Evolution concepts and mechanisms

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Evolution concepts and mechanisms

  1. 1. AP Biology Rapid Learning Series - 12 Rapid Learning Center Chemistry :: Biology :: Physics :: Math Rapid Learning Center Presents … p g Teach Yourself AP Biology in 24 Hours *AP is a registered trademark of the College Board, which does not endorse, nor is affiliated in any way with the Rapid Learning courses. Evolution: Concepts o ut o Co cepts and Mechanism AP Biology Rapid Learning Series Wayne Huang, PhD Andrew Graham, PhD Elizabeth James, PhD Casandra Rauser, PhD Jessica Habashi, PhD Sara Olson, PhD Jessica Barnes, PhD Rapid Learning Center www.RapidLearningCenter.com/ © Rapid Learning Inc. All rights reserved. © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 1
  2. 2. AP Biology Rapid Learning Series - 12 Learning Objectives By completing this tutorial, you will learn about: Understand the concept of Evolution. Apply the concept to your life and the environment around you. Hone your skills of analysis by judging the soundness of Darwin’s theory of Evolution. 3/37 Evolution Concept Map DNA Chemical Structure Genes Mendelian Laws Chromosomes Meiosis Structure Independent Assortment Law of Seg egat o Segregation Function Mitosis 4/37 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 2
  3. 3. AP Biology Rapid Learning Series - 12 Descent with Modification Define “Descent With Modification” Natural Selection Inheritance Descent with Modification Evolution is the change in inherited traits of a population. Changes in genes are a function of mutations and selection. Selection acts on the “generations”. Bacteria with a life span of 20 – 45 minutes will evolve more rapidly then an organism that requires years to produce new generations. 6/37 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 3
  4. 4. AP Biology Rapid Learning Series - 12 Natural Selection To understand Darwin’s theory you need to understand the meaning of : descent, descent modification and natural selection. Modification M difi ti Modification is a mechanism or process of interaction between the environment and an organisms heritable constitution adaptation Descent Refers to the idea that current day organisms arose from older ancestral species over time. Natural Selection The process in which favorable traits that are heritable become more common in subsequent generations. 7/37 Definition of Inheritance Heritable and inheritance describes a trait that can be passed down from one generation to the next. This includes hair color, height etc. l h i ht t 8/37 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 4
  5. 5. AP Biology Rapid Learning Series - 12 Modification = Natural Selection The main mechanism of modification is via “Natural Selection”. Random variation of traits in a population Adaptation more offspring y g carrying advantageous traits 9/37 Interaction of species with environment Differential reproductive success of species carrying particular traits Natural Selection Targets Natural selection acts on the phenotype which is the observable characteristics of an organism. Individuals with favorable phenotypes are more likely to survive and reproduce than those with less favorable phenotypes. f bl h t Over time this will result in an “adaptation” which causes the organism to specialize for a certain niche. This can even lead to the emergence of a new species. 10/37 If the phenotype is due to a genetic difference that genotype will be selected for and its frequency in the next generation increased. © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 5
  6. 6. AP Biology Rapid Learning Series - 12 Genetic Variation and Selection Genetic variation can occur when different organisms of a population have different versions of a gene (allele). (allele) Beak variation is an example. Some traits are the result of a single gene. Most traits are a result of interactions of many genes. Pleiotropy happens when a single gene influences many different phenotypic traits. A new mutation in the gene will have effects on all traits simultaneously. Genetic linkage occurs when particular alleles are inherited together. 11/37 Origin of the Species Evolution and speciation Species origin Phylogenetic tree © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 6
  7. 7. AP Biology Rapid Learning Series - 12 Speciation & Origin A species is a taxonomic group who's members can interbreed and produce fertile offspring. Speciation is the evolutionary process giving rise to a new species. There are four modes of natural selection that give rise to a new species and involves geographic isolation: allopatric, peripatric, parapatric and sympatric. New species may also be produced by genetic engineering and animal husbandry. 13/37 Kinds of Geographic Speciation Allopatric speciation, a population is split into two geographically isolated ones. The isolated populations then undergo l ti th d genotypic divergence. Peripatric speciation a new species is formed in small isolated peripheral populations which are prevented from exchanging genes with the main population. 14/37 Parapatric speciation, the geographic zones of the two diverging populations are separate but do overlap. Individual of each species may come in contact or mate but the fitness of the heterozygote is reduced so selected against. Sympatric speciation species diverge while inhabiting the same place e.g. insects which become dependent on different host plants in the same area. © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 7
  8. 8. AP Biology Rapid Learning Series - 12 Phylogenetic Tree of Life A phylogenetic tree is a branching graph that shows the evolutionary interrelationships between species and shows the common ancestor. Each node represents the most recent common ancestor of the descendants. The lengths of the branches are time estimates. 15/37 Phylogenetic Tree Speciation events are shown in this phylogenetic tree. The relationship between ancestor and descendant is based on the number of shared characteristics h d h i i between them. Old world monkeys k New World Monkeys Pro-simians Gorillas Gibbons Orangutans Gibb Chimpanzees Humans 16/37 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 8
  9. 9. AP Biology Rapid Learning Series - 12 Darwin’s Theory Reproduction Genetic variation Darwin’s Hypothesis Reproduction Effects on Evolution Sir Darwin, can you y tell me about your observations that lead you to the theory of evolution? First I observed that reproducing organisms will produce more offspring then the environment can pp p g support if all offspring survive to reproduce. This is the struggle for existence. 18/37 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 9
