Fruit or vegetable — Do you know the difference?
By Jennifer K. Nelson, R.D., L.D. and Katherine Zeratsky, R.D., L.D. August 15, 2012
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According to botanists (those who study plants) a fruit is the part of the plant that develops from a flower. It's
also the section of the plant that contains the seeds. The other parts of plants are considered vegetables.
These include the stems, leaves and roots — and even the flower bud.
The following are technically fruits: avocado, beans, peapods, corn kernels, cucumbers, grains, nuts, olives
peppers, pumpkin, squash, sunflower seeds and tomatoes. Vegetables include celery (stem), lettuce (leaves),
cauliflower and broccoli (buds), and beets, carrots and potatoes (roots).
From a culinary standpoint, vegetables are less sweet — or more savory — and served as part of the main
dish. Fruits are more sweet and tart and are most often served as a dessert or snack. Both fruits and
vegetables can be made into juice for a refreshing beverage. Some fruits are "grains" or "nuts" or "seeds" —
and are served accordingly.
Matt, like you, I was taught simply that a vegetable is a root, stem or leaf, and that just about everything else is a fruit. I wasn't
really sure about the corn and nut thing, so after consulting several encyclopedias and my old botany textbook, I found the
following definition, which all sources seem to basically agree upon:
A fruit is the matured ovary of a flower, containing the seed. After fertilization takes place and the embryo (plantlet) has begun
to develop, the surrounding ovule becomes the fruit. Yum. I won't go on about the four types of fruit--simple, aggregate,
multiple and accessory--which explain things like berries and pineapples.
A vegetable is considered to be edible roots, tubers, stems, leaves, fruits, seeds, flower clusters, and other softer plant parts. In
common usage, however, there is no exact distinction between a vegetable and a fruit. The usual example is the tomato, which
is a fruit, but is eaten as a vegetable, as are cucumbers, peppers, melons, and squashes. The classification of plants as
vegetables is largely determined by custom, culture, and usage.
Okay, now the part which may surprise you. A grain is described as the dry fruit of a cereal grass, such as the "seedlike fruits of
the buckwheat and other plants, and the plants bearing such fruits." So, grain is also a fruit.
Which brings us to the nut. Yes, you guessed it, a nut is, in botany, "a dry, one-seeded, usually oily fruit." True nuts include
the acorn, chestnut, and hazelnut. The term nut also refers to any seed or fruit with a hard, brittle covering around an edible
kernel, like the peanut, which is really a legume. A legume is defined as "(the) name for any plant of the pulse family; more
generally, any vegetable. Botanically, a legume--a pod that splits along two sides, with the seeds attached to one of the
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sutures--is the characteristic fruit of the pulse family." Say what? A "pulse" is "the common name for Leguminosae or
Fabaceae, a large family of herbs, shrubs, and trees, also called the pea, or legume, family. " Please, make it stop!
So I guess we have learned today that just about everything is a fruit, unless of course, it's a vegetable or a legume. Aren't you
glad you asked?
— Terey
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The Difference Between Fruits and Vegetables
TERYNN BOULTON SEPTEMBER 4, 2013 4
Candace asks: What makes a fruit a fruit and a vegetable a vegetable?
An apple is a fruit, right? So is a banana. How about a cucumber? A
vegetable, right? Not really, from a botanical standpoint.
The good news is that, nutritionally speaking in terms of what you should eat daily, fruits and vegetables are typically grouped
together, so you can simply pick your favorites and eat away without completing a science degree. The surprising news is that,
scientifically speaking, many of the foods we refer to as vegetables are actually fruits!
For instance, would you believe that beans, corn, bell peppers, peas, eggplant, pumpkins, cucumbers, squash and tomatoes are all
fruits? That’s because, botanically speaking, fruits are the part of flowering plants that contain the seeds and are the means by
which such plants disseminate those seeds.
So even nuts are fruits. Grains, which are really just oversized seeds, are also fruits.
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So what about vegetables? Botanically speaking, vegetables are all the other parts of the plant, including the leaves (e.g. lettuce
and spinach), roots (e.g. carrots and radishes), stems (e.g. ginger and celery) and even the flower buds (e.g. broccoli and
cauliflower).
To sum it up – if it is from a plant and has seeds (or would have seeds if it wasn’t genetically engineered or cultivated to not have
them, as with things like seedless grapes), it is a fruit; if it doesn’t, it is a vegetable.
So why in the world do we learn that such things as peppers, corn and cucumbers are vegetables? Why when we shop in the
produce section of the grocery store are these foods found in the veggie section? We can blame it on the culinary traditions where
the part of the plant we are eating does not generally matter in terms of its classification - taste does! When it comes to cooking,
fruits are generally sweet tasting and vegetables are more savory and less sweet. Fruits are also typically served as part of dessert
or as snacks, and vegetables are often part of the main dish.
So, in the end, the scientific classification system makes a clear dividing line between fruits and vegetables as described above,
while the culinary system of classification is considerably more ambiguous, hence why so many are confused as to what is a
vegetable and what is a fruit. But, at least now you needn’t be confused any longer.
If you liked this article, you might also enjoy:
The Color Orange was Named After the Fruit
Almonds are Not Nuts
15 Facts You Probably Didn’t Know About Bananas
The Difference Between Jelly and Jam
Carrots Used to Be Purple Before the 17th Century
Bonus Facts:
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China is the leading cultivator of vegetables in the world, with top productions in potato, onions, cabbage, lettuce, tomatoes and broccoli.
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Apples float in water because they are 25% air which makes bobbing for apples at Halloween so much easier… though still not exactly hygienic.
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The Cavendish banana is the most common type of banana sold today even though it has only been in existence since 1836. Further, just a bit
over a half century ago, exceptionally few stores carried them. At that time, the Gros Michel banana was king, before being nearly wiped out on a
global scale quite suddenly thanks to a certain type of fungus. More here: Commercial Banana Plants are All Perfect Clones of One Another
The term “Adam’s apple” came from the notion that the forbidden “apple” (not actually originally thought to have been an apple) got stuck in
Adam’s throat when he swallowed it.
Dirty cantaloupes can spread bacteria. In 2011, 21 people died in the United States from cantaloupes harboring listeria bacteria.
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Although the United States Supreme Court did acknowledge that, botanically speaking, a tomato is a fruit, the court ruled unanimously in Nix v.
Hedden that a tomato is correctly identified as, and thus taxed as, a vegetable, for the purposes of the Tariff of 1883 on imported produce.
Tomatoes are the world’s most popular fruit! More than 60 million tons are produced every year. The banana is the second most popular fruitm
with 44 million tons of bananas produced every year.
Peppers have their own heat scale. Yes, the heat of a pepper is measured in scoville units and ranges from 0 (like that of a green pepper) to
1,000,000 scoville units. The only pepper that measures 1,000,000 scoville units is the bhut jolokia pepper from India. It is so strong that the Indian
militia has started putting it in grenades to immobilize crowds and fight terrorists.
Sponge

Animal
 Sponges are animals of the phylum Porifera. They are multicellular organisms that have bodies full of pores and channels allowing water
to circulate through them, consisting of jelly-like mesohyl sandwiched between two thin layers of cells. Wikipedia
  Scientific name: Porifera
 Rank: Phylum
 Higher classification: Parazoa
 Lower classifications: Hexactinellid, Homoscleromorpha, Demosponge,Calcareous sponge
Poriferans are commonly
referred to as sponges. An early branching event in the history of animals separated the sponges from
other metazoans. As one would expect based on their phylogenetic position, fossil sponges are among
the oldest known animal fossils, dating from the Late Precambrian. Since then, sponges have been
conspicuous members of many fossil communities; the number of described fossil genera exceeds 900.
