Exam 1 Study Guide PDF

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Study guide including detailed notes from all of the lectures and relevant book chapters needed for the first exam. ...

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● Exam 1 Study Guide (CH 22-26) Chapter 22 - Darwinian view of Life ○ Evolution - Descent with modification ■ Pattern of evolution - revealed by data from biology, chemistry, physics and geology ■ Process of evolution- the mechanisms causing the change ○ History of evolution ■ Carolus Linneaus ● Developed binomial way of naming species (homo sapiens) ● Created nested classification system, grouped similar species into general categories ■ Georges Cuvier ● the older the stratum, more differences among fossils ● Opposed evolution. Thought extinction was common, and catastrophic events got rid of old species and brought new species ■ Lamarck ● Use and disuse - used parts of body get bigger/stronger, parts not used deteriorate ● Acquired characteristics - Traits acquired throughout life (such as building muscles) are passed onto offspring ○ Darwin’s theories ■ Adaptations- inherited characteristics increasing chance of survival/reproduction ● Natural Selection- individuals survive and reproduce at higher rates BECAUSE of certain inherited traits ● Trees diagrams ○ Used tree diagrams to explain morphological gaps and links between present day species all the way back to extinct species ○ Types of selection ■ Artificial Selection ● Humans modifying species by selecting and breeding those with desired traits. ■ Natural Selection. Darwin made 2 observations, and 2 inferences ● O1- Members of population vary in inherited traits ● I1- Members with traits that help them survive and reproduce, leave more offspring than others. ● O2- All species can produce more offspring than environment can support ● I2- Inability of all species to survive allow favorable traits to accumulate over generations ■ Soapberry bug example

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Natural selection selects the soapberry bugs who are able to efficiently eat, which only happens when their beak is the correct length for the food source. Native species, in southern florida who feed on balloon vine, have larger beaks because the seeds are deep in the fruit. These species were introduced to central florida, where balloon vines are rare. Here, they feed on goldenrain tree fruit, which has the seeds in a much more shallow position. Over time, soapberry bugs with shorter beaks were selected for in central florida, because they had better access to food. Homology - similarities resulting from common ancestry ■ Anatomical/molecular homologies ● Forelimbs of all mammals have the same arrangement of bones ● All vertebrate embryos have a tail posterior to anus, and a pharyngeal arch ○ Pharyngeal arch develops into gills in fish, and ears/throat in humans ● Vestigial structures - remnants of features that served a purpose in ancestors ○ Certain snakes have parts of a pelvis and walkin bones ● Convergent evolution ○ Independent evolution of similar features, but from different lineages/ancestries ■ Sugar glider and flying squirrels Biogeography - study of geographic distributions of species ■ All continents used to be a part of Pangea ● Can predict where fossils would be found based on where continents used to be ■ Island species ● Certain species on islands are endemic, or found nowhere else in the world. But these species are closely related to species found on the nearest mainland. ● Species colonized the island from the mainland, and gave rise to new species

Objectives Answered 1. Adaptations: characteristics that enhance survival and reproduction a. Important b/c individuals with certain traits tend to reproduce more, which leads to a higher chance that these traits won’t disappear over time 2. Evolutionary process: 5 key principles/observations a. All species of such great fertility b. Most populations are normal size

c. Individuals of population vary in characteristics d. Much of this variation is heritable e. Natural resources are limited 3. Evolutionary fitness: organism’s ability to survive and reproduce, which determines its genetic contribution to next generation a. Increase fitness=enhanced survival 4. Evidence supporting Darwin a. Drug-resistant bacteria b. Homology c. Fossil record d. Biogeography Flash cards: https://www.easynotecards.com/notecard_set/88916 ●

Chapter 23 The Evolution of Populations ○ Microevolution ■ Change in allele frequencies in a population of generations ● 3 CAUSES ○ Natural selection ○ Genetic drift ○ Gene flow ■ Genetic Variation ● Mutations - change in nucleotide sequence of DNA ○ Harmful mutations can be quickly removed ○ Can persist for generations via heterozygotes (Cystic fibrosis) ○ Neutral variations - mutations in noncoding regions that do not cause selective advantage or disadvantage ● Duplication of genes due to errors in meiosis ○ Duplications that aren't severe can persist over generations leading to expanded genome and variability ● Rapid reproduction ○ The greater generations/unit time, the more mutations will accumulate which generates more genetic diversity ● Sexual reproduction ○ Most variation comes from the combination of alleles from parents ■ Hardy Weinberg equilibrium - population is not evolving, genotype frequencies remain the same from generation to generation ● 5 conditions to be met ○ Random mating ○ Large population (prevents genetic drift)

