Evolution

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Evolution

  1. 1. EvolutionAND THE ORIGIN OF LIFE
  2. 2. KeywordsTHINKS TO KNOW
  3. 3. Species Reproductively isolated systems of breeding populations with similar morphology. In simple terms; organisms, that look the same, that are able to breed and produce fertile offspring.
  4. 4. Adaptation & Mutation Adaptation  The evolutionary process whereby an organism becomes better able to live in its habitat  The change of an organism to be better suited to live in its respective environment Mutation  Changes in the DNA caused by radiation, viruses and errors in DNA replication  A change in the DNA that causes a significant change in the organism’s phenotype or expressed traits
  5. 5. Common Decent, Ancestor & Descendant Common Decent  A group of organisms that share the same ancestor  Organisms that descended from the same organism Ancestor  An earlier type  A progenitor Descendant  A later evolutionary type  The offspring of an earlier organism
  6. 6. Variation and Natural Selection Variation  The difference in characteristics typical of the group  The difference between an organism’s traits and another of the same species Natural Selection  The process where favorable traits become more common in each successive generation  The process where nature selects the traits that best suit the environment the particular organism lives in
  7. 7. Missing Link The intermediate organism between arthropod apes and humans
  8. 8. Genetics, DNA & Genes Genetics  The study of the patterns of inheritance of specific traits DNA  Deoxyribonucleic acid  Contains the genetic material for cell growth, division and function Genes  Segments of DNA that are located on the chromosomes  Controls the traits of an organism
  9. 9. RNA, Allele & Heredity RNA  Ribonucleic acid  Single stranded Allele  One member of a pair of genes occupying a specific part on the chromosome  Can either be dominant of recessive Heredity  The passing on of traits from parent to offspring
  10. 10. Central Dogma, Nucleotides & Proteins Central Dogma  DNA is the carrier of genetic information in organisms. Nucleotides  Structural unit of DNA/RND  Made up of a 5-carbon sugar, a 3-phosphate group and one of 5 nitrogen bases; namely Adenine, Thymine, Guanine, Cytosine and Uracil Proteins  Chains of amino acids
  11. 11. Chromosomes & Genetic Drift Chromosomes  Organized structure of DNA and proteins  Controls the expressed traits of an organism Genetic Drift  A change in allele frequency  Can be caused by a change in the environmental conditions or a change in the reproductive selection of the species
  12. 12. Phylogenetic Tree A branching diagram showing inferred evolutionary relationship
  13. 13. Convergent and Divergent Evolution Convergent Evolution  Different organisms develop similar traits to serve similar functions  Butterfly and Bird. They developed wings for the same purpose. Divergent Evolution  Similar organisms evolve to become more diverse until they eventually become different species  An population becomes separated and each separate population adapts to a different niche and does so until they become two different species
  14. 14. ScientistsWHO CONTRIBUTED TO THE THEORY
  15. 15. Carolus Linnaeus (1707-1778) Swedish Naturalist Nested Hierarchies Order of Nature Systema Naturae (1735) Father of Taxonomy Organized from species to kingdom Two-part Name  Binomial Nomenclature
  16. 16. Carolus Linnaeus (1707-1778)Influenced by Plato  Idealism and essentialism Aristotle  Scala Naturae, The Great Chain of Being  Organisms are arranged in increasing complexity Judeo - Christian  Creationism  Species are individually designed and are permanent
  17. 17. Thomas Malthus (1766-1834) English economist and clergyman “An Essay on the Principles of Populations” Food supply  Arithmetic Population growth  Geometric, logarithmic Food supply limits population growth
  18. 18. Georges Cuvier (1769-1832) French Paleontologist Catastrophism  A catastrophic event leads to extinctions of species that are replaced by distant migrating species Earth’s age  4000 - 6000 Strongly opposed evolution The history of living organisms are recorded in layers of as fossils
  19. 19. Jean Baptiste Lamarck French naturalist Early concepts of evolution Philosophie Zoologique (1809)  Desire to change  Use and disuse  Passing on of acquired traits Species change over time into new species via natural processes
  20. 20. Charles Lyell Scottish geologist Principles of Geology (1830) Uniformitarianism Geological processes are so uniform that their rates and effects must balance outInfluenced by James Hutton (1726-1797)  Gradualism
  21. 21. Gregor Mendel (1832-1884) Austrian Monk Father of genetics Proposed the laws of inheritance Used pea plants with different characteristics
  22. 22. Alfred Russel Wallace British Naturalist Studied in the Amazon Forest and in the Malaysian Isles “On the Tendency of Varieties to Depart from the Original Type”
