Marine Protozoans

Sub kingdom: protozoa of Kingdom Protista 31,250 species in 7 phyla Features:

unicellular,

free living or parasitic,

mostly solitary though some colonial (ciliate and flagellates)

Marine Protozoans

move by

pseudopodia,

flagella, or

cilia,

some amoeba with tests,or shells,

ciliates possess a mouth (cystostome) and nuclei of two sizes,

reproduction mainly asexual,

sexual reproduction in some groups.

 

Marine Protozoans

Special marine ones... Subphylum Sarcodina (including amoeba) produce so-called pseudopodia-flowing extensions of the cell which can extend one or more at a time (depending what species) .

Marine Protozoans

Amoeboid marine protozoans, the Foraminiferans and Radiolarians build cases around themselves. Forams secrete a calcium (chalky) carbonate shell or test, which resembles a microscopic snail shell.

Foraminiferans

Foraminifera, or 'forams' as they are often called, are small marine creatures that build a delicate house (called 'test') from chalk. Although they resemble molluscs they are in fact single cellular protists, but they can be quite large for organisms with only one cell. The largest forams are more than 10 centimetres wide. The pyramids of Egypt are made of stone cantaining these creatures. The forams in this gallery are up to 2mm. and were collected from beaches around the world.

 

 

Marine Protozoans

Their pseudopod extend through pores to form a network used to trap diatoms and other minute organisms suspended in water.

Most live on the bottom either free or attached.

The covering of forams is potmarked with numerous holes which the pseudopods extend through to capture smaller ciliates and detritus.

 

Marine Protozoans

As these die, they sink to the ocean floor to form ooze which makes up thousands of square miles of the ocean floor. (white cliffs of Dover are foram tests).

 

Marine Protozoans

Scientists use the fossil tests to measure variations in the worlds temperatures as the structure and sizes of the tests change with water temperature changes.

Forams living in cold water have fewer pores than those in warm water.

Marine Protozoans

Marine Protozoans

They are among the largest protozoans with some reaching 100mm but usually .5 to 1.0 mm The tests are various shapes--oval, tubular, branched, spiral, etc.

Most shells are multi chambered consisting of a series of successively larger chambers which are separated internally with pores or canals connecting them.

Marine Protozoans

The cytoplasm is found in all the chambers and is continuous through pores connecting the chambers.

By passing though the pores of the test, the cytoplasm forms a layer (ectoplasm) over the test which connects to the endoplasm through the pores. As the animal grows it adds successive chambers to the initial chamber.

Marine Protozoans

They capture their prey by means of their pseudopodal network which exhibits active streaming movements.

They are found in marine and brackish water and only a few in fresh.

A few are pelagic or sessile but most are creeping bottom dwellers (benthonic).

Marine Protozoans

A third of the ocean bottom is covered with Globigerina ooze, made mainly of the accumulation of the tests of this common foram. (usually in water under 4000 m deep because tests dissolve in the high concentration of CO2 in deep water.)

Good fossils are important in detecting oil bearing strata.

Marine Protozoans

Radiolaria (Subclass) Radiolarians form a glass like test composed of silica which is studded with long transparent spines to increase buoyancy and ward off predators.

Typical shells are spheric with radiating spines though the structure varies...thin needlelike pseudopod capture food.

Marine Protozoans

The radiolarians also form ooze, though radiolarian ooze and is usually found deeper being able to resist more pressure than the calcium carbonate foram tests.

 

Marine Protozoans

Ciliates are some of the protozoans that use cilia for locomotion. ..creeping over the bottom, living in gills, attached etc.

The Tintinnids build their own quarters that drift in the water.

 

Marine Protozoans

Reproduction is usually asexual binary fission whereby each effort results in two identical daughter cell (MITOSIS).

This occurs when conditions are favorable...warm, lots of food etc.,. but sexual reproduction can occur in some when adverse conditions (drying up) occur as a survival method.

