Key Animal Phyla of the Oceans

TAXONOMY

EVERY BIOLOGIST, REGARDLESS OF HIS AREA OF INTEREST, MUST LEARN THE FUNDAMENTALS OF CLASSIFICATION. INDEED, THE FIRST STEP IN ANY STUDY IS THE CORRECT IDENTIFICATION OF THE ORGANISMS BEING STUDIED, AND THIS IS A MATTER OF TAXONOMIC PROCEDURE.

TAXONOMY IS THE SCIENCE OF CLASSIFICATION, WHICH PROVIDES A LOGICAL INTERNATIONAL SYSTEM FOR THE NAMING OF ORGANISMS.

OUR SYSTEM OF CLASSIFICATION, KNOWN AS THE BINOMIAL SYSTEM (TWO NAMES), WAS ORIGINATED BY A SWEDISH BIOLOGIST NAMED LINNAEUS.

EACH ORGANISM IS GIVEN A SCIENTIFIC NAME CONSISTING OF TWO LATIN WORDS.

THE FIRST WORD OF THE SCIENTIFIC NAME, ALWAYS WRITTEN WITH A CAPITAL, IS THE GENERIC NAME, THAT IS, THE NAME OF THE GENUS IN WHICH THE ORGANISM IS PLACED.

THE SECOND WORD IS THE SPECIFIC NAME, WHICH IS NOT CAPITALIZED, AND IS THE SPECIES OF THE ORGANISM.

THUS THE MALLARD DUCK, WHICH OCCURS ALMOST THROUGHOUT THE WORLD, MAY BE KNOWN BY MANY COMMON NAMES IN VARIOUS COUNTRIES, BUT ITS SCIENTIFIC NAME, Anas platyrhynchos, IS THE SAME EVERYWHERE.

EACH SPECIES BELONGS TO A SERIES OF HIGHER CATEGORIES, ALSO ORIGINATED BY LINNAEUS. THIS HIERARCHICAL CLASSIFICATION INCLUDES, FROM GREATEST TO SMALLEST, THE FOLLOWING CATEGORIES: How to remember them KINGDOM King

PHYLUM Phillip

CLASS Came

ORDER Over

FAMILY For

GENUS Good

SPECIES Soup THERE ARE FIVE RECOGNIZED KINGDOMS IN THE CLASSIFICATION SYSTEM. THEY ARE:

PROTISTA - THE PROTIST KINGDOM INCLUDES THE PROTOZOANS (FIRST LIFE). MANY PROTISTS ARE UNICELLULAR MICROSCOPIC ORGANISMS. PROTISTS ARE EUKARYOTES, OR ORGANISMS WITH A TRUE NUCLEUS.

MONERA - THE MONERAN KINGDOM INCLUDES ALL BACTERIA AND THE BLUE-GREEN ALGAE. MONERANS ARE UNICELLULAR PROKARYOTES, OR ORGANISMS WITHOUT A TRUE NUCLEUS.

PLANTAE - MOST PLANTS ARE MULTICELLULAR ORGANISMS WITH SPECIALIZED TISSUES AND ORGANS. PLANTS ARE AUTOTROPHIC, THAT IS THEY MAKE THEIR OWN FOOD FROM SIMPLE SUBSTANCES, AND CONTAIN CHLOROPHYLL. PLANT CELLS HAVE CELL WALLS.

FUNGI - MOST FUNGI ARE MULTICELLULAR ORGANISMS THAT HAVE SIMPLE STRUCTURES. ALL FUNGI ARE EUKARYOTES, AND HETEROTROPHIC. THIS KINGDOM INCLUDES MUSHROOMS, MOLDS, AND YEAST.

ANIMALIA - THE ANIMAL KINGDOM IS MADE UP OF ONLY MULTICELLULAR ORGANISMS. ANIMALS ARE HETEROTROPHS. THESE ORGANISMS ARE THE MOST COMPLEX, HAVE TISSUES, AND MOST HAVE ORGANS AND ORGAN SYSTEMS. ANIMAL CELLS DO NOT HAVE CELL WALLS OR CHLOROPHYLL.