The approximately 5,000 living sponge species are classified in the phylum Porifera, which is
composed of three distinct groups, the Hexactinellida (glass sponges), the Demospongia, and
the Calcarea (calcareous sponges).
Sponges are characterized by the possession of a feeding system unique among animals. Poriferans
don't have mouths; instead, they have tiny pores in their outer walls through which water is drawn.
Cells in the sponge walls filter goodies from the water as the water is pumped through the body and
out other larger openings. The flow of water through the sponge is unidirectional, driven by the
beating of flagella which line the surface of chambers connected by a series of canals. Sponge cells
perform a variety of bodily functions and appear to be more independent of each other than are the
cells of other animals.
There is an exception to the general description of sponge feeding that you just read above. Read
more in the Life History & Ecology section to learn about the weird and interesting carnivorous
sponges.
Sponge Note:
The sponges in the image above are Clathria basilana (Levi, 1959) and Haliclona
fascigera (Hentschel, 1912). Identification provided over the net by spongiologist Rob van Soest
of the Institute for Systematics and Population Biology (Zoologisch Museum), University of
Amsterdam. Thanks!
Label Sponge: Cross-Section
Label Sponge: External
Sponge Coloring/Info. Printout
EnchantedLearning.com
Sponges
Animal Printouts
Label Me! Printouts
Sponges (poriferans) are very simple animals that live permanently
attached to a location in the water - they are sessile as adults. There are
from 5,000 to 10,000 known species of sponges. Most sponges live in
salt water - only about 150 species live in fresh water. Sponges
evolved over 500 million years ago.
The body of this primitive animal has thousands of pores which let
water flow through it continually. Sponges obtain nourishment and
oxygen from this flowing water. The flowing water also carries out
waste products.
Anatomy: The body of a sponge has two outer layers separated by
an acellular (having no cells) gel layer called the mesohyl (also called
the mesenchyme). In the gel layer are either spicules (supportive
needles made of calcium carbonate) or spongin fibers (a flexible skeletal material made from protein).
Sponges have neither tissues nor organs. Different sponges form different shapes, including tubes, fans,
cups, cones, blobs, barrels, and crusts. These invertebrates range in size from a few millimeters to 2 meters
tall.
Diet: Sponges are filter feeders. Most sponges eat tiny, floating organic particles and plankton that they
filter from the water the flows through their body. Food is collected in specialized cells
called choanocytes and brought to other cells by amoebocytes.
Reproduction: Most sponges are hermaphrodites (each adult can act as either the female or the male
in reproduction). Fertilization is internal in most species; some released sperm randomly float to another
sponge with the water current. If a sperm is caught by another sponge's collar cells (choanocytes),
fertilization of an egg by the traveling sperm takes place inside the sponge. The resulting tiny larva is
released and is free-swimming; it uses tiny cilia (hairs ) to propel itself through the water. The larva
eventually settles on the sea floor, becomes sessile and grows into an adult.
Some sponges also reproduce asexually; fragments of their body (buds) are broken off by water currents
and carried to another location, where the sponge will grow into a clone of the parent sponge (its DNA is
identical to the parent's DNA).
Classification:
Kingdom Animalia (animals)
Phylum Porifera (sponges)
Classes: Calcarea (calcerous sponges - having
spicules), Demospongiae (horn sponges, like the
bath sponge), Scleropongiae (coralline or tropical
reef sponges), and Hexactinellida (glass sponges).
Glossary of Sponge Terms:
archaeocytes (amoebocytes) - Cells
with pseudopods, located in the mesohyl. They are
used in processing food, distributing it to other
cells, and for other functions.
benthic - living at or near the bottom of the seas.
choanocyte - also called collar cells, choanocytes line the inner cavity of the sponge. They have a
sticky, funnel-shaped collar (that collects food particles) and a flagellum (which whips around, moving
water). The sponge obtains its nutrients and oxygen by processing flowing water using choanocytes.
Choanocytes are also involved in sponge reproduction; they catch floating sperm.
epidermis (pinacocyte) - the epidermis is the layer of cells that covers the outer surface of the
sponge. The thin, flattened cells of the epidermis are called pinacocytes.
flagellum - the whip-like structure of a choanocyte; the flagellum moves, pushing water (which contains
nourishment) through the sponge.
hermaphrodite - an animal in which each adult can act as either the female or the male in
reproduction.
holdfast - root-like tendrils that attach the sponge to rocks.
invertebrate - an animal without a backbone.
mesohyl (mesenchyme) - the gelatinous layer between the outer body of the sponge and the
spongocoel (the inner cavity).
osculum - a large opening in a sponge through which water flows out of the sponge. Sponges may have
more than one oscula.
ostia - a series of tiny pores all over the body of a sponge that let water into the sponge. One of these is
called an ostium.
pinacocyte - pinacocytes are the thin, flattened cells of the epidermis, the sponge's outer layer of cells.
porocyte - cells with pores that allow water into the sponge; they are located all over the sponge's body.
sessile - permanently attached to a substrate and unable to move on its own. Adult sponges are sessile.
spicule - spicules are sharp spikes (made of calcium carbonate) located in the mesohyl. Spicules form the
"skeleton" of many sponges.
spongin - the flexible, fibrous fibers that form the skeleton of horny sponges; spongin is located within
the mesohyl.
spongocoel - the central, open cavity in a sponge through which water flows.
water flows into the sponge - water flows into a sponge through cells with pores (these cells are
called porocytes) located all over its body.
water flows out of the sponge - water flows out of a sponge through large openings called
oscula (plural). Each of these large openings is called an osculum.
Related Pages:
Sponge
Coloring/Information
Printout
A printable coloring/information
page about sponges.
Sponge External
Anatomy: Label Me!
Printout
Label the external anatomy of a Label the cross-section of a sponge
sponge and the flow of water
and the flow of water through it.
through it.
Answers
Answers
Invertebrates
Invertebrates are animals that
lack a backbone.
Sponge Internal
Anatomy: Label Me!
Printout
Ocean Animals
Coral Reef Animals
The seas and oceans of the
world are teeming with life.
Coral reefs are warm, clear, shallow
ocean habitats that are rich in life.
Sponge Links:
Animal Diversity Web: Phylum Porifera by the University of Michigan Museum of Zoology
The Sponge Reef Project
Sponges and Hermit Crabs, by Floyd Sandford
http://www.enchantedlearning.com/subjects/invertebrates/sponge/
Cnidaria

Animal
 Cnidaria is a phylum containing over 10,000 species of animals found exclusively in aquatic and mostly marine environments. Their
distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey.Wikipedia
  Scientific name: Cnidaria
 Rank: Phylum
 Higher classification: Eumetazoa
 Lower classifications: Anthozoa, Jellyfish
Introduction to Cnidaria
Jellyfish, corals, and other stingers
Cnidarians are incredibly diverse in form, as evidenced by colonial siphonophores,
massive medusae and corals, feathery hydroids, and box jellies with complex eyes.
Yet, these diverse animals are all armed with stinging cells called nematocysts.
Cnidarians are united based on the presumption that their nematocysts have been
inherited from a single common ancestor.
The name Cnidaria comes from the Greek word
"cnidos," which means stinging nettle. Casually touching many cnidarians will make it clear how
they got their name when their nematocysts eject barbed threads tipped with poison.
Many thousands of cnidarian species live in the world's oceans, from the tropics to the poles, from
the surface to the bottom. Some even burrow. A smaller number of species are found in rivers
and fresh water lakes.
There are four major groups of cnidarians:
Anthozoa, which includes true corals, anemones, and sea pens;
Cubozoa, the amazing box jellies with complex eyes and potent toxins;
Hydrozoa, the most diverse group with siphonophores, hydroids, fire corals, and many medusae;
and
Scyphozoa, the true jellyfish.
http://www.ucmp.berkeley.edu/cnidaria/cnidaria.html
CNIDARIANS: SIMPLE ANIMALS WITH A STING!
