Innehållsförteckning
Hur tar sig tagghudingar fram?
De flesta tagghudingar förökar sig genom att de sprutar ut sina spermier eller ägg i vattnet. Där möts äggen och sperma, det bildas då ett plankton. De sjunker sedan till bottnen och utvecklas till fullvuxna organismer. Detta kallas yttre befruktning.
Hur rör sig en sjögurka?
Sjögurkor rör sig ofta långsamt och har svårt att snabbt fly undan fiskar, krabbor, sjöstjärnor och and ra djur som gärna äter hela sjögurkor eller delar av dem (t. ex. tentakler som sticker upp ur sedimen- tet).
What is Holothuria?
Holothuria is a genus of marine animals of the family Holothuriidae. Members of the genus are found in coastal waters in tropical and temperate regions. They are soft bodied, limbless invertebrates that dwell on the ocean floor. They resemble a cucumber in form. The genus contains some species that are harvested for food and sold as sea cucumber .
Is Holothuroidea a class or clade?
Class Holothuroidea is a sister clade to class Echinoidea, which together make up the clade Echinozoa. Highly simplified overview of Echinodermata phylogeny based in part on the hypothesis of relationships presented by Reich et al. (2015).
Is Holothuriida polyphyletic?
Holothuriida is an order of sea cucumbers. Taxa within the order Holothuriida were previously classified in the order Aspidochirotida, which was determined to be polyphyletic in 2017. Some taxa were also reclassified into the clades Synallactida and Persiculida.
Do Holothuroidea have bilateral or bilateral symmetry?
Holothuroideans, or sea cucumbers, appear to have bilateral symmetry in their adult form, but several structural characteristics are still formed in five parts. Class Holothuroidea is a sister clade to class Echinoidea, which together make up the clade Echinozoa.