Question

how do seashells form?

Answer 1

@cody7744

Answer 2

cause when i look at sand they get scared and from into a shell

Answer 3

they cant handle e

Answer 4

lol haha bueatiful face cody

Answer 5

lol

Answer 6

lol that was sucha great answer so u dont get a medal yay for u

Answer 7

you like to read right

Answer 8

read this

Answer 9

The exoskeletons of snails and clams, or their shells in common parlance, differ from the endoskeletons of turtles in several ways. Seashells are the exoskeletons of mollusks such as snails, clams, oysters and many others. Such shells have three distinct layers and are composed mostly of calcium carbonate with only a small quantity of protein--no more than 2 percent. These shells, unlike typical animal structures, are not made up of cells. Mantle tissue that is located under and in contact with the shell secretes proteins and mineral extracellularly to form the shell. Think of laying down steel (protein) and pouring concrete (mineral) over it. Thus, seashells grow from the bottom up, or by adding material at the margins. Since their exoskeleton is not shed, molluscan shells must enlarge to accommodate body growth. This pattern of growth results in three distinct shell layers: an outer proteinaceous periosteum (uncalcified), a prismatic layer (calcified) and an inner pearly layer of nacre (calcified).

In comparison, turtle shells are part of the vertebrate animal's so-called endoskeleton, or skeleton from within the body. Surface scutes are epidermal structures, like our fingernails, made of the tough protein keratin. Underneath these scutes are the dermal tissue and calcified shell, or carapace, which is actually formed by fusion of vertebrae and ribs during development. By weight, such bone consists of about 33 percent protein and 66 percent hydroxyapatite, a mineral composed largely of calcium phosphate with only some calcium carbonate. Why exoskeletons of snails and clams are calcium carbonate while the endoskeleton of vertebrates like turtles are primarily calcium phosphate is not known. Both shells are strong, allow for protection, attachment of muscles and resist dissolution in water. Evolution works in mysterious ways.

Unlike seashells, turtle shells have living cells, blood vessels and nerves, including a large number of cells on the calcareous shell surface and scattered throughout its interior. Bone cells that cover the surface and are dispersed throughout the shell secrete protein and mineral and more or less entomb themselves. The bone can grow and reshape continuously. And when a bone breaks, cells are activated to repair the damage. In fact, turtle shell grows from within just like leg bones in humans. Nutrients such as protein and calcium are supplied by blood vessels within the bone, not from outside of the bone tissue. Damaged seashells, on the other hand, use secretions of proteins and calcium from the mantle cells underneath the shell for repair.

Construction of both turtle shells and seashells share some fundamental mechanical properties. The currently accepted understanding of how shell forms is that the protein matrix of bone and seashell is secreted out of the cells. These proteins tend to bind calcium ions while guiding and directing calcification. Binding of calcium ions to the protein matrix enhances crystal formation according to precise hierarchical arrangements. Exact details of this mechanism remain unclear in both turtles and seashells, but many proteins have been isolated that are known to play a role in shell formation. Whether the calcium carbonate crystal is calcite, as in the prismatic layer, or aragonite, as in the nacre of a seashell, seems to be protein-determined. Secretion of different kinds of proteins at different times and places in the seashells seems to direct the type of calcium carbonate crystal formed. Calcified bone or shell of turtles, on the other hand, does not readily form different crystals.

Whereas turtles grow their bones like humans or other land animals and thus make more room for themselves, snails and clams have to gradually enlarge and extend their shells by adding new organic matrix and mineral to the outer margins of the shell. The newest part of the snail shell, for example, is located around the opening where the animal pokes out. The outer edge of its mantle continuously adds new shell at this opening. First, an uncalcified layer of conchiolin--protein and chitin, a strengthening, naturally produced polymer--is formed. Then comes the highly calcified prismatic layer that is followed by the final pearly layer, or nacre. The iridescence of the nacre occurs, incidentally, because crystal aragonite platelets function like a diffraction grating in dispersing visible light. Sadly, turtles lack this mechanism, which keeps their shells more dull, but their shells are perfect for hiding in the undergrowth or murky waters. Clearly, not all shells are the same.

Answer 10

Oysters, clams, snails, and certain other kinds of mollusks make seashells. The shells help protect these animals’ soft bodies from dangers such as parasites, sharp objects, heavyfooted animals, and especially from animals that would try to eat them. A shell grows as the surface of the mollusk’s body secretes a chemical that contains calcium, the same element that makes bones hard. The calcium helps form the hard shell, and when the mollusk dies, the shell is left behind.

this is a wayy better answer

Answer 11

there my answer

Answer 12

i think that covers everything

Answer 13

lol mines is still better

Answer 14

talk to the 100110011 that is my hand

Answer 15

blah blah

Answer 16

whatevs

Answer 17

lol <3

Answer 18

pm me

Answer 19

what does < 3 mean

Answer 20

heart

Answer 21

love

Answer 22

lol obviously

Answer 23

the pink thing inside you

Answer 24

really i thought it was a duck and im serious

Answer 25

*faceplam* wow

Answer 26

dont judge

Answer 27

lol ooohay lol ;-;

Answer 28

and what is ;-;

Answer 29

lol i dont judge cody cause im weird 2

Answer 30

is it a vampire

Answer 31

so am i o.o

Answer 32

wats a vamp?

Answer 33

lol no this > ;-; thats not a vampire

Answer 34

this is a vampire O,..,O

Answer 35

oh brb ok??

Answer 36

ok :P

Answer 37

then what is it

Answer 38

idk o.o tears i guess ;-;

Answer 39

k cya soon i guess

Answer 40

the life of cody

Answer 41

hello!! wassup? he left?

Answer 42

xbox, wii, food, sleep, tacos, going to football games,playing football, watching football on tv, wings, riding sport bikes, going camping, going to the dunes and girls

Answer 43

this is my life

Answer 44

lol id think u wanna hear mine

Answer 45

yes i would and i forgot one going cliff diving

Answer 46

lol ok dont say id warn u

XBOX my fav, playing basket, runnning around like a crazy person, being weird, hitting my brothers, swimming, drawing, eating food that tastes good, sleeping, going to school, riding my dirt bike, reading being a boss retricefeather!! lol and singing and playing music

Answer 47

:O

Answer 48

lolu have an xbox?? cool wass ur gamertag?

Answer 49

i do its just my dads

Answer 50

OHHH

Answer 51

my friend has one thought he might add you

Answer 52

Well anyway my gamertag is Farie Queen1

Answer 53

ur freind??

Answer 54

yes y?

Answer 55

ur freinds gonna add me and u ask me y??

Answer 56

what games are you good at

Answer 57

on xbox? lol alot gta 5, minecraft, grand theft auto, destiny, disney infity, um just dance

Answer 58

yup thats all i can see right now

Answer 59

i love destiny what level are you

Answer 60

lol 15

Answer 61

im almost done yay!!!!

Answer 62

thats nice

Answer 63

lol u?

Answer 64

20

Answer 65

ohhh cool!!!!

Answer 66

u finsished

Answer 67

no what do you mean finished

Answer 68

the game.. inst there on 20 levels???

Answer 69

ohhhhhhh i meant the level of your person

Answer 70

oh ok well i gtg byeee luv ya guys :D

Answer 71

btw you may want to close this question o.o

Answer 72

lol ik i was just gonna do it thx!! cya 2mrrw maybe

Answer 73

ok :333

Answer 74

ok