What is a major difference between adult sea urchin and a larval sea urchin?
83720
Adult sea urchins are radially symetrical. Larval sea urchins start out bilaterally symetrical. \n\nAdult sea urchins are move exclusively by crawling whereas larval urchins are free swimming.
1057715
Juvenile or adult blue crabs can tolerate a wide range of salinities and water temperatures in contrast to the zoeae and megalopae. Juveniles and adults are exposed to a salinity range of 0 to 35 ppt.
995191
They're critters that permanently attach themselves to something and live out their lives there, like many sea creatures- usually they are motile as larvae and then settle on an object as an adult. Very few are sessile their entire lifespan but many many spend their adulthood that way.\n\nExamples- barnacles, sponges, corals\n\nWhen applied to plants (I assumed you meant animals, but just in case... ) it refers to leaves or stems that grow directly from the stem without a stalk.
666290
Echinoderms are not segmented, as others have already said.\nAnd the word "echinodermarta" literally means "spiny skin", and they do have skeletal "plates" on their outsides, though in some echinoderms (like sea cucumbers) these are kind of soft.
468701
Depends on which part of the life cycle and which species.  For example, some species have a laval life span of several years, and an adult (breeding stage) life span of weeks to months...
992190
an immature cell is a newly born cell which was just produced by the process of cell division.it differentiates and matures to form certain kind of cell to perform it's specific function.\nfor example in animals, an immature cell consisting of all the cell organelles, but as u know that the cells in each tissue in an animal's body is so different.thus the immature cell differentiates or develops and takes the form of the cell that is need in the particular tissue.\nsee, a neuron,the nerve cell that is,doesn't have a centriole because the mature neuron cells don't need them as mature neuron cells don't divide,and that is the reason why when one has a head injury,its hard to recover.\ntake for instance an RBC in the blood tissue doesn't have a nucleus while WBCs have differently shaped nucles having lobes or in the shape of kidney etc.\nso this means each tissue has a different cell.hence the immature cells have to develop themselves as per the need of the body.\nsame thing happens in the plant cell . just that the tissues are entirely different from that of the animal's and here in plant cell an immature cell has the ability to divide,called meristematic cell.these cells after the growth of the plant becomes mature,differentiate and form permanent non dividing cells.\nthese permanent cell again de-differentiates for the secondary growth in the plant and starts dividing again.\neach tissue of the plant body has different types of cells...\n\nand chondroblasts are the same in the case of animals.\nthese are cells found in the cartilage tissue.these are immature cells which develops to form mature chondrocytes.\nnote : the cartilage tissue is mostly connected to the areolar connective tissue for the nourishment of the chondrocytes present in the cartilage as the cartilage doesn't have a blood supply but the connective tissue does.and the chondroblasts are the immature cells present in the connective tissue which moves to the cartilage tissue and forms a part of the cartilage as chondrocytes.
952433
The adult's plumage is black and white. Its facial skin is yellow (it turns orange during nesting periods) and devoid of feathers. The tail is wedged and easily distinguished in flight. The nestlings are dark brown and gradually go light until they reach adulthood at the age of 5.\n\nYou could get more information from the link below...
4558
After the last of several molts the larva is transformed into a pupa with a hard, often sculptured outer integument, within which it changes to the adult form. The butterfly pupa is called a chrysalis, or chrysalid. Most chrysalids (unlike the pupae of most moths) are not enclosed in a cocoon; however, they are usually suspended from some object by a silken thread and may have a partial covering. Except in those species that winter in the pupa stage, the adult usually emerges from the integument in two or three weeks. Members of some species winter in the egg stage, others as larvae or adults. The adults of most species, however, live only about a month.
420240
Most starfish reproduce in a method similar to the sponge. The starfish gather in a group (using environmental signals to coordinate the timing), metamorphose into juvenile sea stars and can begin living on the ocean floor.\n\nSea stars are developmentally (embryologically) known as deuterostomes. Since echinoderms and chordates share this same embryological pattern, they are thought to be closely related. Nevertheless, as these creatures are invertebrates and not actually fish, most marine biologists are pushing to completely replace the term starfish with sea star.
301358
Nearly all animals undergo some form of sexual reproduction. Adults are diploid or occasionally polyploid. They have a few specialized reproductive cells, which undergo meiosis to produce smaller motile spermatozoa or larger non-motile ova. These fuse to form zygotes, which develop into new individuals.\n\nMany animals are also capable of asexual reproduction. This may take place through parthenogenesis, where fertile eggs are produced without mating, or in some cases through fragmentation.\n\nA zygote initially develops into a hollow sphere, called a blastula, which undergoes rearrangement and differentiation. In sponges, blastula larvae swim to a new location and develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement. It first invaginates to form a gastrula with a digestive chamber, and two separate germ layers - an external ectoderm and an internal endoderm. In most cases, a mesoderm also develops between them. These germ layers then differentiate to form tissues and organs.\n\nAnimals grow by indirectly using the energy of sunlight. Plants use this energy to turn air into simple sugars using a process known as photosynthesis. These sugars are then used as the building blocks which allow the plant to grow. When animals eat these plants (or eat other animals which have eaten plants), the sugars produced by the plant are used by the animal. They are either used directly to help the animal grow, or broken down, releasing stored solar energy, and giving the animal the energy required for motion. This process is known as glycolysis.
