...Speciation Speciation is known to take place in two general ways. Species are known to change over time into something that is so extremely different they are considered a completely different species. In other words, a species can change so drastically that it splits into two separate groups that no longer share a similar gene pool. In each case of speciation, reproductive isolation occurs. Even for a single definition of species, there are many ways for speciation to occur. Under the biological species concept, speciation is the evolution of one or more reproductive isolating mechanisms. Under the cohesion species concept, speciation is the evolution of isolation or otherwise distinct reproductive communities and/or the evolution of novel and shared adaptations that create lineage cohesion due to natural selection. Populations can be recognized as distinct species if they are reproductively isolated from each other, if they have distinct morphological characteristics, or if they form independent branches on a phylogenetic tree. The evolution of novel adaptations occurs through ordinary natural selection: the population consequence of lineage cohesion is just a by-product that sometimes occurs. The evolution of isolating mechanisms is not so straightforward: by definition, an isolating mechanism reduces or eliminates the ability to reproduce -- seemingly goes against natural selection. Isolation is not a phenotype of an individual, but emerges as an interaction among individuals...
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...Speciation Melinda Jones Bio/240 Anna Maria Sloan March 8, 2016 Speciation Charles Darwin’s thoughts on species and how they evolve into organisms that have different characteristics are complicated. Not all naturalists are satisfied with his definitions of species and speciation but they all have a general idea of what he meant. Species can be broken down into four categories; typological, nominalist, evolutionary and biological species. Speciation, according to Darwin, “is this process of multiplication, occurring when one population splits into two reproductively isolated populations” (Charles Darwin and Evolution, 2009, para. 4). Darwin’s idea was that, through both gradual evolution and isolation, species will eventually turn into two distinct species. There are three examples of speciation that can further explain the process of speciation. Those examples are; allopatric speciation, sympatric speciation and Polyploidy. Allopatric speciation Allopatric speciation is defined as species “originating in or occupying different geographical area” (Dictionary.com, 2013, para. 1). This example goes on to explain how, although it may be the same species, if living in different areas of the world they may exhibit different characteristics to help them adapt and survive in their environment. The one species will turn into two very different species due to a physical...
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...Phase 2 Lab Report TITLE: Speciation • Purpose o The purpose of this lab is to evaluate what would happen if a species within a population were suddenly split into 2 groups by an earthquake that would create a physical barrier. • Introduction o If a population is divided indefinitely by a barrier, the members of the population are unable to breed amongst a group as a whole changing the speciation. Over time the abiotic and biotic conditions may become different on either side of which the earthquake occurred (M.U.S.E.). • Hypothesis/Predicted Outcome o I would expect if the biotic and abiotic conditions changed it would cause the species to change and the species to either die off or forced to adapt. As we know, what a species is forced to adapt this is what we call evolution and I would see this happening. • Methods o The initial separation would consist of some species from the mainland reaching the isolated Island, then after that the isolated population would begin to diverge because of the genetic drift and natural selection, then after that overtime divergence may eventually become sufficient to cause reproduction isolation. (M.U.S.E). • Results/Outcome o As a result, Natural selection will cause different selective and adaptive pressures to occur between the two divided populations and they will continue to evolve. Over time this will result in speciation which is the creation of two...
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...“The longer you live the longer you should live” –Wiley “Evolution’s a bitch” –Wiley “Suckers are good to eat” –Wiley WHAT HAS EVOLUTION DONE FOR ME What has evolution done for me • Agricultural crops and animal breeding for the past 8,000 years • With the discovery of methods to reconstruct evolutionary relationships there is been a vast increase in the relevance of evolutionary biology to human society. Reconstructing Phylogenies • 1859-1950- No coherent empirical methods • 1950-1966- Emergence of Phylogenetic Systematics • Phylogeny by discovery of the order of evolutionary innovation Ribotyping • Fingerprinting or sequencing RNA • Many diseases have unknown causes • However, diseased tissues can be ribotyped. (Wiley Death Fish) • This process involves extracting DNA from diseased tissues and then sequencing the DNA that codes for rRNA. • If a disease agent such as a bacteria is present, then we will get ribosomal DNA sequences from the host (you) and the bacteria (the infection agent). Ribotyping: Phylogeny matching • Once we have the rDNA sequences, we can plug them into a sequence matrix of all life and see where our unknowns appear on the tree of life. Our Food Chain • Some products are easy to identify, but others are not. • A slab of fish fillet from a sea bass looks like a slab of sih fillet from a farmed Asian catfish. • But the sea bass costs $10/pound while the Asian catfish...