  10. 10. AP Biology Rapid Learning Series - 12 Darwin & Genetic Variation Sir Darwin how does genetics impact your theory? I observed that for any given population of individuals there is a range of heritable characteristics. 19/37 Survival & Inherited Traits How does an organism’s traits effect a species? 20/37 Survival depends on an organisms inherited traits. If a trait or set of traits enables an organism to survive and g reproduce that species will survive. See these birds? Ability to fly high and hunt will be helped by big wings in some environments. In other environments like dense forests smaller wings will have the advantage. © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 10
  11. 11. AP Biology Rapid Learning Series - 12 Darwin’s Hypothesis The hypothesis states that the attributes leading to a better fit in an environment leads to a greater chance of survival and leaving behind viable offspring. Disproportionate reproductive success within population members gradually leads to a change in traits of that particular population. 21/37 Support for Darwin’s Hypothesis How can you test your theory? The theory is tested by looking into the fossil record and studying taxonomy. By comparing embryological and anatomical information similarities and ancestry can be discovered. Today with modern molecular biology techniques, it is possible to determine evolution on the basis of genetics. 22/37 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 11
  12. 12. AP Biology Rapid Learning Series - 12 Fossils and Evolution Support Fossils are ancient impressions left by biological forms in sedimentary rock rock. These impressions often reveal the skeletal framework of an extinct species. 23/37 Fossil Records Younger fossils have species with traits common to older fossils plus some additional traits or similar traits reorganized. The oldest fossils record the oldest species living. Jurassic "clams" Cretaceous ammonite Cretaceous ichthyosaur Miocene beaver skull 24/37 Pleistocene saber toothed cat Fossil record indicates that there are shared traits between ancestors and descendants. This supports Darwin’s theory. Pleistocene mammoth © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 12
  13. 13. AP Biology Rapid Learning Series - 12 Taxonomy Science of Classification Taxonomy is the science of classification. It is a hierarchical grouping of organisms with descending i ith d di categories having more specific characteristics. Organization is based on similarity of traits. 25/37 Taxonomic Groupings The taxonomic grouping support Darwin’s theory that all species within a group can be shown to be related to one another. Taxonomic groupings are by shared traits among different species leading to evolutionary relatedness. Flowers having similar traits would be grouped together. 26/37 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 13
  14. 14. AP Biology Rapid Learning Series - 12 Comparative Taxonomy Comparative Anatomy, Embryology: These lines of evidence involve making comparisons of various structures and i f i t t d determining the degree of similarity among them. For Example, flippers, wings, paws, hands. All have similar bone structures, despite overall external differences - Remember descent with modification 27/37 Genetics & Darwin’s Theory Mechanisms of genetic evolution include: natural , , selection, mutation, random genetic drift and gene flow. Genetic evolution refers to the change in the frequency of a gene or alleles in a population. Natural selection is the best explanation for genetic evolution. evolution Once gene frequencies change and adaptation due to natural selection occurs, advantageous genes will be selected again and again because of directional selection. 28/37 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 14
  15. 15. AP Biology Rapid Learning Series - 12 Evidence Summary Types of Evidence Does the evidence corroborate Darwin’s Theory Darwin s Fossil Record Yes Taxonomic Groups Yes Independent Traits Yes Y Genetics Yes 29/37 Modern Evolutionary Theory Variations of evolutionary theory. Environmental effects and selection. © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 15
  16. 16. AP Biology Rapid Learning Series - 12 Variations on Evolutionary Theory My original theory believed that evolution was a very gradual p process. Referred to as gradualism. Today evidence shows that evolution may be better characterized by punctuated equilibrium. A spurt and plateau pattern. Darwin 31/37 Environment and Evolution The ecosystem plays a bigger role in stimulating accumulation of new species then was previously thought. Yes, an example is dinosaur extinction which is thought to be a consequence of climate change. Environmental changes can select for new traits required by that environment and lead to new species formation. 32/37 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 16
  17. 17. AP Biology Rapid Learning Series - 12 Gene Flow & In Breeding There are other mechanisms of species modification that have a minor role in evolution of species. These include: gene flow and non nonrandom mating (in breeding). Gene flow: individual species breed outside their native group. ti Non random mating: in breeding mating is not random. 33/37 Question: Review The process in which favorable traits become more frequent. Natural selection ___________ The science of classification. Taxonomy ___________ What record supports Darwin’s hypothesis? Fossil record ___________ Evolution is characterized by spurts and plateaus, this is t d l t thi i known as what? Punctuated equilibrium ___________ Minor mechanisms of evolution include these. Gene flow, in-breeding ___________ 34/37 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 17
  18. 18. AP Biology Rapid Learning Series - 12 Learning Summary Darwin’s theory may be described as “descent with modification”. The major force in evolution is natural selection Survival of the fittest means an organism can create offspring that are viable. Genetic variation can occur when different organisms of a population have different versions of a gene (allele). The fossil record and molecular biology support Darwin’s theory. Congratulations You have successfully completed the core tutorial Evolution Rapid Learning Center © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 18
  19. 19. AP Biology Rapid Learning Series - 12 Rapid Learning Center Chemistry :: Biology :: Physics :: Math What’s N t Wh t’ Next … Step 1: Concepts – Core Tutorial (Just Completed) Step 2: Practice – Interactive Problem Drill Step 3: Recap – Super Review Cheat Sheet Go for it! 37/37 http://www.RapidLearningCenter.com © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 19

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