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○ No natural selection ○ No mutations (hardest to control in lab) ○ No gene flow ● 2 equations ○ P+q=1 ○ p^2 + 2pq + q^2 = 1 Allele variations ● Natural selection ○ Certain traits, exhibited by certain alleles, enhance individuals ability to survive (flies with resistance to DDT) ○ Adaptive evolution-Over time, alleles allowing for greater survival, become more prevalent ○ Relative fitness contribution of an individual to the gene pool relative to contributions of other individuals ● Genetic drift ○ Chance events that cause allele frequencies to fluctuate ○ Small populations ● Founder effect ○ Group isolated from large population create new population with differing gene pool ○ Genetic drift can occur ● Bottleneck effect ○ Large population decrease by something like a fire or flood ○ Genetic drift can cause different alleles to become more frequent, altering the allele frequencies Adaptive evolution ● Directional stabilization ○ Conditions favor one end of phenotypic range, shifting population frequency curve in that direction ● Disruptive selection ○ Individuals at both end of phenotypic extreme are selected for, causing a decrease in intermediate phenotypes ● Stabilizing selection ○ Selects against both extremes, favors intermediates Sexual Selection - individuals with certain inherited characteristics are more likely to reproduce ● Sexual dimorphism - difference in secondary sexual characteristics between males and females

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Intrasexual selection- individuals in one sex competing for mates of opposite sex ● Intersexual selection- mate choice, individuals being choosy in their mate Balancing selection - selection preserves variation at loci, leaving 2 or more phenotypic forms in a population ● Includes Frequency dependent selection (FDS) and heterozygote advantage ● FDS ○ Fitness of phenotype depends on how common it is ■ Scale eating fish. Prey learned to defend themselves against left mouth fish when they were more prevalent, therefore right mouthed fish were selected for. Pg. 499 ● Heterozygote advantage ○ Heterozygotes have a greater fitness than both homozygotes ■ Sickle cell allele

Objectives answered: 1. Four Processes of evolution a. Natural and sexual selection b. Genetic drift c. Gene flow d. Mutation 2. Requirements and equation of Hardy-Weinberg a. 2 alleles- p and q p+q=1 p^2 and q^2 : homozyotes 2pq : heterozygote p^2 +2pq + q^2 = 1 b. Conditions i. No natural selection ii. No gene flow iii. No genetic drift iv. To mutation v. Random mating 3. Different types of selection a. Directional i. Higher frequency of one allele ii. Reduces diversity b. Disruptive i. Extreme phenotypes ii. Maintains diversity iii. Can cause speciation

c. Stabilization i. Intermediate produce more ii. Reduces genetic diversity iii. No change in popular characteristic d. Other selections i. Balancing selection 1. Certain alleles are favored at diff times or in diff places 2. Increase genetic variation ii. Frequency Dependant Selection 1. Certain alleles are favored when rare, but not when they are common 4. Effects of sexual selection a. Asymmetry of sex i. Females invest more resources in offspring b. Two types i. Female choice: physical characteristics, resources ii. Male-male: competition for territories Flash Cards: https://www.easynotecards.com/notecard_set/88935 ●

Chapter 24 The Origin of Species ○ Speciation : the process by which one species splits into two or more species ■ This explained to Darwin why there are many features that organisms share; when one species splits into two, the species share many characteristics because of their common ancestor ■ Forms a conceptual bridge between microevolution and macroevolution ● Microevolution : changes over time in allele frequencies in a population ● Macroevolution : broad pattern of evolution above the species level ○ Species ■ Latin for “kind” or “appearance” ■ Morphologically distinct species differ in many ways besides their body forms ○ Biological Species Concept ■ Species is defined as a group of populations whose members have the potential to interbreed and produce viable, fertile offspring, but do not produce viable, fertile offspring with members of other such groups ■ ex.) A woman in America may be unlikely to meet a farmer in Mongolia but if they should meet and mate, they could produce viable babies who grow to be fertile adults, but that same woman

