Topic 9: Origin of Life Flashcards

• earths biodiversity is built on profound similarity between what two areas of study

  biochemical and genetic similarity
• 6 features of a living organism: organization


  • structurally composed of one or more cells (basic unit of life)
• 6 features of a living organism: metabolism


  system of management of energy and materials via chemical reactions
• 6 features of a living organism: homeostasis


  maintenance of some internal chemical and/ or thermal consistency relative to variation outside of the entity
• 6 features of a living organism: adaptation


  the ability to change over a period of time in response to the enviornment
• what do viruses have that allow them to mutate and respond to natural selection, and can reproduce themselves

  nucleic acids
• what two eons make up the precambrian era

  archaean + proterozoic
• what eon contains the last half billion years and encompasses multicellular eukaryotic life

  phanerozoic
• major boundaries between geological divisions correspond to major what

  major extinction events in the fossil record
• When did the Cambrian explosion occur?

  the beginning of the Paleozoic Era and the end of the proterozoic era
• When did the Permian extinction occur?

  after the paleozoic era and the begining of the mesozoic era
• When did the Cretaceous extinction occur?


  after the mesozoic era and the begining of the cenozoic era
• What era are we currently in?

  Cenozoic Era
• what provides direct evidence for evolutionary history

  fossil records
• what is a fossil

  preserved remnant/ evidence of organisms that lived in the past
• Where are fossils usually found?

  sedimentary rock
• distinct layers of rock are called what

  strata
• how are rocks formed

  accumulation of mud, slit, or sand
• what are the three main contributions of fossils

  -calibrate phylogenies-record extinct species-link evolutionary events with geological and environmental changes on earth
• what are the two downfalls to the fossil record

  biased and incomplete
• why is the fossil record biased and incomplete

  because fossilization requires:-burial in sediment
• why does the fact that fossilization requires burial in sediment contributes to the fossil record being biased and incomplete

  sediments accumulate episodically and discontinuously, and fossils typically preserve only the hard parts of organisms
• when does a cast form

  when minerals fill space in sediment where the organism decayed after having been buried
• how do replacement or petrified fossils form

  fossils have their tissues replaced by minerals
• what are trace fossils

  record evidence of behavior (tracks, burrows, feces)
• what are preserved fossils


  original organic material retained (carbon films, amber, tar or peat, frozen
• What is a sub-fossil?

  preserved fossil what has a high % organic matter
• what are the 5 types of fossils

  -cast-replacement/ petrified-trace-preserved-sub-fossil
• what are the two kinds of fossil dating

  -relative dating-absolute dating
• what is relative dating

  sedimentary strata reveal relative ages of fossils and we can tell which fossil came 1st, 2nd, etc.
• relative dating does not indicate what


  how long ago the fossil was created
• relative dating does not provide what

  the absolute age of a fossil
• what are the two main challenges to relative datin

  -common to have gaps in a sedimentary sequence-sediments can be tipped or even inverted by major land movements
• how do gaps in sedimentary sequence occur

  inconsistent sediment deposition; erosion of uplifted strata
• how can we over come the challenge of sediments be tipped or inverted by major land movements when doing relative dating

  -use widespread common index fossils which help to read incomplete or scrambled layers
• what is absolute dating also known as

  radiometric dating
• what is absolute dating

  radioactive decay of isotopes of elements provides a means of dating fossils or rocks
• how does absolute dating work

  Scientists can assign a specific date (within a range) by looking at the isotopes of certain radioactive elements in fossils.
• what is a half life

  50% of atoms in a given amount of radioactive substance have decayed
• C-14 is good for what kind of fossils

  young fossils