Phylum Cnidaria Characteristics

Phylum Cnidaria
Characteristics
• True tissue level of
organization
• Gastrovascular cavity:
one opening, a mouth,
where food enters and
waste leaves.
• Tentacles radiate
outward around the
mouth
Phylum Cnidaria
Anthozoa (Sea Anemones)
Phylum Cnidaria
Hydrozoa (Jellyfish)
Jellyfish belong to a group of animals called scyphozoans. Jellyfish are not really fish
(they lack a spine and many other adaptations found in real fish). Jelly"fish" are
medusoid in shape and are free-floating—they are not attached to anything. They
swim around the ocean with their mouth and tentacles pointing down. Some jelly
"fish" are very poisonous to humans, occasionally even fatal. However, most jelly
"fish" are not dangerous to people, their poison will only cause a mild rash similar to
poison ivy.
Phylum Cnidaria
Body Shape
• The polypoid is the shape of corals and anemones. It is
characterized by the mouth and tentacles facing up, and the
other side being anchored to a colony of the same creatures
(like a coral reef).
• Medusoids are usually free swimmers, like jellyfish. Their
tentacles and mouths are generally pointed down, the
opposite of polypoids.
Phylum Cnidaria
Anthozoa (Sea Anemones)
Phylum Cnidaria
Anthozoa (coral)
Hydroids and bowl animals (anemones, corals) usually live at the bottom of the ocean. These
creatures usually have a polypoid shape, which means their mouths and tentacles face up while
their other side is attached to something. Some live alone, but others live in colonies (like coral
reefs). A coral reef is really a colony of hundreds or thousands of polyps (which look like tiny
anemones). The polyps live together, anchored to each other, sharing living tissue and food
resources.
Phylum Cnidaria
Anthozoa (Coral)
Phylum Cnidaria
Stalked Jellyfish
Stalked jellyfishes do not have an
alternation between a polyp and medusa
stage. Most of them have a trumpetshaped body with a stalk and a number of
branches or arms with tentacles on the
end. Eggs are spawned and form creeping
larvae. The larva crawl around until it
finds a suitable spot on a rock or algae.
The stalked jellyfishes also practice
asexual reproduction by splitting their
body into new individuals.
Most species are found in cold waters,
close to the shoreline.
Phylum Cnidaria
Jelly fish
Jellyfish belong to a group of animals called scyphozoans. Jellyfish are not
really fish (they lack a spine and many other adaptations found in real fish).
Jelly"fish" are medusoid in shape and are free-floating—they are not attached
to anything. They swim around the ocean with their mouth and tentacles
pointing down. Some jelly "fish" are very poisonous to humans, occasionally
even fatal. However, most jelly "fish" are not dangerous to people, their poison
will only cause a mild rash similar to poison ivy.
Phylum Cnidaria
Box Jellyfish
Box jellies are so named because their
bodies are box shaped, rather than bell
shaped like most other jellyfish. Box
jellies are special, because unlike other
jellyfish they are capable of vision. They
have complex eyes complete with a
retina and cornea. Compared to other
jellyfish, their vision allows them more
maneuverability—they can swim around
things, fewer wash up on shore and some
can even recognize each other by sex,
which helps with mating.
Phylum Annelida
• Annelids generally live either in
freshwater or soil, though some can
live on land as well. Some Annelids
obtain nutrients by passing soil
through their bodies, while others,
such as leeches, are parasitic, sucking
the blood of other animals. A few
leeches are even carnivorous.
• Characteristics:
–
–
–
–
Coelem: fluid filled cavity
segmentation
Nervous system
Sense organs (antennae, eyes
Phylum Annelida
Earthworm
• Earthworms' bodies are made up of
ringlike segments called annuli. These
segments are covered in small bristles,
which the worm uses to move and
burrow.
• Earthworms are vital to soil health and
to plants growing in it because they
transport nutrients and minerals from
below to the surface via their waste.
• An earthworm can eat up to a third of
its body weight in a day.
Phylum Annelida
Earthworm
Their bodies are characterized by a "tube within a
tube" construction, with an outer muscular body wall
surrounding a digestive tract that begins with the
mouth in the first segment. As they burrow, they
consume soil, extracting nutrients from decomposing
organic matter like leaves and roots.
