Define the following terms and describe their significance in classifying animals.?

Question

Acoelomates
Pseudocoelomates
Coelomates
Protostomates
Deuterostomes
spiral, determinate cleavage
radial, indeterminate cleavage
blastopore

Answer 1

Acoelomates ---- Acoelomate animals, like flatworms, have no body cavity at all. Organs have direct contact with the epithelium. Semi-solid mesodermal tissues between the gut and body wall hold their organs in place.

Pseudocoelomates ---- Pseudocoelomate animals have a pseudocoel, (literally “false cavity”) which is fully functional body cavity. Tissue derived from mesoderm only partly lines the fluid filled body cavity of these animals. Thus, although organs are held in place loosely, they are not as well organized as in a coelomate. All pseudocoelomates are protostomes; however, not all protostomes are pseudocoelomates.

Coelomates --- Coelomate animals (also known as eucoelomates--"true coelom") have a fluid filled body cavity called a coelom with a complete lining called peritoneum derived from mesoderm (one of the three primary tissue layers). The complete mesoderm lining allows organs to be attached to each other so that they can be suspended in a particular order while still being able to move freely within the cavity. Most bilateral animals, including all the vertebrates, are coelomates.

Protostomes ----animals with bilateral symmetry and three germ layers. In protostome development, the first opening in development, the blastopore, becomes its mouth.Protostomes have what is known as spiral cleavage which is determinate, this meaning that the fate of the cells is determined as they are formed.Protostomes are schizocoelomates, meaning a solid mass of the embryonic mesoderm split to form a coelom.

protostome animals can be divided into three major groups:

* Ecdysozoa, e.g. arthropods and roundworms
* Lophotrochozoa, e.g. molluscs and annelids
* Platyzoa, e.g. flatworms


Deuterostomes ---- Deuterostomes are distinguished by their embryonic development; in deuterostomes, the first opening (the blastopore) becomes the anus.In deuterostomes, the early divisions occur parallel or perpendicular to the polar axis. This is called radial cleavage, and also occurs in certain protostomes, such as the lophophorates. Cleavage is indeterminate - the cells' fates are not determined early on. Thus if the first four cells are separated, each cell is capable of forming a complete small larva, and if a cell is removed from the blastula the other cells will compensate.In deuterostomes the mesoderm forms as evaginations of the developed gut that pinch off, forming the coelom. This is called enterocoely.

There are four living phyla of deuterostomes:

* Phylum Chordata (vertebrates and their kin)
* Phylum Echinodermata (starfishes, sea urchins, sea cucumbers, etc.)
* Phylum Hemichordata (acorn worms and possibly graptolites)
* Phylum Xenoturbellida (2 species of worm-like animals from the Baltic Sea)

Spiral, determinate cleavage ---- In embryonic development, spiral cleavage is one of two types of holoblastic or complete cleavage. At the third cleavage the halves are oblique to the polar axis and typically produce an upper quartet of smaller cells that come to be set between the furrows of the lower quartet. All groups showing spiral cleavage are protostomia.

Radial, indeterminate cleavage --- Radial cleavage is a cleavage pattern characteristic of some animal groups, for instance vertebrates and echinoderms, in which the spindle axes are parallel or at right angles to the polar axis of the oocyte

Blastopore --- A blastopore is an opening into the archenteron during the embryonic stages of an organism. The distinction between protostomes and deuterostomes is based on the direction in which the mouth (stoma) develops in relation to the blastopore.

Answer 2

RE:
Define the following terms and describe their significance in classifying animals.?
Acoelomates
Pseudocoelomates
Coelomates
Protostomates
Deuterostomes
spiral, determinate cleavage
radial, indeterminate cleavage
blastopore

Answer 3

define terms describe significance classifying animals

Answer 4

Acoelomate Definition

Answer 5

For the best answers, search on this site https://shorturl.im/av4BJ

Do Your Own Homework