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could not produce offspring with another species Reproductive Isolation ■ The existence of biological barriers that prevent members of two species from mating and producing viable, fertile offspring ■ Major factor in the formation of a new species ■ These aforementioned barriers block gene flow between species and limit the formation of hybrids ● Hybrids : offspring that result from an interspecific mating ■ Prezygotic barriers : block fertilization from occuring ● Habitat Isolation : two species that occupy different habitats within the same area so they rarely, if ever encounter each other ● Temporal Isolation : species that breed during different times of the day/season/year so they never mate ● Behavioral Isolation : courtship rituals that attract mates and other unique behaviors that are not recognized by any member outside the species ● Mechanical Isolation : Mating is attempted but morphological differences prevent its successful completion ● Gametic Isolation : sperm from one species cannot fertilize the egg of another species ● If a sperm cell from one species is able to overcome the prezygotic barriers and fertilizes the egg of another species, postzygotic barriers may contribute to reproductive isolation ■ Postzygotic Barriers : contribute to reproductive isolation after the hybrid zygote is formed ● Reduced Hybrid Viability : the genes of different parent species interact in a way that impairs the hybrid’s development or survival ● Reduced Hybrid Fertility : hybrids that survive are sterile ● Hybrid Breakdown : some first-generation hybrids may be viable and fertile, but when they mate with one another or with either parent species, their offspring are feeble or sterile Limitations to the Biological Species Concept ■ The number of species this concept can be usefully applied to is limited ● There is no way to evaluate the reproductive isolation of fossils ■ It does not apply to organisms that produce asexually, such as prokaryotes ■ Species are designated by the absence of gene flow, but there are

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many pairs of species that are distinct yet gene flow occurs between them ● ex.) grizzly bears and polar bears pg 508 Morphological Species Concept ■ Distinguishes a species by body shape and other structural features ■ Can be applied to asexual and sexual organisms ■ Can be useful even without information on gene flow ■ Disadvantageous because it relies on subjective criteria where scientists may disagree which feature distinguishes a species Ecological Species Concept ■ Defines a species in terms of its ecological niche, or the sum of how members interact with the nonliving and living elements of their surroundings ● ex.) two species of oak might differ in size and ability to tolerate dry conditions, yet still occasionally interbreed ■ Can accommodate asexual and sexual species ■ Emphasizes disruptive natural selection as organisms adapt to different environments Speciation with or without geographic separation ■ Allopatric Speciation : gene flow is interrupted when a population is divided into geographically isolated subpopulations ● ex.) water level in a lake is reduced, resulting in two or more smaller lakes home to separated population ● Can also occur without geological remodeling, such as when descendents become geographically isolated from the parent population ● Once geographic isolation occurs the separated gene pools may diverge and natural selection and genetic drift may alter allele frequencies in different ways in the separate populations ■ Sympatric Speciation ● Speciation occurs in populations that live in the same geographic area ● Polyploidy : a species that originates from an accident during cell division that results in extra sets of chromosomes ○ Can occur in animals but is way more common in plants ○ Autopolyploid : an individual who has more than two chromosome sets all derived from a single species ■ ex.) in plants a failure of cell division can cause an offspring to have double the

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chromosomes, from 2n to a tetraploid number 4n ● This reproductively isolates the 4n plants from the 2n ● In just one generation this causes reproductive isolation without any geographic separation ○ Allopolyploid : various mechanisms change a sterile hybrid into a fertile polyploid ■ Occurs when two species interbreed and produce a hybrid offspring, which is infertile, but can asexually reproduce which causes subsequent generations to be fertile Sympatric speciation can be driven by sexual selection ○ ex.) 600 species of cichlids appeared within the last 100,000 years in the same area due in part to differing coloration of breeding males pg. 513 Sympatric speciation can be driven by habitat differentiation ○ This occurs when a subpopulation exploits a habitat or resource not used by the parent population ■ ex.) North American apple maggot fly’s original habitat was the hawthorn tree but ~200 years ago some populations colonized apple trees which caused habitat isolation and temporal isolation, combined with natural selection, this has resulted in sympatric speciation although the two species are considered subspecies pg 514