The Tealia anemone is a good example of an Anthozoan.
These flower-like animals resemble plants, but they have a mouth
at the center of their tentacles, and a primitive digestive system.
© Jonathan Bird/ORG
For educational use only.
The phylum Cnidaria (pronounced nid-AIR-ee-ah) contains
approximately 9000 living species worldwide. They are among
the simplest of the so-called "higher" organisms, but are also
among the most beautiful. The creatures in this phylum are
radially symmetrical. This means that the parts of the body
extend outward from the center like the spokes on a bicycle
wheel. A common example of radial symmetry is the sea star (a
member of the Echinoderm phylum) or the anemone, a Cnidarian
(seen below).
The Cnidarians include the hydroids, jellyfish, anemones, and
corals. All Cnidarians have tentacles with stinging cells in their
tips which are used to capture and subdue prey. In fact, the
phylum name "Cnidarian" literally means "stinging creature." The
stinging cells are called cnidocytes and contain a structure called
a nematocyst. The nematocyst is a coiled thread-like stinger.
When the nematocyst is called upon to fire, the thread is
uncoiled, and springs straight. The harpoon-like thread punctures
through the cnidocyte wall and into the prey. Most Cnidarians
also have a toxin in their stinger which helps to disable the prey.
The nematocyst is fired either by the tentacle touching
something, or in some cases by a nerve impulse from the animal
telling it to fire.
The two different forms of a Cnidarian body.
Most Cnidarian's nematocysts are not harmful to humans, as the
stinger cannot penetrate sufficiently into human skin to inflict any
harm. There are some jellyfish, however, which can deliver
extremely painful, and in a few cases, even fatal, stings to
humans.
The Cnidarian can have one of two basic body types, polypoid or
medusoid. The polypoid (POL-ip-oyd) is the configuration of
corals and anemones, with the tentacles and mouth generally
facing up, and the other side affixed to a substrate or connected
to a colony of other creatures of the same species. In the
Medusoid, the organism is essentially upside-down, with the
mouth and tentacles generally pointed down. These types of
Cnidarians are usually free-swimmers, like jellyfish. This is why
the anemone is sometimes called an upside-down jellyfish; that's
just about what it is!
The Phylum is divided up into 3 Classes, called the Hydrozoans
(meaning "water-animals"), the Anthozoans (meaning "Floweranimals") and Scyphozoans (meaning "bowl-animals").
A coral colony consists of hundreds or thousands of tiny
polyps. Each polyp is an individual animal (basically a small
anemone) but they live together as a group.
HYDROZOANS
The Hydrozoans (hydroids) and Anthozoans (anemones, corals)
are mostly all bottom dwelling animals, in a polypoid shape. This
means that they live attached to the bottom with their tentacles
and mouth pointing up. The northern Red Anemone is a good
example of an Anthozoan. Some are solitary, meaning that they
live alone, but some are colonial, meaning that they live in
groups, connected together with living tissue, and share food
resources.
SCYPHOZOANS
The Scyphozoans (SKY-foe-zo-ans) are the animals we call
jellyfishes, although since they aren't real fishes, a better word is
"jellies." The jellies drift along in the water generally with the
mouth and tentacles pointing down. We call this a medusoid
body form. Some jellies are extremely venomous to humans.
Some can even kill people with enough contact of tentacle on
bare skin, but most are not that dangerous, producing only a mild
rash similar to that caused by poison ivy.
Watch the new free internet TV series about the
underwater world:
The Lion's Mane Jelly is a venomous Scyphozoan which can
sting people with its long tentacles. Since the tentacles can
hang so far down, the jelly can use these tentacles to kill fish
which swim through them without ever seeing the jelly itself
way up above! This is an example of a cnidarian with
a medusoidshape.
JONATHAN BIRD'S BLUE WORLD
The are Pink Hearted hydroids, members of the class
Hydrozoa. They look like delicate plants but they are animals
that sting and capture food.
This is fire coral. It has a potent sting that leaves an itchy rash
on human skin. It is not technically a coral, but a kind of
hydroid that encrusts other objects (including other corals).
All images on these pages for non-profit educational use only.
update 6/5/07
Flatworm

Animal
 The flatworms, or Platyhelminthes or Plathelminthes are a phylum of relatively simple bilaterian, unsegmented, soft-bodied
invertebrates. Wikipedia
  Scientific name: Platyhelminthes
 Rank: Phylum
 Higher classification: Platyzoa
 Lower classifications: Trematoda, Turbellaria, Cestoda
Introduction to the Platyhelminthes
Life in two dimensions. . .
The simplest animals that are bilaterally symmetrical and triploblastic (composed of three fundamental cell
layers) are the Platyhelminthes, the flatworms. Flatworms have no body cavity other than the gut (and the
smallest free-living forms may even lack that!) and lack an anus; the same pharyngeal opening both takes in
food and expels waste. Because of the lack of any other body cavity, in larger flatworms the gut is often
very highly branched in order to transport food to all parts of the body. The lack of a cavity also constrains
flatworms to be flat; they must respire by diffusion, and no cell can be too far from the outside, making a
flattened shape necessary.
Life without a coelom : The image at left is a fluke (possibly a species of Probolitrema). Flukes, like other parasitic flatworms, have
complex life cycles often involving two or more host organisms. At right, a planarian (Dugesia). Planarians are free-living
flatworms, and have a much simpler life history. They inhabit freshwater, and are carnivores (even without teeth) or scavengers.
Most are less than a centimeter long. (Click on either of the pictures above for a larger image).
Flatworms were once divided into three groups. The mostly free-living Turbellaria include the
planarian, Dugesia, shown above; these are found in the oceans, in fresh water, and in moist terrestrial
habitats, and a few are parasitic. The Trematoda, or flukes, are all parasitic, and have complex life cycles
specialized for parasitism in animal tissues. Members of one major taxon of flukes, the Digenea -- which
includes the human lung fluke depicted at right -- pass through a number of juvenile stages that are parasitic
in one, two, or more intermediate hosts before reaching adulthood, at which time they parasitize
a definitive host. The Cestoda, or tapeworms, are intestinal parasites in vertebrates, and they also show
anatomical and life history modifications for parasitism.
It now seems likely that the first two of these groups are paraphyletic; that is, they contain some but not all
descendants of a common ancestor. Recent molecular studies suggest that the Platyhelminthes as a whole
may even be polyphyletic, having arisen as two independent groups from different ancestral groups. If this
latter view is correct, then most of the flatworms may belong to the Lophotrochozoa, a large group within
the animal kingdom that includes molluscs and earthworms, while the rest belong near the base of animal
diversity.
Marine flatworms : The marine flatworms (polycladids) are the largest of the free-living flatworms, sometimes reaching lengths of
15 centimeters. Polycladids get their name from their highly branched digestive cavity. These individuals were photographed on a
reef near the island of Guam. (Click on either of the pictures above for a larger image).
Platyhelminths have practically no fossil record. A few trace fossils have been reported that were probably
made by platyhelminths (Alessandrello et al., 1988), and fossil trematode eggs have been found in Egyptian
mummies and in the dried dung of Pleistocene ground sloth. Trematode larvae that parasitize molluscs may
leave pits or thin spots on the inside of the shell, and these pits may be recognized on fossil shells. If the
mollusc is irritated by the presence of trematode larvae, it may be able to surround them with layers of
shelly material - and thus do parasites become natural pearls.
Images of a number of free-living and parasitic flatworms, from Rudolph Leuckart's 19th century
zoological wall charts, are available (look for "Platodes" in the index). More detailed classification of
platyhelminths is available from the Tree of Life at the University of Arizona.
