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2010-09-28 02:21:30

Chapter 1: Biology & the Tree of Life
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  1. What makes something alive?
    • Cellular Organization.
    • All organisms consist of one or more cells with highly ordered structures.
  2. 5 Basic Characteristics of Living Organisms
    • Cells.
    • Energy utilization - sun or chemical energy.
    • Information - genetic information encoded in genes.
    • Growth and reproduction - all organisms grow and reproduce.
    • Evolutionary adaptation - gradual, heritable change.
  3. Cell Theory
    "All living things are made of a cell or cells".
  4. Theory
    A system of ideas for explaining a general phenomenon.
  5. How has life reached its present state?
    • Darwin, Wallace, and Evolution
    • Until the mid 1800s, most people thought that species do not change over time.
    • The work of Charles Darwin and Alfred Russell Wallace provided new insight into changes in species over time (evolution) and lineages of life forms.
  6. Darwin's Notes
    • Characteristics of similar species vary from place to place (variation: change with time? Evolution?).
    • Geographical patterns suggested lineages gradually change as species migrate.
    • Animals and plants on relatively young islands closely resembled those on nearby South American coast.
  7. Theory of Natural Selection
    • Thomas Malthus's Essay on the Principle of
    • Population (1798) was one component in
    • Darwin's thinking
    • Populations can grow faster than resources can keep up
    • Even though every organism has the potential to produce more offspring than can survive, population sizes remain relatively constant over time, because RESOURCES ARE LIMITING
    • Competition plays a role in determining who survives "lean times"
  8. Theory of Natural Selection
    • Individuals that possess certain characteristics are more likely to survive than those that do not possess those characteristics (through competition for limited resources)
    • The ability of an individual to produce offspring is called fitness
    • Over time, a trait that increases fitness (adaptation) will increase in a population
  9. Darwin's Theory of Natural Selection
    • Plant and animal breeders selected certain varieties to produce certain characteristics (artificial selection):
    • Character differences (dogs, chickens, Brassica, etc.) appear greater than those in wild populations--great capacity for variability
    • Natural variation (change::evolution) occurring in natural populations as well:
    • Selective pressure (natural selection) leads to stable change
  10. Darwin and the Theory of Natural Selection
    • Timeline:
    • _Original draft of The Origin of Species was written in 1842 but unpublished
    • _Alfred Wallace: sent manuscript with similar ideas to Darwin in 1858
    • _The Origin of Species published in November 1859
  11. Requirements for Evolution (change) by Natural Selection to Occur
    • 1. Heritable trait variation within a population
    • 2. Survival and reproduction of individuals with specific traits (leading to increase in frequency of that trait)
  12. Evidence Supporting Evolution by Natural Selection
    • Fossil record
    • _Various fossils dating back 3.5 billion years illustrate ancestral and transitional forms of life
    • Mechanisms of heredity
    • _Genetics accounts for new variations through molecular mechanism
  13. Homology
    vertebrate Limbs
  14. Evidence Supporting Evolution by Natural Selection
    • Comparative anatomy
    • _Homologous structures - same evolutionary origin, but now differ in structure and function
    • _Analogous structures - have similar structure and function, but different evolutionary origins (insect wings, bird wings)
  15. Evidence Supporting Evolution by Natural Selection
    • Molecular mechanisms are conserved
    • _Biochemistry, DNA analysis
    • Development patterns
    • _Similarities exist in the development stages of many different organisms
  16. Overview of Evolution and Natural Selection
    • Evolution:
    • _species change over time
    • _based on observations of species differences correlated with different geographical locations
    • Natural selection:
    • _how the species change over time
    • _competition for limited resources
    • _individuals with traits that favor survival and reproduction contribute those traits to the next generations
    • _based on observations of animal breeding
    • (artificial selection leads to variation, why not natural selection doing the
    • same?)
    • _the environment (weather, sun, meteors, other organisms, etc.) plays a major role in defining the traits that permit survival and reproduction
  17. Data Supporting Evolution by Natural Selection
    • Fossils illustrate species change.
    • Genetics (and molecular biology) illustrate:
    • _the determinants of traits (genes).
    • _the nature of the gene (DNA).
    • _the nature of changes in traits (mutations in DNA).
    • _the inheritance of traits (DNA replication and DNA segregation).
    • Comparative anatomy:
    • _bone arrangement in forelimbs is conserved in higher vertebrates
    • Molecular biology and genomics:
    • _many genes are highly conserved in evolutionarily distant organisms
    • Developmental pathways are similar in different organisms
  18. Classifying Life (Taxonomy)
    • Carolus Linnaeus (Karl von Linné): inventor of binomial nomenclature
    • Genus: capitalized
    • species: lower case
    • Both italicized
    • Saccharomyces cerevisiae = "sugar + fungus" "beer"; aka, brewer's yeast
    • Each scientific name is unique
  19. How to classify life forms?
    • What patterns are meaningful representations of
    • ancestral lineage? Similarities, differences?
    • 1) Does it move or not? (Linnaeus: 2 kingdoms: animals, plants)
    • 2) Nucleus or not? (eukaryotes, prokaryotes). Modified Linnaeus scheme, 5 kingdoms: Animals, Fungi, Plants, Protists, Monera
    • 3) Similarity of molecular sequence? Carl Woese's phylogenetic tree. Three domains: Bacteria, Archaea, Eukarya
  20. How do we study life?
    Science: Knowledge of facts, phenomena, and laws, gained and verified by ordered thinking, exact observation, and organized experiment.
  21. How Science Gets Done:
    • Observation
    • Hypothesis - suggested explanation that accounts for observations
    • Prediction - something that ought to be true if hypothesis is correct
    • Experiment - test of prediction
    • Control - checks for factors (other than the one being tested) that might influence experimental outcome
  22. Unifying Themes of Biology
    • Cell theory
    • All living organisms are made of cells, and all living cells come from other living cells
    • Evolutionary change
    • Life-forms have evolved varying characteristics to adapt to varied environments
    • Evolutionary conservation
    • Some characteristics of earlier organisms are preserved and passed on to future generations
    • Molecular basis of inheritance
    • DNA encodes genes which define and help to control living organisms
  23. Taxa (divisions) & Domain (Eukarya)
  24. Taxonomy: Major Distinction Based on Cell Morphology
  25. Sequence Alignments: Similarity and Differenceat the Molecular Level