Marine Protozoans

The forams have alternation between sexual and asexual generations, having asexual reproduction to produce many organisms which secrete shells around themselves and when mature, they produce identical gametes which are liberated into the sea and fuse in pairs to produce individuals which in turn secrete a shell grow to maturity and repeat the cycle.

Marine Protozoans

Life cycles are known for a few foraminiferans.

They have two phases, one asexual and the other sexual.

They are also dimorphic, having two types of individuals in each species, based mainly upon the size of the initial chamber (proloculm) of the test.

Marine Protozoans

Ecology Its complex as it would be for organisms found in every environment.

They occur commonly in plankton...benthic communities, marine depths (13,000 ft for a foram) and since many protozoans exploit bacteria as a food source, they form part of the decomposer food web in nature.

Marine Protozoans

It is thought that they stimulate the rate of decomposition by bacteria by grazing on bacteria and keeping the bacteria community in a state of physiological youth and hence at the optimum level of efficiency.

Ciliates can cause illness in some organisms.

 

Marine Protozoans

Invertebrates

Early invertebrate records are scarce because of the lack of fossil evidence until about 570 million years ago (Cambium) when organisms with external skeletons appeared.

All phyla that had hard outer parts existed 530 million years ago and many soft bodied animals belonging to modern phyla of worms appeared as well.

 

 

Invertebrates

During the jellyfish-worm stage of animal evolution, the various basic designs of animal bodies evolved. First came the jellyfish, a blind sac with only two layers of cells and a single opening serving as both mouth and anus.

 

Invertebrates

They have radial symmetry, meaning they have no front or hind end which is adaptive to only two types of habitats...floating on the surface of the sea or attached in an immobile position on the ocean floor.

Great masses of jellyfish cover wide stretches of the ocean and corals and sea anemones line tide pools in warm waters.

 

Invertebrates

The jellyfish phyla are dominant in these habitats and while their basic body plan adapts them admirably to certain ecological niches, it severely limits their options for colonizing others.

This body plan was also successful in flatworms but nowhere reached the dominance of the body plan of a tube within a tube design.

 

Invertebrates

There are three plans, bilateral symmetry, a diversity of tissues and organs, spaces or body cavities (coelom) filled with fluid and a fourth modification is characterized by radial symmetry found in sea stars etc.

 

Invertebrates

What do crabs, sea urchins, worms, corals all have in common? they have NO backbone and are all invertebrates. Over 95% of all known animals are invertebrates. Their forms range from the microscopic amoeba to giant squids 59 ft. long, inhabit all regions of the world and all have a marine representative.

 

Invertebrates

SPONGES

Phylum Porifera..(pore-bearing). 5000 species of 790 genera...worldwide distribution, fresh and marine. (120 species in Keys!) Size microscopic to 2m

Sponges..animals with many pores, without definite form of symmetry, and do not contain organs or true tissues. They are all sessile.

 

 

Invertebrates

 

 

Invertebrates

The humble bath sponge, used for centuries particularly in the Mediterranean region were originally thought of as plants but are now considered animals (only in 1765)(even its own subkingdom ..Parazoa) They probably originated from flagellated protozoans or primitive metazoans. They are the simplest of multicellular marine animals.

 

Porifera

The humble bath sponge, used for centuries particularly in the Mediterranean region were originally thought of as plants but are now considered animals (only in 1765)(even its own subkingdom ..Parazoa) They probably originated from flagellated protozoans or primitive metazoans. They are the simplest of multicellular marine animals.

 

Porifera

Their colors though are beautiful, Orange, yellow, green, purple, violet or scarlet or rich brown and have survived millions of years without even moving.

Porifera

Size range from micros. to 2m, form thin incrustation on hard surfaces to which they attach, others are massive tubular, branching, urn- or cup- or fan- shaped (amorphous).. Colors range from drab to brightly colored.

 

Porifera

The sponges single purpose in life is to pass water through itself, the water yielding food and oxygen, minerals, and carrying away waste products. The sponges are unchanged since they evolved and were ancient 300 million years ago and appear to be natures orphans

 

Porifera

They are so poorly organized that they are not even included in the direct line of animal evolution.