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...Exam #4 Review Sheet T- Th Spring 2016 Remember that the final exam is cumulative with 50 points from previous material. From the last quarter of material I have provided some questions for you to think about and some example questions. This is not an exhaustive list of topics that will be on the exam. Other material on which I lectured may be tested. What are reproductive clones and how are they produced? What are some examples of reasons why some people are interested in producing animal clones? What is recombinant DNA, how is it made, and what are its uses? When making recombinant DNA using bacterial plasmids, how are restriction enzymes and ligases involved? What are “sticky ends” and how are they important to this process? What are DNA fingerprints, how are they made, and of what do they inform us? Understand the processes and importance of polymerase chain reaction and gel electrophoresis. Who were some of the major scientists (natural and social) whose work affected changes in the way the world was viewed in the 1800’s? What were some of Darwin’s observations in South America and the Galapagos and how did they stimulate his thinking about modern species evolving from ancestral forms, and the effect of the environment on the evolution of species? What are Darwin’s main principles (tenants) for how natural selection occurs? How is there evidence of evolution in each of the following fields of study: Comparative anatomy (including examples...
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...Hybridization and “Genetic” Extinction Can and do we preserve the genetic integrity of species, and if so, how? Hybridization • Hybridization: mating between different species or two genetically distinct populations that produces offspring, regardless of fertility of offspring Golden- and Blue-Winged Warblers Golden wingedwarbler Blue wingedwarbler Hybrid (Brewster’s Warbler) Golden- and Blue-Winged Warblers Introgression • Introgression: the incorporation of genes from one population or species to another through hybridization that results in fertile offspring that further hybridize with parental populations or species (“backcross” ) • Over several generations, introgression can result in a complex mixture of parental genes, while in simple hybridization 50% of genes will come from each of the two parental species. • Without introgression, the parental species or populations are not “contaminated” by hybridization Levels of Hybridization Population or Species A Population or Species B F1 Hybrid Backcross (1st generation) Introgression F2 Hybrid (2nd generation) Backcross Hybrid Zones • Hybrid zones are often observed in nature… Species A Species B Hybrid Zone • How are hybrid zones maintained? – Hybrids may be less fit than parental taxa and selected against, but dispersal into the zone maintains a narrow band of F1’s – Hybrids may be more fit than parental taxa in habitats that are intermediate to parental taxas’ native habitat Hybridization and Conservation...
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...BIO 112 – Spring 2016 Chapter 27 study guide Key Terms Speciation | Phylogeny/phylogenetic tree | Species | Subspecies | Genetic isolation | Allopatry | Genetic divergence | Allopatric speciation | Biological species concept | Dispersal | Reproductive isolation | Vicariance | Prezygotic isolation | Biogeography | Postzygotic isolation | Colonization | Temporal isolation | Sympatry | Habitat isolation | Sympatric speciation | Behavioral isolation | Disruptive selection | Gametic barrier | Niche | Mechanical isolation | Polyploidy | Hybrid viability | Polyploid speciation | Hybrid sterility | Autopolyploid | Morphospecies concept | Allopolyploid | Morphology | Whole genome duplication | Polymorphic species | Secondary contact | Cryptic species | Fusion | Phylogenetic species concept | Reinforcement | Monophyletic group | Hybridization | Clade | Hybrid zone | Lineage | Ring species | Synapomorphy | Hybrid speciation | Common ancestor/common ancestry | | Outline * Speciation occurs when a single ancestral group splits into two or more species * Results from genetic isolation and genetic divergence * How are species defined and identified * Biological species concept * Reproductive isolation * Prezygotic * Temporal * Habitat * Behavioral * Gametic barrier * Mechanical * Postzygotic * Hybrid viability ...
