last bio

• Evolution


  The change in heritable traits through generations - change over time
• Evolution occurs in populations, not individual organisms
• How organisms have changed

  1. The first cells were thought to be anaerobic (requires no oxygen), about 3.8 billion years ago, because there was little oxygen on Earth

  2. As Earth's atmosphere and conditions changed, photosynthetic prokaryotes (cyanobacteria) evolved, using sunlight to produce food, with oxygen as a waste product

  3. Eventually, Earth's atmosphere became filled with oxygen, allowing aerobic (requires oxygen) organisms to evolve

  4. This resulted in the evolution of eukaryotic, complex multicellular organisms we have on Earth today
• The Endosymbiotic Theory


  • The theory states that eukaryotic cells formed from a symbiotic relationship among several different prokaryotic organisms
  • Prokaryotes that use oxygen to generate energy-rich molecules of ATP evolved into mitochondria
  • Prokaryotes that carried out photosynthesis evolved into chloroplasts

  
• While we know prokaryotes to be mostly autotrophic (some heterotrophic), ancestral prokaryotes were strictly heterotrophs until they developed more due to exposure to photosynthesis organisms

  
• Biogenesis


  The concept that living organisms can only arise from other living organisms
• Spontaneous Generation


  The supposed idea that living organisms can spontaneously be produced/come into existence from non-living matter
• Francesco Redi conducted an experiment to disprove the theory of spontaneous generation
• Evidence of Evolution


  • Fossils
  • Homologies
  • Vestigial Structures
  • Comparative Embryology
  • Biochemical Evidence
• Relative Dating


  The process of determining the age of things (either younger or older) based on their relationship
• Fossils are the solidified remains or imprints of once-living organisms. The older a fossil is, the further down in the rock layers it is. Organisms that resemble the living creatures of today are mostly found in the top layers, while more ancestral forms are found lower in the rock layers

  
• Radiometric Dating


  • The process of calculating the age in years of geologic material by analyzing the radioactive elements present in them
  • Half-life = The amount of time it takes for half of the radioactive atoms in an isotope to decay
• Homologies


  Similarities between the anatomical structures of species
• Homologous Structures


  A structure that shows how certain species have inherited a trait from a common ancestor
• Analogous Structures


  A structure in different species that have a similar function indicating no shared ancestor
• Convergent Evolution


  The process where unrelated species adapt to similar environments (niches) and adopt similar qualities
• Divergent Evolution


  The process where two or more related species become dissimilar through evolution
• Vestigial Structures


  Anatomical structures that still appear but are no longer used! Suggests that these structures may have existed at a previous time or in an ancestor
• Whales came from an ancestor that originated from land, and we can tell this because whales have a vestigial structure they don't use anymore and that structure is leg bones
• Humans have vestigial structures like wisdom teeth and appendix
• Comparative Embryology


  Insects and animals often have very similar embryonic development, suggesting a common ancestor
• Biochemical Evidence


  Comparison of DNA and macromolecules between organisms, tells us what organisms are closely related
• Cytochrome C


  An enzyme that is highly conserved (does not break in organisms), many related organisms share this same enzyme indicating evolutionary relationships
• Fossil A


  • Which modern day organism does this fossil remind you of?

  
• Miller-Urey Experiment


  1. Flask with water = Earth's water

  2. Bunsen Burner = Heat sources on Earth

  3. Electrode = Lightning

  4. Gases Add (water vapor, ammonia, methane and nitrogen) = Early Earth atmosphere
• The Miller-Urey experiment was done to figure out if the creation of macromolecules was possible in the organisms of pre-existing life
• Amino acids were formed in the collected sample made
• Evolution is change over time that occurs in populations
• Charles Darwin set out on a five year voyage on a ship called the Beagle


  1831
• As he traveled, he filled notebooks with observations and sketches of the organisms he found
• This experience led Darwin to develop the idea of evolution and natural selection that we know today
• Traits organisms have are best suited for environment

  Were passed to offspring
• Populations have natural variation at birth

  Organisms could become extinct
• Organisms could gain traits during their lifetime

  Acquired traits were passed to offspring
• Darwin


  Survival of the fittest
• Lamarck


  No extinction
• Survival of the fittest

  Those organisms best adapted to their environment will survive, reproduce, and pass on genes
• Adaptation


  Any heritable trait an organism has that helps it to survive
• If an organism does not have adaptations to best fit its environment, it will die
• "Common descent with modification" was a very popular quote said by Darwin especially regarding his different finches because he was able to note they descended from a COMMON ancestor but with slight MODIFICATIONS from evolutionary changes