Unit 4 Study Guide
Unit 4 Study Guide BIOL 1030-003
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This 14 page Study Guide was uploaded by Alexa Rosenfeld on Wednesday December 2, 2015. The Study Guide belongs to BIOL 1030-003 at Clemson University taught by Kristi J. Whitehead in Fall 2015. Since its upload, it has received 221 views. For similar materials see General Biology I in Biology at Clemson University.
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Date Created: 12/02/15
UNIT 4 Study Guide Chapter 13 1. What are adaptations? Adaptations are inherited traits that provide an advantage in terms of survival, reproduction but it is only based on the selective pressure for a particular environment 2. How did thoughts on evolution change from early Greek philosophers to Lamarck to Darwin? What role did the fossil record play in this change in thinking? Lamarck oHad an idea of why and how they would change oDisagreed with Darwin oOrganisms change based on use and disuse Ex: giraffes had a short neck but with Lamarck’s theories he believes that giraffes necks stretched longer and longer so that they can reach leaves on trees oThe parts of your body that you use more will become stronger and the ones you don’t will eventually weaken Darwin oOrganisms change and The changes help them survive better in their environments There is variations in a population (some good and some bad) Good variations: adaptationsorganisms survive better with these variations and they reproduce at higher rates Populations always overs produce based on what the environment can support which then leads to competition oIf there is competition and one variation is surviving and reproducing better, they will win and their rates will increase within the population Accumulation of adaptations to allow organisms to “fit” in certain environments Fossil Records oControversial oShows us that things have changed oMillions of years old and show that things are different than what we have today onot every organism is in the fossil record so it does not provide exact information but they are constantly being found and the records change 3. Explain how Darwin’s voyage on the HMS Beagle contributed to his theories on evolution. Darwin took this trip in his mid 20’s and came to the conclusion that the earth was much older than we thought it was. It is not just old but it has been changing over time o Figure 13.1 A, Page 256 The pressures and environments that living organisms live in are changing Geography seemed to matter also Tortoise o Figure 13.1 C, Page 257 oWere at the brink of extinction (15 they could find and were isolated and breadedover 1500 baby tortoises have been breaded within 45 years from this) Iguana oFigure 13.1 B 4. What is meant by “descent with modification”? How does natural selection fit with this? Descent with Modification: The adaptations accumulate through inheritance and are being modified as they descend o Natural selection is the process through which evolution happens which is involved with how a species descends 5. Explain the idea of natural selection. What observations lead Darwin to propose this as the mechanism of evolution? How are the observations connected to evolution? Natural Selection is where over time, you will see more and more individuals with the same adaptation in which populations are what evolves, not individuals. Observations: oThere are many variations that exist in a population oSpecies can produce more offspring than an environment can support Connections: oAntibiotic resistance oIdea that the competition will eventually select what will have the particular adaptation 6. What is the difference between natural and artificial selection? Artificial selection: humans put selective pressures on selected things to provide advantages oEx: seedless watermelon, dog breeding, pigeon breeding o Figure 13.6, Page 262 Natural Selection: the environment and population has selective pressures that evolve throughout the population 7. Be able to recognize an example of natural selection. Figure 13.2B, Page 258 8. What evidence supports the ideas of evolution? Include an explanation of the evidence or reasoning provided by the fossil record, biogeography, comparative anatomy, and molecular biology. Fossil Record: Gives a general time line oLooking at where we find fossils relative to each other (deeper older, closer younger) oOnly certain types of artifacts can form fossils oFossils can be destroyed and the Fossil record isn’t perfect oCombination of fossil records and molecular biologists that come together with their hypotheses oDecent of the whale from different hypotheses Figure 13.3B, Page 259 oFossil record: Shows the order in which organisms existed oBased on certain techniques, it can give us a relative time oOldest prokaryotic organisms 3.5 billion years old Oldest unicellular eukaryotic organisms after a billion years Oldest multicellular eukaryotic organisms after a billion years Biogeography oDecent from a common ancestor in a similar geographical area Comparative anatomy oBone structure Figure 13.4 A, Page 260 oHomology is when we have structural similarities based on common ancestry Figure 13.4 B, Page 260 Molecular biology oDNA, amino acid protein sequences oEach time you have a branch point, you have a common ancestor Figure 13.5, Page 261 oMolecular biologists do the same thing but instead of looking at physical characteristics they look at DNA 9. At what biological level of organization do we observe evolution? Population 10. How do mutations and sexual reproduction introduce variation at the population level? Why are chromosomal duplications particularly important? Mutations oStable changes in DNA sequence oSomething has changed and the change is passed on at least for several generations (get alleles) oTend to be more harmful than beneficial oRare for a beneficial mutation to come about due to mutations from the past Sexual reproduction oCrossing over oMetaphase I oRandom fertilization Chromosomal duplications is where a portion is copied and moved, having two of the same region of a chromosome oCould lead to the production of better proteins and the expansion oMouse has over 1300 genes that help them smell and they are derivatives of the one ancestral gene that was followed by mutational events 11. What is the HardyWeinberg principle (what types of populations does it apply to? What does it state?) What factors allow a population to remain in HardyWeinberg equilibrium? What factors will disrupt HardyWeinberg equilibrium? Principle: oTwo scientists interested in whether or not a population was evolving during a certain time oA population where there is sexual reproduction, when dealing with diploids, the norm is that the gene pool will stay the same unless there is some outside pressure causing it to shift. oWhat is in the population when you study it Maintaining oLarge population oNo gene flownew alleles coming into or leaving the population , no gene flow means nobody goes anywhere oNo mutation oRandom mating – no preference for particular traits in terms of traits and mating, completely random, no selection oNo natural selection – can’t have any type of outside force that puts pressure on any members of the population oIf all are true, the population is not evolving and will be in the equilibrium Disrupting oSmall populationsingle member undergoing change can have a major impact oGene flow members can come in and leave population oMutations always have a chance to be advantageous oNonrandom mating some sort of selection oNatural selection something is providing pressure to make them survive and reproduce better 12. Given allele frequencies for a particular gene locus for a population in HardyWeinberg equilibrium, be able to calculate the genotype frequencies for that population. oComplete dominance Nonwebbed WW, Ww Webbing ww (homozygous recessive) Figure 13.10 A, Page 266 Only applies to diploid organisms 500 organisms, 1000 chromosomes Allele frequencies How many dominant? Recessive? 640 WW 40 ww 160 W 160 w Figure 13.10 B, Page 266 In order to tell if the population is evolving, you have to look at the next generation (genotypic and allele frequencies if there is no evolution occurring) If you don’t find exactly this, your population is evolving Be able to tell genotypic frequencies and allele frequencies and have an appreciation that if it changes, evolution is happening Figure 13.10 C, Page 266 13. In what ways does microevolution occur? Explain the three main ways. Natural selection oCompetition oSome are better at reproducing than others because of variation oMost consistent effect because there is variation that directly impacts reproductive success Genetic drift oChange due to chance Gene flow oGene flow between the population where members from one population is leaving the other and vice versa oReduces differences oOver time the population can become extremely different but with gene flow, that likelihood is very small 14. Explain bottleneck and founder effects. Bottleneck Effect oSome type of natural disaster effects the alleles and the total size of the population is cut way down and what is remaining in the small population, you do not have the same distribution of alleles as you did in the initial population oCan lose alleles and the frequencies can change Figure 13.12 A, Page 268 Founder Effect oNot a natural disaster oLarge population with different alleles and a portion is going to leave the original population and found a new population oThe likelihood of the allele frequencies being the same, is very small oNumber of cases in the human population Colonies 15. Why/how does natural selection lead to adaptive evolution? Natural selection is the only one that consistently allows for alleles to be better at competing in the environment The others are totally due to chance and there is not a guarantee that the outcome will be beneficial Some variations are going to be favored over others because of the pressures from the environment with a sorting process that is also blended with chance 16. What are the three ways in which natural selection can impact variation in the population? Explain each. 3 ways: oStabilizing The intermediate phenotypes are the ones that are most well adapted and the extremes are the least fit and are selected against making the alleles lost from the population oDirectional There is some selected pressure that favors over another population Darker colored mice over the light colored mice oDisruptive Either extreme is selected for and the intermediate is selected against Figure 13.14, Page 270 17. What is sexual selection? Intrasexual selection? Intersexual selection? Sexual Selection is a form of