Hybrid Zone ■ Region in which members of different species meet and mate, producing offspring of mixed ancestry ● Across a “slice” the frequency of alleles can decrease or increase ○ ex.) yellow-bellied toads and fire-bellied toads pg. 515 ■ Environmental conditions may move these zones to different locations ● Can be a source of genetic variation that improves survival ability of one or both parent species to cope with changing environmental conditions ■ Three common outcomes ● Reinforcement of barriers ○ Natural selection strengthens prezygotic barriers to

reproduction, reducing formation of unfit hybrids Fusion: weakening reproductive barriers ○ A lot of gene flow can occur where the gene pools of the two species become more and more alike, causing a reversal in the speciation process which fuses the hybrids into a single species ● Stability ○ Hybrids continue to be produced Speed of speciation ■ We can see speed of speciation by studying patterns in the fossil record ● New species can be seen to appear suddenly in a geologic stratum, remain steady, then suddenly disappear, which is known as punctuated equilibria ● Other species show gradual change over long periods of time Speciation rates ■ The existence of punctuated patterns suggests that once the process of speciation begins, it can be completed rapidly ■ On average, millions of years may pass before a new species gives rise to another new species The genetics of speciation ■ A single gene can cause reproductive isolation ■ In other instances a larger number of genes and gene interactions causes speciation Speciation can begin as small differences that accumulate and lead to the formation of new groups of organisms that differ greatly from their ancestors As one group increases in size another may experience extinction which all leads to the sweeping evolutionary changes in the fossil record ●

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Objectives Answered 1. What is speciation? a. Occurs when populations of the same species become genetically separated 2. 4 definitions of a species and how they operate a. Biological species concept *most common* i. Def: populations are different species of they are reproductively isolated ii. Either: populations do not interbreed or do not produce viable offspring iii. No gene flow between populations iv. Disabilities: 1. no ability to evaluate fossils 2. Asexual organisms? b. Morphological species concept i. Species identified based on morphological differences (structure)

c. Phylogenetic species concept i. Reconstructing the evolutionary history of populations ii. Phylogenetic: evolutionary development d. Ecological species concept i. Based on ecological niche ii. Applies to all species sexual/asexual iii. Disruptive selection is important iv. How an animal lives and interacts with their environment 3. Pre and post-zygotic barriers a. Prezygotic barriers: different species are prevented from mating i. Habitat isolation ii. Temporal isolation iii. Behavioral isolation iv. Mechanical isolation v. Gametic isolation b. Postzygotic barriers: “after zygote”, different species do mate, but the offspring have low fitness and do not produce offspring of their own i. Reduced hybrid viability or fertility ii. Hybrid breakdown 4. Types of speciation a. Allopatric: physically separate areas i. Genetic isolation, leads no no gene flow b. Sympatric: same area i. No physical barrier preventing gene flow ii. Example: apple/hawthorn flies 1. Flies prefer scent of own fruit, apple or hawthorn 2. Prezygotic barrier: habitat isolation Chapter 26 Objectives Answered 1. What a phylogeny shows you and does not show you a. Phylogeny: evolutionary history of a species or group of related species b. Systematics = taxonomy(naming organisms) + phylogeny(evolutionary relationships) c. Phylogenetic trees i. Can predict 1. Adaptive radiations 2. Mass extinctions d. Does not show i. Phenotypic similarity ii. Amount of change in a lineage 2. Difference between homology and homoplasy a. Homology: phenotypic/genetic similarities due to shared ancestry i. Molecular systematics

b. Homoplasy: similar characteristics that are not the result of common ancestry i. Analogous characters 3. Terms to describe trees a. Rooted: common ancestor of all taxa in the tree is represented b. Basal taxa: taxon that diverged near the common ancestor of the group c. Node: point where two branches diverge d. Tip (terminal node): endpoint of a branch (usually represents a species) e. Polytomy: node for which more than two groups emerge Chapter 25 Objectives answered: 1. what a fossil is and what the fossil record tells us a. 2. age determination of rocks a. 3. the geologic time scale and the timing of major events a. 4. how mitochondria and plastids became incorporated in host cells a. 5. Pangaea and what it can tell us about Earth’s floral and faunal history a. 6. the history of earth including mass extinctions, adaptive radiations, and land mass movements a. ● Organic compounds early on Earth ○ 4.6b years ago the planet formed ■ Atmosphere had little O2 ■ UV energy provides energy to form organic compounds, and early oceans provided “primitive soup” ● Abiotic Synthesis ○ RNA could have been formed fro...