BSC108- Test 3
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This 13 page Study Guide was uploaded by Leah Larabee on Thursday March 26, 2015. The Study Guide belongs to BSC 108 at University of Alabama - Tuscaloosa taught by Dr. Yates in Spring2015. Since its upload, it has received 262 views.
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Date Created: 03/26/15
EVOlLllIlOl l 3 Change OVBT39 time Natural selection mechanism for the change CHAPTER 13 Charles Darwin 0n the Origin of Species by Means of Natural Selection Published November 24 1859 o The two main points 1 That contemporary species arose from ancestors Through a process of descent with modification with natural selection as the mechanism 2 Challenged the notion that the Earth was relatively young and populated by unrelated species 0 The basic idea of natural selection Organisms can change over generations Individuals with certain heritable traits leave more offspring than others The result of natural selection is evolutionary adaption He based his theory of natural selection on two key observations 1 Observation 1 Overproduction All species tend to produce excessive numbers This leads to a struggle for existence 2 Observation 2 Individual variation Variation exists among individuals in a population Much of this variation is heritable Conclusion Unequal reproductive success natural selection Those individuals with traits best suited for the local environment leave more fertile offspring Biological Evolution Fossils Are preserved remnants or impressions left by organisms that lived in the past Are often found in sedimentary rocks The fossil record Supports evolution Is the ordered sequence of fossils as they appear in rock layers Reveals the appearance of organisms in a historical sequence 0 Paleontologists Are scientists that study fossils Have discovered many transitional forms that link past and present Biogeography Is the study of the geographic distribution of species Comparative anatomy Is the comparison of body structure between different species Confirms that evolution is a remodeling process Homologous structures Is the similarity in structures due to common ancestry Comparative embryology Is the comparison of structures that appear during the development of different organisms Comparative embryology of vertebrates supports evolutionary Whale theory Examples of natural selection include 1 Pesticide resistance in insects 2 The development of antibioticresistant bacteria T 3 Drugresistant strains of HIV gt73 Mutations and Sexual Recombination O39 C Produce genetic variation E5 0 Muta tions Are changes in the DNA of an Original phenotypes furcolor organism population 0 Sexual recombination Shuf es alleles during 1 meiosis Of all causes of microevolution only natural selection promotes adaptation I I The modern synthesis is the fusion of genetics 51 With eVOIUtionary biOIOgY a Directional selection b Disluptive selection c Stabilizing selectio Directional selection o Shifts the phenotypic quotcurvequot of a population 0 Selects in favor of some extreme phenotype Disruptive selection 0 Can lead to a balance between two or more contrasting morphs in a population Stabilizing selection 0 Maintains variation for a particular trait within a narrow range Sicklecell disease 0 Affects about one out of every 400 African Americans 0 Is more common among African Americans but why Confers resistance to the disease malaria Is adaptive in the African tropics where malaria is common CHAPTER 14 Microevolution Changes in allele frequencies within populations Often associated with adaptation Can be measured from one generation to the next Macroevolution Major changes in the history of life Origin of new species Generates biological diversity Species Are groups of organisms whose members have the potential to interbreed with one another in nature to produce fertile offspring reproductively isolated from other such groups The gene pools of two or more populations must be separated from each other 0 Allopatric Speciation Species evolve in geographic isolation Usually associated with a geographic barrier preventing members of two populations from mating with one another Involves independent evolution of the populations after the barrier arises Geographic barriers like deep canyons and oceans can isolate populations As the surface of the earth changes so do the chances that different organisms might interbreed Chances for allopatric speciation increase if the population is small Small populations are more likely to have restricted gene pool founder effect Small populations can change more rapidly by both genetic drift and natural selection 0 Sympatric Speciation Species evolve without geographic isolation species remain together with potential to interbreed Probably associated with a genetic barrier due to a single mutational event Important in plants but not widespread among animals More difficult than allopatric speciation because it requires a subdivision of the gene pool of a single population Keeping those subdivisions isolated requires special circumstances 0 Segregation of habitat 0 Major alterations in mate recognition or behavior 0 Genetic incompatibility Accidents during cell division that lead to extra chromosome sets are one mechanism of sympatric speciation Polyploidy is the condition of having extra sets of chromosomes Evolution is how organisms change over time 0 Some polyploid plants have more than one parent species Pace of Speciation Gradualism o Mechanism envisioned by Darwin Slow and steady accumulation of small changes leads to Curvier Lines production of species over vast stretches of time Leads to the prediction that the fossil record should show numerous forms in a continuous series of change from ancestral to descendant species Punctuated Equilibrium o Mechanism proposed by Eldredge and Gould Species diverge in spurts of rapid change followed by long periods of stasis Leads to the prediction that the fossil record should show the most drastic changes in appearance at the time that new species branch from parent species Unfortunately the fossil record does not support the hypothesis that speciation occurs as a gradual process Fossil species show remarkable consistency of form over long periods of time New species appear suddenly