| A | B |
|---|
| palentologist | scientists that studies early life on earth using fossils |
| radioisotope | unstable element that gives off radiation as it becomes more stable |
| mycorrhiza | partnership between plant root and fungi |
| isotope | same element with different atomic mass |
| continental drift | movement of earth's land masses over time |
| multicellular | more than one cell |
| protists | members of the kingdom of multicellular and unicellular eubacteria |
| half life | time it takes for half the amount in an element to change |
| endosymbiosis | theory that mitochondria are decendants of aerobic bacteria |
| eubacteria | prokaryotes with peptidoglycan in cell walls; disease |
| microsphere | vesicles made of short chains of amino acids; may be first step towards cellular respiration |
| vertebrate | animals with back bones |
| cyanobacteria | among the first bacteria to appear |
| spontaneous origin | origin of life from simple chemicals |
| mass extinction | the death of all membrs of many different species |
| mutualism | partnership in which both organisms benefit |
| fossil | preserved remains of an organism |
| radiometric dating | calculating age by measuring radioactive isotopes |
| archaebacteria | prokaryotes without peptidoglycan in cell wall; needs no sun |
| arthropod | animal with hard outer skeleton and jointed legs |