  23. 23. Charles Robert Darwin English Naturalist Studied in the Galapagos Islands “On the Origin of Species by means of Natural Selection or the Preservation of Favored Races in the Struggle for Life”
  24. 24. EvidencesPALEOEMBRYOANATOGEOCHEMISTRY
  25. 25. Paleontology Organisms evolved in a historical sequence The present id linked to the past Fossils form by chance and the quality varies Fossil reconstruction requires a thorough knowledge of Anatomy Fossil  Preserved remains or traces of organisms Dating rocks and fossils  Geological or relative dating (strata)  Numerical or radiometric dating (isotopes)
  26. 26. Comparative Anatomy Homologous Structures  Features with different functions but similar structure due to common ancestry  Due to divergent evolution  One species gives rise to many species that appear different externally but are similar internally Analogous Structures  Similar in appearance and function but of different origins  Due to convergent evolution  Different organisms develop similar structures to serve the same purpose
  27. 27. Comparative Embryology Closely related organisms often have similar stages or structure during early development Similarities in early development should mean that similar genes are at work This is like a heritage acquired from their common ancestor
  28. 28. Biochemistry Similarity of the DNA between individuals determine their degree of relatedness Based on the concept that similar proteins are based from the same DNA or a common genetic code creates the same protiens
  29. 29. Biogeography Observations about marsupial distribution show that they are only found in America, Australia and New Guinea Species were not distributed everywhere that they could survive Islands have species endemic but are closely related to species on the mainland
  30. 30. The 5 Evidences for Evolution Fossil Record  Paleontology Similarities in Body Structure  Comparative Anatomy Similarities in Early Development  Comparative Embryology Similarities in Chemical Compounds  Biochemistry Distribution of Species  Biogeography
  31. 31. Genetics A G T C U
  32. 32. ScientistsRediscovered Mendel’s work Hugo de Vries Carl Correns Erich von Tshermak-SeyseneggDiscovered the structure of DNA James Watson Francis Crick
  33. 33. Nucleic Acids Polymers made up of monomers called nucleotides There are 2 kinds  DNA – uses A, T, G, C  RNA – uses A, U ,G, C Stores and transmits information from one generation to another Found in the nucleus of all cells
  34. 34. Proteins, Genes & Alleles Protein  Polymers made up of monomers called amino acids  Workhorses of living systems Gene  A segment of DNA that codes for a particular trait  The basic unit of heredity Allele  A particular form of a gene
  35. 35. Genetic Code Set of rules by which information in DNA/RNA is translated into amino acid sequences Red in groups of three called codons
  36. 36. TraitsThere are two kinds of traits Single-gene trait  Only controlled by a pair of genes  There are only two varieties  Example, Presence of the widows peak Polygenic trait  Controlled by numerous genes  Has multiple varieties  Example, Height.
  37. 37. Natural Selection as an Evolutionary Mechanism Overproduction  Each species produce more offspring than will survive to maturity Variation  There is a variation of traits among the offspring Competition  Organisms compete with one another for limited resources Survival to Reproduce  Individuals that passes the most favorable combination of characteristics are most likely to survive and reproduce
  38. 38. Genetic Variation Mutation  Any change in the DNA sequence  Due to an error in DNA replication  Due to environmental factors such as radiation Gene Shuffling / Genetic Recombination  Results from sexual reproduction Genetic Drift  When an allele becomes more common in a population by chance  Implies that all characteristics of an organism don’t have to contribute to the fitness of the organism to be favored
  39. 39. Genetic Variation Natural selection is not always necessary for genetic change to occur Genetic variation is not controlled or directed toward a cause. When a variation does occur, natural selection goes to work If a species has enough genetic variation for it to evolve quickly enough to keep up with the environment, it will survive; if not, it will become extinct
  40. 40. Ecology & Evolution No two species can occupy the same niche in the same location for a long period of time  This idea helps us understand how one species evolves into many species Speciation by Reproductive Isolation  Separation of populations stops interbreeding between the two  Separate populations adapt to different environments so the gene pool becomes dissimilar  The long separation eventually inhibits the interbreeding between the two populations permanently

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