Bio

• 8 characteristics of life

  • Reproduce
  • Evolve
  • Made up of cells
  • Obtain and use material and energy
  • Maintain a stable internal environment
  • Respond to their environment (stimuli)
  • Grow and Develop
  • Based on a universal genetic code (DNA + RNA)
• This information is copied and passed from parent to offspring
• Viruses

  A contagious microbe, containing genetic material, that replicates inside the living cells of another organism. They reside in every type of habitat, infecting any living organism. They cannot reproduce on their own or create copies of their own genes as they don't have cellular structure, cellular organization and cannot maintain a stable internal environment. Viruses give out instructions to an organism's host cell and reprogram it to replicate more of itself. A host cell has to be inserted with their certain virus genetic material in order to force the cell to make more viruses.
• Prions


  Abnormal pathogenic agents constructed of long chains of connected amino acids that can provoke diseases in humans and animals by triggering normal proteins in the brain to abnormally fold. Prions exist in two forms. The normal proteins, PrPc, are found abundantly on the surface of cells in the central nervous system. These are harmless. PrPsc is the form that causes problems. These are formed when the two proteins come into contact with each other and the prion influences the normal protein to convert into its dangerous form, creating another abnormal prion. These act as a template which alters the brain structure. This pathogen is considered dangerous because it uses a hosts' normal protein, which was already coded for in the body, to create more versions of itself.
• Viroids


  Small, circular naked single strands of RNA molecules containing nucleic acids without a protein coat. They are simply RNA molecules that act like infectious agents. These pathogens are the smallest found so far and they infect plants. They are mostly found on agricultural products. They replicate via a rolling circle mechanism reliant on RNA which involves three steps: RNA polymerization, cleavage and ligation. In order to create more, they need to enter the nucleus of the plant cells, however they can only infect damaged cells due to the lack of proteins they have for attachments to host membranes.
• Francesco Redi's Experiment


  To challenge the prevailing theory of spontaneous generation, which proposed that living organisms could arise spontaneously from non-living matter. Used three jars (open, covered with gauze, sealed with a lid) to see which would allow adult flies to reach the mean to lay eggs. Conclusion: Maggots were found only in control jars b/c that was the only place where adult flies could reach the meat to lay eggs.
• Lazzaro Spallanzani's Experiment


  Used open flasks to boil meat broth but sealed the flasks of the experimental group by melting the glass necks of the flasks closed. The broth inside remained uncontaminated by microorganisms. With the help of a microscope, it is now proved that microorganisms in the air arise spontaneously from a "vital force" which produces living organisms. Did NOT disprove the hypothesis that microorganisms could arise from a vital force. Discovered sterile technique, canning.

  
• Louis Pasteur's Experiment


  He used a flask w/ a curved but open neck. This stopped microorganisms from entering. It only became contaminated when the curved necks were removed from the flasks. Longer curved necks prevented solid particles (microorganisms) from entering the body of the flask, but air could still get in.
• John Needham's Experiment


  English naturalist and Roman Catholic cleric, but was also the first clergyman to be appointed a fellow of the Royal Society of London for his theory of spontaneous generation and the evidence he had. He also contributed to botany and the mechanics of pollen.
• Stanley Miller and Harold Urey' Experiment


  Chemical experiment that simulated the conditions thought at the time to be present and tested the chemical origin of life under those conditions. This experiment proved Oparin's and J.B.S.

  
• Lynn Margulis's Experiment


  Symbiosis in biological evolution.
• Jean-Baptists Lamarck


  Suggested that organisms could change during their lifetimes by selectively using or not using various parts of their bodies. Also that individuals could pass these acquired traits on to their offspring which enables species to change over time.
• Thomas Robert Malthus


  English economist that noted that humans were being born faster than people were dying which causes overcrowding. Reasoned that if the human population grew unchecked, there wouldn't be enough living space and food for everyone. Forces that work against population growth, as suggested by Malthus, are: War, Famine , Diseases
• Alfred Russel Wallace


  Published the theory of evolution by natural selection with Charles Darwin. His pioneering work on evolutionary biogeography (the study of how plants and animals are distributed) led to him becoming recognised as that subject's 'father'.
• Alfred Wegener


  German polar researcher, geophysicist and meteorologist. He was primarily known for his achievements in meteorology and as a pioneer of polar research, but today he is most remembered as the originator of the theory of continental drift by hypothesizing in 1912 that the continents are slowly drifting around the Earth.
• Theodosius Dobzhansky


