private Integer differenceBetweenSpecieLists(List<Specie> list1,
			List<Specie> list2) {
		Integer difference1  = 0;
		for (Specie s : list1) {
			if (!list2.contains(s)) {
				difference1++;
			}
		}
		Integer difference2 = 0;
		for (Specie s : list2) {
			if (!list1.contains(s)) {
				difference2++;
			}
		}
		return Math.max(difference1, difference2);
	}