humans changing ecosystems usually has a negative impact on an ecosystem / organisms living in an ecosystem & humans building homes in an ecosystem causes that ecosystem to change ->  humans building homes in an ecosystem has a negative impact on an ecosystem and organisms living in the ecosystem  humans building homes in an ecosystem has a negative impact on an ecosystem and organisms living in the ecosystem & a wetland is a kind of ecosystem -> humans building homes in a wetland has a negative impact on a wetland and organisms living in the wetland