EXAMPLES: HUMAN ASPEN

KINGDOM ANIMALIA PLANTAE

PHYLUM CHORDATA TRACHEOPHYTA

CLASS MAMMALIA ANGIOSPERMAE

ORDER PRIMATES APETALAE FAMILY HOMINIDAE SALICACEAE

GENUS Homo Populus

SPECIES sapiens tremuloides What is diversity of life? Variety is the spice of life! Diversity is simply the wide variety of organisms in our world. Species diversity is a measure that combines the number, or richness, of species and their distribution on land and in the sea. Diversity is the key! Diversity is the key that unlocks the success of organisms in our world. There are a variety of habitats in our world such as mountains, valleys, deserts, and oceans. Animals and plants that thrive in various habitats each play a unique role. For example, a killer whale plays the role of a top predator in our oceans because of its adaptations for survival, such as its size, powerful swimming, and coloration. To take this animal and place it into another environment such as a tropical rain forest would be absurd; it would not survive. Animals and plants take many forms, inhabitating every environment in our world. Diversity is the key that unlocks the success of organisms in our world. Animals and plants take many forms, inhabitating every environment, from forests on land to forests in the sea. A species is a special group. A species is a group of plants or animals that are genetically similar and so are able to reproduce with each other. A population is a group of plants or animals of the same species that live in the same area and have the opportunity to breed with each other. For example, there is a population of killer whales in Pacific Northwest waters and a separate population in the Antarctic. Although the animals are the same species, they are geographically isolated and therefore do not commonly breed with each other. Whicn ones will survive? Natural selection refers to proecesses that result in the survival and reproduction of individuals best suited for the environment in which they live. All species tend to produce more offspring than the environment can sustain. Not all individuals can survive. Some fish lay millions of eggs, only a few of which will live to be adult fish and reproduce. But which ones will survive? Variety is the basis for natural selection. Individuals within a population are not all exactly the same. Genetically, they vary. Individuals with favorable variations tend to survive, and those with less favorable variations die. Survivors reproduce others with favorable traits. A gene pool contains all the traits or genes in any one population that can be passed on through generations. The gene pool may change slightly over long periods of time as traits change for better survival in specific habitats, but the pool is mainly consistent to ensure the success of the population. Plants and animals with biological characteristics better suited for their environment are better represented in future generations. So through successive generations, gradual and continuous changes occur in the population. Eventually these changes result in new adaptations and species. That's a lot of species. About 1.4 million species of plants and animals have been identified. Some scientists estimate that there may be as many as 100 million species! How do we keep track of them all? More than 2,000 years ago Aristotle, a Greek philosopher, devised the first classification system with two kingdoms and simple categories to name plants and animals. In the eighteenth centruy, a Swedish botanist, Carolus Linnaeus , created a classification system based on similarities and differences among organisms that separate them into categories. The sequence of categories is as follows: kingdom, phylum, class, order, family, genus, species. Linnaeus prepared the scientific names of each organism in Latin. Even today, we use Latin or Greek to describe organisms so that taxonomists world-wide can communicate. Linnaeus used two words to name each organism, a genus name and a species name. In his system, called binomial nomenclature or two-word naming, the genus describes the group to which the organism belongs, and the species describes the specific animal. Species vary in a world abounding with an array of life forms. Imagine a world filled with just one species. Diversification ensures a species-rich world. Organisms have been divided into a five-kingdom classification system.

As scientists discovered new organisms and changed their ideas about what characteristics are important in classifying organisms, the classification system changed. Today's classification system contains five kingdoms: Monera (prokaryotes), Protista (single-celled eukaryotes), Fungi (molds and yeasts), Planate (plants), and Animalia (animals). This five-kingdom classification system was suggested by R.H. Whittaker in 1969. Linnaeus used a genus name and a species name to describe each organism. The scientific name for the West Indian manatee is Trichechus manatus. Kingdom Animalia Members of the animal kingdom share these basic characteristics:  mulitcellular (bodies made up of more than one cell)  eukaryotic (each cell contains a nucleus and membrane-enclosed organelles)  cell membranes without cell walls  heterotrophs (do not make their own food but consume other organisms) The following phyla include some of the most common animals.

Key Animal Phyla of the Oceans Phylum: Porifera  characteristics: aquatic, asymmetrical animals lacking distinct tissues and organs; sessile body consists of two layers supported by a stiff skeleton; reproduce sexually or asexually.  example: sponges

Phylum: Cnidaria (formerly Coelenterata) characteristics: radial symmetry, central mouth surrounded by tentacles, nematocysts; reproduces sexually or asexually. Corals are members of the phylum Cnidaria. examples: corals, sea anemones, jellyfishes, hydras  Class Hydrozoa--Portuguese man-of-war  Class Scyphozoa--Jellyfish  Class Anthozoa--Corals and sea anemones

Phylum: Platyhelminthes characteristics: three cell layers; digestive cavity having one opening; no circulatory or respiratory systems; reproduce sexually or asexually. examples: flatworms (tapeworms, flukes, planarians)

