klasifikasi dan ciri-ciri chordata, klasifikasi ciri-ciri
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Klasifikasi dan ciri-ciri Chordata, klasifikasi, ciri-ciri dan hubungan kekerabatan Vertebrata
PHYLUM CHORDATAGENERAL CHARACTERISTICS: BODY SIMMETRY : BILATERAL COELOM TRIPOBLASTIC DIGESTIVE SYSTEM COMPOSES MOUTH, ESOPHAGUS, STOMACH, INTESTINE, ANUS DEUTEROSTOMIA
REPRODUCTION SYSTEM: SEXUAL (MOSTLY) AND ASEXUAL (SOME UROCHORDATE)
DEFINING CHARACTERISTICS PHYLUM CHORDATANotochord Dorsal nerve cord Pharyngeal gill slits / Pharyngeal pouch Post-anal tail. -
These attributes are always found in the larval forms or early embryo (although they may be absent in the adult).
1) The Notochord The notochord is mainly composed of fibrous connective tissue For those animals in which it persists into the adult form, the notochord provides support (it acts like our backbone) and increases swimming efficiency
In animals like ourselves, bony structures called vertebrae develop near the notochord and eventually replace it during embryogenesis
2) Pharyngeal Gill Slits Pharyngeal gill slits are cuts in the pharynx that connect to a cavity surrounding the pharynx For organisms in which they remain in the adult, they are often elaborated into respiratory structures (and are sometimes involved in filtering food during feeding).
The morphological equivalent of gill silts are seen briefly during our own development (weeks 4-5), but they usually close or develop into other structures
3) The Postanal Tail In all the phyla we have studied up to this point, the anus was terminal (at the tip of the tail) Chordates, on the other hand, follow the anus with a tail of variable length (again, an adaptation for locomotion). In us, the tail is short and fused (the coccyx at the base of your spine).
4) Hollow Dorsal Nerve Cord Our nerve cord, like that of other chordates is hollow (even in the adult). Well, what else is there to say?!?!?
Lets start at the very beginning . . . Phylum Chordata is divided into three subphyla: Subphylum Urochordata Subphylum Cephalochordata Subphylum Vertebrata
Subphylum Urochordata (Tunikata) Defining Characteristic : Notocorord and dorsal nerve cord present only in larval stage, being reabsorbed at metamorphosis Contoh: Molgula sp.
General featuree Reproduction: sexual and asexual (Thaliacea) Excretory system: Mostly (diffusi) some have specialized organ (renal sacs, renal vessicles) Nerve system composes of brain and cerebral ganglion
Subphylum Urochordata At first glance, you might mistake this creature for a sponge. Adult tunicates look like small sacs (about 3 cm tall) and are stationary, lacking a nerve cord, a notochord, and a post-anal tail. Lacking three of the four distinguishing hallmarks of the chordates, it would seem impossible for these animals to be placed in phylum Chordata.
Subphylum Urochordata However, tunicates begin life in a larval state, which have a post-anal tail, a nerve cord, and a notochord. Therefore, these immobile animals with tadpole-like larvae are considered chordates.
Subphylum Urochordata Urochordates have a notochord that extends from just behind the tail to the head (rather than from head to tail; Urochordata means "tail-cord") Many urochordates are more commonly referred to as sea squirts
Subphylum Urochordata The body of an adult tunicate is quite simple, being essentially a sack with large gill structures that form two siphons through which water enters and exits. Water is filtered inside the sack-shaped body.
Subphylum CephalochordataDefining Characteristics : Notochord and nerve cord are found along entire length of body and persist throughout the life cycle; The notocord is contractile, composed of longitudinal series of flattened disc containing myosin Example:Amphioxus sp.
Subphylum VertebrataDEFINING CHARACTERISTICS Vertebral column, or a chain of bony elements (vertebrae). The vertebral column more or less replaces the notochord as the chief "stiffener" of the body in locomotion. Cranium (brain case) Mostly possess paired appendages and limb girdle
Subfilum Vertebrata Ciri-ciri :1. Bony or cartilaginous vertebrae (columna vertebralis) surrounding spinal cord; notochord in all embryonic stages, persisting in some of the fishInterdorsal Spinal cord Basiodorsal Notocord Spinal cord Basiodorsal Interdorsal Basioventral Gnatostomata
Karakter lain yang dimiliki oleh Vertebrata2. Dua pasang anggota badan 3. Modifikasi kulit menjadi sisik, bulu dan rambut 4. Selom yang berisi organ2 visceral 5. Skeleton dalam (endo skeleton) yang terdiri dari skeleton utama (aksial) dan skeleton tambahan (apendikular) 6. Sistem peredaran darah tertutup dengan jantung bersekat (atrium dan ventrikel) dan pembuluh darah 8. Sistem respirasi dengan paru-paru atau insang 9. Sistem ekskresi dengan unti fungsional nefron.Sistem ini berhubungan dekat dengan sistim reproduksi dan menggunakan saluran bersama
10. Relatively large brain plus a unique set of sensory and motor cranial nerves;
Klasifikasi vertebrataSuperclass Agnata - Class Myxini - Class Cephalaspidomorphi Superclass Gnatostomata - Class Chondrichthyes - Class Sarcopterygii Sometime both classes were combined - Class Actinopterygii into a Class Osteichthyes Class Amphibia Class Reptilia Class Aves Class MamaliaKlasifikasi ini disusun berdasarkan Nelson (1994), Zug (1993), Ernst & Barbour (1989), Wilson & Reeder (1993)