natural selection o In a lot of animal species, there are phenotypic differences between males and females o Sexual dimorphism o Some characteristics lead to a larger likelihood for mating Intrasexual selection o Within a gender o Males will fight with each other for the female o Figure 13.15 B, Page 271 Intersexual selection o Selection happens between the genders o One of the genders is flashier than the other gender o Darwin thought it was fascinating (birds) o Figure 13.15 A, Page 271 Chapter 14 1. What is speciation? Speciation is what a species actually is It is when one species is split into multiple species oTakes a long time but can happen through microevolution oNo longer the same species oRepresents both the diversity and unity of life oDiversity because different selective pressures can lead to different species oUnity because you can see evidence of the ancestor species 2. In what ways do scientists define species? Be able to explain each. (Biological, morphological, ecological, and phylogenetic species concepts). Defining a Species oBiological you have groups of populations where the members can breed with each other and when they breed, the result is fertile Ex: horses and donkeys are different species but they can breed together to make a mule (sterile, not fertile) oMorphological Physical characteristics Morphology: shape, color, etc. More similarity in physical characteristics, the more chance they are the same species Sexually reproducing Which traits are more important than others in terms of characterizing a species: webbed feet matter more than nonwebbed? TOO SUBJECTIVE oEcological How animals fit into the ecology, how they fit in the environment and other animals What is their role? They should have similar roles in the environment if they are the same species How specific do you get? Overlapping (tricky) oPhylogenetic Actually attempt to look at the evolutionary history of an organism and its species All evolved from a common ancestor with a tremendous amount of similarity (DNA sequence, Protein sequence) Creates a giant phylogenetic tree, relating all organisms to each other 3. What are hybrids? The offspring that is made when species interbreed 4. Explain the various types of prezygotic and postzygotic barriers. Recognize the examples for each given in class. Prezygotic oSomething is going to prevent the sperm fertilizing the egg oNo fertilization and in most cases, no mating oHabitat isolation Two similar species live in the same general area Specific place where they occupy doesn’t overlap Even though they live in the same general area, one is a water garden snake and the other spends all their time on land (will never meet up with each other in order for them to mate) Postzygotic oFertilization will happen oSomething will go wrong after the zygote is made oNothing to prevent fertilization oReduced hybrid viability zygote will form but will either not fully develop or the offspring will be very weak and not survive until reproductive stage and if they do, they will not be successful (won’t be fit) ex: salamanders trying to interbreed 5. What is allopatric speciation? Populations of the same species but they are now separated geographically If members cannot move, there is no gene flow within the population oKeeps populations similar to each other because there is a constant move of species Big barrier that prevents species moving There is nothing keeping the two populations similar so they will eventually become different Gene flow s prevented by things like mountain ranges Geographic barriers oSome are quick events and some are long oFormation of a mountain range between two populations, making them no longer interbreed oLong term water shortage leading to several smaller lakes that separate the populations geographically oMembers from a big population go over to an island and they will become enable to go back and more than two distinct species will arise (founder effect) (Ex: finches) oTwo distinct species of squirrels that are separated by the grand canyon Figure 14.4 A, Page 282 oThis all depends on the animals that you are talking about and their characteristics (this example will not apply to birds) (human intervention can mess things up) 6. What is sympatric speciation? Two populations are living close to each other Still new species will arise There is still reduction of gene flow Habitat differentiation oHabitats differ even though they are in the same general area Sexual selection oNot the same between the species oJust don’t like each other 7. Why are reproductive barriers important?