Pre-Finals & Finals

• Life Science - Studies living organisms and processes. It spans a vast swatch of scientific research, from aiding our understanding of microorganisms such as viruses or bacteria, to deciphering and physiological processes of the largest land and marine animals on the planet
• Characteristics of Life:

  • They respond to their environment
  • They grow and Develop
  • They are capable of reproduction
  • They exhibit metabolism
  • They maintain homeotasis
• 4.5 BYA- The earth is said to be violent because of the meteorites and volcanic eruptions. With this condition, zircon crystals was formed
• 3.9 B.Y.A - Meteorites bombarded Earth bringing along water and other elements. The earth’s atmosphere became mostly carbon dioxide, water vapor, methane, and ammonia. 
• 3.8 B.Y.A - The surface of Earth changed from molten to solid rock. Water started condensing in liquid form. Earth day was 15 hours long.
• 3.5 B.Y.A - First simple cells, oxygen producing bacteria. 
• •3.4 B.Y.A - Stromatolites demonstrated photosynthesis; a process used by plants and other organisms to convert light energy captured from the sun into chemical energy. 
• •2.2 B.Y.A - Organisms with mitochondria capable of aerobic respiration appeared. 
• 1.6 B.Y.A - Complex single-cell life appeared. 
• •1.5 B.Y.A - Organisms with complex cells containing nucleus appeared. 
• •1.4 B.Y.A - Sexual reproduction appeared, increasing the rate of evolution.
• •1.0 B.Y.A - Multicellular life appeared. 
• •700 M.Y.A - Snowball Earth, the entire Earth was covered in ice for many million years.Mass extinction of 70% of dominant sea plants.
• •580 M.Y.A - Simple, soft-bodied organisms developed i.e. Jellyfish. The accumulation of atmospheric oxygen allowed the formation of the ozone layer. This blocked ultraviolet radiation, permitting the colonization of the land.
• •580 M.Y.A - The ozone layer is found at approximately 20 to 30 kilometres (12 to 19 miles) above Earth, it absorbs 97–99% of the Sun’s medium-frequency ultraviolet light which potentially damages exposed life forms.
• •570 M.Y.A - Arthropods appeared, ancestors of insects. 
• •560 M.Y.A - Earliest Fungi
• •530 M.Y.A - The fish appeared. Major diversification of living things in the oceans.
• •443 M.Y.A - Mass extinction, 49% of life disappeared. 
• •434 M.Y.A - The first primitive plants moved onto land, having evolved from green algae living along the edges of lakes. They are accompanied by fungi, which may have aided the colonization of land through symbiosis.
• •410 M.Y.A - Fish developed teeth and jaws.Spiders, Centipedes appeared.
• •353 M.Y.A - Diversification of amphibians. 
• •320 M.Y.A - Beetles appeared. 
• •251 M.Y.A - Reptiles appeared
• •225 M.Y.A - First small dinosaurs appeared. 
• •220 M.Y.A - Forests dominated the land. 
• •201 M.Y.A - Mass extinction, 20% of all marine species killed; caused by oceanic anoxic event. 
• •200 M.Y.A - Mammals appeared. 
• •150 M.Y.A - Birds appeared
• •130 M.Y.A - Flowering plants evolved with structures that attract insects and other animals to spread pollen. This innovation causes a major burst of animal evolution through co-evolution. First freshwater pelomedusid turtles. 
• •110 M.Y.A - Crocodile appeared. 
• •110 M.Y.A - First bees evolved
• •90 M.Y.A - Snake appeared
• •80 M.Y.A - Ants appeared
• •68 M.Y.A - Tyrannosaurus rex, the largest terrestrial predator of North America thrived.
• •65 M.Y.A - Meteor impact, 170 km crater Chicxulub, Yucatan, Mexico.Mass extinction of 80-90% of marine species and 85% of land species. Dinosaurs became extinct. Mammals became dominant species. Rapid diversification in ants.
• 55 million years - whales appeared
• 52 million years - Bats appeared.
• 40 million years - Modern-type butterflies appeared
• 30 million years - Pigs and Cats appeared.