologous structures are the remnants of structures that served important functions in the organism s ancestors Molecular Homologies 0 Biologists also observe homologies among organisms at the molecular level 0 Such as genes that are shared among organisms inherited from a common ancestor Anatomical Resemblances among Species 0 Are generally reflected in their molecules their genes and their gene products The Evolution of Drug Resistance HIV 0 Scientists designed the drug 3TC to interfere with the reverse transcriptase the enzyme that HIV uses to copy its RNA genome in the DNA of the host cell 0 Because 3TC is similar in shape to the cytosine nucleotide of DNA HIVE s reverse transcriptase incorporates 3TC into its growing DNA chain instead of cytosine This error terminated elongation of DNA and thus prevent HIV reproduction 0 3TC resistance varieties of HIV have a form of reverse transcriptase that can discriminate between cytosine and 3T0 0 These viruses have no advantage in the absence of 3T0 In fact they replicate more slowly than viruses with normal reverse transcriptase 0 Once 3TC is added to their environment it becomes a powerful selective agent favoring reproduction of resistant individuals Darwin s Main Ideas 0 Natural selections is differential success in reproduction unequal ability of individuals to survive and reproduce Ecology Community Key Concepts 0 A habitat is the type of place where individuals of a species normally live A community is defined as an assemblage of species living close enough together for a potential interaction Every species in the community has its own niche Interactions among species influence the structure of a community Dominant species are those in a community that have the highest abundance or highest biomass the sum weight of all individuals in a population Keystone species exert an important regulating effect on other species in a community Ecosystems and Communities Ecos stem and biotic all factors affecting an organism s survival abiotic Individuals of a species form populations living in a given habitat Several populations interact to form communities within a habitat Many communities abiotic factors form an ecosystem Everything interacts Cogpetition Interspecific competition for resources can occur when resources are in short supply 0 There is potential for competition between any two species that need the same limited resource Competitive Exclusion Principle for the same limiting resources two species with similar needs cannot coexist in the same place The ecological niche is the sum total of an organism s use of abioticbiotic resources in the environment 0 An organism s niche is its role in the environment The Competitive Exclusion Principle can be restated to say that two species cannot coexist in a community if either niche are identical Predation A predator eats prey Herbivore in which animals eat plants In parasitism predators live onin a host and depend on the host for nutrition Predator Adaptions many important feeding adaptations of predators are both obvious and familiar o Claws teeth poison speed and agility Plant defenses against herbivores includes chemical compounds that are toxic Animals defense against predation Behavioral defenses fleeing hiding self defense Camouflage mechanical defenses include spines chemical defenses odors and toxins coloration warning colors mimicry of other animals parasites and pathogens can also be considered predators Parasite take nourishment from host which is harmed in the process Endoparasite live within the parasite Ectoparasite live s on the surface Pathogens disease causing organisms Commensalism 0 An organism of one species benefits from its interactions with another while the other species neither benefits nor is harmed EX epiphytes barnacles clownfish and anemones Mutualism 0 A relationship where two species live together in close association where both benefit 0 One species usually gets protection andor support while the other gets food or a home or transportation 0 Dominant species species in a community that have the biggest abundance or highest biomass 0 Keystones exert an important regulating effect on other species in a community Ecology Major Biomes Key Concepts 0 Biomes terrestrial ecosystems within specific regions 0 Energy from the sun is the initial energy source for nearly all ecosystems on Earth 0 Interactions among global air circulation patterns and ocean currents result in regional variations in patterns of temperature and rainfall 0 A biome is a large until of land that is characterized by the climate vegetation of the ecosystem within its boundaries 0 Water covers more than 71 of the Earth s surface The Sun and its Effects on Climate 0 Biomes are characterized determined by temperature and rainfall climate and geographic features mountains etc 0 Heat from the sun and its seasonal variations 0 Global atmospheric and oceanic circulation patterns The 9 Biomes 0 Tundra 0 Location Mostly northerly biome in Eurasia North America between Taiga forests and permanent ice latitudinal arctic tundra and montane tundra alpine tundra Alaska timberline Rocky Mountains Central Mexico o Vegetation Meadow like vegetation few grasses and 0 Weather lichens 30cm of top soil thaws during the growing season roots can freely penetrate below that the soil water is permanently frozen a similar tundra vegetation occurs in high mountains Long cold winters with low annual rainfall permafrost permanent ice never melts warmest month has an average daily temperature of 10 C or less short summer growing season 2 4 months 0 Species Reproduce by asexual reproduction very few 0 Succession species the simplest biome very slow 0 Taiga Cold Conifer 0 Location 0 Vegetation 0 Weather 0 0 Northern coniferous spruce pine fir Eurasia forest belt the largest biome Dominant bearing plants are cone bearing plants North America spruce Picea fir Abies and pine Pines leaves are evergreen and needle like low shrubs and forbs almost no grasses growing season 3 5 months with the temperature above 30 C sometimes Long cold winters little precipitation short winter days and vice versa rapid growth in summer daily temperature is below freezing six months out of the year Siberia average daily temperature is 43 C in January Species Rapid reproduction sexual large mammals abundant Succession Slow forbs shrubs and trees 0 ngperature Deciduous Forest 0 O O O 0 Location Seasonal principal forests of the Northern hemisphere Vegetation More vegetation on the forest floor more light growing season is about 200 days typical four seasons dominant plants are maple Acer and oak Quercus Weather Warm summers cold winters moderate rainfall areas with cold winters have an abundant coniferous forests about 30 60 inches of rain per year Species Animal life on ground floor and in trees Succession Slow forbs grasses pines and oaks 0 Grassland Temperate O O 00 Location North America Vegetation Large quantities of grasses few shrubs or trees rich soil often converted to agriculture Weather Hot summers and cold winters Species many burrowing rodents herds of large grazing animals o Succession Slow 0 Relic Conifer Forest 0 Location Dominant in northern regions 60 65 million years ago remain a little but in California Pacific coast regions of California and Canada 0 Vegetation Cone bearing trees related to spruce fir Sequoia Dendron Sequoia and Metasequuoia found in China early last century living fossil tallest and biggest trees 0 Weather 0 Species o Succession 0 Chaparral Mediterranean 0 Location Western side of continents between 30 40 latitude o Vegetation Dominant plants are drought and fire adapted shrubs forbs fire climax leaf with wax hard thick well developed underground stems and roots 0 Weather Cool wet winters warm dry summers 0 Species o Succession Very rapid 0 Desert 0 Location American Southwest Southwestern Africa 0 Vegetation Dominant plants are succulents adapted to drought large number of annual shrubs wettest plants found in the desert 0 Weather Extremely dry and hot dry air flows over desert region and moisture is lost to tropical forest or windward sides of mountains temperature extremes 30 C difference from night and day 0 10 inches of rain a year uneven may rain plenty one year and none at all the next year 0 Species various adaptions of plants and animals to conserve water and to stay cool 0 Succession Very slow 0 Savanna o 0 Location Found between tropical forests and deserts o Vegetation Dry forest monsoon forest open grasslands tall grasses scattered shrubs and trees equatorial but the rainfall cannot support forests grasses can grow 0 Weather Two seasons dry and wet 4 6 months of rain and 6 8 months no rain rainfall is lO 60 inches a year could be as high as 500 inches 0 Species Large herds of herbivores zebra gazelles carnivores lions etc invertebrates many insects including termites o Succession relatively fast 0 TropicalRainforest


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