To find out more about tapeworms and flukes that cause human disease, read this handbook published by
the U.S. Food and Drug Administration, view these pages produced by the World Health Organization. The
disease schistosomiasis, or bilharzia, is a serious health problem in many parts of the world; you can learn
more about it from the World Health Organization.
1. See results about
2.
Ascaris lumbricoides
Ascaris lumbricoides is the giant roundworm of humans, belonging to the phylum Nematoda. An ...
3.
Nematode
The nematodes or roundworms constitute the phylum Nematoda. They are a diverse animal phylum ...

Nematode
 The nematodes or roundworms constitute the phylum Nematoda. They are a diverse animal phylum inhabiting a very broad range of
environments. Wikipedia
  Scientific name: Nematoda
 Rank: Phylum
 Higher classification: Nematoida
 Lower classifications: Adenophorea, Secernentea
Nematodes
(Rhabditida: Steinernematidae & Heterorhabditidae)
By David I. Shapiro-Ilan, USDA-ARS, SEFTNRL, Byron, GA &
Randy Gaugler, Department of Entomology, Rutgers University, New Brunswick New Jersey
Nematodes are simple roundworms. Colorless, unsegmented, and lacking appendages, nematodes may be free-living, predaceous, or parasitic.
Many of the parasitic species cause important diseases of plants, animals, and humans. Other species are beneficial in attacking insect pests,
mostly sterilizing or otherwise debilitating their hosts. A very few cause insect death but these species tend to be difficult (e.g., tetradomatids) or
expensive (e.g. mermithids) to mass produce, have narrow host specificity against pests of minor economic importance, possess modest virulence
(e.g., sphaeruliids) or are otherwise poorly suited to exploit for pest control purposes. The only insect-parasitic nematodes possessing an optimal
balance of biological control attributes are entomopathogenic or insecticidal nematodes in the genera Steinernema and Heterorhabditis. These
multi-cellular metazoans occupy a biocontrol middle ground between microbial pathogens and predators/parasitoids, and are invariably lumped
with pathogens, presumably because of their symbiotic relationship with bacteria.
Entomopathogenic nematodes are extraordinarily lethal to many important insect pests, yet are safe for plants and animals. This high degree of
safety means that unlike chemicals, or even Bacillus thuringiensis, nematode applications do not require masks or other safety equipment; and reentry time, residues, groundwater contamination, chemical trespass, and pollinators are not issues. Most biologicals require days or weeks to kill,
yet nematodes, working with their symbiotic bacteria, can kill insects within 24-48 hours. Dozens of different insect pests are susceptible to
infection, yet no adverse effects have been shown against beneficial insects or other nontargets in field studies (Georgis et al., 1991; Akhurst and
Smith, 2002). Nematodes are amenable to mass production and do not require specialized application equipment as they are compatible with
standard agrochemical equipment, including various sprayers (e.g., backpack, pressurized, mist, electrostatic, fan, and aerial) and irrigation
systems.
Habitat
Steinernematid and heterorhabditid nematodes are exclusively soil organisms. They are ubiquitous, having been isolated from every inhabited
continent from a wide range of ecologically diverse soil habitats including cultivated fields, forests, grasslands, deserts, and even ocean beaches.
When surveyed, entomopathogenic nematodes are recovered from 2% to 45% of sites sampled (Hominick, 2002).
Annelid

Animal
 The annelids, formally called Annelida, are a large phylum of segmented worms, with over 17,000 modern species including ragworms,
earthworms and leeches.Wikipedia
  Scientific name: Annelida
 Rank: Phylum
 Higher classification: Lophotrochozoa
 Lower classifications: Polychaete, Clitellata
Segmented worms make up the Phylum Annelida. The phylum includes earthworms and their relatives,
leeches, and a large number of mostly marine worms known as polychaetes. Various species of polychaete
are known as lugworms, clam worms, bristleworms, fire worms, sea mice, and "EWWW! I stepped on that
THING!"
Annelids can be told by their segmented bodies. Polychaetes (meaning "many bristles") have, predictably,
many bristles on the body, while earthworms and leeches have fewer bristles. There are about 9000 species
of annelid known today.
Molluscs

Animal
 The molluscs or mollusks, compose the large phylum of invertebrate animals known as the phylum Mollusca. Around 85,000 extant
species of molluscs are recognized. Wikipedia
  Scientific name: Mollusca
 Rank: Phylum
 Higher classification: Lophotrochozoa
 Lower classifications: Bivalvia, Pleistomollusca, Chiton, More
What is a Mollusk?
Defining the mollusk
Mollusca, from the Latin root for “soft,” might seem an odd descriptor for these animals if you’re mostly familiar with mollusks in a culinary, shellcollecting, or decorative context. In many of our most familiar mollusks, the hard shell is widely considered either the most interesting and valuable
part or the chief barrier between you and your meal.
If you’re inclined to agree with the former, you view mollusks in much the same way as many snail and bivalve taxonomists do. If you hold the
“barrier” view, you are in sympathy with a wide range of marine wildlife, in addition to billions of human diners. Either way, you have a valid point,
but it neglects several important groups of mollusks. In addition to the bivalves and snails that immediately spring to the shell-focused mind,
consider the octopus and squid, whose highly reduced “shells” are completely internal. And let’s not forget the slugs. There are several branches
within the Gastropoda with reduced, barely noticeable shells, much like the cephalopods, and others whose shells have been entirely lost. Then
there are the aplacophorans, which throughout their evolution never possessed a shell. If we are to define the mollusks using traits widely shared
among the major groups, we must rely heavily on features of their soft tissue.
Habitat, physiological characters, and behavior
Vital organs: reduce, reuse, recycle
Mollusks are very efficient in the use of their body parts. They never settle for one function when an organ could serve two or six purposes at once.
A good example of this is the mantle, a membranous projection of a mollusk body wall. The mantle encloses and protects the animal’s internal
organs, leaving room for an open internal space called the mantle cavity. The cavity is positioned differently in different mollusk groups and is filled
with air or water—whatever is in the outside environment of the animal. It can serve as a space to exchange carbon dioxide for oxygen from that
air or water (respiration, in either case), a chamber through which to pump water and filter out food particles, a sampling area for sensory organs to
test the air or water, a threshold through which to dump waste products, or a safe place to keep eggs while they mature. Some groups use it for all
five (Tudge, 2000).
The mantle also secretes the shell, in those mollusks that have one. In many gastropods and cephalopods, the mantle is brightly colored and
important for communication. In giant clams, the outer mantle tissue is colonized by symbiotic algae that provide their host with food energy in
exchange for shelter. Since in bivalves the mantle is the tissue closest to the outside world, it’s the best place to put sensory organs,
like eyes or sensory tentacles, or both. In many bivalves and snails, and in cephalopods, part of the mantle is modified into a siphon, which can be
used to pump water through the mantle cavity for respiration, feeding and/or jet propulsion.
Freshwater and marine mollusks have gills (called ctenidia) for respiration, located in the mantle cavity. In most bivalves, these are enlarged and
serve to trap food particles as well (Morton 1983).
The nephridia, or kidneys, are responsible for final processing of urine, receiving it from the coelom, filtering out any usable nutrients and dumping
in additional waste products before ejecting it into the mantle cavity. In many mollusks, the gonads also feed into the coelom, and the egg and
sperm cells they send there also need to get to the mantle cavity. The nephridia perform this function, too (Ruppert et al. 2004).
Most mollusk groups do share one other structure that is neither soft nor (apparently) multipurpose: the radula, a filelike feeding apparatus; all
groups but the bivalves and some aplacophorans have one. Though the structure is shared among many species, its shape and features vary
widely according to the diet of the owner, and it can be an important characteristic in classification.
