This practice was used to treat various ailments before the rise of modern medicine, and the popular demand of “leeching” has created a special occupation called “leech collector” in the nineteenth-century Europe (Figure 1c). Leeches also have an important role in the development of Western medicine as living leeches were applied on the patients to perform bloodletting since the Middle Ages (Figure 1b). In ancient Chinese herbal medicine, dried leeches were taken orally to alleviate certain gynecological symptoms and to treat injuries and bruises (Figure 1a). On the other hand, leeches have made tremendous contributions to human well-being in the past. Nonetheless, human's fear of leech is not unfounded since most people's first encounter with leeches comes from being attacked by blood-sucking leeches. The leech occupies a special place in popular culture as it signifies horror and serves as a prototype for monsters. In this review, we focus on developmental evolution that underlies the origin of the leeches-the annelid group that makes the most significant presence in human life since antiquity. However, in addition to this, comparing development between annelid groups can provide no less luminous insights into how animal body plan adapts and evolves (Kuo, 2009, 2017). In the past two decades, annelid developmental biology has received the most attention in the research areas relating to the reconstruction of Urbilateria (De Robertis & Sasai, 1996 Ferrier, 2012). Given its extraordinary body plan flexibility, Phylum Annelida should house a rich collection of research materials for addressing this question. This phenomenal taxonomical expansion signifies the extreme flexibility of the annelid body plan, permitting radical modifications for adaptions to a great variety of habitats and lifestyles.Ī key question in evolutionary developmental biology (EvoDevo) is how animal body plans are modified to create new forms. Thus, Phylum Annelida not only includes all the soft-bodied segmented worms but also many unsegmented worms derived from segmented ancestors. An astonishing outcome of the molecular revolution in metazoan taxonomy is the inclusion of several former phyla, including Echiura, Sipuncula, Pogonophora, and Vestimentifera, as well as some enigmatic parasite groups, such as myzostomids and orthonectids, into Phylum Annelida (Bleidorn et al., 2007 Kojima, 1998 McHugh, 1997 Schiffer, Robertson, & Telford, 2018 Struck et al., 2011). We only began to realize the hidden breadth of annelid diversity after molecular phylogeny has been used to resolve metazoan interrelationships. Despite already being one of the largest metazoan phyla, the within-phylum morphological disparity of Annelida has been severely underestimated in the past. Annelida is a major metazoan phylum, consisting of approximately 20,000 species of soft-bodied segmented worms.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |