GEN BIO

• RELATIVE


  Estimates whether an object is younger or older than other things found at the site. Relative dating does not offer specific dates, it simply allows to determine if one artifact, fossil, or stratigraphic layer is older than another.

  
• ABSOLUTE


  Provide more specific origin dates and time ranges, such as an age range in years. How specific these dates can be will depend on what method is used.

  
• The geologic time scale is the "calendar" for events in Earth history. It is divided into named units of abstract time called - eons, eras, periods, and epochs.

  
• The three main era of time of Earth's history from oldest to youngest


  • Paleozoic Era
  • Mesozoic Era
  • Cenozoic Era

  
• The Phanerozoic Eon started from 543 million years ago to present.
• The three eras of the Phanerozoic Eon

  • Paleozoic Era
  • Mesozoic Era
  • Cenozoic Era
• Paleozoic Era


  • Known as the "OLD LIFE", started from 542 mya and lasted for 251 mya
  • Subdivided into six periods: Permian, Carboniferous, Devonian, Silurian, Ordovician, Cambrian

  
• Ordovician Period (490 to 443 mya)


  Fungi, plants, and animals colonizes the land
• Silurian Period (443 to 416 mya)


  First vascular plants appeared
• Devonian Period (416 to 360 mya)


  Bony fishes diversified, insect and first amphibians appeared
• Carboniferous Period (360 to 299 mya)


  1. First seed plants appear

  2. Origin of reptiles and amphibians dominate
• Permian Period (299 to 251 mya)


  1. Reptiles diversify

  2. Major extinction of marine organism

  3. About 96 percent of all marine species

  4. Three of every four species on land died out
• Mesozoic Era


  • Started from 248 mya and lasted for 65 mya
  • Subdivided into three periods: Triassic period, Jurassic period, Cretaceous period
• Triassic Period (251 to 200 mya)


  Dinosaurs evolve, origin of mammals, and gymnosperms dominate
• Jurassic Period (200 to 145 mya)


  Dinosaurs abundant, first birds appear, gymnosperms dominate
• Cretaceous Period (145 to 65 mya)


  1. Angiosperms diversify

  2. Dinosaurs extinct at the end of this period
• Cenozoic Era

  • Quaternary Period (2.6 mya - Present)
  • Pleistocene epoch: Ice ages and origin of Homo
  • Holocene epoch: The time since the end of the last major glacial epoch, or "ice age", the current time we are living in
• Mass Extinction


  A short period of geological time in which a high percentage of biodiversity, or distinct species - bacteria, fungi, plants, mammals, birds, reptiles, amphibians, fish, invertebrates - dies out
• Charles Robert Darwin is the Father of Evolution
• Fossil Records


  The most direct evidences that evolution had occurred
• Fossils can document important transitions, for example, the transition from land to sea in the ancestors of cetaceans
• Fossil records have shown how cetacean evolution had resulted to the loss of hind limbs and the development of cetaceans
• Transitional feature


  A fossil that shows an intermediate state between an ancestral trait and that of its later descendants
• A number of fossils of whale ancestors have been discovered in countries such as Pakistan, Egypt, and North America
• Biogeography


  The discipline of biology that studies the present and past distribution patterns of biological diversity and their underlying environmental and historical causes
• Comparative Anatomy


  An important tool that helps determine evolutionary relationships between organisms and whether or not they share common ancestors
• Homologous Structure


  Similar physical features in organisms that share a common ancestor, but the features serve completely different functions
• Analogous Structure


  Similar physical features and functions in organisms that do not share a common ancestor
• Many vertebrates have a very similar bone structure despite their limbs looking very different on the outside. This structure is known as the pentadactyl (five fingered) limb. This suggests that many vertebrates descended from the same common ancestor.
• Although the limbs of crocodiles, birds, whales, horses, bats and humans all look very different they share the same five fingered bone structure. This provides evidence for the theory of evolution.
• Comparative Embryology


  Reveals anatomical homologies not visible in adult organisms
• Vestigial Structures


  Organs, tissues or cells in a body which are no more functional the way they were in their ancestral form of the trait
• Scientists claim appendix is not a vestigial organ
• Wisdom teeth are considered a vestigial organ -- no longer useful -- because our diet has evolved.
• The coccyx currently serves as an anchor for muscles; that wasn't its original purpose, so that's why it's considered vestigial.
• Evidence from Molecular Biology


  Closely related species will be more similar to one another than their more distantly related species. Molecular similarities provide evidence for the shared ancestry of life. DNA sequence comparisons can show how different species are related.
• Comparing the human genetic code with that of other organisms will show that chimpanzee and baboons are human's closest relations.
• Genetic similarities between the chimpanzees from the humans only differ 1.2%
• Amino Acid Difference Compared to Human


  • Human
  • Horse
  • Gorilla
  • Chimpanzee
  • Zebra
• Central Dogma


  A theory stating that genetic information flows only in one direction, from DNA, to RNA, to protein, or RNA directly to protein.