Masters of mucus
If you’re acquainted with terrestrial mollusks, you’re already aware of the importance of mucus to these animals. In mollusks that move by gliding
along on their muscular foot, lubricating mucus is an important part of this process. Locomotory mucus can take up to 23% of the energy budget of
some intertidal snails (Davies et al. 1989). In the evolution of the shelled mollusks, an early stage of the shell probably involved a protective mucus
coating, which eventually became a rigid cuticle before finally becoming hardened with calcium carbonate into the familiar modern mollusk shells
(Marin et al. 2000). The most widespread function of mucus in the mollusks is for digestion. Strands of mucus originating at the mouth trap and
transport food particles through the digestive tract to the anus. In the standard body plan all of this is internal, but some marine species go fishing
with their mucus strands, casting them out into the water and swallowing them once they’ve trapped enough passing food particles (Walsby et al.
2009).
So what about the shell?
A hard outer shell has been an invaluable asset to many a mollusk—some successful extant lineages may owe their survival to this feature.
Mollusk shells have even influenced the fate and evolution of non-mollusks, of which hermit crabs may be the best example. So despite the fact
that shells are not a requirement for molluskhood, they’re still worthy of discussion.
Mollusk shells are made up of chitin (the chief component of crustacean shells) and proteins, reinforced with calcium carbonate. This mineral
occurs naturally in a couple of different crystal structures, aragonite and calcite. Mollusk shells rely chiefly on aragonite, possibly because this was
the crystal more easily precipitated from sea water at the time when mollusks first started calcifying their shells (Porter 2007). Aragonite is also
used by scleractinian corals for their skeletons, so it’s not surprising that sand in many productive marine regions consists largely of aragonite; it’s
mostly the broken, ground up shells and skeletons of mollusks and corals past.
Their aragonite preference may leave both corals and mollusks especially vulnerable to ocean acidification. At its present pH level, the ocean is
well supplied with the minerals needed for all organisms that use calcium carbonate to build their shells or skeletons. It has been estimated that by
the year 2050, rising acidity will begin to deplete the available ions below optimal levels for aragonite building in the cold waters of the Southern
Ocean (Orr et al. 2005). Species that can build with calcite, like sea urchins and some sponges, will be slightly less sensitive to the change.
Masquerade and mistaken identities
If any of these mystery mollusks fooled you, you’re in good company. When the name “Mollusca” was first coined, it also included barnacles (later
discovered to be crustaceans), brachiopods (a separate phylum) and sea squirts (which are actually chordates, like you and me!) (Tudge 2000).
Among the currently recognized mollusks, aplacophorans have historically been classified as sea cucumbers, as well
as sipunculans, priapulids and other worms (Heath 1868). Nudibranchs frequently appear in identification guides together with flatworms since
observers have trouble distinguishing them. The animals can take part of the blame for this last confusion—there are convincing cases of mimicry
between the two groups. The exact details of most cases are not known, but overall it’s not surprising; mimicry is common in cases in which a toxic
or unpalatable organism uses visual cues, such as striking color patterns, to help predators learn to recognize and avoid it. Many nudibranchs
carry distasteful chemicals from the sponges they feed on, and advertise their identity with bright colors and patterns; other nudibranchs as well as
flatworms have evolved similar color patterns in order to take advantage of this warning (Seifarth 2002).Mimicry aside, the widespread confusion of
mollusks with other animals is testament to their incredible diversity of form.
This wide range of shapes and sizes may help explain how Mollusks have become such a globally cosmopolitan success. There are nearly 100
000 known species and this is likely to be a gross underestimate of the total number, considering how many mollusks we’ve already found in
remote habitats, like the deep sea, that we have as yet only barely sampled. There are mollusks crawling through leaf litter and climbing in trees,
clinging to rocks in lakes and rivers and on shorelines, and gliding along or burrowing under the ocean floor at every depth and latitude; there
are winged mollusks soaring through the sunlit waters of the epipelagic zone, giant mollusks grappling with sperm whales in the abyssal depths,
and countless tiny interstitial mollusks living between grains of sand (Giere, 2009), which we have scarcely begun to catalog (eg: Burghardt et al,
2006).
Major molluscan groups
Aplacophorans, the mollusks that never had a shell, are now known to be two separate groups, the caudofoveates and the solenogastres.
Though they lack shells, they do have calcified spicules on their skin, which give them a fuzzy appearance. Both groups lack eyes and tentacles,
but at least some of them are equipped with a radula, which varies widely in shape, depending on the diet and feeding method of the animal (Bunje
2003). Most are just a couple of centimeters long, but a few measure as long as 30 cm. Caudofoveates burrow in the seafloor, throughout the
global oceans, at all depths (Salvini-Plawen, 2008), and feed on microbes and detritus; they are well adapted for burrowing. They are slender and
vermiform, and protected from abrasion by a tough cuticular head shield. Solenogastres are broader bodied and equipped with a long,grooved
foot and pedal gland, good for gliding over hard substrate, and over the corals and other cnidarians they feed on (Heath 1911, Salvini-Plawen
1980). They probably locate their prey by smell (Scheltemaa and Jebb 2007). Some species have shown regenerative capabilities—if the
posterior end is cut off, it will grow back. This occasionally results in a forked tail (Baba 1940). Caudofoveates have separate sexes but
solenogastres are hermaphrodites, starting life as males and become females when they’re older.
Bivalves’ shells are divided in two halves, hinged by an elastic ligament. Within mollusks, bivalves are second only to snails in number of known
species, and are incredibly diverse in size, shape, and mode of life. One of the major subgroup of bivalves, the Protobranchia, contains burrowing
species that commonly feed on deposited sediment, using tentacles that extend from their mouth (called palp proboscides). Another major
subgroup, the Pteriomorphia, includes species that suspension-feed and most live above the sediment, in various ways. They may attach to rocks
or other hard substrata using proteinaceous threads (called byssus), cement their shell to exposed surfaces, bore into rock or coral, or simply
recline on the sea bottom. Pteriomorphians comprise some of the most familiar and economically important bivalves, such asscallops, oysters,
and marine mussels. Most members of the third and last major bivalve subgroup, the Heteroconchia, are burrowers that suspension-feed by
filtering water circulated through their mantle cavity via a pair of siphons. However, Heteroconchia also includes species that live above the
sediment, such as the wood-boring shipworms or the giant clams.Freshwater clams, manila clams and quahogs are among the most familiar
heteroconchs.
Cephalopods are one of the smaller mollusk groups at around 800 known species, but they are the most familiar group to many of us thanks to
their elaborate, well documented behavior. Cephalopods are found throughout the world oceans at all depths. In this group, only
the Nautiluses have a substantial outer shell. In other cephalopods it has been reduced to a small internal structure, the “pen” in squid or the
“cuttlebone” in cuttlefish. The un-armored cephalopods rely for safety on an array of strategies including camoflage, constructed shelter, and flight.
In a pinch, digging works too. Cephalopods are intelligent and highly visual. They’re great visual communicators; elaborate posturing and skin
pigment displays accompany social behavior, including aggressive behavior. All cephalopods can get around using jet propulsion; however, all but
the Nautiluses rely chiefly on their fins except when high speed is urgently needed. Fins are attached to the mantle and vary from a continuous
encircling skirt to a pair of stubby (but effective) flappers. Some cephalopods show parental care; eggs may bebrooded by the mother or attached
in a sheltered nook on the seafloor, where in some species they are tended until hatching.
Chitons (Polyplacophora) are protected on their dorsal side by eight overlapping shell plates, which provide protection while allowing flexibility, as
the animal crawls over curved and uneven surfaces, including other mollusks. The underside isunprotected, but the animal may have additional
armament around the shell plates, on the girdle. This can be in the form of spicules or spikes. Chitons scrape food from rock or other hard surfaces
with a well-developed radula; their diet can include algae, bacteria, and small sessile animals such as sponges or bryozoa. The largest known
species, the Giant Pacific Chiton, can grow to about a foot long.