Old species disappear suddenly Evolution incorporates both gradual and punctuated episodes 0 Gradual changes include microevolution the changes in allele frequencies within populations These changes may not be preserved in fossil record eg sickle cell anemia or moth coloration 0 Rapid changes include macroevolutionary events such as the production of new species through polyploidy or through other genetic mutations Because rapid changes can take thousands of years many have resulted from microevolutionary processes Straight Line Reproductive Barriers Prezygotic barriers prevent mating or fertilization between species 0 Can result from natural selection Temporal isolation o Mate at different times of year Habitat isolation o Occupy different habitats land water Behavioral isolation 0 Blue footed boobies and many other animals use complex courtship displays in selecting mates Because other species cannot mimic these displays offspring are not produced Mechanical isolation 0 Differences in the shapes of their shells prevent them from succeeding Snails Gametic isolation 0 Although the sperm and eggs of these two sea urchin species are released into the water they are unable to fuse because the proteins on the surface of the eggs and sperm cannot bind to one another Postzygotic barriers prevent survival or reproduction of hybrid offspring 0 Not the result of natural selection May be instrumental in selection for prezygotic barriers Hybrid inviability 0 Different salamander species sometimes mate but the offspring fail to complete development Hybrid sterility 0 Different species may mate and produce viable offspring that are sterile preventing further mixing of gene pools Mules Hybrid breakdown o The first generation of hybrids may be both viable and fertile but due to genetic factors the offspring of these hybrids are weak feeble or sterile Changes that can lead to speciation can involve development and expatiation Evodevo is the scientific interface between evolutionary biology and the study of embryonic development 0 Naming Species Species Panthera pardus El E1 quot39 Family Felidae 13 IE IZIIZIEI Order Carnivora Domain Eukarya Archaea 1 st En Inna Humanuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu uh0p87 1 Domain Eukaryota Kingdom Animilia Phylum Chordata M Mammalia Order Primates Family Hominidae Genus Homo 93991953quot 51 Sapiens CHAPTER 18 Ecology o Is the scientific study of the interactions between organisms and their environments Environment 0 The abiotic componen The nonliving chemical and physical factors in an environment Energy source Temperature Water Wind Rocks and Soil 0 The biotic componen The living factors in an environment Four levels of Ecology 1 Organismal ecology Is concerned with evolutionary adaptations that enable individual organisms to meet the challenges posed by their abiotic environments 2 Population ecology Is concerned with populations groups of individuals of the same species living in the same area Concentrates mainly on factors that affect population density and growth 3 Community ecology Is concerned with communities assemblages of populations of different species Focuses on how interactions between species affect community structure and organization 4 Ecosystem ecology Is concerned with ecosystems which include all the abiotic factors in addition to the community of species in a certain area Focuses on energy ow and the cycling of chemicals among the various abiotic and biotic factors 0 The biosphere I Is the global ecosystem 0 Global distribution patterns Re ect regional differences in climate and other abiotic factors 0 Habitats Are specific environments in which organisms live 0 Three types of adaptations Enable organisms to adjust to changes in their environments 1 Physiological o The ability to acclimate 2 Anatomical 0 Some type of change in body shape or anatomy 3 m o Respond to change in the environment by moving to a new location 0 Population ecology o Is the study of how members of a population interact with their environment 0 Focuses on factors that in uence a population s size growth rate density and structure Biomes o A major terrestrial or aquatic life zone characterized by vegetation type in terrestrial biomes or the physical environment in aquatic biomes Aguatic Biomes o Freshwater biomes Lakes streams rivers and wetlands Salinity Usually a salt concentration less than 1 Use for drinking water crop irrigation sanitation and industry Two categories 0 Standing water Includes lakes and pond o Flowing water Includes rivers and streams 0 Marine biomes Oceans intertidal zones coral reefs and estuaries Salinity Usually a salt concentration 3 o Wetlands Transitional biome between an aquatic ecosystem and a terrestrial one Among the richest of biomes in species diversity 0 Estuaries Are areas where a freshwater stream or river merges with the ocean Are one of the most biologically productive environments on Earth Terrestrial biomes are determined primarily by climate especially temperature and rainfall o If the climate in two geographically separate areas is similar the same type of biome may occur in them 0 Are named for major physical or climatic features and for their predominant vegetation The Water Cycle All parts of the biosphere are linked by the global water cycle and by nutrient cycles Tree Line Altitude effects vegetation and animal distribution Geographic Range 0 The area over which a species is found 0 Limitations Competition for resources Intolerable conditions Physical obstacles 0 Sustainable development Balances human needs with the health of the biosphere CHAPTER 19 Population 0 Group of individuals of a single species that occupy a defined area Population Ecology 0 Study of factors that affect population density and growth Population Density 0 Is the number of individuals of a species per unit of area or volume 0 Measuring Markrecapture method Animals are trapped marked and then recaptured after a period of time Population Age Structure The age structure of a population is the proportion of individuals in different age groups Breeding male fur seals thousands h The age structure of a population can help us understand the history of a population s survival or reproductive success and how it relates to environmental factors Also a useful tool