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...Caribbean Anolis Lizards. In: Adaptive Speciation, eds. Dieckmann U, Doebeli M, Metz JAJ & Tautz D, pp. 322–344. Cambridge University Press 2004. c International Institute for Applied Systems Analysis Please cite as: J.B. Losos and R.S. Thorpe. Introduction. Pp. 322-324 in Adaptive Speciation, reference above 16 Evolutionary Diversification of Caribbean Anolis Lizards 16.1 Introduction Jonathan B. Losos and Roger S. Thorpe The diversification of the lizard genus Anolis on Caribbean islands surely represents one of the best-studied cases of adaptive radiation in evolutionary biology. Over the course of the past four decades, researchers have studied almost every aspect of anole evolutionary ecology. These include systematics; community, physiological, and behavioral ecology; functional morphology; ethology; and demography. Studies have been conducted in the laboratory and in the field, and have included basic natural history, geographic and temporal comparisons of populations, and a wide variety of experimental approaches to the study of phenotypic plasticity, ethology, ecology, and evolution [recent reviews include Losos (1994) and Roughgarden (1995)]. The result is an unusually broad and detailed understanding of the factors that promote and sustain evolutionary diversification and species coexistence. Speciation and adaptation in anoles Two conclusions from the current body of work are obvious. First, the genus Anolis has experienced extensive speciation. With more than 400 described...
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...flow between two populations ceases, the potential for _____ exists. Speciation Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species that lived side by side in parts of their ranges. However, recent books show them as eastern and western forms of a single species, the yellow-rumped warbler. Apparently, the myrtle warbler and Audubon's warbler _____. A) Successfully interbreed and produce fertile offspring successfully interbreed and produce fertile offspring Imagine that part of a population of South American finches is blown by a storm onto an island far offshore and manages to survive and reproduce there for a period of 10,000 years. After that period, a climate change results in lower sea levels and the reconnection of the island with the mainland. Members of the formerly isolated island finch population can now interact freely with members of the original mainland population. Which of the following observations would, by itself, lead you to conclude unequivocally that the island finch population had evolved into a distinct species, according to the biological species concept? A) Individuals from the different populations sometimes mate with each other, but all of the resulting eggs are sterile. Which of the following conditions is necessary for speciation to occur? D) Reproductive isolation At which point in the adaptation of a population is it clear that speciation has occurred? B) Gene pool changes establish reproductive barriers...
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...BROCK UNIVERSITY Final Examination Course: ERSC 1F90 Date of Examination: April 21, 2011 Time of Examination: 19:00-22:00 Number of Pages: 7 Number of Students: 468 Examination Time: 3 hours Instructor: Hess No examination aids other than those specified on the examination script are permitted. NO TEXTING!!! Use or possession of unauthorized materials or use of any device other than those specified will automatically result in the award of a ZERO GRADE for this examination. This means you should not have your mobile device out for ANY REASON!!! 1. 2. Answer ALL questions on the provided SCANTRON sheet. Please use a pencil. Turn in the question sheet AND SCANTRON sheet at the end of the examination. ######### Name ________________________ -P~.d. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. as + 1. The positive feedback mechanism in which a population falls below a threshold level, mutations proliferate due to reduced genetic diversity, and the population is further reduced is called: A) inbreeding depression B) toxic genetics C) environmental resistance D) dieback 2. About how much solar radiation is reflected back by the atmosphere of our planet? A) 25% B) 85% C)3% D) 5% 3. The correct order for layers of the atmosphere, from the top to the ground surface, is as follows: A) thermosphere, stratosphere, mesosphere, troposphere B) troposphere, stratosphere, mesosphere, thermosphere C)...
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...m Biology 2 – Study Guide # 1 Chapters 24 & 25 - Macroevolution What are the two main points of Darwin’s book? What is microevolution? Macroevolution? What are the two theories of macroevolution? What are the three types of gradualism? What is punctuated equilibrium? What is a biological species? What is allopatric speciation? What conditions favor allopatric speciation? Sympatric speciation? What is autopolyploidy? Allopolyploidy? What is a hybrid zone? What are the three outcomes? What is the origin of novelty? (exaptations) What is evo-devo? What is allometric growth, heterochrony, paediomorphosis, paediogenesis? What are hox genes (homeotic genes)? How do evolutionary trends behave? What is adaptive radiation? Know the ways fossils are formed and what fossilizes. What are the limitations of the fossil record? Know how to do a radiometric problem? What is a half-life? Know the geological time scale. What is continental drift? Plate tectonics? K-T boundary? Pangaea? Laurasia? Gondwana? Chapter 17 – Viruses Know the structure of viruses. Know how viruses replicate. Know the viral genome structure. What are bacteriophages? What are the lytic and lysogenic reproductive cycles? Know the information give on HIV virus. What are the treatments? Chapter 27 – Bacteria Know the structure of a prokaryotic cell. Know how bacteria reproduce asexually and through genetic combination. (binary fission, transduction, transformation, conjugation)...