** Reproductive barriers are important because the barriers provided geographically is not enough. o Gene pools stay isolated so that there is no gene flow in different places so that new species are not created o Prevent breeding within similar or same species 8. In terms of sympatric speciation, how is gene flow reduced between populations? There is still a reduction of gene flow but new species are arising This can be caused by the differences in habitats, sexual selection, or polyploidy 9. How might new species arise through polyploidy? How quickly might speciation occur through this mechanism? Polyploidy is very rare but if it is successful, it can create new species very quickly If you have a diploid gamete trying to fertilize a haploid gamete, you will end up with a triploid zygote and it is impossible to get an even distribution of chromosomes so the new offspring can only reproduce with itself, not the parent species, making it a new species oFigure 14.6 A, Page 284 oFigure 14.6 B, Page 284 oMore common: two different species with different numbers of chromosomes trying to breed with each other Hybrid is sterile because there is no homologous pairs 10. Why are islands important for the study of evolution? Islands are a great model to provide evidence for allopatric speciation Islands have different habitats with lots of selective pressures within different islands Far enough apart to prevent gene flowgood source of isolation but are not completely which means species can be dispersed between them (change selective pressures, further lead to changes) Close enough together to keep things from stagnating 11. What is adaptive radiation? Start with a single species (common ancestor) and from that, you get a lot of other species (Darwin’s finches) Figure 14.8, Page 286 12. What are hybrid zones? What are the possible outcomes from hybrid zones? Be able to explain each. Hybrid Zones: where some species start to go back to a single species; an area where we can see that two species are interbreeding and producing hybrids 3 possible outcomes oReinforcement Basic idea that although hybrids will form, they will not be as successful as the parent so you will end up strengthening the barriers between the species No selection for the hybrids because they are way less fit which creates more selective pressures (maintained and reinforced) Increase in reproductive barriers Figure 14.10 B, Page 288 separated by geography so there is no selective pressure making them look similar, sometimes the females can’t even notice the difference (allopatric) but when the barriers are reinforced, the females can tell the difference (sympatric) oFusion Not any selective pressures to maintain the two species Hybrids will eventually overtake the population and take over the two original species Figure 14.9 B, 14.10 C, Page 287288 Lake Victoria: murky water has made the females not able to tell the difference and a lot of hybrids are forming and overtaking the original species oStability Hybrids will form and keep forming in low numbers each generation but will not be totally eliminated so it will stay stable Figure 14.10 A, Page 288 13. What are the proposed patterns of speciation? Explain what is meant by each. Punctuated oObserve in fossil record oWhen we see speciation events occur, they occur suddenly and then will stay the same until another sudden event (very jerky) Gradual oAll the time, gene and allele pools are changing, allele frequencies are changing and all of the sudden, the allele frequencies have changed enough where they are no longer able to interbreed Chapter 15 1. What is macroevolution? Macroevolution is where big changes have occurred and looking at how the earth began 2. What were the characteristics of early Earth? Water vapor Volcanic eruptions UV radiation Intense lightning Figure 15.1, Page 294 artist rendition 3. Explain the four step process through which early life is thought to have formed. Be able to explain each step plus any evidence that was discussed for each (including Miller’s 1953 experiment). 1. Synthesis of small organic molecules oMonomers oHow did this happen? How did we get the ones we got? Stanley Miller experiment In a lab, he simulated the conditions that were thought to be on early earth (water vapor, atmosphere (methane, ammonia, hydrogen), lightening, and then it was cooled down to settle out a solution into the ocean that he formed) and see what he ended up with (amino acids and hydrocarbons) Figure 15.2, Page 295 2. Formation of polymers oProteins and nucleic acids oOnce we have amino acids, how did we get to peptides? Hot surfaces (clay, sand, water) water with biological compounds washed up onto the hot surfaces. The water then evaporated and the monomers were concentrated and then made polymers 3. Packaging of molecules into “protocells” oLife begins at the cellular level oPrecells Formation of membranes If you put phospholipids into an aqueous solution, they form a membrane with the heads and tails 4. Origin of selfreplicating molecules oAbility to reproduce oCan make more of themselves without any other type of machinery DNA molecules aren’t that known for selfassembling, it is reliant on other enzymes to replicate RNA is known to selfassemble so if it is put into a solution with nucleotides, it can selfassemble into strands of RNA Can act as enzymes Probable had RNA in the first forming molecules Figure 15.3 B, Page 296 oTheories in this order in order for life to begin 4. In what general order did organisms appear on Earth? Figure 15.4, Page 297 5. Explain the theory of plate tectonics. What is continental drift? Plate tectonics oEarth’s crust is divided into pieces that float on top of the mantle oSome kind of disturbance that moves the mantle and the plates oMantle moves = plates move 6. What is Pangea? What impact did the formation and breakup of Pangea have on biological diversity? 