Porifera

Rachel Carson wrote that "nature seems to have gone back and made a fresh start with other materials" with no evidence of any relationship between them and coelenterates, leaving sponges in an evolutionary blind alley.

 

Porifera

Structure.. most are similar in structure, simple body wall containing cells and connective tissues and cell types like amoebocytes which wander through the inner tissue secreting and enlarging the skeletal spicules and laying down spongin threads.

 

 

 

 

 

 

 

Porifera

Most have a skeleton of spongin, elastic, but resistant fibers of protein which may be the only means of support but can be found together with spicules.

 

 

 

Sponges, like all animals, possess some sort of a skeleton that gives their bodies shape.

As a whole, poriferans have diverse skeletal elements including calcareous laminae, organic filaments, and siliceous and calcareous spicules. The skeletons of each of the major poriferan groups are distinctive and have been used to reconstruct their evolutionary relationships.

 

Spicules come in an array of beautiful shapes, as seen in the SEM images to the left.

These images were obtained using UCMP's Enivronmental Scanning Electron Microscope. Spicules are often categorized by size, the larger being megascleres and the smaller microscleres. Some spicules are formed of the mineralized substances calcium carbonate and silica, while others are made of an organic substance called spongin.

 

Spongin skeletons were and are used as scrubbers in bathtubs, though they are fairly expensive. The ubiquitous bathtub accessory called a lufa is NOT a sponge, but a plant. The mineralized forms are considerably more hard and are not as frequently used for commercial purposes.

 

Porifera

The internal skeleton can be made of hard rod or star shaped calcareous or siliceous spicules, the shapes genetically determined for each sponge, and/or the meshwork of protein fibers called spongin (bath sponge) which is similar to silk and the horns of many animals.

 

Porifera

Sponges are filter feeders straining off bacteria and fine detritus from the water. O2 and dissolved organic matter are also absorbed and waste materials are carried away. Water is pumped inward through small pore cells into the inner chambers lined by flagellate cells called collar cells.

 

 

Porifera

They ingest the food particles and water is expelled through the sponges surface through the osculum.

Reproduction can occur asexually by budding off new materials, by fragmentation in which parts grow into new sponges, and in sexual reproduction, eggs from amoebocytes and sperm from collar cells (or amoebocytes) usually at different times within the individual.

 

 

 

Porifera

Sperm is shed into the water but eggs stay in the sponge and is fertilized there. This is called spawning. A larva (amphiblastula) may be produced, swim for a few days and settle changing into colonies. Some Antarctic sponges (mature) have not grown in over 10 years.

 

Porifera

Classification...because they adapt to their environment their shape is of no help to identify them so they are classified by their skeletons, "lime sponges, glass sponges, and fibrous or horny skeletons.

 

Porifera

Ecology. Sponges live on a firm substratum, vertical range from intertidal to 27,000 ft (one fresh) and the intertidal are seldom exposed to air for any time.

They are eaten by sea slugs (nudibranches) , chitins, sea stars, turtles, some tropical fish

 

Porifera

Usually more than half the exposed species are toxic to fish. The toxins not only prevent predation but keep the surface of the sponge clean of animal larva and plant spores from settling on them and may prevent neighboring invertebrates from overgrowing and smothering them.

 

Porifera

Sponges contain antibiotic substances, pigments, chemicals like steroids, toxins, anti-inflammatory, and anti-arthritis compounds. Boring sponges (Cliona) weakens oyster shells, and damage and weaken tropical stony corals excavating chambers by chemical and mechanical methods.

 

 

Porifera

On reefs some weaken, while some bind skeletons together, some protect undersurface of coral from attacks by boring organisms and are most successful under low light. Other..sulfur sponge is able to dissolve seashells into calcium and accounts for conversion of shells to sand on the ocean

 

Porifera

Loggerhead sponge, shaped like barrels, host up to 12,000 pistol shrimps and other creatures. The sea orange wraps itself around a hermit crab shell, obtaining transport in exchange for the camouflage and Neptunes Cup grows out of the sea floor in the shape of a goblet.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Porifera

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