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...that rather than being an evolutionary dead end, polyploidy is a route to evolutionary success. A recent study (3) confirmed the ubiquity of polyploidy, with about 35% of vascular plant species being recent polyploids (“neopolyploids,” having formed since their genus arose), representing 15% of speciation events in flowering plants and 31% in ferns. It remains unknown, however, whether the abundance of polyploids is a consequence of higher diversification rates following polyploidy or of frequent polyploid formation. We estimated diversification rates of neopolyploids relative to their diploid congeners. We compiled a data set of angiosperm (n = 49) and seed-free vascular plant (SFVP, including ferns and lycophytes; n = 14) generic-level groups in which ploidy levels could be estimated from cytological and phylogenetic data (4). Over 500 ploidy shifts were inferred with a probabilistic model of chromosome number evolution that accounts for aneuploid and polyploid transitions but not diversification rate differences (5). This allowed us to label all descendants of a polyploidization event as neopolyploids, even when lacking chromosome data. heteroploid speciation, the difference in speciation rates between diploids and polyploids was no longer significant (P > 0.1). Nevertheless, the...
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... Date: 12/1/2014 Instructor’s Name: Staci Lynn Assignment: SCI203 Phase 2 Lab Report TITLE: Speciation • Purpose o The purpose of this lab is to evaluate what would happen if a species within a population were suddenly split into 2 groups. • Introduction o If a population is divided indefinitely by a barrier members of the divided population will not have the opportunity to breed with each other, over years, the biotic and abiotic conditions on either side of the barrier will vary from one another. (M.U.S.E). • Hypothesis/Predicted Outcome o Based on what I’ve learned I expect that species will undergo changes if they were split into 2 different groups, some would adapt and some wouldn’t. • Methods o The methods I used in this lab came from M.U.S.E. The initial separation would consist of some species from the mainland reaching the isolated Island, then after that the isolated population would begin to diverge because of the genetic drift and natural selection, then after that overtime divergence may eventually become sufficient to cause reproduction isolation. (M.U.S.E). • Results/Outcome o As a result, Natural selection will cause different selective and adaptive pressures to occur between the two divided populations and they will evolve forever. Over time this will result in speciation which is the creation of two new species. (M.U.S.E). • Discussion/Analysis o I did obtain...
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...This is a steady and slow rate of change in population over time. The differences between the two are the rate of evolution. Phyletic gradualism is very slaw and is constant for species. In punctuated equilibrium the rate is very fast and is related to geologically side of things. In my opinion, the differences lay in the definitions of the species and of course the theories behind punctuated equilibrium and phyletic gradualism. Many expert and researchers have annotated that punctuated equilibrium implies a prediction about patterns of genetic differences among many species. It predicts that many evolutionary changes takes place in a short span of time and is tied to speciation events.” Punctuated equilibrium predicts that the fossil record at any one site is unlikely to record the process of speciation. If a site records that the ancestral species lived there, the new species would probably be evolving somewhere else. The small size of the isolated population which is evolving into a new species reduces the odds that any of its members will be fossilized. The new species will only leave fossils at the same site as the old one if it becomes successful enough to move back into its ancestral range or different enough to exist alongside its relatives” (Evolution: Library: Punctuated Equilibrium, n.d., p....
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...Lecture 11 Biological Species Concept Speciation: the process in which one species splits into 2 or more species Microevolution: changes in allele frequency in a population Macroevolution: Broad pattern of evolution above the species level Species: a group of populations that are able to interbreed and produce viable fertile offspring. -Gene flow within a population holds members of the population together genetically Reproductive Isolation: Barriers that prevent members of different species from interbreeding 1-Prezygotic Barriers: Habitat Isolation: species live in different areas Temporal Isolation: mating occurs at different seasons Behavioral Isolation: members of a species practice mating rituals unique to their own species Mechanical Isolation: morphological differences prevent transfer of gametes Gamete Isolation: gametes fail to fuse due to biochemical differences 2-Postzygotic Barriers: Reduced Hybrid fertility: Difference in chromosome number causes problems in meiosis Reduced Hybrid viability: genes of parent species may have interactions that affect hybrid health Hybrid breakdown: the first generation of offspring may be healthy and fertile but the second generation will be sterile or unhealthy Morphological Species Concept: Species characterized by body shape Ecological Species Concept: based on species ecological habitat Phylogenetic Species Concept: based on DNA and morphology How Does Speciation occur? * Allopatric Isolation: an...
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