for predicting future changes in a population Population Growth Model The growth rate is the change in population size per time interval Exponential Growth Model Describes the rate of expansion of a population under ideal unregulated conditions Key feature is the rate at which a population grows depends on the number of individuals already in the population Logistic Growth Model The reality of a Limited Enviroment 500 A O 450 0 400 350 39 300 250 200 Population size N 150 100 In nature a population may grow exponentially for a while but eventually one or more environmental factors will limit its growth Populationlimiting factors restrict population growth Describes growth of an idealized population that is slowed by limiting factors L O on O5 1915 1925 1935 19 Biotic potential Maximum rate of growth of a population under ideal conditions Determined Number of offspring produced by each member Length of time individuals reach reproductive maturity Raito males to females Number of reproductive age individuals Usually follows Exponential Growth Curve I shape Exponential Growth Rate 0 Population doubles repeatedly over similar time periods 0 How to calculate M Divide 72 by the growth rate per year Human Population Growth 0 Increased biotic potential factors Agricultural development Improved medical care Vaccines Antibiotics Improved transportation Improved housing 0 O O Advances in communication 0 Rate is 12 year Carrying Capacity 0 Is the number of individuals in a population that the environment can just maintain with no net increase or decrease The US Endangered Species Act Defines an endangered species as one that is quotin danger of extinction throughout all or a significant portion of its range Defines a threatened species as one likely to become endangered in the foreseeable future CHAPTER 20 Community Is an assemblage of species living close enough for potential interactions Interspecific Competition May occur when two or more species in a community rely on similar limiting resources May limit population growth of the competing species 0 Ecological Niche Is the sum total of a species use of the biotic and abiotic resources in its environment Is the species ecological role Russian ecologist G F Gause studied the effects of interspecific competition in two closely related species of protists o This concept is the Competitive Exclusion Principle Simply stated two species cannot coexist in a community if their niches are identical There are two possible outcomes of competition between species with identical niches 1 Extinction of one species 2 Evolution of one species to use a different set of resources Predator Interaction in which one species the predator kills and eats another the prey 0 Many predators Have adaptations such as claws teeth fangs stingers or poison to help catch and subdue prey Are fast and agile Most predators have acute senses Defenses for prey 0 Passive defenses such as hiding Camou age or cryptic coloration Makes a potential prey difficult to spot against its background 0 Active defenses such as escaping Distraction displays 0 Direct the attention of the predator away from a vulnerable prey to another prey that is more likely to escape 0 Mechanical defenses such as hard shells or quills Animals with chemical defenses are often brightly colored This is a caution to predators called warning coloration Mimicry Is a copycat adaptation in which one species mimics the appearance of another 0 Coral VS King snake o Behavioral defenses include Alarm calls Mobbing Mutualism symbiotic relationship Both species benefit from an interaction 10 loss at o Anemone and Clown fish each level Trophic structure x r f Divides species in a community based on their v l k consumers main sources of nutrition A food chain is the sequence of food transfer between trophic levels 0 Detritivores Consume detritus often known as scavengers o Decomposers fungi Secrete enzymes that digest molecules in organic material fungi and bacteria Derive their energy from the dead material left by all trophic levels 0 Eutrophication Rapid growth of plant life leading to death of animal life resulting I i J1 Carnivore Tertiary consumers M C Carnivore 39 7 ex Secondary consumers r V Carnivore from excessive organic or Pr39marli consumers 1norgan1c nutr1ents Food Webs L gt y Producers 39 J Phytoplankton A terrestrial food chain A marine food chain The feeding relationships in an ecosystem Are typically not as simple as in an unbranched food chain Are usually woven into elaborate food webs o Humans rely on biodiversity for I Food clothing shelter I Oxygen soil fertility medicinal substances Biological magnification Is a process in which toxins become more concentrated in successive trophic levels of a food web Ex accumulation of mercury in fish 0 We I Is the use and reuse of chemical elements within the ecosystem Quaternary tertiary and secondary consumers Tertiary and secondary consumers Secondary and primary consumers Primary consumers quotquot i r I u Producers plants 39 1 i Producers get 2 Energy from Energy Pyramids Sunlight Energy ows through an ecosystem when consumers feed on producers 0 Cannot be recycled within an ecosystem but must ow through continuously 0 Limits the length of food chains I The diversity of a community has two components 1 Species richness the total number of different species in the community 2 Relative abundance of the different species Four main nutrients that cycle And problems 1 Carbon Cycle Since the Industrial Revolution the concentration of C02 in the atmosphere has been increasing due to the burning of fossil fuels and wood and to deforestation 2 Phosphorous Cycle Sewage treatment facilities and fertilizers Also add large amounts of phosphates to aquatic systems causing eutrophication of lakes 3 Nitrogen Cycle Sewage treatment facilities and fertilizers Add large amounts of nitrogen to aquatic systems causing heavy growth of algae 4 Water Cycle Destruction of tropical rain forest Will change the amount of water vapor in the air May alter local and global weather patterns Causes of Declining Biodiversity Habitat Destruction Invasive Species Overexploitation of wildlife quotWe do not inherit the earth from our ancestors we borrow it from our children
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