http://classroom.synonym.com/human-activities-affect-ecosystem-9189.html [2]
http://www.skwirk.com/p-c_s-57_u-520_t-1393_c-5363/human-impacts-on-the-... [3]
http://en.wikipedia.org/wiki/Human_impact_on_the_environment [4]
http://catalog.flatworldknowledge.com/bookhub/reader/3157?e=gittell_1.0-... [5]
http://www.mheducation.ca/school/learningcentres/file.php/9780070726901/... [6]
Links
[1] https://hootsgo.org/?q=node/6369
[2] http://classroom.synonym.com/human-activities-affect-ecosystem-9189.html
[3] http://www.skwirk.com/p-c_s-57_u-520_t-1393_c-5363/human-impacts-on-the-environment/qld/human-impacts-on-the-environment/a-question-of-balance-australian-environments/civilisation-and-the-ecosystem
[4] http://en.wikipedia.org/wiki/Human_impact_on_the_environment
[5] http://catalog.flatworldknowledge.com/bookhub/reader/3157?e=gittell_1.0-ch02_s03
[6] http://www.mheducation.ca/school/learningcentres/file.php/9780070726901/olc2/dl/699403/1_5.pdf