Snails (Gastropoda) are the largest Mollusk subgroup, with about 400 living familes and tens of thousands of species. Snails are globally
distributed in nearly every habitat, on land and under water. Most marine and aquatic snails are benthic, but a few are swimmers. Snails
encompass a myriad of lifestyles, from predators to algae grazers, as well as an incredible diversity of form, most obviously in the shape and
position of the shell- or its absence. When present, the shell is usually coiled, and usually, but not always, in a right-handed direction. Sometimes
an operculum is also present, a door which fits in the opening of the coiled valve, shutting the animal inside for defense. In some snails the entire
shell is internal, covered with skin. In groups lacking the protection of a shell, like the nudibranchs, many species are elaborately colored, either to
blend with a similarly colored background, or to warn predators of noxious taste. Some pelagic snails, both shelled and shell-less, are transparent.
Monoplacophorans bear a single shell and if you were looking at one shell-side up you might confuse it with a bivalve. Modern
Monoplacophorans live in the deep sea, though fossil relatives once lived in shallow water also. We first discovered living representatives of this
group only sixty years ago.
Tusk shells (Scaphopoda) can be 3–15 cm long and are protected by a curved, tubular shell shaped like an elephant’s tusk. The shell is open at
both ends, and both the head and foot of the animal are at the broader end. The animal creates a current through the shell using its cilia and
occasional contractions of its muscles to bring in water for respiration, which exits the narrow end of the shell. They live in the sediment and most
feed chiefly on foraminiferans, but detritus, microbes, and other small prey are also taken by their fine, cilia-covered tentacles.
Echinoderm

Animal
 Echinoderms are a phylum of marine animals. The adults are recognizable by their radial symmetry, and include such well-known
animals as starfish, sea urchins, sand dollars, and sea cucumbers. Wikipedia
  Scientific name: Echinodermata
 Higher classification: Deuterostome
 Rank: Phylum
 Lower classifications: Sea urchin, Somasteroidea, Crinozoa
A nyone who has been to the beach has probably seen starfish or sand dollars. The more intrepid
beachcomber may find brittle stars, sea cucumbers, or sea urchins. These and many other organisms, living
and extinct, make up the Echinodermata, the largest phylum to lack any freshwater or land representatives.
Most living echinoderms, like this sand dollar from Baja California, are pentameral; that is, they have
fivefold symmetry, with rays or arms in fives or multiples of five. However, a number of fossil echinoderms
were not pentameral at all, and some had downright bizarre shapes. Echinoderms have a system of internal
water-filled canals, which in many echinoderms form suckered "tube feet", with which the animal may
move or grip objects.
ECHINODERMS
5 pages with over
300 photos of echinoderms
There are 5 related classes in the phylum Echinodermata (the Latin name means "spinyskinned"). For a detailed list with all classifications click here:
ECHINODERMS
(Echinodermata)





Sea star or starfish (Asteroidea)
Brittle stars, basket stars, serpent stars (Ophiuroidea)
Sea urchins, heart urchins and sanddollars (Echinoidea)
Holothurians or sea cucumbers (Holothuroidea)
Feather stars and sea lilies (Crinoidea).
Characteristics of Echinoderms
Echinoderms are characterized by radial symmetry, several arms (5 or more, mostly grouped 2
left - 1 middle - 2 right) radiating from a central body (= pentamerous). The body actually
consists of five equal segments, each containing a duplicate set of various internal organs.
They have no heart, brain, nor eyes, but some brittle stars seem to have light sensitive parts
on their arms. Their mouth is situated on the underside and their anus on top (except feather
stars, sea cucumbers and some urchins).
Echinoderms have tentacle-like structures called tube feet with suction pads situated at their
extremities. These tube feet are hydraulically controlled by a remarkable vascular system. This
system supplies water through canals of small muscular tubes to the tube feet (= ambulacral
feet). As the tube feet press against a moving object, water is withdrawn from them, resulting
in a suction effect. When water returns to the canals, suction is released. The resulting
locomotion is generally very slow.
Ecology and range of Echinoderms
Echinoderms are exclusively marine. They occur in various habitats from the intertidal zone
down to the bottom of the deep sea trenches and from sand to rubble to coral reefs and in
cold and tropical seas.
Behavior of Echinoderms
Some echinoderms are carnivorous (for example starfish) others are detritus foragers (for
example some sea cucumbers) or planktonic feeders (for example basket stars).
Reproduction is carried out by the release of sperm and eggs into the water. Most species
produce pelagic (= free floating) planktonic larvae which feed on plankton. These larvae are
bilaterally symmetrical, unlike their parents (illustration of a larvae of a sea star below). When
they settle to the bottom they change to the typical echinoderm features.
Echinoderms can regenerate missing limbs, arms, spines - even intestines (for example sea
cucumbers). Some brittle stars and sea stars can reproduce asexually by breaking a ray or arm
or by deliberately splitting the body in half. Each half then becomes a whole new animal.
Echinoderms are protected through their spiny skins and spines. But they are still preyed upon
by shells (like the triton shell), some fish (like the trigger fish), crabs and shrimps and by other
echinoderms like starfish which are carnivorous. Many echinoderms only show themselves at
night (= nocturnal), therefore reducing the threat from the day time predators.
Echinoderms serve as hosts to a large variety of symbiotic organisms including shrimps, crabs,
worms, snails and even fishes.
Sea stars (starfish)
Characteristics of sea stars (or starfish)
(Asteroidea)
Sea stars are characterized by radial symmetry, several arms (5 or multiplied by 5) radiating
from a central body. Mouth and anus are close together on the underside, the anus is at the
center of the disc together with the water intake (madreporite). The upper surface is often
very colorful. Minute pincer-like structures called pedicellaria are present. These structures
ensure that the surface of the arms stay free from algae. The underside is often a lighter color.
There are a few starfish that have 6 or 7 arms, for example Echinaster luzonicus or
Protoreaster, some even more like the elven-armed sea star (Coscinasterias calamaria). Others
normally have 5 arms but now have more arms, because after an injury an arm divided and
grew into two arms.
Ecology and range or sea stars
The starfish lives everywhere in the coral reef and on sand or rocks.
Behavior of sea stars
Regeneration
The ability of an organism to
grow a body part that has been
lost
The majority of sea stars are carnivorous and feed on sponges, bryozoans, ascidians and
molluscs. Other starfishes are detritus feeders (detritus = organically enriched film that covers
rocks) or scavengers. Some starfish are specialized feeders, for example the crown-of-thorns
that feeds on life coral polyps.
Autotomy
The spontaneous self amputation
of an appendage when the
organism is injured or under
attack. The autotomized part is
usually regenerated.
Starfish have no hard mouth parts to help them capture prey. The stomach is extruded over
the prey, thus surrounding the soft parts with the digestive organs. Digestive juices are
secreted and the tissue of the prey liquefied. The digested food mass, together with the
stomach is then sucked back in. This method can be observed, if you turn around a starfish,
that sits on prey or sand - you will see the stomach retreating.
Budding
Is asexual reproduction in which
an outgrowth on the parent
organism breaks off to form a
new individual
Fission
Self-division into two parts, each
of which then becomes a
separate and independent
organisms (asexual reproduction)
Starfish are well known for their powers of regeneration. A complete new animal can grow
from a small fragment such as a arm. In some species (Linckia multifora and Echinaster
luzonicus) one of the arms will virtually pull itself away, regenerates and forms a new animal.
Autotomy (self amputation) usually is a protective function, losing the body part to escape a
predator rather than being eaten. But here it serves as a form of asexual reproduction. In
other species of sea stars (Allostichaster polyplax and Coscinasterias calamaria) the body is
broken into unequal parts (= fission) then the missing limbs regenerate.
