UMary Allen
Ama-mollusk yiqembu lezilwane. Abanawo amathambo angaphakathi, okusho ukuthi abanamathambo. Isibonelo esihle ingwane. Amanye ama-mollusk anegobolondo eliqinile njengamathambo awo angaphandle, njengezimbaza noma ezinye iminenke.
Izinhlobo eziningi zihlala olwandle. Kodwa zitholakala nasemachibini nasemifuleni. Amanzi azisiza ukuthi zithwale umzimba. Bese engenasisindo. Izinhlobo ezincane kuphela ezihlala emhlabeni, njengeminenke ethile.
I-mollusks ibizwa nangokuthi "ama-mollusks". Leli gama livela egameni lesiLatini elithi "soft". Ku-biology, ama-mollusk akha isizwe sawo, njengoba kwenza izilwane ezinomgogodla noma ama-arthropods. Kunzima kakhulu ukubala ukuthi zingaki izinhlobo ze-mollusk ezikhona. Abanye ososayensi babiza i-100,000, abanye ngaphansi. Lokhu kungenxa yokuthi kunzima ukuhlukanisa phakathi kwezinhlobo ezahlukene. Ukuze uqhathanise: Kukhona nezilwane ezinomgogodla ezingaba ngu-100,000, kuyilapho izinambuzane zingaba izigidi ezimbalwa.
I-mollusk ifana ngani?
Ama-mollusk anezitho ezintathu zomzimba: ikhanda, unyawo, nesaka eliqukethe amathumbu. Nokho, ikhanda nonyawo ngezinye izikhathi kubukeka sengathi zenziwe ngesiqephu esisodwa, isibonelo endabeni yeminenke. Ngezinye izikhathi igobolondo lenezelwa njengengxenye yesine, njengezimbaza.
Wonke ama-mollusk ngaphandle kwezimbaza anolimi oludlwengulayo emakhanda azo. Kunzima njengefayela. Izilwane zihlikihla ukudla ngakho ngoba azinawo amazinyo.
Wonke ama-mollusk anemisipha eqinile ebizwa ngokuthi “unyawo”. Ibonakala kahle eminenke. Ungayisebenzisa ukuhambisa noma ukugebha.
Amathumbu alele esikhwameni se-visceral. Lesi yingxenye ehlukile yomzimba ezungezwe ijazi. Iqukethe umminzo, isisu, namathumbu. Kukhona inhliziyo elula. Nokho, lokhu akumpompi igazi emzimbeni, kodwa kunalokho uketshezi olufanayo, i-hemolymph. Bathi "i-hemolums". Ezingxenyeni eziningi ze-mollusk, iphuma emathunjini, lapho idonsa umoya-mpilo. Iminenke ehlala emhlabeni kuphela enamaphaphu. Inhliziyo iphampa i-hemolymph emzimbeni.