due to extreme pollution of their habitatshas been causeddue to extreme pollution of their habitats

the variety and interdependence of all living thingshas ledthe variety and interdependence of all living things

a level of extinction in the natural world that has not been seen since the Permian Extinction , which killed the dinosaurs 250 million years agoare currently causinga level of extinction in the natural world that has not been seen since the Permian Extinction , which killed the dinosaurs 250 million years ago

whatevercould causewhatever

extinction of a species throughoverharvesting , pollu tion , habitat destruction , introduction of newpredatorsand foodcompetitors , overhunting , and other influencescan causeextinction of a species throughoverharvesting , pollu tion , habitat destruction , introduction of newpredatorsand foodcompetitors , overhunting , and other influences

contraction of seed shadows of plant species ... followed eventually by dying out of marginal colonies outside the reproductive core of the plant speciescould have causedcontraction of seed shadows of plant species ... followed eventually by dying out of marginal colonies outside the reproductive core of the plant species

Major perturbation(passive) caused byMajor perturbation

the chain of anwould causethe chain of an

alsowill ... contributealso

in missing pieces to the puzzle of life on earthcould resultin missing pieces to the puzzle of life on earth