Predators of starfishes
Triton Trumpet - Charonia
tritonis
INFO - Harlequin Shrimp Hymenocera elegans
Reef Crab - Trapezia sp
The crown-of-thorns (Acanthaster planci) is one of the largest and the most venomous
starfishes. It can reach 50 cm diameter and has numerous (10 to 20) spiny arms with
formidable thorn like toxic spines. Don't touch them! A species of small cardinalfishes
(Siphamia fuscolineata) and a commersal shrimp (Perliclimenes soror) live among those
spines. The crown-of-thorns feed on live coral polyps. They "graze" the corals which are left
behind white and dead. Their predators are the giant triton shell (Charonia tritonis) and some
puffer fish. Scientist have also found out, that some crown of thorns are deterred from eating
the coral polyps by the small crabs living among the coral branches (Trapezia sp). These crabs
defend their coral host by breaking them off at the pedicellaria. Other small crabs (Tetralia sp)
only pinch the tube feets of the starfish. Crown of thorns prefer corals, that are not hosts to
these crabs.
The cushion star (Culcita nouvaeguineae) doesn't look like a starfish at all, more like a large
sea urchin without spines. Its pentagonal appearance gives only the slightest indication that
this organism is related to other starfish.
Photos of sea stars (photo collection) click for enlargement
Crown-of-thorns starfish (Acanthaster
planci)
Spiny Cushion Starfish - Culcita
schmideliana
Necklace Sea Star - Fromia monilis
Starfish / sea star (Nardoa variolata)
Horned Sea Star - Protoreaster nodosus
Egyptian Sea Star - Gomophia egyptiaca
Starfish Shrimp - Periclimenes soror
Regeneration of an arm: Luzon Sea StarEchinaster luzonicus
Comb Jelly on Starfish - Coeloplana
astericola
Feather stars
Characteristics of feather stars
(Crinoidea)
Feather stars also known as crinoids. They are characterized by radial symmetry. The body of
a typical feather star is cup-shaped, their numerous feathery arms project from a central disc.
Some have five arms, others as many as 200. The arms, called pinnules are coated with a
sticky substance that helps to catch food. There are appendages known as cirri attached to the
underside of the body with which they cling to to sponges or corals. Both their mouth and their
anus are situated on the upper side.
Ecology and range of feather stars
Feather stars are primarily nocturnal but they are seen in the open during the day with their
arms rolled up.
Behavior of feather stars
Feather stars can crawl, roll, walk and even swim but usually they cling to sponges or corals.
Feather stars are very abundant in areas exposed to periodic strong currents, because they
feed on plaktonic food.
Numerous animals live in close association with feather stars. Echinoderms are hosts to various
symbiotic animals such as the crinoid clingfish (Discotrema crinophila), the elegant squat
lobster (Allogalathea elegans) or the crinoid shrimp (Periclimenes sp.). These animals receive
shelter and food (left over) and also feed on microorganisms living on feather stars.
Photos of feather stars (photo collection) click for enlargement
Feather star (Lamprometra) half open,
holding on to sponge with its cirri
(appendages)
Rolled up feather star (Himerometra
robustipinna) by day
Pinnules of a feather star (Pontiometra)
coated to help catch food
Crinoid shrimp (Laomenes pardus) on
featherstar (Oxycomanthus)
Feather star (Stephanometra sp.) - gallery
Central body of a feather star with mouth
and anus
Brittle stars
Characteristics of brittle stars
(Ophiuroidea)
Brittle stars are close relatives of sea stars. Characterized by radial symmetry with a central
body from which five snakelike arms protrude. The arms are highly flexible. There is no
replication of internal organs, just one set in the central disk. Compared to starfish, brittle stars
have a much smaller central disc and no anus. Wastes are eliminated through the mouth
which is situated on the underside center.
On the underside of the body disk there is a splitlike opening at the base of each side of each
arm. These ten openings are breathing and reproductive outlets, taking in water for oxygen
and shedding eggs or sperm into the sea.
Basket star
(Astroboa nuda)
The basket stars are a specialized type of brittle stars. They have a series of complexly
branched arms which are used to catch plankton.
Serpent stars are seen coiled snakelike around branches of gorgonians.
Ecology and range of brittle stars
Brittle stars are very cryptic and hide in crevices under corals. Best seen at night time, when
they emerge to feed on plankton. Usually at places exposed to strong currents.
Serpent stars feed mostly on small invertebrates like mollusks, worms and crustaceans and are
generally found in crevices and beneath rocks or in holes in the sand.
Snake stars (for example Ophiothela danae) are found entwined in the branches of black
corals or gorgonians where they feed on the rich mucus of their host, in turn performing
cleaning functions.
Behavior of brittle stars
As the name suggests, the arms of the brittle stars are rather liable to break. This is actually
an escape mechanism. Those arms regenerate quickly and an entire new organism can
regenerate, if the broken arm is attached to a seizable portion of the disk. Brittle stars can
reproduce asexually by self-division. Brittle stars are the most active and fastest moving
echinoderms.
Brittle stars feed on plankton but also on detritus, coral-shed mucus, bottom detritus (detritus
= organically enriched film that covers rocks), mollusks and worms.
Photos of brittle stars (photo collection) click for enlargement
Many snake stars (Ophiothela danae) on
gorgonian
Brittle Star - Ophiothela sp
Black brittle star (Ophiomastix variabilis)
INFO - Serpent star (Ophiarachna
incrassata)
Erna's basket star (Astroboa ernae)
Basket star (Astroglymma sculptum)
Sea urchin
Characteristics of sea urchins
(Echinoidea)
Radial symmetrical body with a external chitinous skeleton and a centrally located jaw (called
Aristotle's lantern) with horny teeth. The mouth consists of a complex arrangement of muscles
and plates surrounding the circular opening. The anus is located on the upper surface. Some
sea urchins have a spherical, bulb like cloaca (to store fecal material) that protrudes from the
anal opening. It can be withdrawn into the shell.
Depending on the species, movable spines of various sizes and forms are attached to the
body. These spines often are sharp, pointed and in some cases even venomous. Pincer like
pedicellaria for grabbing small prey. Some pedicellaria are also poisonous.
Ecology and range of sea urchins
Rubble and sand. An abundance of sea urchins can be a sign for bad water conditions.
Behavior of sea urchins
Locomotion by tube feet but also by movement of the spines on the underside of the body.
Sea urchins are generally nocturnal, during the day they hide in crevices. However some sea
urchins such as Diadema sometimes form large aggregations in open exposed areas. Despite
their sharp spines sea urchins are easy game for some fishes, particularly triggerfishes and
puffers. A triggerfish grabs the sea urchin with its hard beak like mouth by the spines or it
blows some water towards the sea urchin and turns it on its back. The underside of a sea
urchin has much shorter spines and those are easily crushed. During the breeding season the
body cavity is crammed with eggs or sperms. This is one of the main reasons urchins are so
attractive to fish predators (Japanese also like them for the same reason).
Some sea urchins are camouflaged. They hold on with their tube feet onto some bottom debris
like rubble or pieces of seagrass and carry them on their back. Some even carry live soft corals
or anemones.
Most sea urchins are algal grazers but some feed on sponges, bryozonans and ascidians and
others on detritus (detritus = organically enriched film that covers rocks).
The sexes are separate and the young are formed indirectly by the fusion of sperm and eggs
released into the water.
Many animals live in symbiotic relation with sea urchins. Even on the poisonous spines of the
fire urchin (Asthenosoma varium) small shrimps (Periclimenes colemani) can be found. One
shrimp(Stegopontonia commensalis) is striped black and white lengthwise and perfectly
camouflaged and lives in spines of the long-spined sea urchin (Diadema setosum). Some
cardinalfishes and juvenile shrimpfishes also like to take shelter in-between these spines, but
even small cuttlefish hide there. It has been observed, that they change their coloring also to
black and white. Some flatworms wrap around the thicker spines of the diadema sea urchin
(Echinothrix calamaris).