Phylum Nematoda characteristics: mostly parasitic; tubular body, bilateral symmetry; digestive tract with two openings; reproduce sexually examples: roundworms (ascaris, hookworms)

Phylum: Bryozoa characteristics: microscopic, aquatic organisms; form branching colonies; feed with ciliated tentacles in U-shaped row. examples: moss animals Phylum Mollusca characteristics: soft-bodied, true coelom, muscular foot, visceral mass and mantle; most aquatic; many have shells; reproduce sexually. examples: clams, octopuses, snails  Class Polyplacophora--Chitons  Class Gastropoda--snails and slugs  Class Bivalvia--clams, mussels, oysters, scallops  Class Cephalopoda--Squid, octopi, cuttlefish, nautiloids

 Phylum Annelida--Segmented worms characteristics: true coelom; longitudinal and circular muscles; fairly complex circulatory, digestive, respiratory, and nervous systems; reproduce sexually. examples: segmented worms (leeches, earthworms)

 Phylum Arthropoda  characteristics: segmented body; paired, jointed appendages; exoskeleton; open circulatory system; complex nervous system with brain and two ventral nerve cords; reproduce sexually. The spiny lobster exhibits arthropod characteristics of an exoskeleton and paired, jointed appendages.  examples: horseshoe crabs, lobsters, insects  Subphylum Crustacea--Crabs, lobsters, shrimp, copepods, ostracods, barnacles  Subphylum Chelicerata--Horseshoe "crabs" and sea spiders  Subphylum Uniramia--Insects (nearly all terrestrial)  Subphylum Trilobita--Trilobites (all extinct)

 Phylum Echinodermata  characteristics: radial symmetry; calcium endoskeleton; open circulatory system; complex nervous system with brain and two ventral nerve cords; reproduce sexually.  examples: sea stars, sea cucumbers, sea urchins  Class Stelleroidea--Sea stars and brittle stars  Class Echinoidea--Sea urchins and sand dollars  Class Holothuroidea--sea cucumbers  Class Crinoidea--Sea lilies and feather stars

 Phylum Chordata characteristics: has a notochord, throat slits, and tail at some stage of development; reproduces sexually. People are in the phylum Chordata. But we're not the only ones. Chordates are divided into the following classes:

Class: Cephalaspidomorphi characteristics: circular mouth has sucking disc, no jaw, no paired fins, one nostril. example: lampreys

Class: Myxini characteristics: circular mouth has barbles, no jaw, no paired fins, one nostril, no eyes. example: hagfishes Phylum Chordata continued

Class: Chondrichthyes characteristics: skeleton made of cartilage, jaws, paried fins, paired nostrils, scales, two-chambered heart. examples: sharks, skates, rays, chimaeras

Class: Osteichthyes characteristics: skeleton made of bone, jaws, fins, most with scales, two-chambered heart. example: bony fishes

Class: Amphibia characteristics: begin life in the water, gills replaced by lungs in the adult form, lay eggs, three-chambered heart. examples: frogs, toads, salamanders

Class: Reptilia characteristics: thick, scaly or platelike skin; ectothermic (cold-blooded); embryo develops in the shell (young born live or hatch from egg); four-chambered heart. examples: snakes, lizards, turtles, crocodiles

Class: Aves characteristics: outer covering of feathers, endothermic (warm-blooded), have front limbs modified as wings, lay eggs, four-chambered heart. examples: all birds including penguins, flamingos, eagles, parrots, and ducks

