BIO2 ME1 SEM3

• species is Latin for “kind” or “appearance”
• Concept of species - a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring—but do not produce viable, fertile offspring with members of other such groups.
• Reproductive Isolation - biological species are defined in terms of reproductive compatibility, the formation of a new species hinges on reproductive isolation—the existence of biological factors (barriers) that impede members of two species from interbreeding and producing viable, fertile offspring
• Pre-zygotic isolation mechanisms - prevent fertilization and zygote formation
• Geographic or Ecological or Habitat Isolation – potential mates occupy different areas or habitats thus, they never come in contact
• Temporal or Seasonal Isolation – different groups may not be reproductively mature at the same season, or month or year
• Behavioral Isolation – patterns of courtship are different
• Mechanical Isolation – differences in reproductive organs prevent successful interbreeding
• Gametic Isolation – incompatibilities between egg and sperm prevent fertilization
• Post-zygotic isolation mechanisms allow fertilization but nonviable or weak or sterile hybrids are formed.
• Hybrid Inviability – fertilized egg fails to develop past the early embryonic stages
• Hybrid Sterility – hybrids are sterile because gonads develop abnormally or there is abnormal segregation of chromosomes during meiosis
• Hybrid Breakdown - F1 hybrids are normal, vigorous and viable, but F2 contains many weak or sterile individuals.
• Allopatric Speciation or Geographic Speciation - occurs when some members of a population become geographically separated from the other members thereby preventing gene flow
• Sympatric Speciation - occurs when members of a population that initially occupy the same habitat within the same range diverge into two or more different species
• Parapatric Speciation – occurs when the groups that evolved to be separate species are geographic neighbors. Gene flow occurs but with great distances is reduced.
• Genetically Engineered Plants


  • Flavr Savr Tomato
  • Arctic Apple
• Genetic engineering


  • Artificial manipulation, modification, and recombination of DNA
  • Used for the modification or manipulation of organisms through the processes of heredity and reproduction
  • Process of using recombinant DNA (rDNA) technology to alter the genetic makeup of an organism
• Artificial insemination


  Introduction of semen into the vagina of cervix of a female by any method other than sexual intercourse
• In Vitro Fertilization


  Medical procedure in which mature egg cells are removed from a woman, fertilized with male sperm outside the body, and inserted into the uterus of the same or another woman for normal gestation
• Test tube baby


  Louise Joy Brown, the world's first baby to be conceived in IVF
• Cloning


  The process of generating identical copy of a cell
• Dolly the sheep


  Cloned from a cell taken from the mammary gland of a six year old Finn Dorset sheep and an egg cell taken from a Scottish Blackface sheep
• Genetic Cloning


  Process of making an exact duplicate of the genetic material
• Producing Transgenic Organism


  1. Cut the DNA fragment out of one organism

  2. Connect the DNA fragment to a carrier

  3. Insert the DNA fragment and its carrier to a new organism
• Recombinant DNA


  Created when DNA molecules from two different species are combined in a host organism to create new genetic combinations
• Four major steps of Recombinant DNA Technology


  1. DNA fragment containing the gene of interest is obtained from the donor cell

  2. A suitable plasmid is obtained from a bacterium

  3. The DNA fragment containing the gene of interest is cut using an enzyme called restriction enzyme

  4. The DNA fragment containing the gene of interest is inserted into the open plasmid with the help of another enzyme called DNA ligase
• Applications of Recombinant DNA Technology


  • Food and Agriculture
  • Health and Diseases
  • Environment
• Recombinant DNA technology has major uses which made the manufacturing of novel enzymes possible which are suitable in conditions for specified food-processing
• Gene therapy


  An advanced technique with therapeutic potential in health services
• Production of Antibodies


  Antibodies are protective proteins produced by the immune system in response to the presence of a foreign substance called antigens
• Investigation of the Drug Metabolism


  An understanding a drug metabolism is critical for safe and useful pharmaceuticals
• Development of Vaccines and Recombinant Hormones


  A fear free and painless technique to transfer adenovirus vectors encoding pathogen antigens is through nasal transfer which is also a rapid and protection sustaining method against mucosal pathogens
• Abiotic stress


  The negative effect of inorganic factors on living organisms
• The Geologic Time Scale (GTS)


  Earth Old 4.6 billion years
• Precambrian


  • Hadean - characterized by earth's initial formation
  • Archean - records of earth's primitive atmosphere and oceans emerge in the earliest archean
  • Proterozoic - the atmosphere and oceans changed significantly
• Phanerozoic


  The span of geologic time extending about 541 million years from the end of the proterozoic eon to the present
• Paleozoic


  Means "old life"
• Periods under Mesozoic


  • Triassic
  • Jurassic
  • Cretaceous
• Periods under Cenozoic


  • Tertiary
  • Quaternary