Modern Biology II- Exam 1
Modern Biology II- Exam 1 BIO 1421 - 005
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This 7 page Study Guide was uploaded by Angela O. on Tuesday September 20, 2016. The Study Guide belongs to BIO 1421 - 005 at Texas State University taught by Kavita S. Kakirde in Fall 2016. Since its upload, it has received 8 views.
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Date Created: 09/20/16
Exam 1 Study Guide Objective vs. Subjective Objective Science helps answer by research and polls Ex.) What is the most common car people drive? Subjective Cannot be answered based on science, depends on personal opinions Ex.) Which religion is the most accurate? Science Is: Similar to being a detective Answer questions about the natural world Study of the natural world and its phenomena Objective and measurable world around us Lots of data supporting scientific evidence Not: No questions about crimes Not a collection of facts Cannot answer questions about immeasurable things (subjective) Scientific Method Hypothesis Tentative explanation for observations Testable Ask question based on observation Prediction Based on hypothesis If/then statement Experiment Observation Allows you to collect data Draw conclusion Is hypothesis supported or not? Peer review Other scientists evaluate validity of methods, data, and conclusions Variables, confounds, controls Variable: One variable being tested Ex. In fly experiment, variable included the gauze Confound: Something that messes with accurate results Ex. Non consistent variables Control: Something that does not change Ex. In fly experiment, controls included time, temperature and place Repeatability, bias Repeatability is essential Scientific conclusions more reliable if can be repeated Followup studies may reveal flaws Scientific theory vs. every day theories and facts Theories: explain things in the natural world scientific theory: explanation in natural world that has been repeatedly tested, well supported, uses facts everyday usage: “educated guess” Facts: only describe things in the natural world Pseudoscience scientificsounding claims mistakenly or falsely regarded as being based on scientific method not supported by trustworthy scientific studies ex.) based on inappropriate study, accidentally getting it wrong, misinterpreted, not based on research, madeup results Biology and Characteristics of living things Biology: scientific study of living things Living things: organization requires energy and nutrients reproduce growth develops homeostasis responds to stimuli evolves Prokaryotic vs. Eukaryotic Prokaryotic: no nucleus, lack of membrane bound organelles Eukaryotic: with nucleus Autotrophs vs. Heterotrophs Autotrophs: produces own food Heterotroph: consume other living organisms Three domains of life, and subdivision Eukarya Bacteria Archaea Eukarya Evolution: a change over time in the characteristics of a population “descent with modification” Plato & Aristotle: evolutionary ideas, started classifying organisms Darwin & Wallace: species arise due to natural selection Buffon: species change when they spread from original location Hutton: changes in nature are gradual Lamarck: new species come from existing species through environmental forces, acquired characteristics Cuvier: fossils represent extinction Lyell: all changes in nature are gradual Principle of superposition and fossils: new rock overlays older rock fossil record separated by rock layers showed how life changed over time Variability within populations: all organisms are unique, variations arise from mutations Heritability: traits passed on from parent to offspring; inheritance Reproductive success: because of limited resources, illness, defects, etc., more offspring are born than survive; some have more offspring than others Homologous vs. Analogous: Homologous: same origin different appearance different function Analogous: different origin same function Vestigial: when a structure comes to have no function at all evolutionary leftovers Convergent evolution: analogous structures when structures come to serve similar functions Natural selection: Artificial selection: controlled breeding to produce favorable traits human involvement Observations: nonhuman interference guppies evolved to become more colorful in predator free environments insects evolved to resist pesticide Experiments: human interference lizards were moved to new habitat and adapted to have shorter thinner legs when predators were introduced into guppy environment, they became less colorful fruit fly experiment Fitness= reproductive success Genetics of evolution changes occur from generation to generation, causing descendants to differ from their ancestors occurs because of heritable genes Genes: Sections of DNA (located on chromosomes) that give an organism its traits Eukaryotes 2 copies of every gene Prokaryotes 1 copy of every gene Different versions of genes Alleles: Different versions of genes 1 allele from each parent Each gene has from 1100 different alleles Homozygous: 2 matching alleles Heterozygous: 2 different alleles The dominant allele will mask the recessive allele. Genotype: 2 alleles carried by an organism (genetic makeup) Phenotype: how alleles are expressed (how they show up) Gene pool= all the alleles from all of the genes in all of the individuals Allele frequency= number alleles/gene pool Major causes of evolutionary change: Mutationspontaneous changes in the DNA Gene flow movement of alleles from one population to another Nonrandom mating choosing mates based on preferences and bias Genetic drift change in allele frequencies by chance Population bottleneck: drastic reduction in population size brought about by a natural catastrophe or overhunting; causes lack of variation Founder’s effect: when a small number of individuals leave a large population & establish a new isolated population; over time might exhibit new allele frequencies Competition: interaction among individuals who attempt to use or gain a limited resource Coevolution: constant, mutual feedback between 2 species, exerting intense natural selection; predatorprey relationships Sexual selection: a type of natural selection resulting from variation in the ability to obtain mates Intrasexual selection: members of one sex competing among themselves for members of the opposite sex Intersexual selection: members of one sex (usually females) choose mates based on preferences for certain traits Patterns for evolutionary change: Directional favors individuals with extremevalue trait (Ex. Either light OR dark) Stabilizing favors individuals with average value trait (ex. Medium birth weight) Disruptive favors individuals at both extremes of a trait (ex. Light AND dark) Species: Originally, “if two organisms look similar, they must be the same species”, i.e. based on appearance, however there are misleading appearances. Biological species concept: a group of organisms who can potentially interbreed and produce fertile offspring Exceptions o Asexual reproduction o Extinct organisms o Successful interbreeding with different species in the wild o Successful breeding in captivity that wouldn’t happen in nature Reproductive isolation: Premating isolation o Geographical isolationdifferent places o Ecological isolationdifferent habitats o Temporal isolation breed at different times o Behavioral isolation different courtship signals/mating rituals/ behaviors o Mechanical isolation reproductive structures incompatible Postmating isolation o Gametic incompatibility sperm from one species cannot fertilize eggs of another o Hybrid inviability hybrid offspring fail to survive maturity; miscarriages; born but unable to reproduce o Hybrid infertility hybrid offspring are sterile or reduced fertility Speciation: process by which new species form Reproductive isolationprevents gene flow Genetic divergence driven by genetic drift, mutations, nonrandom mating and natural selection Allopatric speciation isolating mechanism is a physical barrier (separation) Sympatric speciation isolation occurs without geographical separation; 2 distinctly different habitats (ecological isolation) o Simple forking pattern: similar to usual family tree, most common, new species come about over long periods of time o Adaptive radiation: rise of many new species over relatively short period of time Extinction: death of all members of a species Causes: o Habitat loss o New predators o New diseases o Catastrophes o Less variation, higher risk o Climate/environment changes o Human interaction****leading cause**** VIDEO Sickle cell anemia changes the shape of red blood cells, crescents instead of discs. Anthony Allison noticed most people with sickle cell anemia lived the same regions as malaria. People with sickle cell anemia were immune to malaria. Sickle cell anemia compromises the ability of the parasite to reproduce.
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