385579
Caddisfly larvae, a variety of insect in the order Trichoptera, construct an outer casing made of silk and pebbles.  They will wear this until they reach adulthood.  You could say the same for a cocoon on a moth or butterfly pupa, a shell on a clam, or the outer casing on a barnacle or tube worm, but these are all constructed strictly from secretions made by the body.  Caddisflies are the only things I can think of that actually construct an outer layer with the tools at hand (plus bodily secretions).  Hermit crabs will find a shell of a gastropod to live in until they grow out of it and need a new one.
279735
Well, with regards to animal science, direct development is the type of development in which there are no larval/nymphal or other intermediate stages in life between the egg (or birth) and the adult morphology. \nWhen there is indirect development, the animals that hatches or emerges is more or less different from the adult and has to undergo metamorphosis.
110483
Very true. Mollusc anatomy and physiology could fill a book.  Anatomy of a snail? A squid? A chambered Nautilus? A seahare? They are all molluscs yet very widely in their anatomy and physiology.\n\nThe books the above poster referenced are excellent college level texts that cover most invertebrate life.  I would also suggest for a more simple approach the Marine Biology Coloring Book. It is not a kids book, but has some good diagrams on a variety of molluscs.\n\nThere are a number of websites that have valid information as well. If you edit your questions, I can post some links to specific species informative web sites.
897987
Because they develop similarly. Read this: http://www.ucmp.berkeley.edu/chordata/chordata.html
366521
In insects that exhibit paurometabolous or hemimetabolous metamorphsosis (an 'incomplete' metamorhphosis in which there is no pupal stage), the juvenile stage (between egg and adult) is known as a nymph.  In aquatic forms, like dragonflies or mayflies, it is also sometimes referred to as a naeid.\n\nBTW:  Why is this in Earth Science?
837167
Sea stars or starfish are marine invertebrates belonging to the phylum Echinodermata, class Asteroidea. The names sea star and starfish are also (incorrectly) used for the closely related brittle stars, which make up the class Ophiuroidea. They exhibit a superficially radial symmetry. Starfish typically have five or more "arms" which radiate from an indistinct disk (pentaradial symmetry). In fact, their evolutionary ancestors are believed to have had bilateral symmetry, and sea stars do exhibit some superficial remnant of this body structure.\n\nSea stars do not have movable skeletons, but instead possess a hydraulic water vascular system. The water vascular system has many projections called tube feet, located on the ventral face of the sea star's arms, which function in locomotion and aid with feeding.\n\nDistribution\nThere are about 1,800 living species of sea star, and they occur in all of the Earth's oceans. The greatest variety of sea stars are found in the tropical Indo-Pacific. Areas known for their great diversity include the tropical-temperate regions around Australia,the tropical East Pacific, and the cold-temperate water North Pacific (California to Alaska). Asterias is a common genus found in European waters and on the eastern coast of the United States; Pisaster, along with Dermasterias ("leather star"), are usually found on the western coast. Habitats could range from tropical coral reefs, kelp forests to deep-sea floor, although none of them live within the water column; all species of sea stars found are living as benthos. Echinoderms need a delicate internal balance in their body, no sea stars are found in freshwater environments.\n\nYou could get more information from the link below...
468060
crao_craz is correct.  \n\nOne of the main differences in the two groups is in the form of the pen/cuttlebone.\n\nCephalopod groups differ in the level to which they have retained or lost the shell ancestral to their mollusc lineage.\n\nThe extinct ammonites had a large, robust shell that protected their body and also provided ballast and buoyancy for deep diving.\n\nThe modern nautilus has a shell, but it is not as robust as the ammonite shells were.\n\nAnother extinct group, the belemnites, had an internal shell, used primarily for buoyancy issues.  It looked almost like a cigar encasing the rear portion of their anatomy.\n\nCuttlefish also have the remnant of an internal shell.  It's essentially a turtle-like shield of bone that sits on the back of the animal.  It is porous and can trap gases, useful as ballast.  They used to use this cuttlebone for a number of purposes, including maintaining/sharpening the beaks of pet birds.  You can still buy cuttlebones for this purpose, and they're still in the cuttlebone shape, but are no longer made from actual cuttlefish bone.\n\nIn squids, the shell is reduced to nothing but a pen.  This is a sheet of stiffening cartilage-like material in the mantle that provides support and structure to the squid's body.  In most species it's transparent, and about the thickness and consistency of the plastic they use to make blister packs of batteries.\n\nIn octopus, the pen is gone completely, allowing them to squeeze through cracks and crevices as long as they can fit their eyeballs and beaks through.