19.2 The Age of Earth I. The importance of __________ A. Life has existed for ____ billion years and ____% of that time life was only in __________ 1. ________ rays would kill land ___________ B. As _______________ produced oxygen it floated into upper ______________ 1. oxygen ________ into _________ (O3) 2. this ________ the sun’s _____ rays and made land living _______

II. __________ & ___________ A. Were the ________ to invade _________ 1. 1st problem was how to ___________ on bare ___________ a. ________________ plants could not get __________ out of bare rock b. __________ could not be photosynthetic but could get _________ 2. _____________ – association between plants and animals a. fungi live in the ________ of plants 1. plants give fungi _______ and fungi give plants __________ b. _____________ – “you help me and I help you” relationship

III. ______________ A. Have _______ outer skeleton and jointed _________________ 1. examples – _________, __________, __________, & ____________. 2. the first arthropods to move on land were ______________ B. Insects have become the most ______________ and ___________ group of animals _________ 1. There are _________ million insects for every human 2. Insects were the first animals to evolve __________ a. Allow for a partnership between __________ & _____________ plants

IV. ______________follow onto land A. Any animal with a ______________ 1. First vertebrates were _______, dominated ______ for millions of yrs B. Came onto land ______ mya 1. ______________ were the first a. Ancestors of today’s _________, __________, & _________________ C. Because of strong flexible ____________ they could grow ________ and soon ___________ the landscape