Class: Mammalia characteristics: breathe air, have hair at some stage of development, give live birth, mammary glands, examples: humans, whales, horses, bears What is diversity of life? Variety is the spice of life! Diversity is simply the wide variety of organisms in our world. Species diversity is a measure that combines the number, or richness, of species and their distribution on land and in the sea. Diversity is the key! Diversity is the key that unlocks the success of organisms in our world. There are a variety of habitats in our world such as mountains, valleys, deserts, and oceans. Animals and plants that thrive in various habitats each play a unique role. For example, a killer whale plays the role of a top predator in our oceans because of its adaptations for survival, such as its size, powerful swimming, and coloration. To take this animal and place it into another environment such as a tropical rain forest would be absurd; it would not survive. Animals and plants take many forms, inhabitating every environment in our world. Diversity is the key that unlocks the success of organisms in our world. Animals and plants take many forms, inhabitating every environment, from forests on land to forests in the sea. A species is a special group. A species is a group of plants or animals that are genetically similar and so are able to reproduce with each other. A population is a group of plants or animals of the same species that live in the same area and have the opportunity to breed with each other. For example, there is a population of killer whales in Pacific Northwest waters and a separate population in the Antarctic. Although the animals are the same species, they are geographically isolated and therefore do not commonly breed with each other. Whicn ones will survive? Natural selection refers to proecesses that result in the survival and reproduction of individuals best suited for the environment in which they live. All species tend to produce more offspring than the environment can sustain. Not all individuals can survive. Some fish lay millions of eggs, only a few of which will live to be adult fish and reproduce. But which ones will survive? Variety is the basis for natural selection. Individuals within a population are not all exactly the same. Genetically, they vary. Individuals with favorable variations tend to survive, and those with less favorable variations die. Survivors reproduce others with favorable traits. A gene pool contains all the traits or genes in any one population that can be passed on through generations. The gene pool may change slightly over long periods of time as traits change for better survival in specific habitats, but the pool is mainly consistent to ensure the success of the population. Plants and animals with biological characteristics better suited for their environment are better represented in future generations. So through successive generations, gradual and continuous changes occur in the population. Eventually these changes result in new adaptations and species. That's a lot of species. About 1.4 million species of plants and animals have been identified. Some scientists estimate that there may be as many as 100 million species! How do we keep track of them all? More than 2,000 years ago Aristotle, a Greek philosopher, devised the first classification system with two kingdoms and simple categories to name plants and animals. In the eighteenth centruy, a Swedish botanist, Carolus Linnaeus, created a classification system based on similarities and differences among organisms that separate them into categories. The sequence of categories is as follows: kingdom, phylum, class, order, family, genus, species. Linnaeus prepared the scientific names of each organism in Latin. Even today, we use Latin or Greek to describe organisms so that taxonomists world-wide can communicate. Linnaeus used two words to name each organism, a genus name and a species name. In his system, called binomial nomenclature or two-word naming, the genus describes the group to which the organism belongs, and the species describes the specific animal. Species vary in a world abounding with an array of life forms. Imagine a world filled with just one species. Diversification ensures a species-rich world. Marine Life throughout Earth History Proterozoic fauna Stromatolites (cyanobacteria or blue-green algae) formed reefs. Acritarchs are cysts of dinoflagellates or green algae. Ediacaran-Vendian fauna (latest Proterozoic) Radiation of soft pancake- and ribbon-shaped creatures. Some workers consider them to be primitive "jellyfish" and "worms," while others believe they are an early radiation of multicellular animals that were thin but had no internal complexity. Tommotian (small shelly) fauna (earliest Cambrian) Tiny cups, caps, and other hard fossils. They probably include primitive sponges and gastropods (snails).

Cambrian fauna Trilobites (many-legged arthropods, now extinct) Inarticulate brachiopods (the two shells come apart after death) Primitive mollusks (look like slugs with pointed hats on) Nautiloids (ancestors of the living chambered nautilus) Weird echinoderms (distantly related to starfish and sea urchins) Archaeocyathids (cone-shaped; the reef builders of the Cambrian) Bizarre soft-bodied Burgess Shale animals such as Opabinia (five eyes and a nozzle), Wiwaxia (sclerites), Hallucigenia (spike legs and seven ?mouths), and Anomalocaris (big carnivore)

Paleozoic fauna (Ordovician to Permian) Articulate brachiopods (the two shells stay attached after death) Graptolites (planktonic animals found in black shales) Conodonts (tiny teeth and plates of an illusive creature) Ostracods (small ball-shaped crustaceans) Rugose and tabulate corals (the primary reef builders) Bryozoans (twig-like animals that helped make reefs) Crinoids (stalked echinoderms like modern sea lilies) Fusilinids (wheat-grain-shaped protists with a hard shell) Ammonoids with simple sutures (arose from nautiloids) Eurypterids (giant carnivorous arthropods) Fishes (jawless, lobe-finned, ray-finned, and shark types)

Mesozoic fauna (Triassic to Cretaceous) Ammonoids with complex sutures Oysters and other bivalve mollusks; gastropod mollusks Rudist bivalves (looked like corals and built reefs) Hexacorals (primary reef builders) Echinoids (sea urchins and sand dollars) Planktonic foraminifera (protists with a hard shell) Teleost fishes (advanced ray-finned fishes) Marine reptiles: ichthyosaurs, plesiosaurs, mosasaurs, crocodiles (some giant), phytosaurs, sea turtles (some giant)

Cenozoic fauna (Tertiary and Quaternary) Invertebrate and fish life similar to the Cretaceous Marine mammals: whales, dolphins, porpoises, seals, manatee