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Prepare for the Biology 202B final exam with this comprehensive review. Topics covered include RNA and DNA, genetic code preservation, adaptation, natural selection, and evolution of populations.
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Review for Final Exam Biology 202B 5/28/13 Materials Needed: paper, pencil/pen and calculator Ext. 3026 Ext. 3124
Work Schedule For Mrs. Ulry’s students
Final Exam In Summary… 100 total points 20 questions Multiple choice format 5 questions from each unit (1,2,3 &4)
Need to Know Topics Unit 1 Differences between RNA and DNA Functions for RNA Cell Location for: DNA, RNA, transcription, translation, protein synthesis Processes for preserving genetic code Polygenetic traits
Need to Know Topics Unit 2 Adaptation Genetic Drift Natural Selection Dichotomous Keys Phylogenetic Trees (aka cladograms)
DNA RNA ~BOTH~
DNA RNA ~BOTH~ Carries genetic Info Found in both the nucleus and cytoplasm. Never moves out of the nucleus. Four nitrogenous bases Protein synthesis
DNA or RNA? • Explain how you Know! Pic D Pic A Pic C Pic B
DNA or RNA? • Deoxyribonucleic Acid (DNA) • Stores genetic code • Double Helix • Ribosomal RNA (rRNA) • Part of the structure of the ribosome • Plays a role in protein production • Messenger RNA (mRNA) • Single Strand • Copy of the genetic code (DNA) • Made through transcription • Transfer RNA (tRNA) • Identifies which amino acid the mRNA is coding for and brings it over to the growing strand
~ Word Bank: Amino Acids, Growing Protein, Nucleus, Ribosome, mRNA, tRNA
Nucleus Amino Acids Growing Protein tRNA mRNA Ribosome
Polygenetic Traits • Several genes contribute an equal, small degree towards the resulting phenotype Examples: skin color (3 or more genes) Height Hair Color Eye Color
Which characteristic is most important for preserving the code from one generation to the next? • Offspring only receive one exact copy of a DNA molecule from each parent • Each time DNA replicated, the same base pairing rules are followed C. DNA backbones are the same for parents and offspring. D. DNA remains in the nucleus for replication
Which characteristic is most important for preserving the code from one generation to the next? • Offspring only receive one exact copy of a DNA molecule from each parent • Each time DNA replicated, the same base pairing rules are followed C. DNA backbones are the same for parents and offspring. D. DNA remains in the nucleus for replication
Evolution of Populations • Gene pool: all the genes from a specific population of organisms • Includes all the different alleles for each type of gene • Ratios of alleles can change over time and influence the population … If the white-white combination causes death, then the new ratio would be 75% black and 25% white allele… Gene Pool in this example has 60% black allele and 40% white allele
Genetic Drift Genetic Drift Genetic drift is a random change in allele frequency that usually leads to a loss of genetic variation.
Natural Selection • The process of some factor in the environment favoring one group of individuals with one kind of allele over another group of individuals with a different kind of allele.
What is an Adaptation? Differences! • Wings longer than body • Thorax & abdomen striped • Red eyes • Wings white • White eyes • Wings black • Wings shorter than body • Thorax striped & abdomen black. Variety…
Natural Selection explains Evolution • Natural selection leads to a change in allele frequencies. When an environment changes, the organisms must change too. The alleles that are favored are passed onto future generations. • Over time, we see these alleles cause changes and adaptations in whole populations of organisms. • This process of change in organisms’ genetics or allele frequency = evolution.
Process of Evolution Organisms that are “fit”, survive, and reproduce • “fit” in that their specific adaptations fit the environment in which they are living best (or better than others in their species), therefore – • they survive, and • reproduce and propagate the species. • There is no disagreement on this point of evolution (i.e. natural selection), sometimes referred to as “micro-evolution.” • Examples abound – Cane Toad in Australia (longer vs. shorter legs), insects becoming resistant to DDT, or bacteria becoming resistant to antibiotics. http://evolution.berkeley.edu/evolibrary/article/_0/evoscales_03
Polling Time! Natural selection acts on the variation in populations of living things, usually through a specific trait. Which statement must be true about that trait? • All forms of the trait have the same impact on survival. • The trait is passed on genetically to the next generation. • The trait is resistant to mutations. • The trait is the same for all organisms.
Polling Time! Natural selection acts on the variation in populations of living things, usually through a specific trait. Which statement must be true about that trait? • All forms of the trait have the same impact on survival. • The trait is passed on genetically to the next generation. • The trait is resistant to mutations. • The trait is the same for all organisms.
Natural Selection • Process by which organisms with favorable traits will survive and reproduce A.) A population of parakeets that have the same size beak B.) An island with lizards that all look alike and are all eating the same food C.) All insects in a certain desert that have the same adaptation for saving water. D.) A population of salmon with different skin colors that are involved in attracting mates • Whichbest describes natural selection?
Selection • Process by which organisms with favorable traits will survive and reproduce A.) A population of parakeets that have the same size beak B.) An island with lizards that all look alike and are all eating the same food C.) All insects in a certain desert that have the same adaptation for saving water. D.) A population of salmon with different skin colors that are involved in attracting mates • Whichbest describes natural selection?
Genus Buggaboo • Wings longer than body • Thorax & abdomen striped • Red eyes • Wings white • White eyes • Wings black • Wings shorter than body • Thorax striped & abdomen black.
Classification • Taxonomy:science of classification • Grouping based on similarities • Reveals shared evolutionary history between organisms (phylogenetic groups) • Phylogeny: • evolutionary • history
Taxonomy Can you explain this?
Modern Classification • Today, organisms are classified based on many fundamental characteristics … • Cell Type: Prokaryotic vs Eukaryotic • How get/obtain food? • DNA profile • Helps with understanding phylogenetic relationships between organisms
Cladogram The following diagram is found in an evolutionary biology textbook. • new species arise throughout time following rounds of mass extinction. • all species share a common ancestor and that change occurs through time. • speciation occurs very quickly with long periods of no change in between. • all species originated during the same period and some have subsequently gone extinct.
Cladogram The following diagram is found in an evolutionary biology textbook. • new species arise throughout time following rounds of mass extinction. • all species share a common ancestor and that change occurs through time. • speciation occurs very quickly with long periods of no change in between. • all species originated during the same period and some have subsequently gone extinct.
Who is the Common Ancestor? • Most Closely Related • Most Distantly Related
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