250 million years agopangea oSuper continent was formed with this drift oOthers have happened but this was most recent oFigure 15.7 B, Page 300 oFigure 15.8, Page 302 Pangea and its breakdown oCaused huge environmental changes oOcean deepened and pulled water away from the shores when continents were formed oShore lines increased greatly oHuge impact on marine life 7. What are mass extinctions? How does the fitness of organisms play into survival during mass extinctions? What phenomena are believed to have caused mass extinctions in the past? How long, in general, does it take for biological diversity to recover after a mass extinction? 5 mass extinctions within the last 500 million years At least 50% of all species on earth have to be eliminated Permian mass extinction oHuge amounts of Volcanic eruptions o96% of all marine organisms oSevere took over 100 million years to recover Cretaceous mass extinction oAsteroid hit the earth oTook out the dinosaurs and left birds oFigure 15.9, Page 303 Why do we care? oRecovery time is huge oTakes millions of years to replace biological diversity th oIn the middle of the 6 mass extinction right now (rate 1001000x greater than normal extinction rate) 8. Why is adaptive radiation important? Many new species evolve from a common ancestor during periods of change May follow extinction events Ancestor usually colonizes new areas Success of mammals and diversity on earth is believed to occur from adaptive radiation after the extinction of the dinosaurs Figure 15.10, Page 304 9. How are changes in the development of organisms related to evolution? (think about gene regulation, new genes, genetic control of the timing/formation of structures, etc). Fossil records cannot tell us the mechanisms The control of development is by genes with rate, timing and spatial patterns What was going on at the DNA level? oHomeotic genes: genes that have a lot to do with basic processes and structure (where the wings on a fruit fly should be) oA lot of what we see with these control genes, when we have different events from evolution, these genes can be altered (where, when, how they are expressed) regulation of the genes, mutations, lead to the differences we see resulting from mass extinctions Genes as a juvenile stage disappears when it moves to an adult stage (timing) Rate in which things change Differences in terms of the development of the jaw bone and the skull in a chimpanzee (result is that skulls look different) Differences is that in fresh water, there is predators in fresh water that would grab the pelvic spine and eat them so then the trait was lost. 10. Is evolution goal directed? Explain. Evolution is not goal directed! Nothing more than pressures from the environment are allowing somethings to grow at a greater rate If the environment changes, all of what was made can become a detriment instead of having advantages (all bets are off) 11. Explain the difference between taxonomy and phylogeny. Taxonomy is naming and classifying species Phylogeny is looking at how things are related from an evolutionary standpoint 12. Know the correct way to write a scientific name (using the binomial genus/species name). Genus and species oEscherichia coli Always written in italics Genus is capitalized and species is lowercase In a lab report when writing multiple times, you can abbreviate to E. coli 13. Differentiate between homologies and analogies. Which of these is related to convergent evolution? Homologies: presence or absence of homologous structures oMorphological Shape similarities oMolecular Sequence of the DNA Complicated by analogies oIt is not impossible that organisms from common environments could have similarities but not have the same common ancestors oSimilar structures that come from similar selective pressures, NOT common ancestry 14. Explain the basic process of cladistics (include ingroups, outgroups, the two important types of characters, etc). Cladistics: field where you create phylogenetic trees oMethod creating Cladesmonophyletic groups (ancestral species and everything that came from it) oCreated by comparing what is the same and what is different between the species oShared ancestral characters Put organisms into a clade Doesn’t allow us to differentiate between them (cannot separate) Ex: having a backbone (vertebrates) oShared Derived characters Mammals make up own branch within the clade of vertebrates Model of constructing the tree In groups (relationship between, the ones you are studying) Out groups (at least one member has to make this up, you know no matter how the in groups are related to each other, the out group is NOT RELATED AT ALL) Look at shared characteristics (more shared, more related) (kangaroo and beaver in this case) Figure 15.16 A, Page 310 More closely the branch point, the more closely related to a common ancestor oFigure 15.16 B, Page 311 15. How do DNA sequences allow a scientist to infer phylogenetic relationships between organisms? What is a molecular clock? More similar DNA sequences are, the more related the organisms are Similarity of differences can be used to determine relatedness Molecular clocks oAll DNA has the possibility to randomly mutate oThere are some genes that we know has a predictable rate of change so we can look at the number of differences to say that the organisms diverged from each other about this long ago oMost reliable molecular clock today: rRNA gene is now in the small subunit of the ribosome ssrRNA 16. What is the current three domain system? (review) Bacteria Archaea Eukarya
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