Phylum Annelida
Leech
Leeches are segmented worms with suction cups at each end. Their
bodies are flattened, much wider than they are thick. They are usually
dark colored, often brown or sometimes black or dark green. Many
leech species have one or more pairs of eyes visible on the top of their
front end. Leech species that suck blood have sharp teeth. Predatory
species may have teeth, or may have only crushing jaws.
Phylum Annelida
Giant Tube Worms
•
The giant tube worm, also known as Riftia pachyptila, was totally unknown to
science until researchers found hydrothermal vents. Powered by volcanic heat,
these vents recirculate water that seeps down through cracks or faults in the rock.
When the water emerges from the vent, it is rich in chemicals and minerals. This
toxic soup of chemicals would be lethal to most animals, so scientists were
shocked to find entire ecosystems of animals living around these vents.
These giant tube worms grow up to
eight feet and have no mouth and no
digestive tract. They depend on
bacteria that live inside them for their
food. This type of mutually beneficial
relationship between two organisms is
known as symbiosis.
Phylum Annelida
Christmas Tree Worm
Each worm has two brightly colored
crowns that protrude from its tube-like
body. These Christmas tree-like crowns are
composed of radioles, or hair-like
appendages radiating from the worm’s
central spine. These appendages are used
for respiration and to catch dinner, which
typically consists of microscopic plants, or
phytoplankton, floating in the water.
Phylum Porifera
• 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.
• Sponge cells perform a variety of
bodily functions and appear to be
more independent of each other than
are the cells of other animals.
Phylum Porifera
Stove Pipe Sponges
• Stove-pipe sponges
(Aplysina archeri) are a
species of tube sponge that
has a long tube-like body
that resemblesa stove pipe.
Stove-pipe sponges can
grow to lengths of up to five
feet. They are most
common in the Atlantic
Ocean and are especially
prevalent in the waters that
surround the Caribbean
Islands, Bonaire, the
Bahamas, and Florida.
Phylum Porifera
Giant Barrel Sponges
Persistently a cup- or barrelshaped sponge with a rough,
often jagged, stone-hard
exterior. Giant specimens may
reach a diameter of up to 2
meters. These specimens may
be over 100 years old, as the
sponges grow only about 1.5
cm a year. Smaller specimens
may assume a cone shaped
form, i.e. with the base
broader than the top. Walls on
the outside irregularly ridged
and pitted
Phylum Porifera
Spongilla lacustris
Spongilla lacustris is a
species of sponge of the
freshwater sponge family
Spongillidae that lives on
fresh water lakes. It often
grows under logs or rocks. It
ranges from North America,
Europe and Asia.
Phylum Mollusca
• Mollusca is one of the most diverse groups of animals on the planet, with
at least 50,000 living species (and more likely around 200,000).
• They occupy a vast range of habitats however both aquatic and terrestrial,
from the arctic seas to small tropical streams and from valleys to
mountainsides 7,000 meters high, there are a few adapted to live in
deserts and some are parasitic.
• They range from large predatory squid to grazing forms with elaborate
sculpted shells. In spite of their diversity, they share a few key
characteristics:
– Muscular foot
– Visceral mass containing internal organs
– A mantle that may or may not secrete a shell
Phylum Mollusca
Nautilus
To swim, the nautilus draws water
into and out of the living chamber
with its hyponome, which uses jet
propulsion. While water is inside
the chamber, the
siphuncle extracts salt from it and
diffuses it into the blood. The
animal adjusts its buoyancy only in
long term density changes
by osmosis, either removing liquid
from its chambers or allowing water
from the blood in the siphuncle to
slowly refill the chambers
Phylum Mollusca
Giant Squid
• In zoology, deep-sea gigantism is
the tendency for species to display
a larger size than their shallowerwater relatives
• It is not known whether deep-sea
gigantism comes about as a result
of adaptation for scarcer food
resources, greater pressure, or for
other reasons.
• The largest of these elusive giants
ever found measured 59 feet (18
meters) in length and weighed
nearly a ton (900 kilograms).
Phylum Mollusca
Scallop
This is the scallop that
most people never see.
This bivalve has
hundreds of tiny eyes to
keep a lookout for
predators (those are the
tiny black dots around
the opening). The
animal feeds by filtering
food from the water.
