Life cycle diferences similarities nematode trematda ①Their definitive hosts are both humans and vertebrates ②they both infect hosts by oral and skin infection ①need ecdysis through its growth, generally 4 times ②do not have alternation of generations ③life cycle include:egg、larva、adult ④have divisions : soil-transmitted nematode(no need of intermediate host) verctor-borne nematode(need one intermidiate host such as mosquito) ⑤infective stage: ovem or larva ①do not go through the ecdysis ②have thealternation of generations(sexual generation and asexual generation) ③life cycle include: ovem, miracidiun, sporocyst, redia, cercaria, encysted metacercaria, metacercaria, adult ④1.need intermediate host,the asexual generation generally happens in imtermediate host and sexual generation in definitive hosts such as humans and other vertebrates 2.some need reservoir host (1th、2th ...intermediate host) to enter definitive hosts 3.most of trematdas need 2 intermediate hosts to complete their life circles (1th is gastropod such as freshwater snail,2th is fish、arthropod、shellfish ⑤infective stage:encysted metacercaria(most), cercaria