Exam 1 Review Sheet Chapter 1 Life Chemical Cellular and Evolutionary Foundations 1 What is the scientific method The Scientific Method is a deliberate way of asking and answering questions about the natural world What are the steps Observations Hypothesis Predictions Experiments Theory 1 Observations the phenomenon that you see occurring in the world around you It allows you to ask a pointed question about a particular aspect of nature 2 Hypothesis a tentative explanation or reason your observation occurs A hypothesis differs from just a guess in two important ways 1 a hypothesis makes predictions as to the results of experiments or other new observations yet unseen and 2 because a hypothesis makes predictions it can be tested 3 Predictions allow the hypothesis to be tested experimentally and can often be answered by yes or a no To test the prediction and ultimately the hypothesis you need to run experiments or make new observations 4 Experimentation a disciplined and controlled way of asking and answering questions about the world in an unbiased manner The hypothesis can be rejected or supported at this point If the original hypothesis is rejected based on your experiments or new observations a new hypothesis can be formulated which would then be tested A test result or an observation that supports the initial hypothesis makes the hypothesis less tentative and more certain 5 Theory is when a hypothesis is supported again and again overtime through experiments and observations it will usually be regarded as an acceptable explanation for what we initially observed At this point the hypothesis becomes a theory For example the theory of evolution has been tested for more than a century and shown to be supported explanation of many biological observations Be able to distinguish between them if given an example What is the difference between a hypothesis and a theory A hypothesis is an explanation of that observation or event that predicts the results of experiments or new observations that will be tested A theory is a broad explanation that accounts for a number of related hypotheses that have been repeatedly supported through vigorous testing often over a long period of time Observations are used to generate a hypothesis a tentative explanation that makes predictions that can be tested On the basis of a hypothesis scientists design experiments and make additional observations that test the hypothesis If a hypothesis is supported through continued observation and experiments over long periods of time it is elevated to a theory a sound and broad explanation of some aspect of the world 2 What are the characteristics of living things Some of the characteristics of living things are consists of one or more cells contain genetic information capable of reproduction capable of metabolism capable of homeostasis are generally related and have evolved can harness energy from the environment complex and change in response to the environment Are viruses living things Why or why not Viruses can t harness energy from the environment so they are not living 3 What is the fundamental unit of life The fundamental unit of life is the cell The cell is the simplest biological entity that can exist independently Information in a cell is stored in the form of the nucleic acid DNA The central dogma describes the usual flow of information in a cell from DNA to RNA to protein What is the difference between a prokaryotic and eukaryotic cell Cells with a nucleus are eukaryotes cells without a nucleus are prokaryotes 4 What is metabolism Metabolism is the set of chemical reactions that are used by cells to build and break down macromolecules and to harness energy What is a plasma membrane The plasma membrane is the boundary that separates the cell from its environment Chapter 21 Evolution 1 What is a phenotype A Phenotype refers to the characteristics or traits of an organism that can be observed such as the color of a flower s petals or a person s height Phenotypes are determined both by an organism s underlying composition of alleles also known as its genotype and by the environment What is a genotype Genotype is an organism s underlying composition of alleles What is responsible for the visible differences between individuals of a species Phenotype A Mutation is heritable change in the genetic material usually a change in the nucleotide sequence of a gene What is the difference between a somatic and germ line mutation Somatic mutation is a mutation that occurs in somatic cells and they are cells that don t give rise to gametes Germ line mutation is a mutation that occurs in eggs and sperm or in the cells that give rise to these reproductive cells and therefore is passed on to the next generation 2 What is a mutation 3 What are alleles the population The different forms of a gene corresponding to different DNA sequences in each different forms How are new alleles created 4 What is an allele frequency An allele frequency is the number of occurrences of a particular allele divided by the total number of occurrences of all alleles of that gene in a population The rate of occurrences of an allele in populations What do population geneticists study Population geneticists study Genetic Variation and Genetic Population They are going to study organisms in the same area 5 What are the 5 assumptions of the Hardy Weinberg equilibrium a There can be no selection meaning that all genotypes must be equally likely to survive and reproduce within the population There will be no differences in the survival and reproductive success of individuals b There can be no migration of individuals into or out of the population Populations must not be added to or subtracted from by migration c There can be no mutation in the DNA sequence of any individuals in d The population must be sufficiently large population to avoid chance e events altering the allele or genotype frequencies Individuals within the population must mate randomly with one another regardless of their genotype 6 What causes allele frequencies to change Allele frequencies change in response to Natural Selection migration mutation and genetic drift These are the primary mechanism of evolution 7 Who developed the theory of evolution Charles Darwin and Alfred Russel Wallace developed the theory of evolution What is natural selection 1 Natural selection is the differential reproductive success of genetic variants 2 It is the process in which when there is inherited
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