Phylum Mollusca
Giant African Land Snail
• Scientists consider the giant African land snail (or GALS) to
be one of the most damaging snails in the world because it
is known to consume at least 500 different types of plants,
and can pose a serious health risk to humans. These snails
could be devastating to Florida agriculture and natural
areas because they cause extensive damage to tropical and
subtropical environments.
Phylum Arthropoda
• The phylum Arthropoda is the largest and
most varied in the animal kingdom. It includes
well over one million described species. This
represents approximately three-quarters of all
known biological organisms, living or extinct.
• Characteristics:
– Jointed paired appendages
– Exoskeleton
– segmentation
Phylum Arthropoda
Class Insecta
• Single pair of antenna
• Three body regions
(head, thorax, and
abdomen)
• Three pairs of legs (adult
insect), one on each
segment of thorax
• Most adult insects with
wings
Phylum Arthropoda
Class Crustacea
• Two body regions (head and
thorax combined into the
cephalothorax)
• One pair of appendages per
body segment. Appendages
terminate in pinchers.
• Primarily an aquatic group,
respiration is by gills even in
terrestrial species.
• Some very unusual groups,
for example, barnacles and
water fleas
Phylum Arthropoda
Class Diplopoda (millipedes)
• Single pair of antennae
• Two body regions, head
and body
• Body segments fused in
pairs, each apparent
segment composed of two
embryonic segments
• Two pairs of appendages
per apparent body
segment, extending out
from sides of body
• Detritivore
Phylum Arthropoda
Class Chilopoda (centipedes)
• Single pair of antennae
• Two body regions, head
and body
• One pair of legs per
body segment
• Appendages of first
body segment modified
into poisonous claws
• Predacious
Phylum Arthropoda
Class Arachnida
• No antennae
• Most with a cephalothorax
and abdomen. Some with a
single body region.
• Most are terrestrial
• Most are predacious.
Phylum Echinodermata
• Characteristics
– Radial symmetry
– Central disc and 5 arms
most common
– Internal skeleton
covered with spines and
skin
Phylum Echinodermata
Class Ophiuroidea (Brittle Star)
•
Brittle stars have long, flexible
arms (hence the other common
name for ophiuroids, "snake
stars" and a central, armored,
disk-shaped body that is clearly
demarcated from the arms.
Instead of crawling on hundreds
of tube feet like starfish, brittle
stars move fairly rapidly by
wriggling their arms. These agile
arms are supported by an internal
skeleton of calcium carbonate
plates that superficially look like
vertebrae.
Phylum Echinodermata
Class Asteroidea (Sea Star)
•
•
Most sea stars sport spiny skin and five
arms, although some can grow as many
as 50 arms. The arms are covered with
pincer like organs and suckers that allow
the animal to slowly creep along the
ocean floor. Light-sensitive eyespots on
the tips of the arms help the sea star
find food.
The sea star eats by attaching to prey
and extending its stomach out through
its mouth. Enzymes from the sea star’s
stomach digest the prey. The digested
material enters the sea star’s stomach.
Tiny organisms can be swallowed
whole. Sea stars occupy every type of
habitat, including tidal pools, rocky
shores, sea grass, kelp beds, and coral
reefs. Some sea stars even live in sands
as deep as 20,530 feet (9,000 meters).
Phylum Echinodermata
Class Echinoidea (Sand Dollar)
• Sand dollars are shaped like
flattened Sea Urchins. When
prone or buried, the sand
dollar feeds on detritus
diatoms and deposits swept
by cilia currents toward the
mouth. When standing
vertically it becomes a
suspension feeder catching
prey and algae with its spines
and tube feet. Sea Stars,
fishes and crabs eat Sand
Dollars.
Phylum Echinodermata
Class Echinoidea (Sea urchin)
• Red sea urchins graze on
attached or drift seaweed
and kelp. Southern
California urchins prefer
giant kelp. The northern
California and north Pacific
urchins eat bull and brown
kelp. Their “teeth” are
used to scrape algae off
rocks. They hold onto kelp
with their tube feet as they
eat. If algae lands on top of
an urchin, it uses a
combination of its spines
and tube feet to pass the
food to its bottom located
mouth.