  American geneticist and evolutionary biologist. He was a central figure in the field of evolutionary biology for his work in shaping the unifying modern evolutionary synthesis. Genetics and the Origin of Species (1937).
• Stephen Jay Gould


  Paleontologist, evolutionary biologist. Most significant contribution to evolutionary biology was the theory of punctuated equilibrium, which he developed with Niles Eldredge in 1972. The theory proposes that most evolution is characterized by long periods of evolutionary stability, which is infrequently punctuated by swift periods of branching evolution.
• E.O Wilson


  The father of sociobiology, biodiversity. the theory of island biogeography, which he developed in collaboration with the mathematical ecologist Robert MacArthur, which is seen as the foundation of the development of conservation area design. He believed in god but denied revealed religion.
• Spontaneous generation


  Prior to the 17th century it was thought that living things could also arise from nonliving things
• Evolution


  Orderly succession of changes
• Biological evolution


  The change of populations of organisms over generations
• Lamarck's Explanation


  Proposed a unified theory of species modification. Proposed that similar species descended from a common ancestor. Living species were descended from similar extinct species (based on fossil records). Dealt w/ invertebrates and related them to living animals based on their similar appearance. Acquired Trait
• Charles Darwin & Alfred Wallace

  Both (independently) proposed the hypothesis that species were modified by natural selection (process by which organisms w/ favourable variations reproduce at higher rates than that w/o such variations). Organisms best suited to their env't reproduce more successfully than other organisms. Therefore, over generations, the proportions of organisms w/ favourable traits increases in a population.
• Darwin's Theories


  Descent with modification: States that the newer forms appearing in the fossil record are actually the modified descendants of older species (same as Lamarck) but Darwin's goes further. Darwin's states that all species had descended from one or a few original types of life. Modification by Natural Selection: States how evolution occurs. Darwin was influenced by Thomas Malthus's theory that pointed out that human populations can redouble but are affected by adverse conditions (war, diseases, limited resources). deduced that although populations of all organisms have the potential to grow, most do not b/c the env't limits the growth of populations by increasing the rate of death or decreasing the rate of reproduction, or both. Some organisms have traits that make them better able to cope w/ their env't, and that these organisms leave more offspring (natural selection).

  
• Natural selection


  A process by which organisms with favorable variations reproduce at higher rates than those w/o such variations. So, that means organisms that are best suited to their environment reproduce more successfully than those that aren't.
• Descent with modification


  One of Darwin's Theories. States that the newer forms appearing in the fossil record are actually the modified descendants of older species (same as Lamarck) but Darwin's goes further. Darwin's states that all species had descended from one or a few original types of life. Ex) All vertebrates probably descended from a vertebrate that lived in the distant past. Geographic location is part of this theory.

  
• Evidences of evolution


  • Structures: Homologous, Analogous and Vestigial
  • Embryology
  • Macromolecule similarities

  
• Homologous structures


  Similar features that originated in a shared ancestor. These can result from modifications that change an original feature to 2 extremely different types. Same structure, different functions
• Analogous structures


  Features that have similar functions but are different in structures
• Vestigial structures


  Features that seem to serve no useful function
• Coevolution


  The change of 2 or more species in close association with each other. Predators and their prey sometimes co-evolve. Parasites and their hosts often co-evolve.
• Convergent evolution


  Occurs when the environment selects similar phenotypes even though the ancestral types were quite different from each other. When organisms look similar but they are not closely related at all.
• Divergent evolution


  Two or more related populations or species become more and more dissimilar. This can be sped up through artificial selection. Divergent evolution sped up what nature would do in the future.
• Adaptive radiation


  When many related species evolve from a single ancestral species.
• Artificial selection


  The process by which humans choose individual organisms with certain phenotypic trait values for breeding.
• Sexual selection


  When species choose who they mate based on certain traits. Acts on an organism's ability to obtain or successfully reproduce with a mate
• Artificial selection


  The process by which humans choose individual organisms with certain phenotypic trait values for breeding
• Adaptive radiation


  When many related species evolve from a single ancestral species
• Galapagos Finches


  • They diverged in response to the availability of different types of food in their different habitats
• Mechanisms of evolution


  • Artificial selection
  • Sexual selection
  • Natural selection