Sea urchin cardinalfish
(Siphamia versicolor)
Shrimpfish
Aeoliscus strigatus Centriscidae)
Sea urchin shrimp
(Stegopontonia commensalis)
Mandarinfish, dragonet
(Synchiropus splendidus)
The mandarin dragonet (Mandarinfish) lives close to congregations of sea urchins and hides
among them if threatened.
There are two specialized types of sea urchins with an unusual appearance: the sand dollar is
very much flattened with very small spines and the heart urchin which are oval and have
bristle like spines. The both bury in sand. The heart urchin "jumps" out of the sand, when
disturbed.
Photos of sea urchins (photo collection) click for enlargement
Heart Sea Urchin - Maretia planulata
Sea urchin (Prionocidaris verticillata)
Sea urchin (Astropyga radiata)
Sea Urchin - Diadema setosum
Toxic sea urchin (Asthenosoma pileolus)
Matha's sea urchin (Echinometra mathaei)
Zebracrab (Zebrida adamsii) on sea urchin
shrimp (Stegopontonia commensalis)
Coleman shrimp (Periclimenes colemani)
Urchin clingfish - Diademichthys lineatus
Comb yellies on seeurchin - Coeloplana
Shrimpfish (Aeoliscus strigatu)
Holothurians
Characteristics of sea cucumbers
(Holothuroidea)
Unlike other echinoderms, holothurians don't have a distinct radial symmetry but are bilateral
(distinct dorsal and ventral side). Holothurians are also called sea cucumbers. As their name
suggests, they are cucumber shaped with an elongated, muscular, flexible body with a mouth
at one end and the anus at the other. Around the mouth there is a number of tentacles
(modified tube feet) used in food collecting. Sea cucumbers come in many sizes, from small
species only a few centimeter in length to long snakelike animals which may stretch up to 2
meter!
Ecology and range of sea cucumbers
Rubble, rocks and sand. Also seen on some sponges in large aggregations.
Behavior of sea cucumbers
Most species feed on the rich organic film coating sandy surfaces. The crawl over the bottom
ingesting sand. The edible particles (organic matter such as plankton, foraminifera and
bacteria) are extracted when passing through their digestive tract and the processed sand is
expelled from the anus (as worm-like excrements).
Sea cucumbers move by means of tube feet which extend in rows from the underside of the
body. The tentacles surrounding the mouth are actually tube feet that have been modified for
feeding.
Other holothurians feed on current-borne zooplankton. They bury in sand extruding their
featherlike tentacles (Pseudocolochirus violaceus, Neothyondium magnum or Pentacta crassa).
The tentacles have the same shape as soft corals or some anenemones. Large congregations
of some small species are found on sponges. They apparently feed on substances secreted by
the sponges as well as detritus from the surface.
Some species of holothurians have separate sexes others are hermaphrodites. The sea
cucumbers hold on to exposed rocks or corals, raise their body to a upright position, rock back
and forth and release the sperm and eggs into the sea.
Sea cucumbers have a remarkable capacity for regenerating their body parts. When attacked
they shed a sticky thread like structure which is actually parts of their guts. The so called
Cuverian threads are toxic (the poison is called holothurin) and can dissuade many potential
predators. These structures quickly regenerate. (see photos below)
Pearlfish
(Carapidae)
Encheliophis homei and
mourlani / Onuxodon
margaritiferae
Holothurians host a variety of symbiotic organisms: crabs, shrimps, worms and even a very
unusual fish. The pearlfish (Encheliophis homei and mourlani / Onuxodon margaritiferae) has a
long slender, transparent body and lives in the gut cavity of the sea cucumber (Boshida argus,
Thelanota ananas, Stichopus chloronotus). They also inhabit some starfish as well as pearl
oyster shells. The fish leaves and enters (tail first) through the holothurian's anus. They
probably feed on the gonads and other tissues of its host. It is said to leave at night to feed on
small fishes and shrimps. Sea cucumbers are used in Asia as a base for soups.
Photos of sea cucumbers (photo collection) click for enlargement
Sea cucumber (Bohadschia argus) with
Cuiverian threads
Sea cucumber (Bohadschia argus) with
Cuiverian threads
Black Sea Cucumber - Holothuria atra
INFO - Emperor Shrimp on Sea Cucumber
- Periclimenes imperator on Opheodesoma
australiensis
INFO - Sea Cucumber - Synaptula media
Pineapple sea cucumber (Thelenota
ananas) - gallery
Sea Cucumber details tentacles (Synapta
maculata)
Sea cucumber skin (Thelenota
rubrolineata)
Horrid Sea Cucumber - Stichopus horrens
Arthropod

Animal
 An arthropod is an invertebrate animal having an exoskeleton, a segmented body, and jointed appendages. Arthropods are members of
the phylum Arthropoda, and include the insects, arachnids, and crustaceans. Wikipedia
  Higher classification: Ecdysozoa
 Rank: Phylum
 Lower classifications: Hexapoda, Chelicerata, Marrellomorph,Myriapoda, Trilobite, Crustacean
Arthropods are invertebrates with segmented bodies and jointed limbs.[4] The limbs form part of an exoskeleton, which is mainly
made of α-chitin, a derivative of glucose.[5] One other group of animals, the tetrapods, has jointed limbs, but tetrapods
are vertebrates and therefore have endoskeletons.[6]
Exoskeleton[edit]
Main article: Arthropod exoskeleton
Seta (bristle)
Epicuticle
Exocuticle
Endocuticle
Epidermis
= Biomineralization, only incrustaceans
= Trichogen cell, produces seta
= Gland cell, secretes epicuticle
Structure of arthropod cuticle
Arthropod exoskeletons are made of cuticle, a non-cellular material secreted by the epidermis.[10] Their cuticles vary in the details of
their structure, but generally consist of three main layers: the epicuticle, a thin outer waxy coat that moisture-proofs the other layers
and gives them some protection; the exocuticle, which consists of chitin and chemically hardened proteins; and the endocuticle,
which consists of chitin and unhardened proteins. The exocuticle and endocuticle together are known as the procuticle.[18] Each
body segment and limb section is encased in hardened cuticle. The joints between body segments and between limb sections are
covered by flexible cuticle.[10]
The exoskeletons of most aquatic crustaceans are biomineralized with calcium carbonate extracted from the water. Some terrestrial
crustaceans have developed means of storing the mineral, since on land they cannot rely on a steady supply of dissolved calcium
carbonate.[19] Biomineralization generally affects the exocuticle and the outer part of the endocuticle.[18] Two recent hypotheses
about the evolution of biomineralization in arthropods and other groups of animals propose that it provides tougher defensive
armor,[20] and that it allows animals to grow larger and stronger by providing more rigid skeletons; [21] and in either case a mineralorganic composite exoskeleton is cheaper to build than an all-organic one of comparable strength.[21][22]
The cuticle may have setae (bristles) growing from special cells in the epidermis. Setae are as varied in form and function as
appendages. For example, they are often used as sensors to detect air or water currents, or contact with objects; aquatic arthropods
use feather-like setae to increase the surface area of swimming appendages and to filter food particles out of water; aquatic insects,
which are air-breathers, use thick felt-like coats of setae to trap air, extending the time they can spend under water; heavy, rigid
setae serve as defensive spines.[10]
Although all arthropods use muscles attached to the inside of the exoskeleton to flex their limbs, some still use hydraulic pressure to
extend them, a system inherited from their pre-arthropod ancestors;[23] for example, all spiders extend their legs hydraulically and
can generate pressures up to eight times their resting level.[24]