Bio

• Creationism


  Belief that organisms do not change over time
• Carolus Linnaeus


  • Swedish naturalist and explorer
  • First to frame principles for defining natural genera and species of organisms
  • Created a uniform system for naming them, known as binomial nomenclature
• Linnaean System of Classification

  1. Kingdom

  2. Phyla

  3. Class

  4. Order

  5. Family

  6. Genus

  7. Species
• Thomas Malthus


  • English cleric, scholar and influential economist
  • Observed that an increase in a nation's food production improved the well-being of the populace, but the improvement was temporary because it led to population growth, which in turn restored the original per capita production level
• Georges Cuvier


  • Father of Paleontology
  • Theory of Catastrophism - boundaries represent floods, droughts, etc. that destroyed many species living at that time
  • Fossils are remains of extinct life forms
• James Hutton


  • Theory of Gradualism - Profound changes can result from cumulative effect of slow but continuous processes
  • Proposed that the Earth was shaped by geological forces occurring over very long periods of time, and is MILLIONS not THOUSANDS of years old
• Charles Lyell


  • Principles of Geology - argued that the formation of Earth's crust took place through countless small changes occurring over vast periods of time, all according to known natural laws
  • His "uniformitarian" proposal was that the forces molding the planet today have operated continuously throughout its history
• Jean Baptiste Lamarck


  • One of first scientists to recognize that living things changed over time and that all species were descended from other species
  • Proposed that the characteristics that an animal acquired during its lifetime in response to life's struggles or felt needs could be passed on to its offspring
• Charles Darwin's voyage


  1. 22-year old Charles Darwin left England as naturalist aboard the HMS Beagle for 5 year voyage around the world

  2. Noticed plants and animals were different from those he knew in Europe

  3. Wrote thousands of pages of observations and collected vast number of Specimens

  4. Spent a month observing life on the Galapagos Islands and realized that each island has different rainfall and vegetation and its own unique assortment of plant and animal species

  5. Collected 14 species of finches and hypothesized that the Galapagos had be colonized by organisms from the mainland that had then diversified on the various islands
• Charles Darwin's reasoning


  • Assumed that species can change over time
  • Saw that Earth and its life were very old, thus there had been enough time for evolution
  • Knew that populations could grow faster than their resources, leading to a "struggle for existence"
  • Knew that some offspring have variations that occur by chance, and that can be inherited
  • Coined the term fitness to refer to an organism's relative ability to survive and produce fertile offspring
  • Inferred that natural selection could also change species over time, and that if a species changed enough, it might evolve into a new species
• A major obstacle in the acceptance of the idea that organisms change over time was the belief of the general public in the doctrine of creationism
• In 1859, Charles Darwin's book On the Origin of Species by Means of Natural Selection was published, presenting evidence and proposing a mechanism for evolution that he called NATURAL SELECTION
• Many people are unaware that humans have been practicing genetic engineering since the ancient times
• Selective breeding or classical breeding


  Altering the genetic make-up of agricultural crops and livestock over centuries so they no longer resemble their non-domesticated relatives
• This practice has been common long before genes were discovered
• Genetic engineering


  Use of molecular techniques to modify the traits of a target organism, including introduction of new traits or enhancement of present traits
• Genetic Engineering Includes


  • Classical Breeding
  • Recombinant DNA technology (rDNA)
• Recombinant DNA technology


  Joining together of DNA molecules from two different species and inserting the recombined DNA molecule into a host organism
• Steps in Recombinant DNA Technology

  1. Cutting or cleavage of DNA by restriction enzymes

  2. Selection of an appropriate vector

  3. Ligation of the gene of interest with the vector

  4. Transfer of the recombinant plasmid into a host cell

  5. Selection process to screen which cells contain the gene of interest

  6. Sequencing of the gene to find the primary structure of the protein
• Ways in which plasmids may be introduced into host organisms

  • Biolistic
  • Plasmid insertion by Heat Shock Treatment
  • Electroporation
• Examples of modified traits using cloned genes and their application

  • Pest resistance in plants
  • Production of human proteins like hormones and enzymes by bacterial cells
• Earth's History spans 4.6 billion years
• Evolution


  Change in the characteristics of a species over several generations
• Organism


  Living thing
• Environment


  Surroundings or conditions in which a person, animal, or plant lives or operates
• Geologic Time Scale


  The "calendar" for events in Earth history
• Precambrian Eons


  • Earliest era in history of Earth
  • Covers approximately 88% of the Earth's history (4.6 billion to 544 million years ago)
  • Earth was transformed from a ball of gas and dust to liquid rock enveloped with hot, non-breathable gases mostly composed of carbon dioxide, nitrogen, and sulfur
  • The molten rock cooled down to form the earth's crust and with that, the gases also changed providing a cooler temperature composed mostly of nitrogen
• Precambrian fossils


  • Only tiny, sessile soft-bodied sea creatures
  • A sponge-like fossils that show the existence of hard body parts and spicules that extended 20-40 cm from the main body
• Few fossils during the Precambrian time span
• Early Precambrian organisms


  • Bacteria, algae, jellyfish-like animal, and sea pen
• The latter part of Precambrian Era (Proterozoic era) was greatly affected by the movement of tectonic plates forming the supercontinent Rodinia
• The Earth's core and atmosphere cooled down and brought about the Ice Ages during the Proterozoic era
• The production of oxygen by the primitive cyanobacteria caused a drastic change in the chemical composition of the Earth's atmosphere
• Paleozoic Era


  Old Life
• Paleozoic Era periods


  • Cambrian (542-488 million years ago)
  • Ordovician (488-443 million years ago)
  • Silurian (443-416 million years ago)
  • Devonian (416-359 million years ago)
  • Carboniferous (359-299 million years ago)
  • Permian (299-245 million years ago)
• Cambrian period organisms


  • Invertebrate sea animals, Pikaia, sponges, trilobite, clam, dinomischus
• Cambrian Explosion


  First fish, many animal phyla diversify, Appearance of the lineages of almost all animals living today, Unique - only time when such a large variety of body types appeared in the fossil record
• Ordovician period organisms


  • Earliest fishes, fungi, plants, animals colonize land, Brachiopod, jawless fish, crinoid
• Silurian period organisms


  • Land plants and animals, first vascular plants
• Devonian period organisms


  • Many types of fishes, early amphibians, ferns and cone bearing plants